ABSTRACT
Irene J. Abbene. RECONSTRUCTION OF THE RECENT PALEOENVIRONMENT
OF PAMLICO SOUND, NORTH CAROLINA, USING FORAMINIFERA, STABLE
ISOTOPES (ô'^C & ô'^N), AND RADIONUCLIDE DATA, (under the co-direction of
Dr. Stephen Culver and Dr. D. Reide Corbett) Department of Geology
Environmental conditions existing within Pamlico Sound over the last century
were analyzed using foraminiferal data, stable isotope (C and N) data, C:N ratios, percent
OC, and radionuclide data. Environmental conditions were evaluated at three time slices;
(1) the modem environment as determined by surficial (0-2cm) sediments, (2) the
intervals representing approximately 40 years BP, as determined by ’^^Cs activity, and (3)
the intervals representing approximately 120 years BP, as determined by ^'°Pb activity.
Cluster analysis distinguished four foraminiferal assemblages at the surface (0-
1cm); (1) Estuarine Biofacies A, (2) Estuarine Biofacies B, (3) Marsh Biofacies, and (4)
Marine Biofacies. Estuarine Biofacies A is distinguished from Estuarine Biofacies B by
the greater relative abundance of the agglutinated species Ammotium salsum and
Ammobaculites crassus in the former and the greater relative abundance of Elphidium
excavatum in the latter. The Marsh Biofacies is characterized by typical marsh
foraminifera such as Tiphotrocha comprimata, Trochammina inflata, Miliammina fusca,
and Haplophragmoides wilberti. The Marine Biofacies is comprised completely of
calcareous foraminifera (e.g., Elphidium excavatum, Hanzawaia strattoni, Cibicides
lobatulus, Elphidium subarcticum, Quinqueloculina seminula, and Elphidium
galvestonense) and is restricted to tidal inlets.
The down-core foraminiferal data indicate that there has been a steadily
increasing marine influence within Pamlico Sound over the last century; supportive
evidence is provided by down-core C:N ratios. Approximately 120 years BP, Pamlico
Sound was dominated by Estuarine Biofacies A, which is indicative of brackish
conditions. The particular abundance of hurricanes at this time may explain the brackish
nature of the foraminiferal assemblage. Up-core, Estuarine Biofacies B becomes the
more prominent assemblage within Pamlico Sound; this is indicative of increased salinity
over time. C:N ratios steadily decrease up-core throughout the sound indicating an
increase in marine influence over the last century.
ô’^N signatures began to steadily enrich at approximately 40 years BP. The
resultant signature is a combination of nitrogen cycling within the water column and
the interaction with surficial sediment, as well as the organic matter source material. An
increase in the amount of shrimp trawling during the early 1960s is a possible explanation
for the enriched signatures. The average range for signatures (-25 to -22) is typical
of terrestrial sediment input and has not significantly changed over time. This suggests
that the source area for the sediments being deposited within Pamlico Sound has not
changed.
RECONSTRUCTION OF THE RECENT PALEOENVIRONMENT OF PAMLICO
SOUND, NORTH CAROLINA, USING FORAMINIFERA, STABLE ISOTOPES (Ô’^C
& ô'^N), AND RADIONUCLIDE DATA
A Thesis
Presented to
The Faculty of the Department of Geology
East Carolina University
In Partial Fulfillment
Of the Requirements for the Degree
Master of Science in Geology
By
Irene Johanna Abbene
July 2004
RECONSTRUCTION OF THE RECENT PALEOENVIRONMENT OF PAMLICO
SOUND, NORTH CAROLINA, USING FORAMINIFERA, STABLE ISOTOPES (ô’^C
& ô'^N), AND RADIONUCLIDE DATA
By
Irene Johanna Abbene
APPROVED BY:
CO-DIRECTOR OF THESIS
Dr. Stephen J. Culver
CO-DIRECTOR OF THESIS
Dr. D. Reide Corl3êtt~-
COMMITTEE MEMBER"
Dr. David Mallinson
COMMITTEE MEMBER
Dr. Martin A. Buzas
CHAIR OF THE DEPARTMENT OF GEOLOGY
Dr. Stephen J. Culver
DEAN OF THE GRADUATE SCHOOL
ÇlâVsàJiy
Dr. Paul Tschetter
ACKNOWLEDGEMENTS
I wish to express my gratitude to Dr. Stephen Culver and Dr. D. Reide Corbett.
The entire experience has been completely rewarding to me because of their
encouragement, enthusiasm, patience, and friendship. I would like to thank my
committee members. Dr. Dave Mallinson and Dr. Martin Buzas. I especially thank Dr.
Buzas for helpful guidance with statistics. I would also like to thank the entire ECU crew
for two full years of memories. Their support and companionship have made times of
stress more bearable and will not be forgotten. And I would like to especially thank my
family for always instilling confidence in me to be the person I am today.
TABLE OF CONTENTS
LIST OF TABLES vi
LIST OF FIGURES vii
INTRODUCTION 1
Objectives 8
PREVIOUS WORK 10
Foraminifera of marginal marine environments on the North American Atlantic
Coast 10
Significance of signatures 18
Significance of ô'^N signatures 21
Significance of C:N ratios 24
Estuarine studies using geochemical tracers 25
Radionuclides 27
METHODS 29
Foraminiferal analysis 30
Laboratory Methods 30
Cluster Analysis 33
Biofacies Fidelity and Constancy 34
Discriminant Analysis 34
Species Diversity 35
Geochemical Analysis 36
Carbon and Nitrogen 36
Radionuclides 37
One-way Analysis of Variance (ANOVA) 39
RESULTS 40
Foraminifera 40
Cluster Analysis; Live Foraminifera 40
Cluster Analysis: Dead Foraminifera 43
Biofacies Fidelity and Constancy 46
Discrimininant Analysis 49
Surficial Discriminant Analysis 49
Down-core Discriminant Analysis 54
Species Diversity 58
Geochemistry 61
Geochronology 61
Stable Isotopes 61
C:N Ratios 82
Percent Organic Carbon 84
One-way Analysis of Variance (ANOVA) for Geochemical Results 86
DISCUSSION 91
Description of the Modem Environment 91
Description of the Paleoenvironment 120 years Before Present 95
Description of the Paleoenvironment 40 years Before Present to Present
Day 98
Explanations 101
CONCLUSIONS 109
REFERENCES Ill
PLATES 121
APPENDIX A: REFERENCES USEFUL IN IDENTFYING TAXA 127
APPENDIX B: RAW CENSUS DATA (SURFACE) 131
APPENDIX C: RELATIVE ABUNDANCE DATA (SURFACE) 138
APPENDIX D: TRANSFORMED ABUNDANCE DATA (SUFACE) 142
APPENDIX E: RAW CENSUS DATA (DOWN-CORE) 147
APPENDIX F: RELATIVE ABUNDANCE DATA (DOWN-CORE) 149
APPENDIX G: TRANSFORMED ABUNDANCE DATA (DOWN-CORE) 151
APPENDIX H: GEOCHEMICAL DATA 153
1.Summary LIST OF TABLESof the habitat zones and characteristic species described by Woo et al.
(1997) in a barrier island lagoon system in Virginia (modified from Woo et al.,
11.A19N9O7)V 152. Biofacies Fidelity and Constancy for the four biofacies, using dead speciescomprisAing 2% or more of the assemblage in any one sample 483. Canonical discriminant functions including the percent of variability for eacheigenvalue 504. Canonical discrimint function scores for group means (group centroids) along thethree canonical variate axes (functions) 505. Canonical discriminant functions including the percent of variability for eacheigenvalue 516. Canonical discriminant function scores for group means (group centroids alongtwo canonical variate axes (functions) 527. Standardized canonical discriminant function coefficients from the analysis 598. Species diversity of foraminifera within the Pamlico Sound estuarine system.... 599. ANOVA test results for ô’^C signatures 8710. ANOVA test results for ô'^N signatures 87test results for C:N ratios 88
12. Contrasts for geochemistry compared to the three time slices 90
13. Summary of modem biofacies described for Pamlico Sound, the key species,
sites, and salinity readings 92
14. Dates of hurricanes to reach coastal North Carolina between the years 1876 and
1899 (Barnes, 2001) 103
LIST OF FIGURES
1. Location of study area, Pamlico Sound, North Carolina 2
2. Bathymetry of Pamlico Sound 4
3. Sediment distribution in Pamlico Sound 4
4. Distribution of organic matter in Pamlico Sound 4
5. Location of tidal exchange, freshwater sources, wind direction, and typical
isohalines for Pamlico Sound (Wells and Kim, 1989) 7
6. Locality of sites for foraminiferal and geochemical analysis within Pamlico
Sound 9
7. Generalized map of nearshore environments displaying typical foraminifera and
thecamoebians (freshwater only) (after Scott et al., 2001) 10
8. Typical range for ô'^C signatures (after Letrick, 2003) 20
9. Typical range for ô'^N signatures (after Letrick, 2003) 24
10. Floating apparatus set-up 31
11. Cluster analysis of surface sites using live foraminifera 41
12. Spatial distribution plot of the results of the cluster analysis using only live
species 42
13. Cluster analysis of surface sites using dead foraminifera 44
14. Spatial distribution plot of the results of the cluster analysis of dead
foraminifera 46
15. Plot of Canonical Discriminant Function 1 versus Canonical Discriminant
Function 2 53
16. Plot of Canonical Discriminant Function 1 versus Canonical Discriminant
Function 2 including three a priori groups and 21 “unknown” down-core samples;
Estuarine Biofacies A, Marsh Biofacies, and Estuarine Biofacies B 55
17. Spatial plot of samples indicated by ‘a’ in Figure 16 56
viii
18. Spatial plot of samples indicated by ‘b’ in Figure 16 59
19. Species diversity distribution plot within biofacies determined using cluster
analysis 60
20. Geochemistry data for PAM02S9 62
21. Geochemistry data for PAM02S10 63
22. Geochemistry data for PAM02S11 64
23. Geochemistry data for PAM02S12 65
24. Geochemistry data for PAM02S22 66
25. Geochemistry data for PAM02S23 67
26. Geochemistry data for PAM02S24 68
27. Geochemistry data for PAM02S27 69
28. Geochemistry data for PAM02S30 70
29. Geochemistry data for PAM02S31 71
30. Geochemistry data for PAM02S32 72
31. Geochemistry data for PAM02S41 73
32. Geochemistry data for PAM02S42 74
33. Geochemistry data for PAM03S50 75
34. Geochemistry data for PAM03S59 76
35. Geochemistry data for PAM03S60 77
36. Geochemistry data for PAM03S61 78
37. Surface (0-2cm) ô’^C signatures for Pamlico Sound 80
38. Surface (0-2cm) signatures for Pamlico Sound 82
39. Surface (0-2cm) C:N ratios for Pamlico Sound 83
IX
40. Surface (0-2cm) percent organic carbon values for Pamlico Sound 85
41. One-way ANOVA plot of means for time slices (as determined by radionuclides)
vs ô'^C signatures 88
42. One-way ANOVA plot of means for time slices (as determined by radionuclides)
vs. signatures 89
43. One-way ANOVA plot of means for time slices (as determined by radionuclides)
vs. C:N ratios 89
44. ô'^C signatures approximately 120 years BP (as determined by radionuclide
data) 96
45. ô'^N signatures approximately 120 years BP (as determined by radionuclide
data) 97
46. C:N ratios approximately 120 years BP (as determined by radionuclide
data) 97
47. signatures approximately 40 years BP (as determined by radionuclide
data) 99
48. ô'^N signatures approximately 40 years BP (as determined by radionuclide
data) 99
49. C:N ratios approximately 40 years BP (as determined by radionuclide
data) 100
50. Comparison of foraminiferal assemblage changes over time 101
51. Comparison of C:N ratio changes over time 103
52. ô'^C signatures versus ô'^N signatures over the last approximate 120 years
BP 107
INTRODUCTION
Pamlico Sound, North Carolina, is one of the largest embayments along the US
east coast, encompassing approximately 5340km^ (2060mi^) (Giese et al., 1985;
Pietrafesa et al., 1986). The Sound is separated from the ocean by a series of barrier
islands, referred to as the Outer Banks. Three main inlets, Oregon, Hatteras, and
Ocracoke promote access to the sound from the ocean. Two rivers, the Pamlico and the
Neuse, discharge fresh water into the sound. The low brackish Albemarle Sound, located
to the north, also drains into the Sound and affects environmental conditions in its
northern section (Figure 1).
Pamlico Sound is an estuary, a partially enclosed body of water, characterized by
the interaction of fresh and salt water. A number of processes (biological, chemical,
physical, etc.) occurring within esturaries make them one of the most productive
ecosystems. Estuaries are important filter systems for nutrients and pollutants carried in
from rivers. They also provide humans with a source of food and recreational activités
(Dyer, 1997).
Pamlico Sound is a drowned-river estuary (Riggs et al., 1995; Riggs and Ames,
2003). Paleo-rivers and tributaries drained through the system during the Pleistocence.
As sea level rose, the system flooded with ocean waters forming the current estuarine
system. The bathymetry of the sound is controlled by the paleogeomorphology of the
river and tributary system (Riggs et al., 1995; Riggs and Ames, 2003).
Two large basins form the deep sections of the Sound. These basins are separated
by Bluff Shoal, a bar of medium grained sand which extends across the Sound in a
2
Figure 1: Location of study area, Pamlico Sound, North Carolina. Inset shows
location within North Carolina.
3
northwest-southeast transect from the mainland to Ocracoke Inlet (Figure 2). Pamlico
Sound is relatively shallow, with a maximum depth no more than 8m (26.4ft) (Giese et
al., 1985). The four major sources for sediment deposition in the Sound are from river
input, shoreline erosion, the continental shelf, and autochthonous biogenic production,
whereas windblown silt from the dunes of the Outer Banks is a minor contribution (Wells
and Kim, 1989). The floor of the Sound is generally covered in fine to very find grained
sand, with silt and clay-sized particles concentrated in the basins and in the channels of
the rivers (Neuse and Pamlico) that extend into the Sound (Figure 3). Medium grained
sand is found at the inlets. Scattered pockets of medium grained sand form sand shoals
within the Sound. The greatest amount of recorded organic matter and carbon correspond
to regions of fine-grained material and the amount decreases with increasing grain size
(Figure 4) (Giese et al., 1985; Pietrafesa et al., 1986; Wells and Kim, 1989).
Pamlico Sound, a microtidal estuary, has an astronomical tidal range between 10
to 100cm. Wind-tide currents dominate the movement of water and physiochemical
conditions within the Sound. Strong winds associated with storms have a dramatic affect
on the tidal range by increasing the water build up in the direction of the wind (Wells and
Kim, 1989; Riggs and Ames, 2003). The large build up of water, or storm tide, floods
and erodes shorelines sometimes causing an incredible amount of damage; up to 15m of
mainland marsh recession during Hurricane Isabel in September 2003 (Riggs and Ames,
2003).
4
Figure 2: Bathymetry of
Pamlico Sound. Black line
indicates the location of Bluff
Shoal. Contours are in
meters (modified from Wells
and Kim, 1989).
Figure 3; Sediment distribution in
Pamlico Sound (from Giese et al.,
1987).
mu Coarse sand
I;.vj Medium sand
EE3 sand
^ Silt
10 5 0 10 20 miles
I j-i ) , 1 , pJ
iO 0 10 20 Î0 kilometers
5
Figure 4: Distribution of organic
matter in Pamlico Sound (from Giese
et al., 1985).
Percent organic matter
UIB 0-1 ESa '-2 ^ 2-'* «14-8
10 5 0 10 ao miles
' rl 1 1 L_, H
10 0 10 20 50 kilometers
The conditions that exist within the Sound are greatly affected by the
freshwater/saltwater interface, mixing currents created by wind tides, and storm events.
These conditions vary on a seasonal scale and a day-to-day basis. Salinity generally
decreases with increasing distance from the inlets westward (Roelofs and Bumpus, 1953;
Wells and Kim, 1989). The Pamlico and Neuse Rivers are the main source of freshwater
for the Sound. Peak discharge from the rivers is during the spring. The direction of the
wind and the volume of water within the rivers control the extent of freshwater into the
sound. Winds are generally from the south/southwest during the spring and summer
time. The increased amount of water draining from the rivers and the general wind
direction form a freshwater wedge that extends far into the northern section of the Sound
6
during the spring and early summer seasons (Figure 5) (Wells and Kim, 1989). A
difference of 6 between surface and bottom salinities was recorded in the southern basin
of the Sound during the spring, summer, and fall, which was attributed to increased
freshwater inflows from the rivers due to a “wetter” than average spring (Pietrafesa et ah,
1986). Tidal exchange between the Sound and the Atlantic Ocean occurs at the inlets.
The extent that the saline waters will disperse into the sound is also controlled by wind
direction. Northerly winds dominate during the fall and winter seasons. Wind direction
and the low flow out of the rivers allow saline water to disperse throughout the Sound
and to extend further up into the rivers (Figure 5) (Wells and Kim, 1989). The salinity
range for the entire Sound is between 0.5 (at the rivers) and 36 (at the inlets) with an
average of 20 (Marshall, 1951; Roelofs and Bumpus, 1953; Pietrafesa et al., 1986; Wells
and Kim, 1989).
The majority of the research conducted in Pamlico Sound has documented
patterns of salinity, temperature, sediment distribution, and water movement throughout
the Sound (Marshall, 1951, Roelofs and Bumpus, 1953, Williams et al., 1973; Singer and
Knowles, 1975; Pietrafesa et al., 1986; Giese et al., 1985; Wells and Kim, 1989). Recent
research has defined the underlying geology of portions of the Pamlico-Albemarle
estuarine system (Riggs et al., 1992; Riggs et al., 1995; Riggs, 1996; Pilkey et al., 1998;
Riggs et al., 2000; Riggs and Ames, 2003). Research involving geochemical and
paleontological analysis has been conducted only for the southernmost section of the
Sound (Grossman, 1967; Grossman and Benson, 1967; Paerl et al., 2001). Other research
7
documented biogeochemical processes occurring within the Neuse and Pamlico Rivers
(Matson and Brinson, 1990; Benninger and Wells, 1993; MODMON, 2001).
35'30'
asw-
TIDAL EXCHANGE
FRESHWATER DISCHARGE
SPRING/SUMWER WINDS
FALL/WINTER WINDS
SURFACE ISOHALINES (OCTOBER)
SURFACE ISOHALINES (APRIL)
7* 00' rs'jo' 76'00' 75*30'
Figure 5: Location of tidal exchange, freshwater sources, wind direction,
and typical isohalines for Pamlico Sound (Wells and Kim, 1989).
8
Objectives
This research is part of the North Carolina Coastal Geology Cooperative
(NCCGC) program. The larger goal of the program is to describe the geologic
framework and the modem anthropogenic/geologic processes of the coastal system. The
purpose of the present study is to characterize the foraminiferal and geochemical (carbon
and nitrogen) distribution patterns for the entire Pamlico Sound estuary and their change
within the past 150 years. The objectives for this project are:
1) To map, for the first time, the distribution of modem foraminifera within the entire
Pamlico Sound.
2) To create a model to interpret paleoenvironments represented by downcore
foraminiferal assemblages.
3) To use stable isotopes of C and N, and C/N ratios to determine the dominant source of
organic matter present in sediment (marine or terrestrial influence).
4) To describe environmental conditions that have existed within Pamlico Sound during
the past 150 years BP (age determined by radionuclide data, provided by Tully, 2004).
A total of 40 sites throughout Pamlico Sound have been chosen for this study
(Figure 6). The surface (0-lcm) sediment of each site has been analyzed to determine the
modem distribution of foraminifera. Down-core geochemical data (stable isotopes C and
N, C:N, percent organic carbon) have been analyzed for 17 of the 40 sites (Figure 6).
Twelve of the 17 sites were chosen for analysis of down-core foraminiferal assemblages
(Figure 6).
9
+ 546
O
.S23
ÁS12
^S22 S14
.524
kS25
?S50 ? l.532
542 327^826kS40
,r>‘^ •EB0252
EB0231
kilometers
Figure 6: Locality of sites for foraminiferal and geochemical analysis
within Pamlico Sound. The surface (0-lcm) of each site was used to
determine surficial foraminiferal analysis. Closed triangles represent
core locations for geochemcial and down-core foraminiferal analysis,
and closed diamonds represent core locations for geochemical analysis
Closed circles represent those locations analyzed for surficial (0-lcm)
foraminiferal assemblages only.
PREVIOUS WORK
Foraminifera of marginal marine environments on the
North American Atlantic Coast
Each foraminiferal species is adapted to a particular set of abiotic and biotic
environmental variables (e.g., food availability, competition, salinity, temperature,
substrate, dissolved oxygen, etc); thus they are excellent indicators of modem and paleo-
environments (Boltovoskoy and Wright, 1976; Scott et al., 2001). Many studies have
used foraminiferal assemblages to define differences between shallow marine
environments (Buzas, 1965; Nichols and Norton, 1969; Ellison and Nichols, 1970; Woo,
1992; Goldstein et al., 1995; Collins, 1996; Culver et al., 1996; Woo et al., 1997; Saffert
Figure 7: Generalized map of nearshore environments displaying typical
foraminifera and thecamoebians (freshwater only) (after Scott et al., 2001).
11
and Thomas, 1998; Scott et al., 2001; Robinson and McBride, 2003; Vance, 2004)
(Figure 7). Foraminifera have also proven to be valuable indicators of environmental
stress, both natural (i.e., storm induced) and anthropogenic (e.g., Collins, 1996; Karlsen
et al., 2000; Thomas et al., 2000; Scott et al., 2001; Bratton et al., 2003; Buzas-Stephens
et al., 2003).
A considerable amount of research has described the distribution patterns of
foraminifera on the Atlantic continental margin of North America (Culver and Buzas,
1980). This project involves foraminifera found within marginal environments along the
east coast. Therefore, the following summary of previous work concentrates on
foraminiferal distribution patterns recognized within marginal marine environments
between Texas and Long Island Sound.
While much research has been conducted along the eastern seaboard, the only
research in Pamlico Sound is in the southernmost part of the sound (Grossman, 1967;
Grossman and Benson, 1967). Five foraminiferal assemblages were distinguished: an
estuarine, an open-sound, a saltwater lagoon, a tidal-delta, and a marsh biofacies.
Ammobaculites and Elphidium were the most abundant taxa found throughout the study
area. Ammobaculites was dominant in the estuarine biofacies, and, when present with
Elphidium, characterized the open-sound biofacies. The presence of Quinqueloculina
distinguished the tidal-delta biofacies from the saltwater lagoon biofacies. The saltwater
lagoon was distinguished by several species of Elphidium, such as E. gunteri and E.
tumidum (= E. excavatum of this study). Typical marsh foraminifera, such as
Arenoparrella mexicana, Trochmmina, and Haplophragmoides wilberti, distinguished the
12
marsh biofacies. The distribution of these assemblages was considered to be strongly
influenced by salinity, vegetation, and tidal currents (Grossman, 1967).
Research conducted by LeFurgey (1976) defined a foraminiferal transition zone
between the Albermarle and Pamlico Sounds. The upper Roanoke Sound, Croatan
Sound, and Stumpy Point Bay (Figure 1) contained foraminifera characteristic of a
lagoonal environment {Miliammina fusca and Ammobaculites crassus) where salinities,
temperatures, and availability of calcium carbonate are low. With the influence of the
adjacent Oregon Inlet, environmental conditions present within the lower Roanoke Sound
were reported as having moderate temperatures, salinity, and calcium carbonate
availability. M. fusca and Elphidium selseyense (=E. excavatum of this study) were
considered to be the characteristic foraminifera for this nearshore marine environment
(LeFurgey, 1976).
Research in the Albemarle Sound estuarine system using dead foraminifera
distinguished five assemblages (Vance, 2004); nearshore marine and inlets, estuarine
shoal, estuarine, inner estuarine, and marsh biofacies. Sediment type and salinity were
determined to be the controlling factors for the distribution of the assemblages.
Agglutinated species dominated the study area; Ammobaculites crassus was the most
widespread species (present in four out of five biofacies). Elphidium excavatum,
Ammonia parkinsoniana, Hanzawaia strattoni were the dominant and characteristic
species of the normal salinity nearshore marine and inlet biofacies. Two species, A.
crassus and Ammotium salsum, characterized the estuarine sandy shoal biofacies. The
estuarine biofacies was dominated by three agglutinated species, A. salsum, A. crassus.
13
and Miliammina fusca. The inner estuarine biofacies was located near areas of
freshwater inflow. Characteristic species for the inner estuarine biofacies were
Ammobaculities subcatenulatus, A. salsum, M. fusca, and A. crassus. The foraminifera
that distinguished the marsh biofacies were A. crassus, M. fusca, Haplophragmoides
wilberti, and Jadammina macrescens. Foraminiferal assemblages present in two short
cores were used to reconstruct the recent (ca. 150 years) paleoenvironment for the
Albemarle estuarine system. Two biofacies were recognized down-core (inner estuarine
and estuarine). The presence of these biofacies, as well as sedimentation rates (as
determined using radionuclides), determined a change in depositional patterns for
Albemarle Sound (Vance, 2004).
At St. Catherines Island, Georgia, marsh foraminifera were used to differentiate
between marsh zones (high, transitional, and low). Miliammina fusca. Ammonia
beccarii, Ammotium salsum, Ammobaculites dilatatus, Trochammina inflata, and
Arenoparrella mexicana were dispersed throughout the marsh. Siphotrochammina lobata
and Haplophragmoides wilberti were determined to be the key species to distinguish
between the three marsh zones. S. lobata was only found at low marsh zones and H.
wilberti was found at low and transitional marsh zones (Goldstein et al., 1995; Goldstein
and Watkins, 1999).
In South Carolina, Collins (1996) also used foraminifera to delineate marsh zones
and compared his findings between three marsh field sites. He found that the distribution
of foraminifera was sensitive to salinity, sea level, river discharge, and anthropogenic
influences. Only one marsh location was recognized to have “typical” marsh
14
foraminiferal assemblages present. Foraminifera found at the low marsh region were
Ammotium salsum and Miliammina fusca, while the high marsh region was defined by
the presence of four species; Haplophragmoides wilberti, Ammoastuta inepta,
Trochammina inflata, and Arenoparrella mexicana. An unusual localized abundance of
Ammonia beccarii and Elphidium spp. was recognized at a higher elevations (>40cm).
Since these particular species are not generally found in these marsh settings, it was
concluded that they represented an overwash deposit associated with a storm surge from
Hurricane Hugo in 1989. Foraminiferal assemblages were not easily recognized at the
other two marsh locations due to anthropogenic influence at one and a high river
discharge at the other (Collins, 1996).
Foraminifera have been used to classify subenvironments in a barrier-island
lagoon system in Virginia (Woo, 1992; Culver et al., 1996; Woo et al., 1997). This
region is virtually untouched by human activity and the initial survey of foraminiferal
assemblages provides a baseline of expected foraminiferal biofacies under natural
conditions. Particular species were found to be distinct indicators of back barrier
lagoonal environments and sensitive to a variety of environmental conditions (wave
energy, sediment, and salinity). Seven environments (habitat zones) were distinguished
based on the distribution of characteristic species. A summary of the seven habitat zones
and characteristic species is given in Table 1.
Recent research in Long Island Sound compared changes in foraminiferal species
abundance and distribution in the late 1940s (Parker, 1952a) and the early 1960s (Buzas,
1965) to species abundance and distribution documented in the 1990s (Thomas et al..
15
Table 1: Summary of the habitat zones and characteristic species
described by Woo et al. (1997) in a barrier island lagoon sytem in
Virginia (modified from Woo et al., 1997).
Habit Zone Characteristic Species
Brackish Ammonia beccarii
environments Trochmmina infiata
Trochammina squamata
Fringe Marsh Ammobacuiites exiguas
Ammonia beccarii
Elphidium excavatum
Jadammina macrescens
Miliammina fusca
Textularia earlandi
Trochammina infiata
Valley marsh and tidal Ammonia beccarii
channel margins Elphidium excavatum
Haynesina germánica
Miliammina fusca
Inner and mid-lagoon Ammonia beccarii
environments Elphidium excavatum
Haynesina germánica
Washover fan Ammonia beccarii
Elphidium excavatum
Quinqueloculina seminula
Outer lagoon (sandy) Elphidium excavatum
Shoreface and delta Elphidium excavatum
shoals Elphidum mexicanum
2000). Elphidium, Buccella frígida, and Eggerella advena were the dominant taxa and
assemblages were of low diversity in Long Island Sound during the 1940s and 1960s.
However, research from the late 1990s indicated that the relative abundance of Eggerella
advena decreased while the relative abundance of Buccella frígida increased. Also, the
relative abundance of Ammonia beccarii, a species that can withstand extreme variability
16
in oxygenation, has steadily increased since the 1960s. The change was attributed to the
increased delivery of organic matter into Long Island Sound since the 1960s. An
increase in algal blooms (which create episodes of anoxia/hypoxia) has occurred since the
1970s as a result of increased local nutrient loading in the sound from wastewater
treatment plants. The research concluded that the observed change in the relative
abundance of species over the years is a result of the increased anthropogenic influence in
Long Island Sound (Thomas et al., 2000).
Foraminiferal distributions and abundances are used to delineate zones within
estuaries. Estuaries generally have few species of foraminifera with only one or two
dominant genera, usually Elphidium and an agglutinated taxon, Ammobaculites or
Ammotium. The distribution and abundance of species in these two genera is related to
salinity and depth (Nichols and Norton, 1969; Ellison and Nichols, 1970). Ellison and
Nichols (1970) distinguished foraminiferal assemblages based on salinity and depth in
their study in the Rappahannock Estuary of Chesapeake Bay. In particular, Elphidium
clavatum (= E. excavatum of this study) inhabited deep areas of the estuary with higher
salinities (Basin Biofacies). The presence of Ammbaculites crassus delineated a
transition zone (Shoal Biofacies) between the Basin Biofacies and the Marsh (outer and
inner) Biofacies. The Shoal Biofacies was comprised of mainly agglutinated
foraminifera, such as A. crassus and Miliammina fusca, and extended over a wide range
of fairly brackish water, with a salinity range of 0.5 to 16. Similar seasonal variations
were observed in the Rappahannock Estuary (Ellison and Nichols, 1970) and the James
River Estuary (Nichols and Norton, 1969), both part of the Chesapeake Bay estuarine
17
system. Elphidium increased in abundance with an increase in salinity during the
summer months of low river flow (>14), while Ammobaculites was dominant in regions
containing brackish water (0.5-14) (Nichols and Norton, 1969; Ellison and Nichols,
1970).
Recent research has combined foraminferal assemblages and geochemical
analyses for recognition and explanation of changes in estuarine environmental
conditions over time (e.g., Karlsen et al., 2000; Bratton et al., 2003; Buzas-Stephens et
al., 2003). The abundance oi Ammonia parkinsoniana was found to increase up-core in
deep cores (4.5m) collected in Chesapeake Bay (Karlsen et al., 2000). A. parkinsoniana
is tolerant of a variety of environmental conditions and can be associated with low
dissolved oxygen. Using a number of dating techniques (radiocarbon analysis, pollen
stratigraphy, ^'Vb and ’^^Cs, and paleomagnetic correlation), the first presence of A.
parkinsoniana was found to be in intervals dating back to the turn of the 19'*’ century.
The change in foraminiferal abundances at this time coincides with a boom in agriculture.
The research concluded that the increased abundance of A. parkinsoniana was a direct
result of anthropogenic influences (Karlsen et al., 2000; Bratton et al., 2003).
Recent research analyzed four areas in the Texas Gulf coast for the possible
effects of pollutants on foraminifera (Buzas-Stephens et al., 2003). While no direct
geochemical evidence of pollution was present, change in down-core foraminiferal
assemblages within one area, the Arroyo Colorado, was determined to be an effect of
anthropogenic influence. The present day surface foraminiferal assemblage of the
Arroyo Colorado is classified as an estuarine river assemblage dominated by Elphidum
18
with a small percentage of Ammonia. However, as the amount of sand and grain size
increases down-core, the number Elphidium species decreases as the number of Ammonia
species increases. The foraminiferal assemblage at the bottom of the 70cm core is
dominated hy Ammonia with a small percentage of Elphidium. Radiounuclides (^'°Pb
and '^^Cs) determined that the age of the down-core change in sediment coincided with
the construction of a shipping channel. The study noted coincidence of the change in the
foraminiferal assemblage down-core with the dredging of the channel. However, the
cause of the assemblage change was not evident to the authors (Buzas-Stephens et al.,
2003).
Significance of signatures
Carbon is one of the most abundant elements on Earth; it is found in all living
things and the atmosphere. The two stable isotopes of carbon are '^C and '^C. The
ratio varies among plants as a result of isotope fractionation. The notation
defines the isotope signature of carbon. The value for is found by the following
equation:
Ô'^C = (Eq. 1)
Where ‘spf is for the sample and ‘std’ is for the standard. Calcite from a belemnite
within the PeeDee Formation is the standard for ô'^C and is assigned a value of 0 parts
19
per thousand (%c). Values with a negative 5’^C are depleted in '^C and values with a
positive are enriched (Cifuentes et ah, 1996; Schlesinger, 1997; Faure, 1998).
Photosynthesis is the primary cause of carbon fractionation. Fractionation of
carbon occurs at different rates based on photosynthetic metabolic pathways (Faure,
1998). The varying rates cause different signatures in plants (marine and
terrestrial), the atmosphere, and ocean. Photosynthesis begins the fractionation process
by extracting CO2 gas from the atmosphere and diffuses into the cells of the plants.
Kinetics dictates a more rapid uptake of '^C into plant cells because it is the lighter of the
1 ^
two isotopes. As a result of the diffusion, the CO2 in the plant cells is depleted in C
(Schlesinger, 1997). Most plants are divided into two categories based on their
photosynthetic pathways (C3 or C4), which is based on the number of carbon atoms used
to convert CO2 into simple sugars. Most terrestrial plants use the Calvin-Benson Cycle
(C3) to carry out photosynthesis. In contrast, many grasses, including salt marsh grasses
(such as Spartina alterniflora), which are classified as C4 plants, carryout photosynthesis
using the Hatch-Slack cycle (Waller and Lewis, 1979; Smith and Smith, 1998).
The atmosphere has a signature of -7 %c. When plants uptake CO2 from the
atmosphere, the CO2 becomes depleted in '^C (a more negative value). In general,
organic matter derived from terrestrial sources (plants) is recognized by strongly depleted
(more negative) signatures. The biogenic release of CO2 from HC03' in marine
waters has a ô'^C signature of 0%o. Therefore, the uptake of CO2 by marine plants is
generally more enriched (less negative) in than that of their terrestrial counter parts.
As a result, greater enriched signatures, in comparison to terrestrially derived
20
organic matter, allow the recognition of marine derived organic matter (Waller and
Lewis, 1979; Faure, 1998; Thornton and McManus, 1994). Letrick (2003) summarized
typical range values of ô'^C derived from various sources (Figure 8).
Figure 8: Typical range for ô’^C signatures (after Letrick, 2003).
The specific isotopic signatures of the '^C allow researchers to determine whether
marine or terrestrial biological processes dominate the production of organic matter
present in their study area. Organic matter present in any coastal system has a specific
ô'^C signature. However it is important to remember that there are several sources of
carbon and that a signature is a resultant of all the organic matter present in the
sample. Carbon values obtained from organic matter in sediment have proved to be
important indicators to determine whether estuaries and marshes are marine, riverine, or
terrestrially dominated (Matson and Brinson, 1990; Thornton and McManus, 1994;
Middleburg and Nieuwenhuize, 1998; Maksymowska et al., 2000; Neubauer et al., 2002).
21
Significance of signatures
The stable isotopes for nitrogen are and ’^N. Variations in ratios are
the result of fractionation occurring during biogeochemical processes. The notation
defines the isotope signature of nitrogen. ô'^N signatures are expressed in terms of parts
per thousand (%o). The isotopic signature is calculated as follows:
0^^N = (Eq. 2)
Where ‘spl’ is for the sample and ‘std’ is for the standard. The standard for nitrogen
isotopes is atmospheric nitrogen (N2), which has an isotopic signature equal to zero
(Cifuentes et al., 1988; Cifuentes et al., 1996).
Stable nitrogen isotopes (6*^N) have proved to be a useful tool in determining
possible sources (allochthonous or autochthonous) of organic matter within an estuarine
system (Peters et al., 1978; Cifuentes et al., 1988; Thornton and McManus, 1994;
Middleburg and Nieuwenhuize, 1998; Maksymowska et al., 2000; Graham et al., 2001;
Neubauer et al., 2002; Bratton et al., 2003). The resultant signature is a combination
between nitrogen cycling within the water column and the interaction with surficial
sediment, as well as the organic matter source material (Bratton et al., 2003). Therefore,
it is important to understand the biogeochemical processes occurring within the water
column and sediment before deposition to obtain the conditions that exist within a
system.
22
Nitrogen signatures are altered in the sediment and water-column by a number of
different biogeochemical processes such as ammonification, nitrification, denitrification,
bioturbation, assimilation, and physical mixing of sediment (Thornton and McManus,
1994). Ammonification is the formation of ammonium by the decomposition of
organic matter (Kemp et ah, 1990). Ammonium (NîTi'^) is delivered to the estuarine
system via rivers (Maksymowska et al., 2000; Middleburg and Nieuwenhuize, 2001). In
the estuary, is either oxidized to nitrate (NO3') (nitrification) within the water-
column (Middleburg and Nieuwenhuize, 2001) or taken up by organisms, such as
phytoplankton (assimilation) (Kemp, et al., 1990). Isotopic fractionation during
assimilation of NfK'^ by phytoplankton has been reported to enrich ô’^N signatures up to
6.4 %o (Montoya et al., 1991). The process of denitrification removes NOs' from the
water-column and sediment in gas form as either N2 or N2O (Kemp et al., 1990;
Middleburg and Nieuwenhuize, 2001; Usui et al., 2001), which is composed of the lighter
isotope '“^N, leaving behind the heavier isotope ’^N (Anderson and Fourqurean, 2003).
Denitrification produces the greatest fractionation (up to as much as 40 %c) in comparison
to all other biogeochemical processes (Bratton et al., 2003). The longer organic matter is
suspended, the longer period of time it is exposed to biogeochemical processes within the
water-column. In general, marine plankton and plants have a more enriched ô’^N
signature in comparison to terrestrial vegetation (Peterson et al., 1985; Anderson and
Fourqurean, 2003) as a result of these biogeochemical processes. Therefore, sediment
deposited in marginal marine estuaries is typically enriched in ô'^N.
23
values can also determine the extant of anthropogenic influence in estuaries
(Voss et ah, 2000). Agriculture of the land (adding fertilizers) and direct addition of
sewage increase signatures (Peters et al., 1978; Thornton and McManus, 1994;
Zimmerman and Canuel, 2000; Bratton et al., 2003). Many times, the increased nutrient
loading into the water stimulates eutrophication, which will also enrich nitrogen
signatures (Zimmerman and Canuel, 2000; Bratton et al, 2003). Algal blooms associated
with increased nutrient loading into estuaries have disturbed natural nitrogen levels
(Dortch et al., 1998; MODMON, 2001). Letrick (2003) summarized typical
signatures from various sources (Figure 9).
Once deposited, both aerobic and anaerobic microbial processes continue to
modify the of sediment. Continued denitrification of deposited sediment is
expected to readily continue to remove ’"*N, displaying increased enrichment of sediment
down-core. However, a study conducted in Chesapeake Bay reported ô’^N signatures to
deplete down-core (Bratton et al., 2003). The depletion found down-core was attributed
to bacterial growth during anoxic decay of organic matter. Bacterial growth adds
biomass depleted in ’^N to the sediment (Lehmann et al., 2002).
24
Atm. N
+ (
O'* Plants
Rain (NO3')
I Rain <NH¿S ^
F.Fertilizer,
I Sewage/Warte (NO^'/NH.'^)
|SotlOM|
-l^reshwater phytoplankton
Marine phytoplanjtton
Spagrass^s
Sa| Marsh peat
-15 -10 -5 0 5 10 15 20 25 30
Figure 9: Typical range for ô’^N signatures (after Letrick, 2003).
Significance of C:N Ratios
C:N ratios (carbon to nitrogen weight ratio) have proven to be valuable indicators
of possible sources for organic matter present within estuaries. In general, regions that
are influenced by delivery of terrestrially derived organic matter have high ratios (>12).
In contrast, regions that are influenced by marine processes have lower ratios (~9). Many
studies have used C:N ratios to trace patterns in estuaries between terrestrially influenced
regions and marine influenced regions. In most cases, C:N ratios decrease with
increasing distance from source areas (down-river) (Matson and Brinson, 1990; Thornton
and McManus, 1994; Middleburg and Nieuwenhuize, 1998; Gordon et al., 2001; Graham
et al., 2001). C:N ratios are heavily influenced by processes (such as mixing) occurring
within the sampling region and vary among field areas. Therefore, it is important to use
other geochemcial tracers (ô'^C, 5'^N) to help understand the mechanics of the estuary
and not to rely on C:N ratios alone.
25
Estuarine studies using geochemical tracers
Several studies have used C and N stable isotopes and C/N ratios to determine
dominant source for organic matter present in estuaries (Thornton and McManus, 1994;
Middleburg and Nieuwenhuize, 1998; Müller and Voss, 1999; Struck et al., 2000;
Graham et al., 2001; Neubauer et al., 2002). According to Cifuentes (1988), isotopic
signatures are conserved and the determined signature found in sediments is a result of
the physical mixing between sources (terrestrial versus marine). For this reason, many
studies have defined signatures and ratio values for terrestrial and marine environments to
explain the values found in estuaries. Research in the Schelde Estuary determined four
pools of organic matter: terrestrial, marine, riverine, and estuarine. The estuary was
divided into an upper and lower section. Both sections of the estuary displayed C:N,
ô'^C, and ô'^N (upper: 17, -26, 7 and lower: 10, -23, 9, respectively) indicating mixing
between several sources. However, the observed change between the two sections
determined the upper estuary was more terrestrially influenced where as the lower estuary
was more estuarine influenced (Middleburg and Nieuwenhuize, 1998).
Recent research in the Chesapeake Bay estuary has also used and ô'^N
signatures and C:N ratios from sediment in deep cores (4.5m) to described the
paleoenvironment. The observed profile changes down-core were attributed to an
increase in anthropogenic influence since the turn of the 19* century (as determined by
various dating techniques) (Zimmerman and Canuel, 2000; Bratton et al., 2003).
and C:N profiles, as displayed down-core, signified changes in the estuarine productivity
and delivery of terrestrially derived carbon to the estuary. ô’^N profiles displayed periods
26
of oxygen depletion down-core that indicated an increase in denitrification and nutrient
recycling on seasonal scales (Bratton et al., 2003). An overall ô'^N enrichment in the
cores began at the intervals representing approximately the years 1750-1800 (as
determined by pollen and diatoms). The enrichment was attributed to increased
eutrophication. The time period associated with the change coincides with an intense
boom of agriculture of the land (land clearing and tillage), which also caused an
increased in erosion of the land and sedimentation into the bay (Bratton et al., 2003).
Letrick (2003) used stable isotopes (ô’^C and ô'^N), C:N ratios, and
sedimentology to describe changes within Albemarle Sound estuarine system. North
Carolina, over the last century. The data presented indicate that the system has changed
in the last approximately 150 years from a primarily marine dominated estuary to the
present day terrestrially dominated estuary. Cores collected in the Pasqutank River, a
tributary to Albemarle Sound, indicate ô'^N enriches continually up-core over the last
century (as determined by radionuclide data; Vance, 2004). This region of the estuary is
densely populated. The increased enriched values were attributed to the increase in
anthropogenic influence over time (Letrick, 2003).
Stable carbon isotopes and C:N ratios have been used to determine sources of
organic carbon in the Pamlico and Neuse River estuaries of North Carolina. Matson and
Brinson (1990) determined sediment present in the upper part of the estuaries to have
ô'^C values characteristic of terrestrial plant material. ô’^C values continually enriched
downstream, which signified less terrestrial plant input and more marine influence.
Organic carbon produced from marine phytoplankton is more enriched in C. The
27
increased levels of 13C resulted in a decrease in C:N ratios present downstream. The
change in isotope values and the C;N ratios delineate between the upper and lower waters
within the Neuse River estuary (Matson and Brinson, 1990).
Radionuclides
Lead-210 (^'°Pb) is part of the Uranium-238 decay series. decays
through a sequence of four radionuclides before it decays to Radium-226 (^^*^Ra). In soil,
^^*^Ra decays to the short-lived radionuclide to Radon-222 (^^^Rn) and escapes to the
atmosphere. Once in the atmosphere, ^^^Rn (with a half-life of 3.82 days) continues the
decay series through a series of short-lived radionuclides to ^^'’Pb. Lead-210 may be
removed from the atmosphere in two ways: (1) dry deposition or (2) precipitation. In
normal climate conditions, it can be assumed that ^'°Pb fall-out is constant over the years
(Appleby and Oldfield, 1992). With a half-life of approximately 22 years, ^'°Pb can be
used as a dating technique to construct sedimentation rates in sediment cores up to
approximately 150 years before present (BP). In general, ^'‘^Pb activities will decrease
with increasing depth, which is a result of the radioactive decay of ^’°Pb overtime (letter,
2000).
Cesium-137 (*^^Cs) can also be used to determine calendar dates for core samples.
The source for '^^Cs in the system is from the atmospheric testing of nuclear bombs
beginning in 1954. Continued testing of nuclear bombs through the 1950’s and the early
1960’s places a prominent peak concentration in the record in 1963. Since 1963, a
smaller quantity of *^^Cs is recorded in the sedimentary record (Jeter, 2000).
28
Radionuclides have been used in several studies to obtain sedimentation rates and
ages within estuaries (Ravichandran et al., 1995; Dellapenna, et al., 1998; Buzas-
Stephens et al., 2003; Corbett et al., 2004; Vance, 2004). Cesium-137 has also proven to
be a useful tool to track sediment deposition from hurricanes and other major storms
along the east coast of the United States (Chmura and Kosters, 1994; Donnelly et al.,
2001a; Donnelly et al., 2001b; Corbett et al., 2004).
METHODS
Samples were collected during the summers of 2002 and 2003 using a 1-meter
length manual push coring device and a Ponar grab sampler. Separate samples were
collected for geochemical and foraminiferal analysis. For geochemical analysis, cores
were sectioned into two-centimeter intervals between zero and 30 cm, then three-
centimeter intervals for the remainder of each core. Sediment to be analyzed for
radionuclides was placed into plastic bags while sediment for stable isotope analysis was
placed in plastic vials and kept on ice in the field until they could be frozen in the lab.
For foraminiferal analysis, each core was divided into surface intervals (0-1 and 1-2 cm),
then into 2 cm intervals for the first 30 cm, and 3 cm intervals for the remainder of the
core. Approximately 20 ml of sediment was placed into bottles and preserved in buffered
alcohol for foraminiferal analysis. Two grab samples were collected at each site
wherever a short core was collected. Twenty ml samples from the top 1 cm (0-1 cm) of
sediment were acquired from each Ponar grab sample. Three grab samples were
collected at sites where short cores were not collected. Each site was visited once and the
temperature, salinity, water depth, as well as position were recorded.
30
Foraminiferal Analysis
Laboratory Methods
Forty surface samples (0-1 cm interval) were used for analysis of the modem
distribution of foraminifera (Figure 6). Preparation of the samples followed the same
procedure used by Culver et al. (1996) and Woo et al. (1997).
The samples were washed over a nest of 710-)am and 63-p,m sieves to remove the
mud (silt and clay) and the alcohol used to preserve foraminifera within the sample. The
coarse material (> 710 p,m) was placed into a plastic weigh boat then placed in an oven
set a 60°C to be dried. The remaining material (63 to 710 p-m) was washed into a 400 ml
glass beaker with tap water. A small amount (< 1 g) of sodium metaphosphate ((NaP03)x
• Na20 calgon) was added to every sample to help break apart any remaining mud
aggregates. One to two small tablets of sodium hydroxide (NaOH) were added to
extremely muddy samples in order to help break apart the larger mud aggregates. Rose
Bengal (Walton, 1952) was added to all the surface samples. Rose Bengal stains
cytoplasm of the preserved foraminifera to allow the distinction of live from dead
foraminifera at the time of collection. After eight to twelve hours, the sample was
washed over the sieves once more to remove any excess clay and silt the chemicals may
have disaggregated, as well as the stain. The samples were then washed into plastic
weigh boats and placed in an oven to be dried at 60°C.
Foraminifera were separated from samples containing a high amount of sand
using sodium polytungstate (Munsterman and Kerstholt, 1996). The density of the heavy
liquid can be controlled by the addition or subtraction (by evaporation) of de-ionized
31
water. The density of the heavy liquid is set to allow a piece of gypsum to float and a
piece of feldspar to sink. This allowed foraminifera to float on the surface because they
are composed of chambers filled with air, while sand and other heavy minerals sank in
the solution.
The apparatus for the ‘floating technique’ is set-up as shown in Figure 10.
Sodium polytungstate was poured into the funnel and tubing. The sandy sample was then
sprinkled into the liquid. Once the sample had separated (approximately 15-20 minutes).
Figure 10: Floating apparatus set-up.
32
the liquid and the sand were drained into a plastic funnel lined by an 18.5 cm (diameter)
paper filter with a coarse porosity to allow liquid to readily flow through (pore size
should be no larger than 63p,m). The sand (‘sink’) was captured in the filter while the
liquid drained into a 400 ml glass beaker. Once the sand had drained out, the remaining
liquid containing the foraminifera and lighter material (‘float’) was drained into a
separate funnel lined with another paper filter. The float remained in the filter while
liquid drained into the 400 ml glass beaker. Both the float and the sink were
continuously washed with de-ionized water until all sodium polytungstate had been
removed from the sample. The sediment was then washed from the filters into a plastic
weigh boat, which was placed into an oven to be dried.
Each sample was split into aliquots using a microsplitter. A small portion of the
sample was sprinkled evenly onto a 45-square picking tray to be viewed under a
microscope. Foraminifera were picked out of the sediment using a fine (000 scale)
paintbrush. The foraminifera were placed onto a 60-squared cardboard slide that had
been brushed with gum tragacanth (a water soluble glue). Specimens were sorted based
on their morphologies and whether or not they were alive or dead (surface samples only)
at the time of collection. Live foraminifera were distinguished from the dead by the
presence of cytoplasm stained pink by rose Bengal. Foraminifera identification was
confirmed by comparison with type figured and unfigured specimens kept in the
Smithsonian Institution’s Cushman Collection. Once identification was confirmed,
specimens were counted (both live and dead) and the numbers were tabulated into an
Excel spreadsheet for further manipulation.
33
Down-core foraminiferal assemblages from two intervals representing
approximately 40 and 120 years ago (based on Cs-137 and Pb-210 data, respectively)
were studied in 12 cores. The lack of geochemical indicators in a few cores reduced the
number of down-core samples from 24 to 21. Down-core samples were prepared as for
surface samples except they were not stained with rose Bengal.
Cluster Analysis
A Q-mode cluster analysis was utilized to help recognize foraminiferal
assemblages located within the Pamlico Sound region. The resulting dendrogram, based
on transformed abundance data, reveals patterns of foraminiferal distribution and allows
determination of biofacies (Mello and Buzas, 1968; Culver and Buzas, 1981).
Approximately 300 foraminifera were picked from each surface sample (Buzas, 1990).
Analyses were run using the program SYSTAT for surficial, live and dead assemblages.
Rare species were excluded from the analysis. Only those taxa comprising two percent
or more of the assemblage at any one station were used in the cluster analysis. The
abundance data for each species at each station were transformed using the equation,
2arcsinVp (p = abundance). The Q-mode method was used to compare the species
present at each station to species present at other stations (Mello and Buzas, 1968; Davis,
1973). Q-mode analysis uses the transformed abundance data to allow stations to be
compared geographically to recognize a spatial distribution. The amount of similarity
between samples was measured using Euclidean distances, on a scale from zero to
infinity, with zero distance being most similar. Ward’s linkage method was used to
34
group ‘objects’ together based on similarities between the ‘objects,’ thus creating a
cluster. Clusters were continuously formed until there were no remaining relationships
between unclustered stations, thus forming a dendrogram (Mello and Buzas, 1968; Buzas,
1979).
Biofacies Fidelity and Constancy
Biofacies Fidelity and Constancy (Hazel, 1977) were calculated to determine
which species dominate within each assemblage (biofacies). Constancy (C) refers to how
often the species occurs in an assemblage. Biofacies fidelity (BF) is calculated by
dividing the constancy of the species by the total sum for all constancies.
Constancy (C) = Occurrence x 10 (Eq. 3)
Total number of stations in cluster
Biofacies Fidelity (BF) = C x 10 (Eq. 4)
Z for all C
BF and C are expressed on a scale between zero and ten. If a species scores high for both
C and BF, then that species can be considered a characteristic for a particular biofacies
(Hazel, 1977).
Discriminant Analysis
Multivariate discriminant (canonical variate) analysis was used to test the
hypothesis that the {a priori) groups defined by the cluster analysis are distinguishable
statistically. The analysis, based on the amount of variability and similarity between
groups (Davis, 1973; Buzas, 1979; Hayek and Buzas, 1997), determines which species
35
contribute most to the discrimination between the a priori groups, thus providing a way
to check the biofacies fidelity results. The analysis uses transformed abundance data for
the calculation. A discriminant analysis was run for the surficial groups defined by the
cluster analysis. A second discriminant analysis was run on the same data with
subsurface (down-core) samples included as ‘unknowns’. The program classifies each
‘unknown’ into the most similar a priori group. SPSS (Statistical Package for the Social
Sciences) version 12 was used to run the analyses.
Species Diversity
Benthic foraminiferal species diversity varies spatially. In general, the number of
species increases with decreasing latitudes (Hayek and Buzas, 1997) and with increasing
depth across a continental margin (Buzas and Gibson, 1969). Species diversity is defined
as the relationship between the number of species and number of specimens within an
assemblage (Murray, 1973).
There are a number of ways to determine species diversity. One simple way is the
calculation of the Fisher alpha (a) index:
s
A
_ -1
7" (Eq. 5)5
a
Where ‘N’ is the number of observations and ‘S’ is the number of species. Graphs and
charts have been constructed for easier determination of a, which is based on N and S
(Murray, 1973; Hayek and Buzas, 1997).
36
Geochemical Analysis
Carbon and Nitrogen
Once collected from the push cores, samples for stable carbon and nitrogen
isotopes and C:N were placed in vials, and stored in an ice cooler, which was later
transferred to a freezer. In the lab, the sediment was dried in an oven at 60°C. Any shell
material and organics (i.e., root fragments) were removed to avoid interference with the
true isotopic signature of the sediment. The sediment was then ground into a fine powder
using a mortar and pestle.
Initial percent organic matter present within each sample was determined by the
loss on ignition (LOI) method. Ground sediment (approximately 1-2 grams) was placed
into pre-weighed porcelain crucibles and placed into a desiccator overnight to remove
any moisture. The samples were weighed and placed into a muffle furnace set at 450°C
for four hours. Samples were then placed back into the desiccator to cool. Once cooled,
the samples were reweighed. The difference between the sample weights before and after
the furnace was determined to be the percent of organic matter.
Stable isotopic analysis requires approximately 800-1200 mg of organic carbon.
Assuming that total organic matter (measured by loss on ignition) contains 40% organic
carbon, the range of sediment for analysis can be calculated by:
Minimum sediment (g) = 8.0 x 10'^ g of organic carbon (Eq. 6)
LOI(0.40)
Maximum sediment (g) = 1.2 x 10'^ g of organic carbon (Eq. 7)
LOI(0.40)
37
The calculated amount of sediment was then weighed out into silver capsules and placed
into a micro titre plate. Any inorganic carbon present within the sample can interfere
with the isotopic signature of organic carbon. To ensure that all inorganic carbon was
removed, the samples were fumigated with acid. Each sample was wetted with 50 pi of
de-ionized water and placed in a desiccator for four to six hours with 100 ml of 12 M
hydrochloric acid (HCL). Harris et al. (2001) demonstrated how this fumigation process
removes the inorganic carbon without affecting the stable organic carbon and nitrogen
values. Once the fumigation process was complete, the samples were dried in an oven at
60°C, and shipped to the University of California Stable Isotope Laboratory.
Samples were analyzed on a Europa 20-20 continuous flow isotope ratio mass
spectrometer followed by combustion at 1000°C in a Europa ANCA-GSL CN analyzer to
determine total nitrogen and carbon, as well as nitrogen and carbon signatures. The
isotopic signatures are relative to atmospheric N2 and to Vienna-Pee Dee Belemnite
(Harris et al., 2001).
Radionuclides
The approximate age of the sediment was calculated by evaluating Pb and Cs
activity levels down-core. The total amount of ^'°Pb contained within the sediments
down-core was determined using an alpha spectrometer following an acid leach
technique, ^'^b can be quantified indirectly using its daughter isotope ^'°Po, and
assuming secular equilibrium decay of ^'°Pb and ^*°Po, ^^"^Pb activities can be determined
by counting the alpha decay of ^'°Po (Ravichandran et al., 1995). To analyze the
38
sediments for 15 ml of 8 M nitric acid (HNO3) and 1 ml of ^®^Po (used as a yield
determinant) was added to approximately one gram of dry sediment and digested using a
high-pressure microwave digestion technique. Samples are digested at a constant
pressure of 75psi for approximately 50 minutes. Samples typically reach a temperature
of approximately 150-C for 40 minutes during digestion. Once digestion was complete,
the sample was then centrifuged three times and washed with 8 M HNO3 twice. The
solution was poured into a Teflon beaker and placed onto a hot plate. Hydrogen peroxide
(H2O2) was added to the solution to help remove any residual organics. The samples
were evaporated until approximately 10 ml of solution remained. Ammonium hydroxide
was added until the solution reached a pH of 8, precipitating FeO(OH). The samples
were then centrifuged three more times and rinsed with de-ionized water into Teflon
beakers. Nickel disks, resting on magnetic Teflon stir bars, were placed in the Teflon
beakers with the solution. The beakers were left on a magnetic spinning plate for 24-48
hours to allow the Po to spontaneously plate onto the disks. Ascorbic acid was added to
each beaker to avoid any reaction between the Fe^"^ in solution with the nickel disks
(Ravichandran et al., 1995; Lewis et al., 2002).
Activity levels (dpm/g) of the ^°^Po were graphed against depth (cm) to determine
the depth at which excess ^'°Pb activity (supported minus unsupported) was absent
(dead), which represents approximately 120 years before present. The supported activity
levels for each core were determined by averaging the tight-ranged, low-level Pb
activities found towards the bottom of the core (Lewis et al., 2002). The supported
activity is the result of the natural decay process of ^^^Rn within the sediments, and does
39
not represent the constant amount of ^'°Pb deposition from the atmosphere (Appleby and
Oldfield, 1992). This process determined which down-core interval (representing
approximately 120 years ago) was analyzed for foraminifera.
Cesium-137 activities were determined by gamma emission using a low-
background, high resolution Germanium detector. Samples were dried in an oven (set at
60°C) and crushed into a fine powder using a mortar and pestle. The sediment samples
were packed into plastic vials or aluminum tins and counted for at least 24 hours. The
’^^Cs activity was measured using the 661 keV peak. The measured activities (dpm/g)
were plotted against depth (cm). The observed peak in Cs was assumed to represent
the early 1960s, when atmospheric nuclear testing reached a maximum (Jeter, 2000).
This age determinant marked which down-core interval (representing approximately 40
years ago) was analyzed for foraminifera.
One-way Analysis of Variance (ANOVA)
The ANOVA statistical analyses were conducted using SPSS version 12.0. The
one-way ANOVA with contrasts was used to show if there are significant differences in
the means between the three time frame/intervals (-120 yrs BP, -40 yrs BP, and modem)
for the stable isotopes and ratios. An explanation of the program and mathematical
computation for the analysis can be found in the tutorial section of the program.
RESULTS
Foraminifera
Cluster Analysis: Live Foraminifera
Twenty-one species were found living (rose Bengal stained) at the surface (0-
1cm) at the time of collection. The number of live foraminifera found per site is shown
in Figure 11 and Appendix B. The cluster analyses using only live foraminifera
recognized five groups (Figure 11). However, two of these groups (A and C) were
distinguished based on the presence of only one species {Elphidium excavatum and
Ammonina parkinsoniana, respectively) (Figure 12). The cluster analysis using only live
foraminifera did not result in any meaningful faunal patterns, probably because of the
generally low number of specimens per sample (Figure 11). In addition, the clustering
technique may force samples into groups when they contains very different kinds of
species. For example, the analysis grouped sites located at marshes, comprised of
Siphotrochammina lobata, Tiphotrocha comprimata, and Trochammina inflata, with sites
located at inlets, comprised of Quinqueloculina jugosa, Quinqueloculina seminula, and
Elphidium mexicanum, and did not create a clear distinction between any sub-
environments within the Sound. The analysis also excluded six sites (S2, S9, S12, S23,
S35, and EB02S1) because live foraminifera were not present. An analysis only using
live foraminifera only reflects environmental conditions (i.e., temperature and salinity) at
the time of collection. These conditions change on a seasonal basis and often on a day-
to-day basis in Pamlico Sound.
No. live No. live
specimens: species:
Figure 11 : Cluster analysis of surface sites using live foraminifera. Dendrogram resulting from using
transformed abundance data of all live species. Biofacies are labeled A-E.
42
Figure 12: Spatial distribution plot of the results of the cluster analysis using only
live species. The plot is based on the clusters indicated in Figure 11.
Some researchers (Scott and Medioli, 1980) argue that studying just the live foraminiferal
populations is of limited use. Benthic foraminifera living in shallow water do not have a
long life span. The typical reproductive cycle of foraminifera within Pamlico Sound may
last several days to a year. The duration is dependant upon the species and the
environmental conditions, including season (Boltovoskoy and Wright, 1976). At any one
time, a collection will have a greater number of dead specimens versus live specimens.
Analysis of the total population (live + dead foraminifera) integrates the small seasonal
and spatial variation that is often not seen when analyzing just the live population. The
43
total assemblage gives a better representation of the environmental conditions that exist
in any one region (Scott and Medioli, 1980).
Cluster Analysis: Dead Foraminifera
Forty-four species were found in the surface (0-1 cm) sediment of Pamlico Sound
(Appendices A and B). Several cluster analyses were run using the dead foraminiferal
surface data; one including all species and others using only the dominant species
(abundance greater than 2% or 5%) thus eliminating the rare species. In general, all of
the analyses displayed similar patterns. However, rare species are not reliable indicators
of foraminiferal patterns (Koch, 1987). Therefore, the results of only one analysis is
presented, that utilizing only those dead species comprising two percent or more of the
assemblage (based on abundance data (Appendix C)) at any one station. The data were
entered into the cluster analysis program as transformed relative abundance data
(Appendix D). The resulting dendrogram divided the stations into three main clusters. A
nested set of four samples within group three are geographically distinct from other
samples in that group (Figure 13). Hence, they are treated as a distinct group. The group
names were determined based on species present within each group and location of the
site within the Pamlico Sound. These groups are: (1) Estuarine Biofacies A, (2) Marsh
Biofacies, (3) Estuarine Biofacies B, and (4) Marine Biofacies (Figure 13).
Estuarine Biofacies A contains 16 samples and is dominated by the agglutinated
species Ammotium salsum (approximately 83%). Approximately ten percent of the
assemblage was comprised of calcareous foraminifera; Ammonia parkinsoniana (6%),
Biofacies Biofacies Sample
no. no.
Estuarine
Biofacies
Marsh
Biofacies
Estuarine
Biofacies
Marine
Biofacies
Estuarine
Biofacies
Figure 13; Cluster analysis of surface sites. Dendrogram resulting from cluster analysis of transformed
abundance data of those species comprising of 2% or more of the assemblage in any one sample.
4^
45
and Elphidium excavatum (4%). When plotted spatially, Estuarine Biofacies A is located
along the margins and in the north-central basin of Pamlico Sound (Figure 14).
The Marsh Biofacies (9 samples) is dominated by Ammonia parkinsoniana
(33%), followed by Ammotium salsum (13%). This biofacies is distinguished from the
others by the presence of typical finely agglutinated marsh foraminifera (e.g.,
Trochammina inflata and Haplophragmoides wilberti). Many of the species present in
this group are not found in any of the other biofacies. The nine stations assigned to this
group are generally found close to shores of the sound (Figure 14), with two exceptions
(S5 and S14).
Estuarine Biofacies B is comprised of ten samples. Approximately 77% of the
assemblage is comprised of calcareous foraminifera. Elphidium excavatum (65%),
Ammotium salsum (15%), and Ammonia parkinisoniana (12%), are the dominant species.
Estuarine Biofacies B, with the exception of station S30, is located in the south and the
central sections of Pamlico Sound (Figure 14).
The four stations comprising the Marine Biofacies are located at Ocracoke and
Hatteras Inlets (Figure 14), and are composed completely of calcareous foraminifera;
Elphidium excavatum (70%) is the dominant species. Many of the species {Cibicides
lobatulus, Cibicides refulgens, Elphidium subarticum, Quiniqueloculina lamarckiana,
and Quiniqueloculina seminula) found within this assemblage are not found in any of the
other assemblages and are typical open shelf species (Schnitker, 1971; Workman, 1981).
46
Figure 14: Spatial distribution plot of the results of the cluster analysis of dead
foraminifera. The plot is based on the clusters indicated in Figure 13.
Biofacies Fidelity and Constancy
In order to determine which taxa were most important in distinguishing biofacies,
Biofacies Fidelity and Constancy (Hazel, 1977) were calculated for those dead taxa
comprising two percent or more of the assemblage at any one station (Appendix C). A
species was considered to be characteristic for the assemblage if it received a score of six
or greater for both Constancy (C) and Biofacies Fidelity (BF). No species are
characteristic for Estuarine Biofacies A (Table 2). However, Ammobaculites dilatatus,
Ammobaculites exiguas, and Textularia earlandi, although occurring rarely (Table 1), are
47
present only in this assemblage. Ammotium salsum occurs at every station within this
assemblage, but it has a BF of only four. Coarsely agglutinated foraminifera dominate
Estuarine Biofacies A in comparison to other assemblages.
Haplophragmoides wilberti, Miliammina fusca, Tiphotrocha comprimata, and
Trochammina inflata are characteristic of the Marsh Biofacies (Table 2). Ammoasuta
inepta and Haplophragmoides bonplandi are restricted to this assemblage, but they occur
at few stations (Table 2). In general, the foraminifera of this assemblage are finely
agglutinated.
Estuarine Biofacies B, like Estuarine Biofacies A, does not contain characteristic
species (C and BF values > 6) (Table 2). However, Ammotium salsum and Elphidium
excavatum occur at all ten stations within the assemblage but they have a low BF value.
Elphidium cf. E. mexicanum is restricted to this assemblage but it occurs only at one
station. Estuarine Biofacies B is distinguished from Estuarine Biofacies A by a greater
proportion of calcareous foraminifera (averages of 77% and 10% respectively).
Six species are considered to be characteristic of the Marine Biofacies; Cibicides
lobatulus, Elphidium galvestonense, Elphidium mexicanum, Elphidium subarcticum,
Hanzawaia strattoni, and Quinqueloculina seminula (Table 2). Three additional species,
Cibicides refulgens, Quinqueloculina lamarckiana, and Quinqueloculina sp. C, are only
found in this assemblage but do not occur in as many samples as the six characteristic
species.
48
Table 2: Biofacies Fidelity and Constancy for the four biofacies, using dead
species comprising 2% or more of the assemblage in any one sample. O =
Occurrence, C = Constancy, and BF = Biofacies Fidelity (see equations (1) and
(2) in Methods section). Boxed values indicate characteristic species, defined
arbitrarily or those species with values of >6 for C and BF.
Estuarine Biofacies A Marsh Biofacies Estuarine Biofacies B Marine Biofacies
Species: 0 C BF 0 C BF ° 1 c BF 0 c BF
Ammoastuta inepta 0 0 0 2 2 10 0 0 0 0 0 0
Ammonia parkinsoniana 6 4 1 6 7 2 9 9 3 4 10 3
Ammonia tepida 1 1 1 1 1 2 1 1 2 1 3 5
Ammotium salsum 16 10 4 7 8 3 10 10 4 0 0 0
Arenoparrella mexicana 3 2 3 4 4 6 1 1 1 0 0 0
Asterigerina carinata 0 0 0 0 0 0 1 1 2 2 5 8
Ammobaculites crassus 5 3 4 3 3 4 1 1 1 0 0 0
Ammobacuiites dilatatus 1 1 10 0 0 0 0 0 0 0 0 0
Ammobaculites exiguus 3 2 10 0 0 0 0 0 0 0 0 0
abieldes lobatulus 0 0 0 0 0 0 0 0 0 3 8 10
abieldes refulgens 0 0 0 0 0 0 0 0 0 1 3 10
Elphidium excavatum 11 7 2 5 6 2 10 10 3 4 10 3
Elphidium galvestonense 1 1 1 1 1 1 0 0 0 3 8 8
Elphidium mexicanum 0 0 0 0 0 0 0 0 0 4 10 10
Elphidium c.f. E. mexicanum 0 0 0 0 0 0 1 1 10 0 0 0
Elphidium subarcticum 0 0 0 0 0 0 0 0 0 3 8 10
Hanzawaia strattoni 0 0 0 0 0 0 1 1 1 4 10 9
Haplophragmoides bonplandi 0 0 0 2 2 10 0 0 0 0 0 0
Haplophragmoides wilberti 5 3 3 5 6 6 1 1 1 0 0 0
Jadammina macrescens 1 1 1 4 4 7 1 1 2 0 0 0
Miliammina fusca 3 2 2 6 7 6 2 2 2 0 0 0
Ouinqueloculina lamarckiana 0 0 0 0 0 0 0 0 0 2 5 10
Ouinqueloculina seminula 0 0 0 0 0 0 0 0 0 3 8 10
Ouinqueloculina sp C 0 0 0 0 0 0 0 0 0 1 3 10
Siphotrochammina lobata 1 1 1 4 4 9 0 0 0 0 0 0
Textularia earlandi 4 3 10 0 0 0 0 0 0 0 0 0
Tiphotrocha comprimata 2 1 1 6 7 7 1 1 1 0 0 0
Trochammina inflata 4 3 2 6 7 6 2 2 2 0 0 0
Indeterminate agglutinated 0 0 0 1 1 10 0 0 0 0 0 0
Indeterminate caicareous 0 0 0 0 0 0 3 3 5 1 3 5
Organic lining 3 2 3 4 4 6 1 1 1 0 0 0
49
Discriminant Analysis
Surficial discriminant analysis. The cluster analysis of dead foraminifera in
surface (0-lcm) samples distinguished four biofacies. Discriminant analysis was used to
test the hypothesis that these four a priori biofacies were statistically distinguishable. All
taxa representing two percent or more of the assemblage were included in the analysis;
indeterminate agglutinated, and organic linings were excluded. Therefore, there were 28
species (number of variables, P = 28), and 39 sites (observations, N = 39). S37 was
barren of foraminifera. Four groups (h) were analyzed, and since P is greater than h, a
total of three canonical variates were possible (h -1 = 3).
The first two eigenvalues account for 99.6 percent of the variance between the
four a priori groups (Table 3). The canonical discriminant scores for the group means
(group centroids) can be found on Table 4. Since the fourth group (Marine Biofacies)
proved to be so different from the other three groups (Table 4), the analysis was re-run
excluding those samples belonging to the fourth group.
In this second analysis, where P = 28, N = 39, and h = 3, because P>h, there are
h-1 =2 canonical variates. The first eigenvalue accounts for 84 percent of the variance
between the three a priori groups (Estuarine Biofacies A, Marsh Biofacies, and Estuarine
Biofacies B) (Table 5), and discriminates the Marsh Biofacies from Estuarine Biofacies
A and B. The second axis (function) accounts for approximately 16 percent of the total
variance between the groups (Table 5). The scores for the group centroids along the two
canonical variates (functions) are given in Table 6. Table 7 indicates which species
50
Table 3: Canonical discriminant functions including the percent of variability for each
eigenvalue. These values result from the analysis including all four a priori groups
(Estuarine Biofacies A, Marsh Biofacies, Estuarine Biofacies B, and Marine Biofacies).
Function Eigenvalue % of Variance Cumulative %
1 1437.128 97.2 97.2
2 35.012 2.4 99.6
3 6.588 0.4 100.0
Table 4: Canonical discriminant function scores for group means (group centroids) along
the three canonical variate axes (functions). These values result from the analysis
including all four a priori groups. Group number (1) Estuarine Biofacies A, (2) Marsh
Biofacies, (3) Estuarine Biofacies B, and (4) Marine Biofacies.
a priori Functiongroup
number 1 2 3
1 -11.415 4.663 1.952
2 -13.132 -9.756 1.004
3 -12.402 1.436 -4.007
4 106.213 -0.290 -0.051
Table 5: Canonical discriminant functions including the percent of variability for each
eigenvalue. These values result from the analysis of Estuarine Biofacies A, B, and the
Marsh Biofacies.
Function Eigenvalue % of Variance Cumulative %
1 35.443 84.2 84.2
2 6.659 15.8 100.0
51
Table 6: Canonical discriminant function scores for group means (group centroids) along
two canonical variate axes (functions). These values result from the analysis of Estuarine
Biofacies A, B, and Marsh Biofacies. Group number (1) Estuarine Biofacies A, (2)
Marsh Biofacies, and (3) Estuarine Biofacies B.
a priori Functiongroup
number 1 2
1 4.481 1.859
2 -9.405 0.984
3 1.295 -3.861
(those with large positive or negative values) are most important in distinguishing
between the groups. Ammoasuta inepta, Haplophragmoides wilberti, and
Haplophragmoides bonplandi are responsible for the separation along function 1, which
distinguishes the Marsh Biofacies from the other two biofacies (Table 6). Trochammina
inflata, Elphidium galvestonense, and Siphotrochammina lobata are responsible for
separation of the groups along function 2, which distinguishes Estuarine Biofacies A and
B (Table 6).
The three groups are clearly distinguished from each other when plotted (Figure
15) with 95% confident circles. Therefore, the hypothesis that the three a priori groups.
Estuarine Biofacies A, Marsh Biofacies, and Estuarine Biofacies B, are statistically
different can be accepted.
52
Table 7: Standardized canonical discriminant function coefficients from the analysis.
Foraminifera listed are the source of variability along each axis.
Function
1 2
A. inepta -9.645 -0.199
A. park -0.082 0.214
A. tepida 4.336 0.357
A. salsum 3.480 0.538
A mex 3.911 0.079
A. car -0.693 -0.518
A. crassus -0.866 -0.363
A. dila 2.417 0.262
A. exiguus 2.166 0.098
E. excav 2.885 -0.812
E. gaiv -1.123 -1.261
H. strattoni -0.661 -0.290
H. bon 8.163 -0.515
H. wilberti -6.196 1.100
J. mac -1.920 0.233
M. fusca 4.857 0.403
S. lobata -0.144 3.261
T. eariandi 0.660 1.123
T. comp 1.947 0.184
T. infiata -0.781 -2.625
53
CDF2aisuncnroimcntiinicoaanlt
Canonical Discriminant Function 1
Figure 15: Plot of Canonical Discriminant Function 1 versus Canonical
Discriminant Function 2. The three a priori groups, (1) Estuarine Biofacies A, (2)
Marsh Biofacies, and (3) Estuarine Biofacies B, represented by a box (group
centroids) and 95 % confidence circles, are clearly distinguished from each other.
54
Down-core discriminant analysis. The combined results of the cluster analysis
and discriminant analysis of the surface data provide a model that was used to interpret
foraminiferal assemblages down-core. Discriminant analysis was used to assign down-
core samples into surface biofacies.
To determine the change in environmental conditions over the last approximate
150 years, two separated intervals, representing two separate time slices, were chosen
from each core. Sediment dated using 137Cs represents approximately 40 years BP;
while sediment dated using 210Pb represents approximately 120 years BP. The sediment
accumulation rate for Pamlico Sound is approximately 0.5cm/yr, however, the rate varies
from time to time and regionally (Tully, 2004). Therefore, the two-centimeter intervals
chosen may represent period of several years (approximately 20 years).
Twenty-one taxa were found in 21 down-core samples (Appendices E, F, and G).
These were included in the discriminant analysis including three biofacies (Estuarine
Biofacies A, Marsh Biofacies, and Estuarine Biofacies B) described at the surface. The
Marine Biofacies was excluded because none of the species restricted to this group were
found down-core. Thus, it was assumed that none of the down-core samples represented
an inlet assemblage. In this analysis, N (number of sites/stations) equals 60 and P
(number of variables) was again 28. Therefore, since P > h, a total of two canonical
variates is possible (h - 1 = 2). The down-core samples were not assigned an a priori
group number but were treated as “unknowns” by the statistical model.
Site numbers labeled ‘a’ correspond to samples analyzed at the Cs down-core
interval of peak activity (early 1960’s) down-core (Figure 16). The distribution pattern of
55
the foraminiferal assemblage (Figure 17) is similar to the surficial plot (Figure 14), with a
few exceptions. The presence of marsh foraminifera at S9a changes the assemblage from
the dominantly coarsely agglutinated Estuarine Biofacies A at the surface to a Marsh
Biofacies down-core. At the surface, S30 is included in Estuarine Biofacies B, comprised
mostly of calcareous foraminifera. Down-core, typical marsh foraminifera are present
and thus sample S30a is classified as Marsh Biofacies. At S60, the environment changes
56
Figure 16: Plot of Canonical Discriminant Function 1 versus Canonical
Discriminant Function 2 including three a priori groups and 21 “unknown” down-
core samples; Estuarine Biofacies A, Marsh Biofacies, and Estuarine Biofacies B.
‘a’ denotes the *^^Cs peak interval samples and ‘b’ denotes samples from the interval
where ^'°Pb activity is absent. Shapes correspond to the biofacies that each sample
was most similar to. Dashed line represents territory boundary determined by the
computer program.
57
Figure 17: Spatial plot of samples indicated by ‘a’ in Figure 16. The sediment
comprising those samples was deposited in the early 1960s, as determined by '^^Cs
dating. The solid/dashed line represents the inferred boundary between Estuarine
Biofacies A and Estuarine Biofacies B.
from Estuarine Biofacies B at the surface, to Estuarine Biofacies A down-core. This is
due to the increased proportion of agglutinated foraminifera down-core. In general,
during the early 1960s, the Estuarine Biofacies B (dominated by calcareous taxa) was not
as widespread throughout the Pamlico Sound as it is today. Marsh foraminifera were also
present further into the central sound, as seen at S9 and S30 (Figure 17). It is possible
that these foraminifera were washed into these sites from another location.
58
Site numbers labeled ‘b’ correspond to down-core intervals lacking the presence
of excess ^’^Pb activity, which indicates deposition approximately 120 years before
present (Figure 16). A significant change in assemblage characteristics down-core is
indicated by the analysis (Figure 18). Estuarine Biofacies A dominates the Sound. Only
two sites were classified with Estuarine Biofacies B (S12 and S30), and one station (SI 1)
was classified with the Marsh Biofacies.
Figure 18: Spatial plot of samples indicated by ‘b’ in Figure 16. The sediment
comprise those samples was deposited approximately 120 years before present, as
determine by ^'Vb dating. The dashed line represents the inferred boundary
between Estuarine Biofacies A and Estuarine Biofacies B.
59
Species Diversity
The diversity of total assemblages was analyzed using S (number of species per
sample) and N (number of specimens observed) to calculate alpha (a). Alpha values can
be obtained by using equation 3 (see Methods) or can be found in Appendix 4 of Hayek
and Buzas (1997).
Table 8 lists the results of the diversity analysis and the plot of the a values can
be found on Figure 19. Values for a within the Pamlico Sound estuarine system range
from 0.455 in the sound (S59) to 4.149 at the inlets (EB02S3). The Marine Biofacies
proves to be the most diverse with an average a value of 3.767, followed by the Marsh
Biofacies with an average a value of 1.932 (Table 8). Estuarine Biofaces A and
Estuarine Biofacies B have very similar low diversity a values of 0.999 and 0.909,
respectively (Table 8).
60
Site Biofacies S N a
S1 Marsh Biofacies 287 10 2.008
S2 9 268 1.792
S5 5 349 0.826
S17A 16 299 3.61
S38 10 194 2.248
S45 7 220 1.378
S46 6 59 1.66
Mean 49 200 1.932
S4 Estuarine Biofacies A 5 307 0.847
S9 4 249 0.676
S11 11 286 2.263
S12 2 251 0.297
S22 5 297 0.852
S23 6 183 0.953
S27 6 232 1.127
S39 6 216 0.694
S40 4 329 0.688
S44 8 102 2.046
S50 3 317 0.458
S63 6 271 1.087
Mean 6 253 0.999
S24 Estuarine Biofacies B 3 263 0.476
S30 11 144 2.797
S31 3 282 0.469
S32 8 307 1.51
S41 4 338 0.483
S42 5 306 0.852
S59 3 332 0.455
S60 3 303 0.463
S61 4 250 0.676
Mean 5 281 0.909
S17 Marine Biofacies 16 272 3.723
EB02S1 12 111 3.43
EB02S3 15 147 4.149
Mean 14 177 3.767
Table 8: Species diversity of foraminifera within the Pamlico Sound estuarine system (S
= No. of species, N = No. of specimens observed, and a = Fishers alpha index). Eight
sites (S7, SIO, S14, S15, S25, S26, S35, and EB02S2) contained less than 50 specimens
were excluded from the analysis. The plotted a values can be found on Figure 19.
61
Figure 19: Species diversity distribution plot within biofacies determined
using cluster analysis for the surface (0-lcm).
62
Geochemistry
Geochronology
Cesium-137 and data were obtained from a geochemical study (Tully,
2004), which used the same cores within Pamlico Sound. The intervals representing peak
activity for '^^Cs (40yrs BP) and absence of ^^°Pb activity (120yrs BP) are represented by
lines found on Figures 20-36.
Stable Isotopes
Each interval in all 17 cores were analyzed at the Stable Isotope Lab Facility at
UC Davis. All samples were analyzed at least once via the acid fumigation method
described by Harris et al. (2001; see Methods). The results of the first set of samples that
were sent to the lab had very high fluctuations in ô'^N values in comparison to the rest of
the samples. Acid fumigation always increased the ô'^N signatures (approximately 0.04
to 0.11 %o) of soils used by Harris et al. (2001), but did not have an affect on the ô'^C
signature. However, Bratton et al. (2003), found no statistical difference between
acidified and non-acidified subsurface samples collected from Chesapeake Bay. Reports
from the lab also stated machine malfunction and as a result, some of the readings were a
combined value of several samples. Regardless, several values from the first set of
samples were questionable. Rather than disregard the questionable samples, several
samples were chosen at random for re-analysis. There were two reasons for re-analysis:
(1) to test whether or not acid fumigation had a significant affect on the isotopic
signatures of ’^N, and (2) if the reported error was a direct result of machine malfunction.
63
PAM02 S9
A) S'®N B) C:N
8 10 12 14 16 18
% OC
D)
Figure 20: Geochemistry data for PAM02S9. A) ô'^N (%o) signatures vs depth
(cm). B) C:N ratio vs depth (cm). C) (%o) signatures vs depth (cm). D)
Percent organic carbon vs depth (cm). The 40yrs BP line represents the '^^Cs
peak and the 120yrs BP line represents the interval at which ^’°Pb is considered
to be inactive as determined by radionuclide data (Tully, 2004).
64
PAM02S10
Figure 21 : Geochemistry data for PAM02S10. A) ô’^N (%o) signatures vs depth
(cm). B) C:N ratio vs depth (cm). C) (%o) signatures vs depth (cm). D)
Percent organic carbon vs depth (cm). The 40yrs BP line represents the peak
and the 120yrs BP line represents the interval at which ^'‘^Pb is considered to be
inactive as determined by radionuclide data (Tully, 2004).
65
PAM02 S11
Figure 22: Geochemistry data for PAM02S11. A) (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) (%o) signatures vs depth
(cm). D) Percent organic carbon vs depth (cm). The 40yrs BP line represents
the *^’Cs peak and the 120yrs BP line represents the interval at which ^*°Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
66
PAM02 SI 2
A) 8'®N B) C:N
1 2 3 4 5 6 7 8 10 12 14 16 18
40 - 40 -
50 - 50 -
-26 -24 -22 -20 -18
Figure 23: Geochemistry data for PAM02S12. A) ô'^N (%c) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) ô'^C (%c) signatures vs depth
(cm). D) Percent organic carbon vs depth (cm). The 40yrs BP line represents
the Cs peak and the 120yrs BP line represents the interval at which Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
67
Figure 24: Geochemistry data for PAM02S22. A) ô’^N (%c) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) ô’^C (%c) signatures vs depth
(cm). D) Percent organic carbon vs depth (cm). The 40yrs BP line represents
the ’^^Cs peak and the 120yrs BP line represents the interval at which ^*^Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
68
PAM02 S23
A) ô'=N B) C:N
1 2 3 4 5 6 7
% OC
D)
S- 30- Q
40 40 --
50 50 --
Figure 25: Geochemistry data for PAM02S23. A) ô'^N (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) ô'^C (%o) signatures vs depth (cm).
D) Percent organic carbon vs depth (cm). The 40yrs BP line represents the
’^^Cs peak and the 120yrs BP line represents the interval at which ^*°Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
69
PAM02 S24
A) ô15n C:NB)
1 2 3 4 5 6 7
C) D)
-26 -24 -22 -20 -18 0 1 2 3 4 5
Figure 26: Geochemistry data for PAM02S24. A) (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) (%o) signatures vs depth (cm).
D) Percent organic carbon vs depth (cm). The 40yrs BP line represents the
Cs peak and the 120yrs BP line represents the interval at which Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
70
PAM02 S27
S'®N
A) B) C:N
5'^C % oc
O)
Figure 27: Geochemistry data for PAM02S27. A) ô'^N (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) Ô'^C (%o) signatures vs depth
(cm). D) Percent organic carbon vs depth (cm). The 120yrs BP line represents
the interval at which ^’°Pb is considered to be inactive as determined by
radionuclide data. A '^’Cs peak was not present at this location (Tully, 2004).
71
PAM02 S30
C:N
B)
1 2 3 4 5 6 7
Figure 28: Geochemistry data for PAM02S30. A) (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) (%o) signatures vs depth (cm).
D) Percent organic carbon vs depth (cm). The 40yrs BP line represents the
’^^Cs peak and the 120yrs BP line represents the interval at which ^'°Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
72
PAM02 S31
A) S'®N B) C:N
Figure 29: Geochemistry data for PAM02S31. A) (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) ô'^C (%o) signatures vs depth (cm).
D) Percent organic carbon vs depth (cm). The 40yrs BP line represents the
’^^Cs peak and the 120yrs BP line represents the interval at which ^'°Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
73
PAM02 S32
5'®N
A) B) C:N
1 2 3 4 5 6 7 8 10 12 14 16 18
C) D)
-26 -24 -22 -20 -18 0 1 2 3 4 5
Figure 30: Geochemistry data for PAM02S32. A) (%c) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) ô’^C (%c) signatures vs depth
(cm). D) Percent organic carbon vs depth (cm). The 40yrs BP line represents
the '^^Cs peak as determined by radionuclide data. ^*°Pb was still active at the
base of the core (Tully, 2004).
74
PAM02 S41
A) C:NB)
1 2 3 4 5 6 7
E
Ü
o
Q
% oc
C) D)
-26 -24 -22 -20 -18
10 -
40yrs BP
_ 20 -
E 120yrs BP
I 30
Q
40
50
Figure 31: Geochemistry data for PAM02S41. A) (%o) signatures vs depth
(cm). B) C:N ratio vs depth (cm). C) ô‘^C (%o) signatures vs depth (cm). D)
Percent organic carbon vs depth (cm). The 40yrs BP line represents the '^^Cs peak
and the 120yrs BP line represents the interval at which ^'^Pb is considered to be
inactive as determined by radionuclide data (Tully, 2004).
75
PAM02 S42
A) C:NB)
1 2 3 4 5 6 7 8 10 12 14 16 18
C) D)
-26 -24 -22 -20 -18 0 1 2 3 4 5
Figure 32: Geochemistry data for PAM02S42. A) (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) (%o) signatures vs depth
(cm). D) Percent organic carbon vs depth (cm). The 40yrs BP line represents
the '^^Cs peak and the 120yrs BP line represents the interval at which ^'‘^Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
76
PAM03 S50
S15N
A)
1 2 3 4 5 6 7 8 10 12 14 16 18
Figure 33: Geochemistry data for PAM03S50. A) ô'^N (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) ô'^C (%o) signatures vs depth
(cm). D) Percent organic carbon vs depth (cm). The 40yrs BP line represents
the Cs peak and the 120yrs BP line represents the interval at which Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
77
PAM03 S59
815N
A) C:NB)
1 2 3 4 5 6 7
%OC
C) D)
-26 -24 -22 -20 -18
Figure 34: Geochemistry data for PAM03S59. A) ô'^N (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) ô'^C (%o) signatures vs depth
(cm). D) Percent organic carbon vs depth (cm). The 40yrs BP line represents
the ’^^Cs peak and the 120yrs BP line represents the interval at which ^'^Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
79
PAM03 S61
A) Ô15N C:NB)
1 2 3 4 5 6 7
%OC
D)
-26 -24 -22 -20 -18
40 -
Figure 36: Geochemistry data for PAM03S61. A) ô’^N (%o) signatures vs
depth (cm). B) C:N ratio vs depth (cm). C) (%o) signatures vs depth (cm).
D) Percent organic carbon vs depth (cm). The 40yrs BP line represents the
’^^Cs peak and the 120yrs BP line represents the interval at which ^'°Pb is
considered to be inactive as determined by radionuclide data (Tully, 2004).
78
PAM03 S60
A) 515N B) C:N
8 10 12 14 16 18
40 - 40
50 - 50 '
Figure 35: Geochemistry data for PAM03S60. A) ô'^N (%o) signatures vs depth
(cm). B) C:N ratio vs depth (cm). C) ô'^C (%o) signatures vs depth (cm). D)
Percent organic carbon vs depth (cm). The 40yrs BP line represents the Cs
210
peak and the 120yrs BP line represents the interval at which Pb is considered
to be inactive as determined by radionuclide data (Tully, 2004).
80
To do this, several samples were chosen at random from all sample sets and sent to the
lab, untreated and treated (non-fumigated and acid fumigated). Some samples were re-
analyzed three times. At least four samples were sent as a control (i.e., no reported
problems from the lab and no discrepancies were observed in the values of the samples).
The new values did not show any significant difference in ô’^N signatures between
fumigated and non-fumigated samples (range of difference: 0.08-0.56) for the control
samples. After review of the data, it was found that only those samples from the first set
displayed some discrepancy. It was concluded that the observed high ô'^N signatures
were a result of machine malfunction. The new results for those samples that displayed
questionable values were either averaged with the original data (only if there were no
reported problems with that particular sample) or they completely replaced the original
values. Data used, including the corrected values, are given in Appendix H.
In general, all of the cores display a slight depletion in values up-core. This
suggests a slight change in the estuarine environment over time. Surface signatures vary
between -23.51, in the center of the Sound (S31), and -24.86, at the mouth of the
Pamlico River (S50), with the exception of S27, which has a value of-19.10 (Figure 37).
A similar spatial pattern is recognized down-core (Figures 20-36).
SIO displays the greatest depletion observed up-core for the Sound (Figure 21).
At the base of the core (28-30cm), the signature is -20.01, while at the surface (0-
2cm), the ô'^C signature is -24.40. A peak in depletion is observed at interval 8-10cm
81
>#54.09
tA -2?40 -23.83
i
15 30 ,-24.30
.y"'
Kilometers •-24.21
.66
? -24.27
fc-23.51
|F>» _ ^
24.86 -23.684 •-23.90 -19.10<
0-23.72
-23.86'
,-24.01
? -23.69
Figure 37: Surface (0-2cm) ô*^C signatures for Pamlico Sound.
with a signature of -26.64. The overall up-core shift in isotopic signature may be an
indication of a change in source of organic matter.
The most enriched values are found at S27 (Figure 27). The signature at the
base of the core (18-20cm) is -19.04. The interval representing approximately 120 years
BP (12-14cm), as determined by radionuclide data, has a peak enrichment value of -
18.39. From this interval upwards, the signatures steadily depleted to -19.10 at the
surface (0-2cm). S27 has an isotopic signature that is different from the rest of the
Sound, which indicates the source of organic matter for this area is different than the rest
of the Sound.
The general trend of values increase (enrich) up-core throughout Pamlico
Sound (Figures 20-36). Some cores show steeper gradients than others, as well as greater
82
variations in signatures. S22, S23, S30, and S41 (Figures 24, 25, 28, and 31) show a
steeper gradient increase in the last 40 years BP opposed to the gradual trend seen at
these sites down-core. The top 12cm of S24 fluctuates in signatures between 4.20 (8-
10cm) and 6.96 (0-2cm) (Figure 26). Overall, the most enriched values for the surface
(0-2cm) recorded across Pamlico Sound are found in the center of the Sound (S24, S30,
and S31), while the less enriched values are located along the perimeter of the Sound (S9
and S27) (Figure 38). This pattern varies throughout the Sound down-core; however,
S12, S22, S23, S24, S30, S31, S32, S42, S50, S59, S60, and S61 all appear to enrich at
the same rate up-core (Figure 23, 24, 25, 26, 28, 29, 30, 32, 33, 34, 35, and 36).
The least amount of variation (small isotopic range) in nitrogen signatures down-
core is observed at S32, located near the center of the Sound (Figure 30) and at sites
located in the southern section where the rivers (Pamlico and Tar) drain into the Sound
(S50, S59, S60, and S61) (Figures 33, 34, 35, and 36). At S31 (Figure 29), there is a shift
towards more enriched nitrogen values mid-core for approximately 12cm beginning with
interval 22-24cm up to interval 12-14cm. Above this interval (12-14cm), nitrogen
signatures follow the general increasing upward trend with the rest of core. This shift
coincides with the activity peak of '^^Cs as determined by radionuclide data. This
suggests that there has been an increase in nitrogen-rich sediment deposited in this region
beginning approximately 40 years BP.
S27 reports the lowest average ô’^N value (2.77 for entire core) (Figure 27). The
signature for this particular site varies between 1.98, at the base (18-20cm), and 4.42 just
above the base (16-18). The recorded signature at the surface (0-2cm) is 2.62.
83
Figure 38: Surface (0-2cm) signatures for Pamlico Sound.
C:N Ratios
The greatest surface (0-2cm) C:N values are found in the northern section of
Pamlico Sound (Figure 39). This general pattern of greater C:N values to the north can
be found down-core as well (Figures 20-36). An overall gradual decrease in C:N ratios
up-core is observed at all sites throughout Pamlico Sound, except one (Sll). Sll is the
only core where C:N values increase up-core (Figure 22). At the base of the core (24-
26cm), the C:N value is 12.27, while at the surface (0-2cm), the C:N value is 15.93.
Between the intervals representing 120 and 40 years BP, the C:N values vary between
12.95 (4-6cm) and 15.93 (0-2cm).
84
Figure 39: Surface (0-2cm) C:N ratios for Pamlico Sound.
T = terrestrial and M = marine.
Some localized variation in up-core trends is observed at S9, SIO, S23, S30, and
S59 (Figures 20, 21, 25, 28, and 34). Some rates of changes are greater than others, such
as S30 (Figure 27). S30 displays the greatest amount of change in C:N values. The C:N
value for the base (20-22cm) is 15.97 and the surface (0-2cm) is 9.98. At the base (34-
36cm) of S9, the C:N ratio is 14.80, and at the surface (0-2cm) the ratio is 13.19. Mid-
core, between the intervals representing 120 and 40 years BP, there is an abrupt shift
towards increasing C:N values, peaking at 16.67 (16-18cm). The top 8cm of the core
average out to a ratio of approximately 13.
85
S10 and S23 display a similar pattern mid-core as S30 (Figures 21 and 25).
Within each core, there is a change up-core in the generally gentle and steady trend in
decreasing ratio to a more abrupt and steeper gradient in decreasing ratios. For S10, at
the base (28-30cm), the ratio is 14.71, which steadily decreases to 13.53 mid-core (12-
14cm), then rapidly decreases to a ratio of 10.55 at the surface (0-2cm). The base of S23
(24-26cm) has a ratio of 13.38, which steadily decreases to 14.3 mid-core (10-12cm),
then rapidly decreases to a ratio of 10.77 at the surface (0-2cm).
The pattern observed in the core at S59 is different from the general trends present
in other cores (Figure 34). The C:N ratios increase from 9.92 at the base (30-33cm) to
11.04 mid-core (12-14cm), then the values begin to decrease for remaining intervals up-
core to tbe surface (0-2cm) with a value of 9.72. S59 is located in the southern section of
Pamlico Sound where the two rivers (Pamlico and Neuse) enter into the Sound. The
observed shift from increasing C:N values to decreasing C:N values may be a result of
the location for S59.
Percent Organic Carbon
The amount of organic carbon within Pamlico Sound is very low, averaging
between less than one to approximately five percent. Greater percents of organic carbon
(approximately 3% or greater) are found in areas containing fine sediment (silt and clay)
and vary spatially throughout the study area (Figure 40).
Few sites display a slight increase in organic carbon up-core (SIO, Sll, S32, S60,
and S61) (Figures 21, 22, 30, 35, and 36). These sites are either located next to a marsh
86
(S 10 and SI 1) or along the perimeter of the central basins which define the deepest
sections of the Sound (S32, S60, and S61) (see Figure 2 for bathymetry).
The greatest change down-core in percent organic carbon is observed at S23
(Figure 25). Percent organic carbon fluctuates between 4.5 (near the base) and 0.53 (near
the surface). An overall decrease in organic carbon is observed up-core. Sediment
within the core is described as a sandy mud from the base (24-26cm) to mid-core (8-
10cm), while the top 8cm is described as fine to coarse sands with shell fragments.
For the most part, the average percent of organic carbon present down-core in S30
is less than two percent (Figure 28). However, there is a spike of organic carbon (4.28%)
at the 8-lOcm interval. This interval is found just above the interval representing
approximately 40yrs BP.
87
One-way Analysis of Variance {ANOVA)for Geochemical Results
A one-way ANOVA was used to test statistically the hypothesis that the
geochemical results (ô'^C, ô'^N, and C:N ratios) at the three specified time slices (-120
yrs BP, -40 yrs BP, and the modem) are significantly different. The analysis was run
using SPSS. For each test, the null hypothesis was that there is no significant difference
in values overtime (between -120 yrs BP, -40 yrs BP, and modem). The results are
listed in Tables 9, 10, and 11. Any p(F) < 0.05 was considered significant (95%
confidence). Therefore, the null hypothesis was accepted the ANOVA that compared
signatures; there is no significant change in signatures over time. However
with p(F) values equal to 0.000 and 0.030 for and C:N ratios, respectively, the null
hypothesis was rejected. There is a significant change in signatures and ratio values
overtime. Figures 41, 42, and 43 display the mean proportions of the stable isotope
signatures and C:N ratios for the three time slices.
Contrasts were set-up between the time slices to determine when the greatest
change had occurred. The results are listed in Table 12. As determined before, there is
no significant change in ô'^C signatures. However, ô’^N signatures are observed to have
a statistically significant difference for each contrast except for the comparison of the -40
yrs BP time slice with the modem and -120 yrs BP time slices. This suggests that there
is an increase (enrichment) of ô'^N signatures over time. Three contrasts show a
significant change for C:N ratios, 1) between -120 yrs BP and the modem time slices, 2)
the modem time slice compared with both the -120 and -40 yrs BP time slices, and 3)
88
-120 yrs BP compared to both the modem and -40 yrs BP time slices. This suggests that
C:N ratios decrease down-core.
Table 9: ANOVA test results for ô'^C signatures. The value of the Sum of Squares
between groups is the sum of the difference between averages (means) of the three time
slices (120 yrs, 40 yrs, and modem). Since there are three groups, the degrees of freedom
(df) is equal to 2 (3 groups-l=2). The Mean Square value is the Sum of Squares divided
by the df. The F value is the ratio for the between group variance and the within group
variance. The df for the Within Groups is found by number of samples/sites (49) minus
the number of groups/time slices (3) which is equal to 46.
Sum of
Squares df Mean Square F Sig.
Between Groups 3.321 2 1.660 1.268 .291
Within Groups 60.208 46 1.309
Total 63.529 48
Table 10; ANOVA test results for signatures. The value of the Sum of Squares
between groups is the sum of the difference between averages (means) of the three time
slices (120 yrs, 40 yrs, and modem). Since there are three groups, the degrees of freedom
(df) is equal to 2 (3 groups-l=2). The Mean Square value is the Sum of Squares divided
by the df. The F value is the ratio for the between group variance and the within group
variance. The df for the Within Groups is found by number of samples/sites (49) minus
the number of groups/time slices (3) which is equal to 46.
Sum of
Squares df Mean Square F Siq.
Between Groups 12.035 2 6.018 11.079 .000
Within Groups 24.985 46 .543
Total 37.020 48
89
Table 11: ANOVA test results for C:N ratios. The value of the Sum of Squares between
groups is the sum of the difference between averages (means) of the three time slices
(120 yrs, 40 yrs, and modem). Since there are three groups, the degrees of freedom (df)
is equal to 2 (3 groups-l=2). The Mean Square value is the Sum of Squares divided by
the df. The F value is the ratio for the between group variance and the within group
variance. The df for the Within Groups is found by number of samples/sites (49) minus
the number of groups/time slices (3) which is equal to 46.
Sum of
Squares df Mean Square F Siq.
Between Groups 25.686 2 12.843 3.770 .030
Within Groups 156.697 46 3.406
Total 182.383 48
Figure 41: One-way ANOVA plot of means for time slices (as
determined by radionuclides) vs ô’^C signatures.
90
Figure 42: One-way ANOVA plot of means for time slices (as
determined by radionuclides) vs signatures.
Figure 43: One-way ANOVA plot of means for time slices (as
determined by radionuclides) vs C:N ratios.
91
Table 12: Contrasts for geochemistry compared to the three time slices, where p(F) <
0.05 is significant. 120 and 40 are in years BP.
P(F) P(F) P(F) P(F) P(F) P(F)
Geochemical 120 vs 120 vs 40 vs modern vs 40 vs 120 vs modern,
analysis 40 modern modern 120, 40 modern, 120 40
0.119 0.369 0.484 0.907 0.192 0.157
0.016 0.000 0.035 0.000 0.836 0.000
C;N 0.267 0.009 0.119 0.016 0.800 0.032
DISCUSSION
Combination of surficial foraminiferal and geochemical data gives an indication
of environmental conditions that currently affect Pamlico Sound. Comparison between
the modem surficial conditions with down-core data gives an indication of the
paleoenvironmental conditions over the last approximately 120 years. To observe and
compare the changing environments of Pamlico Sound, this discussion is divided into
four parts; (1) description of the modem environment, (2) description of the
paleoenvironment 120 years BP, (3) description of the paleoenvironment 40 years BP,
and (4) explanations.
Description of the Modern Environment
Analysis of surficial foraminiferal data allowed the distinction of four biofacies;
(1) Marine, (2) Estuarine Biofacies B, (3) Estuarine Biofacies A, and (4) Marsh Biofacies
Biofacies. Canonical discriminant analysis (Figure 15) and species diversity (Table 8,
Figure 19) were used to verify that these groups are different from one another. The
distribution of the biofacies within Pamlico Sound appears to be related to the
distribution of sediments, salinity, and to some extent, depth (Ellison and Nichols, 1970).
Table 13 is a summary of the modem biofacies existing within Pamlico Sound.
The Marine Biofacies, located at Hatteras and Ocracoke inlets, (Figure 14) was
completely dominated by calcareous foraminifera such as Cibicides lobatulus, Elphidium
galvestonense, Elphidium mexicanum, Elphidium subarcticum, Hanzawaia strattoni, and
93
Table 13: Summary of modem biofacies described for Pamlico Sound, the key
species, sites, and salinity readings. Salinity readings were recorded at time of
collection. The salinity value for S4 is questionable due to faulty equipment.
Biofacies: Key Species: Sites: Salinity:
Marsh Biofacies T. comprimata S1 24
T. inflata S2 24
M. fusca S5 22
H. wilberti S10 24
S14 27
S17A 26
S38 21
S45 33
S46 33
Estuarine Biofacies A A. salsum S4 7.4 (?)
A. crassus S7 24
E. excavatum S9 25
S11 22
S12 22
S15 29
S22 25
S23 25
S26 27
S27 27
S35 25
S39 21
S40 21
S44 27
S50 7
S63 20
Estuarine Biofacies B E. excavatum S24 25
A. salsum S25 25
S30 27
S31 26
S32 30
S41 22
S42 24
S59 15
S60 14
S61 15
Marine Biofacies E. excavatum S17 35
H. Strattan i EB02S1 32
C. lobatulus EB02S2 34
E. subarcticum EB02S3 36
0. seminula
E. galvestonense
94
Quinqueloculina seminula. Q. seminula species is typical of inlet environments
(Grossman and Benson, 1967; Robinson and McBride, 2003). The salinity recorded at
these sites was typically greater than 30 (Table 13). Sediment type recorded at the inlets
is medium-grained sand (Figure 3), which is indicative of relatively high-energy
environments.
The central and southern section of Pamlico Sound is the location of Estuarine
Biofacies B (Figure 14), which also defines the deepest sections of the Sound (Figure 2).
The average salinity for this biofacies is greater than 25, with the exception of the stations
located to the south. Salinities in the southern section of the sound are influenced by
freshwater discharge from the Neuse and Pamlico Rivers (Figure 5). Thus, overall
salinity range is between 7 and 25. Calcareous foraminifera are found in great abundance
within this biofacies as well as a significant amount of coarsely agglutinated
foraminifera. Typical foraminifera present within this biofacies are Elphidium
excavatum, Ammonia parkinsoniana, and Ammotium salsum. The surface sediment for
the majority of these sites is silt (Figure 3). Environmental conditions described by this
biofacies agree with the description of the Basin Biofacies located in the Rappahonnock
Estuary (Ellison and Nichols, 1970).
Estuarine Biofacies A, generally located along the platforms of the basins (Figure
2), surrounds Estuarine Biofacies B (Figure 14). The average salinity for Estuarine
Biofacies A is between 20 to 25 (Table 13) and the substrate is generally fine to very fine
sand (Figure 3). Typical foraminifera belonging to this biofacies are coarsely
agglutinated, such as Ammotium salsum and Ammobaculies crassus, as well as some
95
calcareous foraminifera, such as Elphidium excavatum. The environmental conditions for
this biofacies are equivalent to the description of the Shoal Biofacies located in the
Rappahonnock Estuary (Ellison and Nichols, 1970).
The Marsh Biofacies is located along the perimeter of the Sound (Figure 14) and
is typically found at marsh locations. The Marsh Biofacies is comprised primarily of
finely agglutinated foraminfera, such as Trochammina inflata, Tiphotrocha comprimata,
Miliammina fusca, and Haplophragmoides wilberti. Average salinity recorded at time of
collection for this biofacies was high, ranging between 21 to 33 (Table 13). Wide ranges
in salinity are typical for salt marshes (Goldstein et al., 1995; Collins, 1996; Culver et al.,
1996; Woo et al., 1997; Saffert and Thomas, 1998; Goldstein and Watkins, 1999; Scott et
al., 2001). The faunal composition of the Pamlico Sound Marsh Biofacies is comparable
to other marsh biofacies described along the east coast of the United States (Ellison and
Nichols, 1970; Goldstein et al., 1995; Collins, 1996; Culver et al., 1996; Woo et al., 1997,
Saffert and Thomas, 1998; Goldstein and Watkins, 1999; Robinson and McBride, 2003).
Surface ô'^C signatures are slightly less enriched with increasing distance from
the inlets (Figure 37). This reflects a greater marine influence closer to the inlets. S27,
located behind Cape Hatteras, has a signature of -19.10, which is very different from any
other recorded value within the sound. The S27 value can most likely be attributed to a
mixture between marine phytoplankton and C4 plant organic matter (e.g. marsh) (Waller
and Lewis, 1979; Letrick, 2003).
The most enriched surface ô'^N values are found at sites located in the center of
Pamlico Sound (Figure 38). These sites are located in the deepest section of the Sound
96
(Figure 2) where the sediment is typically silt and clay (Figure 3). This suggests that
greater activity (e.g., trawling) here (in comparison to the rest of the Sound) has caused
an increase in biogeochemical processes to enrich the sediment.
The greatest reported C:N ratios are found in the northern section of Pamlico
Sound (Figure 39). SI 1 has a C:N value of 15.93, the highest surface value recorded
throughout the Sound (Figure 39). SI 1 is located next to a marsh. A comparison of the
high ratio value, strongly depleted signature (-24.09) (Figure 37), and locality,
suggest that the erosion of a nearby marsh heavily influences this site.
Description of the Paleoenvironment 120 years Before Present
The foraminiferal assemblage representing approximately 120 years BP (as
determined by radionuclide data) (Figure 18) is very different from the modem day
surface assemblage (Figure 14). The high abundance of Ammotium salsum throughout
the study area characterizes the majority of the sound as Estuarine Biofacies A. Estuarine
Biofacies A is associated with more brackish conditions in comparison to the other three
biofacies (Table 13). There are just two sites (S12 and S30) classified with Estuarine
Biofacies B, and one site (SI 1) classified with the Marsh Biofacies (Figure 18).
signatures ranged between -24.69 and -22.37 throughout Pamlico Sound
approximately 120 years BP (Figure 44). The range signifies a predominantly terrestrial
97
Figure 44: signatures approximately 120 yrs BP (as determined by
radionuclide data).
source (C3 plants) for organic matter (Waller and Lewis, 1979). The distribution pattern
(Figure 44) is comparable to the observed pattern at the surface (Figure 37) with typically
more depleted values found in the northern section of the Sound. Similarities of the
modem and 120 year old distribution patterns may be indicative of the same source area
for organic matter and similar circulation/depositional patterns.
During this time interval, ô'^N values were scattered with no discernable pattern,
ranging between 3.25 and 5.18 (Figure 45). However, the distribution pattern of C:N
values at this time (approximately 120 years BP) (Figure 46) is comparable with the
surface distribution (Figure 39). Ratios range between 10.22 and 15.67. Terrestrially
influenced ratios (>12) are concentrated in the northern section of the Sound and
gradually decrease to the south, indicative of terrestrially influenced organic matter
98
mixing with marine influenced organic matter. The similarity between distribution
patterns (120 years BP compared to the surface/modem day) is indicative of a continued
terrestrial influence in the northern section of Pamlico Sound.
Figure 45: signatures approximately 120 yrs BP (as determined by
radionuclide data).
Figure 46: C:N ratios approximately 120 yrs BP (as determined by
radionuclide data). T = terrestrial and M = marine.
99
Description of the Paleoenvironment 40 years Before Present to Present Day
Peak activity in Cs data dates sediment to be approximately 40 years old (early
1960s). Many of the cores do not display a distinct peak in activity. These cores have
several intervals that have similar elevated activities. It is possible that these intervals
represent an extended period of time of intense mixing, resuspension, or maybe
accumulation (Tully, 2004). Regardless, distinct changes (foraminiferal and
geochemical) are recognized in all cores representing this time frame.
The foraminiferal assemblage represented at this time interval is comparable to
the modem day surficial assemblage. The exceptions are two sites, S9 and S30; which
are classified with the Marsh Biofacies (Figure 17). S9 and S30 are not located at a
marsh. Therefore it is quite likely that marsh foraminifera present at these locations were
washed into the Sound from another location. The smaller area classified as Estuarine
Biofacies B (Figure 17) may suggest that the Sound was not as saline as it is today.
A significant change is not observed in the distribution pattern or range of
signatures between the 120 years BP time interval and the 40 years BP time interval
(Figure 47). Some of the signatures recorded in the north are slightly more depleted than
signatures deeper down-core. However, signatures are enriched at nearly all of the
sites (except two) and a slight distribution pattern has developed (Figure 48). Many of
the cores display an increasing trend in signatures mid-core either at or close to the
interval representing the peak '^^Cs activity. The result of the ANOVA contrast
demonstrated that there is a significant change in signatures over time (Table 12).
This suggests a change in biogeochemical processes to increase nitrification and
100
Figure 47: Ô'^C signatures ratios approximately 40 yrs BP (as determined by
radionuclide data).
Figure 48: ô'^N signatures ratios approximately 40 yrs BP (as determined by
radionuclide data).
101
denitrification and to deposit sediment enriched in '^N. This trend of increasing enriched
ô'^N values continues to the surface for many cores, which suggests denitrification has
continually increased within Pamlico Sound over the last 40 years. This trend increases
to the surface in many cores (S23, S24, S27, S30, and S41), which may indicate that
these sections of the Sound are not stable and continue to be susceptible to changing
environmental conditions.
The majority of the C;N values are lower at the interval representing 40 years BP
(Figure 49) compared to values at the interval representing approximately 120 years BP
(Figure 46). However, the distribution pattern is similar for both time intervals; greater
ratio values are located in the northern section.
Figure 49: C:N ratios approximately 40 yrs BP (as determined by radionuclide
data). T = terristrial and M = marine.
102
Explanations
Figure 50 presents a comparison of the three time slices (as determined by
radionuclides) analyzed for surface and down-core foraminiferal assemblages. Based on
salinity characteristics of Estuarine Biofacies A and B, there has been increase in salinity
in Pamlico Sound over the last 120 years. Recorded storm events and C:N provide an
explanation for this change.
Figure 50: Comparison of foraminiferal assemblage changes over
time. Bottom box represents approximately 120 years BP, the middle
box represents approximately 40 years BP, and the top box represents
present day. Arrows indicate direction of increasing salinity based on
foraminifera present. Arrow is dashed at S12 because the discriminant
analysis plots this sample very close to the territory boundary between
Estuarine Biofacies A and B (see Figure 16 and Results section).
103
During the late 1870s to 1900, 12 hurricanes reached the shores of eastern North Carolina
(Table 14). During some years there were more than one reported hurricane within a
two-month interval. Increased amounts of freshwater have been reported to enter
Pamlico Sound via the Pamlico and Neuse Rivers for an extended period of time after a
wetter than average spring (Pietrafesa et al., 1986). Applying this concept to intense
rainfall associated with hurricanes, it is possible that the brackish conditions indicated by
the foraminiferal assemblage that accumulated approximately 120 years ago was caused
by one or more of the several hurricanes.
Visual comparison of C:N ratios suggest a decrease in values up-core at all sites
except one (S11). Results obtained from a one-way ANOVA test do suggest there are
significant differences between C:N ratios over time (Tables 10 and 11). However, the
general distribution pattern, with greater ratio values found in the northern section of the
Sound, has not changed (Figure 39). The core intervals representing approximately 120
years BP display C:N ratios indicative of mixing between terrestrial and marine
influenced organic matter (Figure 46). A comparison of the three time slices indicates
that, a marine-influenced area (as determined by C:N ratios) has steadily increased in size
and extended into the northern section of Pamlico Sound (Figure 51). Even though there
has a been an increasing marine influence within the Sound over time, current ratios in
the north are representative of mixed terrestrial and marine organic matter sources.
Southerly currents from the Albemarle Sound flow through Roanoke and Croatan Sounds
into Pamlico Sound (Singer and Knowles, 1975; Pietrafesa et al., 1986; Riggs et al.,
2000). These currents flow across eroding peats rich in organic matter (Riggs et al..
104
Table 14: Dates of hurricanes to reach coastal North
Carolina between the years 1876 and 1899 (Barnes, 2001).
Year Date(s) of Hurricane
1876 September 17
1879 September 18
1881 September 9
1882 September 11
September 22
October 22
1883 September 11
1885 August 25
1893 August 27-29
October 13
1899 August 16-18
October 30-31
Figure 51: Comparison of C:N ratios changes over time. Bottom circle
represents approximately 120 years BP, the middle circle represents
approximately 40 years BP, and the top circle represents present day.
Arrows indicate direction of increasing marine influence based on
decreasing C:N ratios.
105
2000). Letrick (2003) reported high C:N values (range between 12.21 and 40), strongly
depleted ô'^C signatures indicative of terrestrial input, and percent organic matter values
ranging between 1.6 and 6.7 from Croatan Sound. It is possible to attribute the terrestrial
signature recorded by the C:N ratios in the northern section of Pamlico Sound to these
eroding peats and other terrestrial inputs from Croatan Sound.
Water draining through the Roanoke and Croatan Sounds into the northern section
of Pamlico Sound is brackish. The foraminiferal assemblage in the northern section of
Pamlico Sound (Estuarine Biofacies A) is indicative of brackish environments. This
observation supports the interpretation of a terrestrial influence on the northern section of
the Sound.
The amount of organic carbon present in cores has increased between the intervals
representing 120 years BP and 40 years BP at some sites. The rate of increase has been
steady for most sites (S31, S32, S41, S42, S50, S59, and S60), while other sites have had
a dramatic increase (SIO and SI 1). These variations are indicative of changing
depositional patterns and possible episodic erosion events. A number of variables are
responsible for shoreline erosion, such as physical setting and boat traffic (Riggs and
Ames, 2003). SIO and SI 1 are located near a marsh. The increased percentages of
organic carbon found in the cores may be explained by erosion of the nearby marsh. S23
shows the greatest fluctuation in percent organic carbon between the intervals
representing approximately 120 years and 40 years BP. There is also a change in
lithology from sandy mud (silt and clay particles) to coarse sands with shell fragments.
This evidence indicates that there has been a change in the distribution of sediments
106
within the Sound with coarse sediments indicative of higher energy environments.
Increased percent organic carbon is observed in the top centimeters at S32, S60, and S61
as well. These sites are located along the platforms defining the central basins. The
sediment found in the upper centimeters is fine, silty material with some shell fragments.
The increased amount of organic carbon and fine sediment in the upper few centimeters
and the location of these sites suggests that S32, S60, and S61 may act as regions of
deposition for eroded material from the mainland.
Marsh foraminifera present at depth at sites S9 and S30 may be indicative of
another storm event about 40 years ago. The Ash Wednesday Storm was a class 5 (as
determined by the Dolan/Davis Northeaster Intensity scale, 1-5) nor’easier that impacted
coastal North Carolina for two days in March 1962. Ranked as extreme, class 5 storms
often cause up to 50m of beach erosion, extensive and widespread destruction of dunes,
massive overwash, and inlet formation (Pilkey et al., 1998). The Ash Wednesday Storm
is considered the most destructive nor’easter of the twentieth century. Strong winds and
waves caused flooding and overwashing for large portions of the beach. Some areas
flooded between 2 to 4 feet. Several breaches were cut into the barrier islands, including
Buxton Inlet, exposing the once protected Pamlico Sound to the Atlantic Ocean (Pilkey et
al., 1998).
Strong northeasterly winds push estuarine water to the southernmost section of
Pamlico Sound. As a result, high standing water in the south flood the area while low
standing water in the north erodes the shoreline (marsh shoreline) (Riggs and Ames,
2003). The affects of this storm could explain the presence of marsh foraminifera found
107
at depth at sites S9 and S30. These foraminifera may have been transported towards the
center of the Sound following severe erosion of the marsh shoreline. Erosion supplies
sand to the platforms and mud to the central basin of the Sound (Riggs, 1996). The Ash
Wednesday Storm could also explain the strong peak (4.28%) in organic carbon seen at
the 8-lOcm interval at S30, which occurs just above the interval representing the peak
activity in '^^Cs.
Figure 52 displays the relationship between ô'^C and ô'^N for the three time
intervals determined by radionuclides. S27 is not included because the recorded
signatures down-core proved the site to be very different from the rest of the sites within
Pamlico Sound.
There is an increasing direct relationship over time between and ô'^N
signatures in Pamlico Sound (Figure 52) but there is very little change in range for ô'^C
signatures for the three time slices. Results from the one-way ANOVA test suggest that
there is not significant change over time in signatures (Tables 8 and 11). This
indicates that the terrestrially influenced source of organic matter has not varied over the
last century. However, the ANOVA results (Tables 9 and 11) indicate that there is an
observed enrichment in signatures over time. The greatest increase is observed
between the 120 years BP and 40 years BP time slices. As mentioned before, a shift in
ô'^N signatures is observed in the 40 years BP time slice in most cores. The change can
be attributed to several processes. For example, an increase in delivery into the
water-column can result in the increase of nitrification-denitrification, and assimilation.
All of these biogeochemical processes result in the enrichment of signatures (see
108
(%o)
Figure 52; ô'^C signatures versus Ô’^N signatures over the last approximate 120 years
BP. Signatures are evaluated at three time slices, approximately 120 years BP (closed
circles), approximately 40 years BP (open squares), and present day (shaded triangles).
Previous Works, significance of ô’^N signatures). A possible explanation for observed
enrichment could be the amount of shrimp trawling within Pamlico Sound.
Shrimp trawling in Pamlico Sound began in 1912. The conditions found within
Pamlico Sound make it an excellent environment for shrimp to proliferate. Shrimp breed
all year long, making them a ‘year long crop.’ By the mid 1950s, trawlers were bringing
in close to seven million pounds of shrimp a year. By the 1960s, it became apparent to
shrimpers that the environmental conditions within the Sound would not allow shrimp to
be overfished (NCFA, 2001). Trawling disturbs the seafloor by resuspending sediments.
The large amount of trawling occurring in the Sound during the early 1960s may have
continuously resuspended sediment. signatures within sediment are a result of
109
nitrogen cycling within the water column and interactions with the surficial sediment
(Bratton et al., 2003). The longer sediment is suspended in the water column, the longer
the time frame for biogeochemical processes to enrich the sediment in
CONCLUSIONS
Significant paleoenvironmental changes for Pamlico Sound, North Carolina, are
observed in down-core sediments. Environmental conditions existing within the Sound
over the last century were analyzed using foraminiferal data, stable isotope (C and N)
data, C:N ratios, percent OC, and radionuclide data. For comparison, these changes were
evaluated at three time slices (1) present day, or modem environment as determined by
the surficial (0-2cm) sediments, (2) the intervals representing approximately 120 years
^10
BP, as determined by Pb activity, and (3) the intervals representing approximately 40
years BP, as determined by Cs activity.
There has been a steady increasing marine influence within Pamlico Sound over
the last century based on foraminiferal assemblages and C:N ratios. Greater C:N ratios
are observed at the depth representing approximately 120 years BP. C:N ratios steadily
decrease up-core, which is indicative of a more marine influence of the Sound over time.
The change in the foraminiferal assemblage patterns observed at the intervals
representing approximately 120 years BP, 40 years BP, and the modem surficial (0-lcm)
intervals confirm that salinity has increased over the last century within Pamlico Sound.
Estuarine Biofacies A, which is indicative of a more brackish environment, was the
dominant assemblage within Pamlico Sound approximately 120 years BP. The
foraminiferal assemblage representing approximately 40 years BP is comparable to the
modem day assemblage. However, Estuarine Biofacies B, which is characteristic of
higher salinity, was not as widespread throughout the Sound as it is today. It is possible
Ill
to attribute these foraminiferal assemblage changes to major storm activity; hurricanes
120 years ago and the Ash Wednesday nor’easter 40 years ago.
An increasing trend is observed between ô'^C and ô'^N signatures over the last
century. The average range for ô’^C signatures is typical of terrestrial sediment input and
has changed little over time. This suggests that the source area for the sediments being
deposited within Pamlico Sound has not changed.
The average range for ô'^N signatures has increased over time. Recorded
signatures are more enriched in ô’^N at the surface than they were approximately 120
years BP. The greatest change is observed at intervals representing approximately the
early 1960s as determined by radionuclide data. These changes can be explained by
anthropogenic influences, in particular, shrimp trawling.
In the early 1960s, trawling for shrimp increased tremendously. Trawling
resuspends sediment into the water column allowing more time for biogeochemical
processes to occur before settling and re-depositing. For example, the longer sediment
remains suspended, the more denitrification occurs thus enriching the ô’^N signature.
The widespread continued increase (enrichment) in ô'^N signatures up-core indicates that
these environmental processes are still occurring within Pamlico Sound.
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122
PLATE 1
(bar = 50 |j,m)
Figures
1 Ammoastuîa inepta Cushman and McCulloch; lateral view
2 Ammobaculites crassus Warren: lateral view
3 Ammobaculites dilatatus Cushman and Bronnimann; lateral view
4 Ammobaculites exiguus Cushman and Bronnimann; lateral view
5, 6 Ammonia parkinsoniana (d’Orbigny); dorsal and ventral view
7,11 Ammonia tepida (Cushman); dorsal and ventral view
8 Ammotium salsum (Cushman and Bronnimann); lateral view
9,10 Arenoparrella mexicana (Komfield); dorsal and ventral view
12,13 Asterigerinata carinata d’Orbigny; dorsal and ventral view
14,15 Buccella frigida (Cushman); dorsal and ventral view
16,17 Buccella inusitata Andersen; dorsal and ventral view
18, 19 abieldes lobatulus (Walker and Jacob); dorsal and ventral view
 
124
PLATE 2
(bar = 50 nm)
Figures
1, 2 Cibicides refulgens Montfort; dorsal and ventral view
3 Elphidium excavatum (Terquem); lateral view
4 Elphidium galvestonense Komfield; lateral view
5 Elphidium gunteri Cole; lateral view
6 Elphidium mexicanum (Komfield); lateral view
7 Elphidium cf. E. mexicanum', lateral view
8 Elphidium subarcticum Cushman; lateral view
9,10 Hanzawaia stratíoni (Applin); dorsal and ventral view
11 Haplophragmoides bonplandi Todd and Bronnimann; lateral view
12 Haplophragmoides wilberti Andersen; lateral view
13 Haynesina germánica (Ehrenberg); lateral view
14, 15 Jadammina macrescens (Brady); dorsal and ventral view
16 Miliammina fusca (Brady); lateral view
17 Miliammina petila Saunders; lateral view
18 Pseudoclavulina gracilis Cushman and Bronnimann; lateral view
19 Nonionella atlántica Cushman; lateral view
 
126
PLATE 3
(bar = 50 |a,m)
Figures
1, 2 Poroeponides lateralis (Terquem); dorsal and ventral view
3 Quinqueloculina lamarckiana d’Orbigny; lateral view
4 Quinqueloculina jugosa (Cushman); lateral view
5 Quinqueloculina seminula (Linné); lateral view
6 Quinqueloculina sp. C; lateral view
7 Reophax sp.; lateral view
8, 9 Siphotrochammina lobata Saunders; dorsal and ventral view
10 Textularia earlandi Phleger; lateral view
11 Textularia cf. T. gramen (Todd and Bronnimann); lateral view
12 Textularia sp.; lateral view
13,17 Tiphotrocha comprimata (Cushman and Bronnimann); dorsal and
ventral view
14,15 Trochammina inflata (Montagu); dorsal and ventral view
16 Trochamminita irregularis Cushman and Bronnimann; lateral view
18 Trochammina sp.; lateral view
 
Appendix A: References useful in identifying taxa to the species level
129
Ammoastuta inepta (Cushman and McCulloch); Grossman, 1967:47, pi. 2:fig. 9. Parker,
1952a, pi. 2:figs. 1,2. [as A. salsa]
Ammobaculites crassus Warren: Warren, 1957:35, pi. 3:figs. 5-7. Grossman, 1967:48,
pi. 1: figs. 4,5,10.
Ammobaculites dilatatus Cushman and Bronnimann: Cushman and Brdnnimann,
1948b:39, pl.7:figs. 10,11. Parker and Atheam, 1959:340, pi. 50:figs. 4,5.
Ammobaculites exiguus Cushman and Brdnnimann: Ellison and Nichols, 1970:15, pi.
2:fig. 6 [as Ammobaculites cf. A. exiguus].
Ammonia parkinsoniana (d’Orbigny): Grossman, 1967:56, pl.l0:figs. 1,2 [as A.
limbatobeccarii].
Ammonia tepida (Cushman): Grossman, 1967:56, pi. 9: figs. 5,9. Loeblich andTappan,
1994:166, pi. 371:figs. 5-10.
Ammotium salsum (Cushman and Brdnnimann): Grossman, 1967:49, pi. 2:figs. 1,2,8.
Scott, et al., 1977:1578, pi. 2:figs. 4,5.
Arenoparrella mexicana (Komfield): Komfield, 1931:86, pi. 13:figs. 5a-c [as
Trochammina inflata var. mexicana], Saunders, 1957:13, pi. 4:fig. 5. Grossman
1967:55, pl.6:figs.2-4.
Asterogeroma carinata d’Orbigny: Parker, 1954:532, pi. 10:figs. 16, 17. Schnitker,
1971:204, pi. 6:figs. 9a-c.
Buccella frigida (Cushman): Anderson, 1952:147, figs. 4-6.
Buccella inusitata Anderson: Anderson, 1952:147, fig 10, 11.
C/¿>/d<ie5/oèalM/Mi (Walker and Jacob): Todd and Brdnnimann, 1957:41, pi. 12:figs.
lla-c. Sen Gupta, 1971:89, pi. 2:figs. 34-36.
Cibicides refulgens Montfort: Todd and Brdnnimann, 1957:41, pi. 12:figs. 12a-c.
Elphidium advenum Cushman: Parker, 1954:508, pi. 6:fig. 14. Buzas et al., 1985:1081,
figs. 6.1, 6.2.
Elphidium excavatum (Terquem): Buzas et al., 1985:1083, figs. 6.7-6.10, 7.1, 7.2.
Elphidium galvestonense Komfield: Grossman, 1967:60, pl. 7:figs. 1,2.
130
Elphidium gunteri Cole: Grossman, 1967:59, pi. 8:figs 1-4. Buzas et al., 1985:1084,
figs. 7.4, 7.5.
Elphidium mexicanum (Komfield): Buzas et al., 1985:1086, figs. 7-9, 10.
Elphidium cf. E. mexicanum
Elphidium subarcticum Cushman: Buzas et al., 1985:1087, figs. 8.1, 8.2.
Hanzawaia strattoni (Applin): Bandy, 1954:136, pi. 31:fig. 4. Grossman, 1967:62, pi.
10:figs. 3-5 [as H. sp. cf. H. strattoni].
Haplophragmoides bonplandi Todd and Bronnimann: Todd and Bronnimann, 1957:23,
pi. 2: fig. 2. Scott and Medioli 1980:40, pi. 2:figs. 4, 5.
Haplophragmoides wilberti Andersen. Grossman, 1967:47, pi. 2:figs. 12-14.
Haynesina germánica (Ehrenberg): Buzas et al., 1985:1088, figs 8.4, 8.5.
Jadammina macrescens (Brady): Parker, 1952a:408, pl. 4:figs. 8 a, b. Parker,
1952b:460, pl. 3:figs 3 a, b.
Miliammina fusca (Brady): Parker, 1952b:452, pl. 2:figs. 6 a, b. Parker and Atheam
1959:340, pl. 50:figs. 11, 12. Grossman, 1967:46, pl. 2:figs. 3-5.
Miliamminapetila Smnâers: Saunders, 1958:88, pl. 1:10, 11.
Nonionella atlántica Cushman: Cushman, 1947:90, pl. 30:figs, 4,5. Parker, 1954:507,
pl. 6:figs. 6,7.
Poroeponides lateralis ÇTerquem): Bandy, 1954:137, pl. 30:fig. 1. Grossman, 1967:56,
pl. 10:figs. 6-8.
Pseudoclavulina gracilis Cushman and Bronnimann: Cushman and Bronnimann,
1948b:40, pl. 7:fig. 18.
Quinqueloculina lamarckiana d’Orbigny: Grossman, 1967:52, pl. 3:figs. 1-3.
Schnitker, 1971:208, pl. 2:figs. 16a-c.
Quinqueloculina jugosa (Cushman): Grossman, 1967:51, pl. 4:figs. 7,11,12. Schnitker,
1971:208, pl. 2:fig. 15a-c.
131
Quinqueloculina seminula (Linné): Komfield, 1931:83-84, pi. 14: figs. 4a-c [as Q.
seminulum], Grossman, 1967:53, pi. 4:figs. 13,14,18. Schnitker, 1971:208, pi.
3:figs. la-c.
Quinqueloculina sp. C
Reophax sp.
Siphotrochammina lobata Saunders. Saunders, 1957:9 pi. 3:figs. 1,2.
Textularia earlandi Phleger: Schafer and Cole, 1978:29, pi. 3:fig. 4.
Textularia c.f. T. gramen (Todd and Bronnimann): Todd and Brdnnimann, 1957:11, pi.
2:fig. 18.
Textularia sp.
Tiphotrocha comprimata (Cushman and Bronnimann): Saunders, 1957:11, pi. 4:figs. 1
4. Grossman, 1967:50, pi. 6:figs. 1,5.
Trochammina inflata (Montagu): Buzas, 1964:57, pi. Lfigs. 9a, 9b.
Trochammina sp.
Trochamminita irregularis Cushman and Bronnimann: Cushman and Brdnnimann,
1948a:17, pi. 4:figs. 1-3. Saunders, 1957:4, pi. 2:figs. 2-8.
Appendix B: Raw Census Data (surface)
Raw census data (numbers of live and dead specimens) for surface samples in Pamlico
Sound. S37 is not listed because it was barren of foraminifera.
Raw Data (Live & Dead)
Station ID SI S2 S4 S5 S7 S9 S10 S11 S12 S14 S15 S17 S17A S22 S23 S24 S25 S26 S27 S30 S31 S32
Number of live specimens 113 0 30 1 1 0 3 3 0 2 3 70 16 8 0 5 1 5 5 14 9 48
Number of dead specimens 174 268 277 348 2 249 30 283 251 35 28 202 283 289 183 258 18 30 227 130 273 259
Total number of specimens 287 268 307 349 3 249 33 286 251 37 31 272 299 297 183 263 19 35 232 144 282 307
Ammoastuta inepta L
D 1 37
Ammobaculites crassus L
D 2 7 1 1 6 5 1 8
Ammobaculites dilatatus L
D 1
Ammobaculites exiguas L 1 1
D 2 15
Ammonia parkinsoniana L 20 26 1 1 1 1 2 1 3 5 1 2
D 100 57 282 1 3 35 19 8 4 14 18 6 33 37
Ammonia tepida L 1
D 7 6 2 24
Ammotium salsum L 15 4 1 3 5 2 3 1
D 18 75 188 56 2 234 220 216 12 18 4 218 148 19 11 24 203 33 4 9
Arenoparrella mexicana L
D 1 1 1 28 6
Asterigerina carinata L
D 1 1
Buccella frígida L
D
Buccella inusitata L
D 2
Cibicides lobatulus L
D 5
Cibicides refulgens L
D 4
Elphidium advenum L
D
Elphidium excavatum L 3 1 6 3 1 5 10 8 38
D 6 7 13 1 10 35 1 146 55 27 220 5 3 2 59 236 84
Elphidium galvestonense L 1
D 2
Raw Data (Live & Dead)
Station ID SI S2 S4 S5 S7 S9 S10 S11 S12 S14 S15 S17 S17A S22 S23 S24 S25 S26 S27 S30 S31 S32
Elphidium gunteri L 3 1
D 1 1 1
Elphidium mexicanum L 1 69 1
D 6
Elphidium cf. E. mexicanum L 7
D 100
Elphidium subarcticum L 3
D 9
Hanzawaia strattoni L
D 9 2
Hapiophragmoides bonplandi L
D 6 2
Haplophragmoides wilberti L 1
D 3 5 1 9 1 2 114 2 4
Haynesina germánica L
D 3
Jadammina macrescens L
D 39 2 1 10 2
Miliammina fusca L 68 1
D 42 53 24 1 1 1 1 3
Miliammina petila L
D 4 3
Nonionella atlántica L
D 3
Poroeponides lateralis L
D
Pseudoclavulina gracilis L
D 1
Ouinqueloculina lamarckiana L
D
station ID SI S2 S4 S5 S7 S9 S10 S11 S12 SI 4 S15 SI 7 S17A S22 S23 S24 S25 S26 S27 S30 S31 S32
Quinquelœulina jugosa L
D
Quinqueloculina seminula L
D 2
Quinqueloculina sp. C L
D
Reophax sp. L 1
D
Siphotrochammina lobata L 1
D 3 1
Textularia earlandi L 2
D 1
Texularia cf. T. gramen L
D 2
Textularia sp. L
D 1
Tiphotrocha comprimata L 1
D 41 1 14 1 4
Trochammina inflata L
D 2 4 1 2 87 1 2 3
Trochamminita Irregularis L
D 6
Trochammina sp. L
D 1 3
Indeterminate agglutinated L
D 7
Indeterminate calcareous L
D 1
Organic lining L
D 1 3 3 5 1 4
Raw Data (Live & Dead)
Station ID S35 S38 S39 S40 S41 S42 S44 S45 S46 S50 S59 S60 S61 S63 EB02 SI EB02 S2 EB02 S3
Number of live specimens 0 15 5 11 22 4 27 55 23 119 2 61 21 37 0 1 4
Number of dead specimens 1 179 211 318 316 302 75 165 36 198 330 242 229 234 111 11 143
Total number of specimens 1 194 216 329 338 306 102 220 59 317 332 303 250 271 111 12 147
Ammoastuta inepta L
D
Ammobaculites crassus L 1
D 3
Ammobaculites dilatatus L
D
Ammobaculites exiguas L 2
D 4
Ammonia parkinsoniana L 6 5 9 3 5 18
D 5 49 4 2 6 18 58 69 12 1 5
Ammonia tepida L
D
Ammotium salsum L 3 4 6 85 4 8 14
D 1 5 200 225 129 93 56 8 144 6 42 16 232
Arenoparrella mexicana L 1
D 21 1 4
Asterigerina carinata L
D 3
Buccella frígida L
D 1
Buccella inusitata L
D
Cibicides lobatulus L
D 2 6
Cibicides refulgens L
D
Elphidium advenum L
D 1
Elphidium excavatum L 2 11 16 34 2 54 8
D 4 89 181 153 3 1 48 306 131 143 69 6 97
Elphidium galvestonense L 1 10 4
D 1 1 1 3
Raw Data (Live & Dead)
Station ID S35 S38 S39 S40 S41 S42 S44 S45 S46 S50 859 S60 S61 S63 EB02 S1 EB02 S2 EB02 S3
Elphidium gunteri L
D 1
Elphidium mexicanum L 2 11
D 1 3 2
Elphidium cf. E. mexicanum L
D
Elphidium subarcticum L
D 3 1
Hanzawaia strattoni L
D 4 1 11
Hapiophragmoides bonplandi L
D
Hapiophragmoides wilberti L 1
D 20 1
Haynesina germánica L
D
Jadammina macrescens L
D 17
Miliammina fusca L
D 7 2 1
Miliammina petila L
D
Nonionella atlántica L
D 1
Poroeponides lateralis L
D 1
Pseudoclavulina gracilis L
D
Ouinqueloculina lamarckiana L
D 3 2
Raw Data (Live & Dead)
Station ID S35 S38 S39 S40 S41 S42 S44 S45 S46 S50 S59 S60 S61 S63 EB02 SI EB02 S2 EB02 S3
Ouinqueloculina jugosa L 1 1
D 1
Ouinqueloculina seminula L 3
D 12 8
Ouinqueloculina sp. C L
D 3
Reophax sp. L
D 3 1
Siphotrochammina lobata L 2
D 4 22 8
Textularia earlandi L 2
D 1 2 1
Texularia cf. T. gramen L
D
Textularia sp. L
D 1
Tiphotrocha comprimata L 2
D 23 2 8 1
Trochammina inflata L 10 53 1
D 82 122 18 1
Trochamminita irregularis L
D
Trochammina sp. L 1
D 2
Indeterminate agglutinated L
D
Indeterminate calcareous L
D 6 11 1
Organic lining L 1
D 4 2
Appendix C: Relative Abundance Data (surface)
Relative abundance data (expressed as percents) of the 31 species comprising two percent
or more of the assemblage in any one sample.
Relative Abundance:
Station ID SI S2 S4 S5 S7 S9 S10 S11 S12 S14 S15 S17 S17A S22 S23 S24 S25 S26
Number of specimens 174 268 277 348 2 249 30 283 251 35 28 202 283 289 183 258 18 30
Ammoastuta inepta 0.6 13.8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ammonia parkinsoniana 57.5 0 20.6 81.0 0 0.4 10.0 12.4 0 54.3 0 4.0 1.4 4.8 0 7.0 0 0
Ammonia tepida 0 0 0 0 0 0 23.3 2.1 0 0 0 1.0 0 0 0 0 0 0
Ammotium salsum 10.3 28.0 67.9 16.1 100.0 94.0 0 77.7 86.1 34.3 64.3 0 1.4 75.4 80.9 7.4 61.1 80.0
Arenoparrella mexicana 0 0 0 0 0 0.4 3.3 0.4 0 0 0 0 9.9 0.0 0 0 0 0
Asterigerina carinata 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 0 0
Ammobaculites crassus 1.1 0 2.5 0.3 0 0 3.3 2.1 0 0 0 0 0 0 2.7 0 0 0
Ammobaculites dilatatus 0 0 0 0 0 0 0 0 0 0 3.6 0 0 0 0 0 0 0
Ammobaculites exiguus 0 0 0 0 0 0 0 0 0 0 7.1 0 0 0 0 0 0 0
Cibicides lobatulus 0 0 0 0 0 0 0 0 0 0 0 2.5 0 0 0 0 0 0
Cibicides refulgens 0 0 0 0 0 0 0 0 0 0 0 2.0 0 0 0 0 0 0
Elphidium excavatum 3.4 0 0 2.0 0.0 5.2 3.3 3.5 13.9 2.9 0 72.3 0 19.0 14.8 85.3 27.8 10.0
Elphidium gaivestonense 0 0 0 0 0 0 0 0 0 0 0 1.0 0 0 0 0 0 0
Elphidium mexicanum 0 0 0 0 0 0 0 0 0 0 0 3.0 0 0 0 0 0 0
Elphidium cf. E. mexicanum 0 0 0 0 0 0 0 0 0 0 0 0.0 0 0 0 0 0 0
Elphidium subarcticum 0 0 0 0 0 0 0 0 0 0 0 4.5 0 0 0 0 0 0
Hanzawaia strattoni 0 0 0 0 0 0 0 0 0 0 0 4.5 0 0 0 0 0 0
Haplophragmoides bonplandi 0 2.2 0 0 0 0 0 0 0 0 0 0 0.7 0 0 0 0 0
Haplophragmoides wilberti 1.7 1.9 0.4 0 0 0 30.0 0.4 0 0 7.1 0 40.3 0 0 0 0 0
Jadammina macrescens 0 14.6 0 0 0 0 6.7 0.4 0 0 0 0 3.5 0 0 0 0 0
Miliammina fusca 24.1 19.8 8.7 0.3 0 0 3.3 0.4 0 0 0 0 0 0 0.5 0 0 0
Ouinqueloculina lamarckiana 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ouinqueloculina seminula 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0
Ouinqueloculina sp. C 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Siphotrochammina lobata 0 0 0 0 0 0 0 0 0 0 0 0 1.1 0 0.5 0 0 0
Textularia earlandi 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3.3
Tiphotrocha comprímala 0 15.3 0 0 0 0 3.3 0 0 0 0 0 4.9 0 0.5 0 0 0.0
Trochammina inftata 1.1 0 0 0 0 0 13.3 0.4 0 0 7.1 0 30.7 0 0 0 5.6 6.7
Indeterminate agglutinated 0 2.6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Indeterminate calcareous 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.4 0 0
Organic lining 0 0 0 0.3 0 0 0 0 0 8.6 10.7 0 1.8 0 0 0 5.6 0
Relative Abundance:
Station ID S27 S30 S31 S32 S35 S38 S39 S40 S41 S42 S44 S45 S46 S50 S59 S60 S61 S63
Number of specimens 227 130 273 259 1 179 211 318 316 302 75 165 36 198 330 242 229 234
Ammoastuta inepta 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ammonia parkinsoniana 0 4.6 12.1 14.3 0 0 0 0 1.6 16.2 5.3 0 5.6 3.0 5.5 24.0 30.1 0
Ammonia tepida 0 0 0 9.3 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ammotium salsum 89.4 25.4 1.5 3.5 100.0 2.8 94.8 70.8 40.8 30.8 74.7 4.8 0 72.7 1.8 17.4 7.0 99.1
Arenoparrella mexicana 0 4.6 0 0 0 11.7 0.5 0 0 0 0 0 11.1 0 0 0 0 0
Asterigerina carinata 0 0 0 0.4 0 0 0 0 0 0 0 0 0 0 0 0 0 0
AmmobacuUtes crassus 0.4 6.2 0 0 0 0 1.4 0 0 0 0 0 0 0 0 0 0 0
Ammobaculites dilatatus 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
AmmobacuUtes exiguas 6.6 0 0 0 0 0 0 0 0 0 5.3 0 0 0 0 0 0 0
Cibicides lobatulus 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Cibicides refuigens 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Elphidium excavatum 0.9 45.4 86.4 32.4 0 0 1.9 28.0 57.3 50.7 4.0 0.6 0 24.2 92.7 54.1 62.4 0
Eiphidium galvestonense 0 0 0 0 0 0 0 0 0 0 1.3 0.0 2.8 0 0 0 0 0
Etphidium mexicanum 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Eiphidium cf. E. mexicanum 0 0 0 38.6 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Elphidium subarcticum 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Hanzawaia strattoni 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Haplophragmoides bonpiandi 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Haplophragmoides wiiberti 0.9 3.1 0.0 0 0 11 0 0 0 0 0 0 0 0 0 0 0 0
Jadammina macrescens 0 1.5 0 0 0 9.5 0 0 0 0 0 0 0 0 0 0 0 0
Miliammina fusca 0 2.3 0 0 0 3.9 0 0 0 0 0 1.2 0 0 0 0 0.4 0
Ouinqueioculina iamarckiana 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Quinqueioculina seminula 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ouinqueioculina sp. C 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Siphotrochammina lobata 0 0 0 0 0 2.2 0 0 0 0 0 13.3 22.2 0 0 0 0 0
Textularia eariandi 0 0 0 0 0 0 0 0.3 0 0 2.7 0 0 0 0 0 0 0.4
Tiphotrocha comprimata 0 3.1 0 0 0 12.8 0.9 0 0 0 0 4.8 2.8 0 0 0 0 0
Trochammina inflata 0 2.3 0 0 0 45.8 0 0 0 0 0 73.9 50.0 0 0 0 0 0.4
Indeterminate agglutinated 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Indeterminate calcareous 0 0 0 0 0 0 0 0 0 2.0 0 0 0 0 0 4.5 0 0
Organic lining 1.8 0 0 0 0 0 0 0 0 0 5.3 0 5.6 0 0 0 0 0
Relative Abundance:
Station ID EB02 S1 EB02 S2 EB02 S3
Number of specimens 111 11 143
Ammoastuta inepta 0 0 0
Ammonia parkinsoniana 10.8 9.1 3.5
Ammonia tepida 0 0 0
Ammotium salsum 0 0 0
Arenoparrella mexicana 0 0 0
Asterigerina carinata 0 0 2.1
Ammobaculites crassus 0 0 0
Ammobacutites diiatatus 0 0 0
Ammobaculites exiguus 0 0 0
Cibicides lobatulus 1.8 0 4.2
abieldes refuigens 0 0 0
Elphidium excavatum 62.2 54.5 67.8
Elphidium galvestonense 0.9 0 2.1
Elphidium mexicanum 0.9 27.3 1.4
Elphidium cf. E. mexicanum 0 0 0
Elphidium subarcticum 2.7 0 0.7
Hanzawaia strattoni 3.6 9.1 7.7
Haplophragmoides bonplandi 0 0 0
Haplophragmoides wilberti 0 0 0
Jadammina macrescens 0 0 0
Miliammina fusca 0 0 0
Quinqueloculina lamarckiana 2.7 0 1.4
Ouinqueloculina seminula 10.8 0 5.6
Quinqueloculina sp. C 2.7 0 0
Siphotrochammina lobata 0 0 0
Textularia earlandi 0 0 0
Tiphotrocha comprimata 0 0 0
Trochammina inflata 0 0 0
Indeterminate agglutinated 0 0 0
Indeterminate calcareous 0.9 0 0
Organic lining 0 0 0
Appendix D: Transformed Abundance Data (surface)
Transformed abundance data of the 31 species comprising two percent or more of the
assemblage in any one sample.
Transformed Abundance:
Station ID SI S2 S4 S5 S7 S9 S10 S11 SI 2 S14 S15 S17
Ammoastuta inepta 0.1518 0.7614 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Ammobaculites crassus 0.2148 0.0000 0.3193 0.1073 0.0000 0.0000 0.3672 0.2923 0.0000 0.0000 0.0000 0.0000
Ammobaculites dilatatus 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.3803 0.0000
Ammobaculites exiguas 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.5411 0.0000
Ammonia parkinsoniana 1.7208 0.0000 0.9417 2.2404 0.0000 0.1268 0.6435 0.7187 0.0000 1.6566 0.0000 0.4007
Ammonia tepida 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 1.0083 0.2923 0.0000 0.0000 0.0000 0.1993
Ammotium salsum 0.6549 1.1149 1.9363 0.8255 3.1416 2.6456 0.0000 2.1589 2.3762 1.2511 1.8605 0.0000
Arenoparrelia mexicana 0.0000 0.0000 0.0000 0.0000 0.0000 0.1268 0.3672 0.1190 0.0000 0.0000 0.0000 0.0000
Asterigerina carinata 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.1408
Cibicides lobatuius 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.3160
Cibicides refulgens 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.2824
Elphidium excavatum 0.3736 0.0000 0.0000 0.2846 0.0000 0.4611 0.3672 0.3782 0.7654 0.3397 0.0000 2.0326
Elphidium galvestonense 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.1993
Elphidium mexicanum 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.3464
Elphidium cf. E. mexicanum 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Elphidium subarcticum 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.4254
Hanzawaia strattoni 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.4254
Haplophragmoides bonpiandi 0.0000 0.3004 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Haplophragmoides wiiberti 0.2634 0.2740 0.1202 0.0000 0.0000 0.0000 1.1593 0.1190 0.0000 0.0000 0.5411 0.0000
Jadammina macrescens 0.0000 0.7828 0.0000 0.0000 0.0000 0.0000 0.5223 0.1190 0.0000 0.0000 0.0000 0.0000
Miliammina fusca 1.0272 0.9217 0.5976 0.1073 0.0000 0.0000 0.3672 0.1190 0.0000 0.0000 0.0000 0.0000
Quinqueloculina lamarckiana 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Ouinqueloculina seminula 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.1993
Quinqueloculina sp. C 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Siphotrochammina lobata 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Textularia eariandi 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Tiphotrocha comprímala 0.0000 0.8037 0.0000 0.0000 0.0000 0.0000 0.3672 0.0000 0.0000 0.0000 0.0000 0.0000
Trochammina infiata 0.2148 0.0000 0.0000 0.0000 0.0000 0.0000 0.7476 0.1190 0.0000 0.0000 0.5411 0.0000
Indeterminate agglutinated 0.0000 0.3247 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Indeterminate calcareous 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Organic lining 0.0000 0.0000 0.0000 0.1073 0.0000 0.0000 0.0000 0.0000 0.0000 0.5942 0.6669 0.0000
Transformed Abundance:
Station ID S17A S22 S23 S24 S25 S26 S27 S30 S31 S32 S35 S38
Ammoastuta inepta 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Ammobaculites crassus 0.0000 0.0000 0.3321 0.0000 0.0000 0.0000 0.1328 0.5014 0.0000 0.0000 0.0000 0.0000
Ammobaculites dilatatus 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Ammobaculites exiguus 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.5200 0.0000 0.0000 0.0000 0.0000 0.0000
Ammonia parkinsoniana 0.2383 0.4438 0.0000 0.5346 0.0000 0.0000 0.0000 0.4330 0.7102 0.7752 0.0000 0.0000
Ammonia tepida 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.6186 0.0000 0.0000
Ammotium salsum 0.2383 2.1044 2.2363 0.5496 1.7949 2.2143 2.4792 1.0561 0.2427 0.3750 3.1416 0.3358
Arenoparrella mexicana 0.6400 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.4330 0.0000 0.0000 0.0000 0.6992
Asterigerina carinata 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.1244 0.0000 0.0000
abieldes lobatulus 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
abieldes refulgens 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Elphidium excavatum 0.0000 0.9028 0.7885 2.3538 1.1102 0.6435 0.1880 1.4784 2.3876 1.2118 0.0000 0.0000
Elphidium galvestonense 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Elphidium mexicanum 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Elphidium cf. E. mexicanum 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 1.3410 0.0000 0.0000
Elphidium subarcticum 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Hanzawaia strattoni 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.2487 0.0000 0.0000 0.0000 0.0000
Haplophragmoides bonplandi 0.1683 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Haplophragmoides wllberti 1.3752 0.0000 0.0000 0.0000 0.0000 0.0000 0.1880 0.3526 0.0000 0.0000 0.0000 0.6816
Jadammina macrescens 0.3782 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.2487 0.0000 0.0000 0.0000 0.6265
Miliammina fusca 0.0000 0.0000 0.1480 0.0000 0.0000 0.0000 0.0000 0.3050 0.0000 0.0000 0.0000 0.3981
Oulnqueloculina lamarckiana 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Quinqueloculina seminula 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Oulnqueloculina sp. C 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Siphotrochammlna lobata 0.2063 0.0000 0.1480 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.3001
Textularia earlandi 0.0000 0.0000 0.0000 0.0000 0.0000 0.3672 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Tiphotrocha comprimata 0.4486 0.0000 0.1480 0.0000 0.0000 0.0000 0.0000 0.3526 0.0000 0.0000 0.0000 0.7332
Trochammina inflata 1.1754 0.0000 0.0000 0.0000 0.4759 0.5223 0.0000 0.3050 0.0000 0.0000 0.0000 1.4869
Indeterminate agglutinated 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Indeterminate calcareous 0.0000 0.0000 0.0000 0.1246 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Organic lining 0.2666 0.0000 0.0000 0.0000 0.4759 0.0000 0.2663 0.0000 0.0000 0.0000 0.0000 0.0000
Transformed Abundance;
Station ID S39 S40 S41 S42 S44 S45 S46 S50 S59 S60 S61 S63
Ammoastuta inepta 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Ammobaculites crassus 0.2390 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Ammobaculites dilatatus 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Ammobaculites exiguus 0.0000 0.0000 0.0000 0.0000 0.4661 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Ammonia parkinsonians 0.0000 0.0000 0.2522 0.8292 0.4661 0.0000 0.4759 0.3499 0.4715 1.0232 1.1621 0.0000
Ammonia tepida 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Ammotium salsum 2.6809 1.9988 1.3862 1.1766 2.0867 0.4440 0.0000 2.0427 0.2705 0.8594 0.5350 2.9564
Arenoparrella mexicana 0.1378 0.0000 0.0000 0.0000 0.0000 0.0000 0.6797 0.0000 0.0000 0.0000 0.0000 0.0000
Asterigerina carinata 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
abieldes lobatulus 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
abieldes refulgens 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Elphidium excavatum 0.2762 1.1149 1.7169 1.5840 0.4027 0.1559 0.0000 1.0296 2.5955 1.6535 1.8223 0.0000
Elphidium galvestonense 0.0000 0.0000 0.0000 0.0000 0.2315 0.0000 0.3349 0.0000 0.0000 0.0000 0.0000 0.0000
Elphidium mexicanum 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Elphidium cf. E. mexicanum 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Elphidium subarcticum 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Hanzawaia strattoni 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Haplophragmoides bonplandl 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Haplophragmoides wilberti 0.1378 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Jadammina macrescens 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Miliammina fusca 0.0000 0.0000 0.0000 0.0000 0.0000 0.2206 0.0000 0.0000 0.0000 0.0000 0.1323 0.0000
Quinqueloculina iamarckiana 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Quinqueloculina semlnula 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Quinqueloculina sp. C 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Siphotrochammina iobata 0.0000 0.0000 0.0000 0.0000 0.0000 0.7476 0.9818 0.0000 0.0000 0.0000 0.0000 0.0000
Textularia earlandi 0.0000 0.1122 0.0000 0.0000 0.3281 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.1308
Tiphotrocha comprimata 0.1950 0.0000 0.0000 0.0000 0.0000 0.4440 0.3349 0.0000 0.0000 0.0000 0.0000 0.0000
Trochammina inflata 0.0000 0.0000 0.0000 0.0000 0.0000 2.0701 1.5708 0.0000 0.0000 0.0000 0.0000 0.1308
Indeterminate agglutinated 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Indeterminate calcareous 0.0000 0.0000 0.0000 0.2828 0.0000 0.0000 0.0000 0.0000 0.0000 0.4297 0.0000 0.0000
Organic lining 0.0000 0.0000 0.0000 0.0000 0.4661 0.0000 0.4759 0.0000 0.0000 0.0000 0.0000 0.0000
Transformed Abundance;
Station ID EB02 S1 EB02 S2 EB02 S3
Ammoastuta inepta 0.0000 0.0000 0.0000
Ammobaculites crassus 0,0000 0.0000 0.0000
Ammobaculites dilatatus 0.0000 0.0000 0.0000
Ammobaculites exiguus 0.0000 0.0000 0.0000
Ammonia parkinsoniana 0.6701 0.6126 0.3762
Ammonia tepida 0.0000 0.0000 0.0000
Ammotium salsum 0.0000 0.0000 0.0000
Arenoparrella mexicana 0.0000 0.0000 0.0000
Asterigerina carinata 0.0000 0.0000 0.2907
abieldes lobatulus 0.2693 0.0000 0.4126
abieldes refulgens 0.0000 0.0000 0.0000
Elphidium excavatum 1.8165 1.6618 1.9355
Elphidium galvestonense 0.1901 0.0000 0.2907
Elphidium mexicanum 0.1901 1.0989 0.2371
Elphidium cf. E. mexicanum 0.0000 0.0000 0.0000
Elphidium subarcticum 0.3303 0.0000 0.1674
Hanzawaia strattoni 0.3820 0.6126 0.5621
Haplophragmoides bonplandi 0.0000 0.0000 0.0000
Haplophragmoides wilberti 0.0000 0.0000 0.0000
Jadammina macrescens 0.0000 0.0000 0.0000
Miliammina fusca 0.0000 0.0000 0.0000
Quinqueloculina lamarckiana 0.3303 0.0000 0.2371
Ouinqueloculina seminula 0.6701 0.0000 0.4776
Quinqueloculina sp. C 0.3303 0.0000 0.0000
Siphotrochammina lobata 0.0000 0.0000 0.0000
Textularia earlandi 0.0000 0.0000 0.0000
Tiphotrocha comprimata 0.0000 0.0000 0.0000
Trochammina inflata 0.0000 0.0000 0.0000
Indeterminate agglutinated 0.0000 0.0000 0.0000
Indeterminate calcareous 0.1901 0.0000 0.0000
Organic lining 0.0000 0.0000 0.0000
4;^
On
Appendix E: Raw Census Data (down-core)
Raw census data (number of dead specimens) for 21 species recorded in down-core
samples, ‘a’ indicates those intervals corresponding with the '^^Cs peak (1963-1964).
‘b’ indicates those intervals dated by ^‘'^b to be approximately 120 years old.
Down-core Raw data
Station ID: S9a S9b S11b S12a S12b S24a S24b S27b S30a S30b S31a S31b S32a S41a S41b S50a S50b S59a S59b S60a S60b
interval (cm): 8-10 18-20 14-16 16-18 20-22 12-14 28-30 12-14 10-12 16-18 16-18 51-54 10-12 12-14 24-26 16-18 36-39 4-6 20-22 12-14 28-30
Number of Specimens: 294 288 293 323 271 328 328 122 294 356 278 310 395 285 283 268 278 408 107 280 281
Ammoastuta inepta 1
Ammonia parkinsoniana 20 7 1 7 37 13 29 118 1 21 17 3 25 2
Ammonia tepida 2 3 2
Ammotium salsum 281 276 281 313 256 33 288 112 253 126 88 180 3 151 249 240 277 133 66 249 272
Arenoparrelia mexicana 1
Ammobaculites crassus 2 5 11 10 13 6 2 9 2 1 3 1
Ammobaculites diiatatus
Ammobaculites exiguus 1
Elphidium excavatum 4 2 274 24 7 14 187 176 96 271 132 34 7 255 37 6 6
Elphidium galvestonense 1
Elphidium gunteri 1 1
Elphidium mexicanum 1
Elphidium cf. E. mexicanum 2
Haplophragmoides wilberti 4 3
Jadammina macrescens 1 1
Reophax sp. 2 1
Textularia sp. 1
Tiphotrocha comprimata 1
Trochammina inflata 2 1 7
Trochammina sp. 1 1
Organic lining 2 1
Appendix F : Relative Abundance Data (down-core)
Relative abundance data of down-core samples expressed as percents, ‘a’ indicates those
intervals corresponding with the '^^Cs peak (1963-1964). ‘b’ indicates those intervals
dated by ^'°Pb to be approximately 120 years old.
Relative Abundance;
Station ID: SSa S9b Sllb SI 2a S12b S24a S24b S27b S30a S30b S31a S31b S32a S41a S41b S50a S50b S59a SSSb S60a S60b
intervai (cm): 8-10 18-20 14-16 16-18 20-22 12-14 28-30 12-14 10-12 16-18 16-18 51-54 10-12 12-14 24-26 16-18 36-39 4-6 20-22 12-14 28-30
Ammoastuta inepta 0 0 0.3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ammonia parkinsoniana 0 0 0 0 0 6.1 2.1 0.8 2.4 10.4 4.7 9.4 29.9 0.4 0 7.8 0 4.2 2.8 8.9 0.7
Ammonia tepida 0 0 0 0 0 0 0.6 0 0 0.8 0 0.6 0 0 0 0 0 0 0 0 0
Ammotium salsum 95.6 95.8 95.9 96.9 94.5 10.1 87.8 91.8 86.1 35.4 31.7 58.1 0.8 53.0 88.0 89.6 99.6 32.6 61.7 88.9 96.8
Arenoparrella mexicana 0 0.3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ammobaculites crasses 0.7 1.7 3.8 3.1 4.8 0 1.8 1.6 3.1 0.6 0.4 1.0 0 0.4 0 0 0 0 0 0 0
Ammobaculites dilatâtes 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ammobacelites exigeas 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.4
Elphidiem excavatem 0 1.4 0 0 0.7 83.5 7.3 5.7 4.8 52.5 63.3 31.0 68.6 46.3 12.0 2.6 0 62.5 34.6 2.1 2.1
Elphidiem galvestonense 0 0 0 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 0 0 0
Elphidiem genteri 0 0 0 0 0 0 0 0 0 0 0 0 0.3 0 0 0 0 0.2 0 0 0
Elphidiem mexicanem 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Elphidiem cf. E. mexicanem 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 0 0 0 0
Haplophragmoides wiiberti 1.4 0 0 0 0 0 0 0 1.0 0 0 0 0 0 0 0 0 0 0 0 0
Jadammina macrescens 0.3 0.3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Reophax sp. 0.7 0 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 0 0 0 0
Textelaria sp. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.2 0 0 0
Tiphotrocha comprímala 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.2 0 0 0
Trochammina Ínflala 0.7 0 0 0 0 0.3 0 0 2.4 0 0 0 0 0 0 0 0 0 0 0 0
Trochammina sp. 0 0.3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.9 0 0
Organic lining 0.7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.4 0 0 0 0
Appendix G: Transformed Abundance Data (down-core)
Transformed abundance data of down-core samples, ‘a’ indicates those intervals
corresponding with the ’^^Cs peak (1963-1964). ‘b’ indicates those intervals dated by
^'Vb to be approximately 120 years old.
Transformed Abundance:
Station ID: S9a S9b S11b SI 2a SI 2b S24a S24b S27b S30a S30b S31a S31b S32a S41a S41b S50a S50b S59a S59b S60a S60b
interval (cm): 8-10 18-20 14-16 16-18 20-22 12-14 28-30 12-14 10-12 16-18 16-18 51-54 10-12 12-14 24-26 16-18 36-39 4-6 20-22 12-14 28-30
Ammoastuta inepta 0 0 0.12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ammonia parkinsoniana 0.17 0.26 0.39 0.35 0.44 0 0.27 0.26 0.35 0.15 0.12 0.20 0 0.12 0 0 0 0 0 0 0
Ammonia tepida 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Ammotium salsum 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.12
Arenoparreiia mexicana 0 0 0 0 0 0.50 0.29 0.18 0.31 0.66 0.44 0.62 1.16 0.12 0 0.57 0 0.41 0.34 0.61 0.17
Ammobaculites crassus 0 0 0 0 0 0 0.16 0 0 0.18 0 0.16 0 0 0 0 0 0 0 0 0
Ammobaculites diiatatus 2.72 2.73 2.73 2.79 2.67 0.65 2.43 2.56 2.38 1.27 1.20 1.73 0.17 1.63 2.43 2.48 3.02 1.22 1.81 2.46 2.78
Ammobacuiites exiguos 0 0.12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Elphidium excavatum 0 0.24 0 0 0.17 2.31 0.55 0.48 0.44 1.62 1.84 1.18 1.95 1.50 0.71 0.32 0 1.82 1.26 0.29 0.29
Elphidium galvestonense 0 0 0 0 0 0 0 0 0 0.11 0 0 0 0 0 0 0 0 0 0 0
Elphidium gunteri 0 0 0 0 0 0 0 0 0 0 0 0 0.10 0 0 0 0 0.10 0 0 0
Elphidium mexicanum 0 0 0 0 0 0 0.11 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Elphidium cf. E. mexicanum 0 0 0 0 0 0 0 0 0 0 0 0 0.14 0 0 0 0 0 0 0 0
Haplophragmoides wilberti 0.23 0 0 0 0 0 0 0 0.20 0 0 0 0 0 0 0 0 0 0 0 0
Jadammina macrescens 0.12 0.12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Reophax sp. 0.17 0 0 0 0 0 0 0 0.12 0 0 0 0 0 0 0 0 0 0 0 0
Textularia sp. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.10 0 0 0
Tiphotrocha comprimata 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.10 0 0 0
Trochammina inflata 0.17 0 0 0 0 0.11 0 0 0.31 0 0 0 0 0 0 0 0 0 0 0 0
Trochammina sp. 0 0.12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.19 0 0
Organic lining 0.17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.12 0 0 0 0
Appendix H: Geochemical Data
Geochemical data for cores collected in Pamlico Sound. Data are listed by site number
and interval. signatures are given in respect to the ô’^N signature of air. ô*^C
signatures are given in respect to the signature of the Pee Dee Belemnite. The last
column (F/NF) represents those samples that were re-sent for either a second or third time
to the stable isotope lab. ‘F’ represents a sample that was fumigated with acid while ‘NF’
represents a sample that was not fumigated with acid before being re-sent. Samples
noted with ‘F & NF’ represent an averaged signature between fumigated and non-
fumigated samples. A indicates samples that were not used in the analysis because
the values are still questionable and were not re-sent to the lab to be double-checked.
155
Site Interval Micro g N Delta Air Micro g C Delta PDB C/N 1 %OC F/NF 1
S9 (0-2) 24.1 3.85 317.9 -24.30 13.19 0.62 I
(2-4) 22.3 3.66 287.6 -24.95 12.89 0.57
(4-6) 11.3 3.25 147.0 -24.59 12.95 0.29
(6-8) 15.2 3.43 197.5 -24.78 12.99 0.39
(8-10) 21.3 3.42 307.3 -24.79 14.44 0.61
(10-12) 20.6 3.04 323.7 -24.80 15.70 0.63
(12-14) 20.5 3.40 290.3 -24.61 14.13 0.57
(14-16) 22.4 2.84 372.9 -24.90 16.65 0.73
(16-18) 23.6 2.52 393.2 -24.68 16.67 0.78
(18-20) 22.8 2.78 345.0 -24.69 15.11 0.68
(20-22) 22.4 3.30 307.7 -24.22 13.74 0.60
(22-24) 24.2 2.98 333.5 -23.95 13.75 0.66
(24-26) 26.8 3.05 367.3 -24.13 13.72 0.72
(26-28) 27.2 2.96 397.0 -24.07 14.59 0.79
(28-30) 22.1 2.68 326.1 -24.10 14.76 0.65
(30-32) 25.9 3.05 392.5 -24.28 15.16 0.77
(32-34 17.6 2.81 256.8 -24.03 14.61 0.51
(34-36) 16.6 2.78 245.9 -24.03 14.80 0.48
S10 (0-2) 64.1 5.10 676.5 -24.40 10.55 2.79
(2-4) 52.2 5.21 557.3 -24.57 10.68 2.70
(4-6) 44.4 4.95 489.0 -24.73 11.01 2.38
(6-8) 66.8 4.60 826.9 -24.79 12.35 1.90 F
(8-10) 36.38 3.81 514.18 -26.64 14.13 1.64 NF
(10-12) 31.48 3.17 461.28 -24.57 14.65 1.31 NF
(12-14) 48.6 3.93 657.5 -24.30 13.53 0.73 NF
(14-16) 33.95 3.62 483.52 -23.71 14.24 0.51 NF
(16-18) 33.80 3.66 478.09 -23.38 14.14 0.60 NF
(18-20) 41.0 6.14 601.5 -22.88 14.66 0.59 *
(20-22) 31.90 3.74 431.30 -22.76 13.52 0.40 NF
(22-24) 47.3 7.57 696.3 -22.12 14.73 0.71 *
(24-26) 29.12 3.02 402.52 -22.20 14.13 0.70 F&NF
(26-28) 36.82 2.72 519.12 -21.88 14.10 0.37 NF
(28-30) 50.82 2.58 738.92 -20.01 14.71 1.02 F
S11 (0-2) 84.3 4.46 1342.5 -24.09 15.93 3.46
(2-4) 58.1 4.52 851.5 -24.85 14.66 1.05
(4-6) 54.21 5.02 502.16 -24.65 12.08 0.54 F&NF
(6-8) 51.26 4.44 718.78 -25.18 14.02 0.55 NF
(8-10) 35.5 2.96 556.9 -24.97 15.67 0.68 F
(10-12) 63.4 3.78 936.2 -24.73 14.77 1.22 F
(12-14) 71.6 4.11 1024.5 -24.79 14.30 1.11 F
(14-16) 52.8 4.15 762.8 -24.53 14.44 1.15 F
(16-18) 39.3 3.93 581.2 -24.66 14.79 0.86 F
(18-20) 55.7 3.21 750.0 -24.29 13.46 1.01
(20-22) 61.5 3.22 882.3 -24.32 14.34 1.18
(22-24) 60.0 3.23 852.9 -23.93 14.22 0.97
(24-26) 62.9 3.24 772.0 -23.35 12.27 1.15
S12 (0-2) 42.2 5.26 417.8 -24.05 9.91 0.51 F
(2-4) 40.50 5.36 399.97 -23.91 9.88 0.29 NF
(4-6) 17.78 5.41 161.62 -23.58 9.08 0.16 F&NF
(6-8) 47.31 5.29 479.57 -24.21 10.14 0.35 NF
(8-10) 54.51 5.50 578.45 -24.18 10.61 0.38 NF
(10-12) 41.2 4.77 434.1 -24.09 10.70 0.35 F
(12-14) 49.7 4.23 566.9 -23.87 11.40 0.55
(14-16) 32.7 4.99 368.8 -24.12 11.23 0.49 F
156
Site Interval Micro g N | Delta Air Micro g C Deita PDB C/N %OC F/NF 1
S12 (16-18) 36.1 4.45 419.8 -23.96 11.62 0.48
(18-20) 19.1 4.27 221.0 -23.93 11.59 0.20
(20-22) 36.4 3.72 425.6 -23.81 11.69 0.99
(22-24) 42.2 4.00 459.5 -23.61 10.90 0.36 F
(24-26) 47.7 4.38 534.6 -23.89 11.21 0.41 F
(26-28) 56.88 4.76 667.44 -23.86 11.73 0.34 NF
(28-30) 29.29 3.79 333.72 -22.84 11.39 0.33 NF
(30-32) 52.73 4.28 614.98 -23.39 11.35 0.62 F
S22 (0-2) 73.9 5.73 744.8 -24.21 10.07 2.19 F
(2-4) 77.2 5.67 808.4 -24.47 10.47 2.62 F
(4-6) 66.2 4.72 684.5 -24.24 10.34 2.30
(6-8) 76.8 4.45 823.5 -24.24 10.73 2.35
(8-10) 59.2 4.22 639.7 -24.24 10.81 2.36
(10-12) 59.7 4.51 630.1 -24.10 10.55 2.30
(12-14) 40.4 4.12 441.2 -23.86 10.92 2.03
(14-16) 46.1 4.18 519.8 -23.93 11.29 1.98
(16-18) 59.3 4.02 689.0 -23.98 11.62 2.12
(18-20) 50.6 3.50 568.4 -23.71 11.23 2.24
(20-22) 48.1 3.47 540.4 -23.66 11.24 2.25
(22-24) 59.4 3.56 691.2 -23.73 11.63 2.19
(24-26) 57.8 3.74 658.7 -23.67 11.40 2.23
(26-28) 49.7 3.86 563.2 -23.64 11.33 2.37
(28-30) 47.6 3.76 596.3 -23.50 12.52 2.30
(30-32) 49.4 3.63 532.3 -23.37 10.78 1.85
(32-34) 41.9 3.79 443.4 -22.83 10.58 1.59
S23 (0-2) 62.0 5.55 667.6 -23.83 10.77 0.76
(2-4) 50.7 4.80 579.8 -24.63 11.44 0.53
(4-6) 60.9 4.31 797.1 -24.87 13.09 1.00
(6-8) 42.2 3.73 650.0 -24.51 15.41 1.51
(8-10) 60.1 3.78 757.3 -23.94 12.60 2.47
(10-12) 21.8 3.22 311.8 -24.66 14.30 0.81
(12-14) 27.4 3.93 384.6 -24.51 14.01 1.65
(14-16) 29.5 3.81 395.4 -24.66 13.40 1.87
(16-18) 29.1 3.54 391.9 -24.68 13.48 1.02
(18-20) 45.0 4.54 603.7 -24.58 13.40 2.90
(20-22) 34.5 5.18 444.8 -24.55 12.89 1.91
(22-24) 47.8 3.40 586.8 -23.95 12.27 4.51
(24-26) 46.3 3.64 619.8 -24.48 13.38 4.37
S24 (0-2) 105.4 6.96 1066.1 -24.27 10.11 2.33
(2-4) 72.1 4.52 706.5 -24.22 9.80 2.27
(4-6) 80.9 4.29 786.7 -24.19 9.72 2.02
(6-8) 72.1 6.38 779.3 -24.27 10.81 2.13
(8-10) 74.8 4.20 808.7 -24.26 10.81 2.11
(10-12) 76.2 5.13 816.1 -24.16 10.71 2.07
(12-14) 67.3 4.17 764.6 -24.30 11.36 2.19
(14-16) 72.8 4.18 830.8 -24.33 11.42 2.01
(16-18) 71.4 4.32 838.1 -24.11 11.74 1.83
(18-20) 62.8 4.13 703.6 -24.10 11.20 1.84
(20-22) 67.9 4.09 772.0 -24.11 11.36 1.82
(22-24) 65.1 4.12 735.2 -24.10 11.29 1.87
(24-26) 74.1 4.02 860.2 -23.98 11.60 1.96
(26-28) 81.6 3.58 941.1 -23.77 11.53 2.05
(28-30) 71.4 3.25 794.0 -23.67 11.12 1.95
157
Site Interval Micro g N Delta Air Micro g C | Delta PDB | C/N %oc F/NF 1
S27 (0-2) 65.3 2.62 618.3 -19.10 9.47 0.59
(2-4) 74.8 3.11 697.0 -19.25 9.32 0.52
(4-6) 56.6 2.93 605.0 -19.49 10.69 0.60
(6-8) 67.8 2.04 735.2 -19.02 10.84 0.71
(8-10) 69.4 1.86 727.1 -18.76 10.48 0.72
(10-12) 70.1 2.58 742.6 -18.53 10.60 0.83
(12-14) 62.3 3.20 661.0 -18.39 10.61 0.78
(14-16) 61.5 2.94 708.7 -18.47 11.53 0.66
(16-18) 64.4 4.42 728.6 -18.68 11.31 0.60
(18-20) 71.1 1.98 819.6 -19.04 11.53 0.73
S30 (0-2) 70.6 6.15 703.9 -23.66 9.98 1.69 F
(2-4) 61.65 5.27 573.50 -23.99 9.30 0.72 NF
(4-6) 55.76 5.07 563.62 -24.14 10.11 0.76 NF
(6-8) 60.6 4.12 705.9 -23.41 11.65 1.47
(8-10) 53.02 3.92 728.82 -24.00 13.75 4.28 F&NF
(10-12) 61.55 4.72 741.60 -23.23 12.05 0.44 NF
(12-14) 48.24 4.35 643.04 -22.33 13.33 0.61 NF
(14-16) 47.7 4.49 687.7 -24.63 14.41 0.99 NF
(16-18) 50.7 4.32 794.1 -24.35 15.67 1.69
(18-20) 42.5 3.58 672.8 -24.25 15.85 1.88
(20-22) 73.98 4.42 1181.62 -21.25 15.97 1.83 NF
S31 (0-2) 60.46 6.02 568.48 -23.51 9.40 1.94 NF
(2-4) 70.89 6.04 657.55 -23.91 9.28 2.10 NF
(4-6) 52.9 6.05 494.0 -23.96 9.33 2.06 F
(6-8) 42.8 5.58 400.7 -23.92 9.36 1.57 F
(8-10) 57.2 5.42 554.8 -24.01 9.70 1.47 F
(10-12) 54.1 5.14 547.7 -23.96 10.12 1.60 F
(12-14) 55.5 5.13 588.3 -24.00 10.60 1.71 F
(14-16) 34.8 5.54 393.4 -23.35 11.29 1.79
(16-18) 35.8 5.32 405.1 -23.60 11.32 1.96
(18-20) 33.4 6.05 381.6 -23.41 11.44 1.87
(20-22) 38.0 5.60 419.8 -23.44 11.06 1.67
(22-24) 58.2 4.32 591.1 -23.68 10.15 1.98
(24-26) 45.6 3.79 469.8 -23.61 10.31 2.19
(26-28) 60.0 4.10 598.5 -23.60 9.98 2.39
(28-30) 57.1 4.00 618.3 -23.41 10.82 2.37
(30-33) 40.5 3.71 428.6 -23.62 10.57 2.14
(33-36) 47.8 3.68 504.4 -23.51 10.55 2.25
(36-39) 49.5 3.72 527.1 -23.61 10.65 2.22
(39-42) 51.2 3.73 537.4 -23.41 10.49 1.85
(42-45) 57.8 3.46 611.7 -23.25 10.58 2.31
(45-48) 52.0 3.66 540.4 -23.25 10.39 2.36
(48-51) 55.0 3.95 572.7 -23.27 10.41 1.89
(51-54) 41.2 3.70 420.5 -23.31 10.22 1.68
S32 (0-2) 46.1 5.10 445.2 -23.90 9.67 2.87
(2-4) 43.2 5.64 438.2 -24.03 10.14 2.85
(4-6) 39.6 5.17 404.8 -23.95 10.22 2.63
(6-8) 39.8 5.19 411.9 -23.89 10.34 2.65
(8-10) 38.2 5.24 382.3 -23.74 10.01 2.49
(10-12) 38.6 5.04 385.7 -23.67 10.00 2.50
(12-14) 34.0 4.88 361.5 -23.29 10.62 2.39
(14-16) 30.7 4.76 353.8 -23.01 11.52 2.34
(16-18) 29.6 4.80 338.2 -23.12 11.43 2.18
(18-20) 26.5 4.57 308.5 -22.67 11.62 2.01
158
Site Interval Micro g N Delta Air | Micro g C | Delta PDB C/N %OC F/NF 1
S32 (20-22) 27.0 4.61 303.9 -22.95 11.26 2.01
(22-24) 27.0 4.50 306.3 -23.23 11.35 2.00
(24-26) 28.8 4.39 333.8 -22.71 11.57 2.15
(26-28) 28.0 4.52 329.2 -22.37 11.74 2.14
S41 (0-2) 93.2 5.86 845.5 -23.72 9.07 1.13
(2-4) 93.2 5.58 830.8 -23.73 8.92 0.96
(4-6) 93.9 5.65 867.6 -23.68 9.24 1.44
(6-8) 91.1 4.92 860.2 -23.67 9.44 1.44
(8-10) 66.2 4.48 630.8 -23.60 9.52 1.24
(10-12) 70.1 4.78 672.0 -23.63 9.59 1.21
(12-14) 67.9 4.25 660.2 -23.59 9.72 1.54
(14-16) 68.7 4.33 698.5 -23.48 10.17 1.44
(16-18) 56.6 4.05 588.2 -23.40 10.39 1.33
(18-20) 65.8 3.97 699.2 -23.47 10.63 1.25
(20-22) 85.0 4.08 926.4 -23.32 10.90 1.49
(22-24) 65.4 4.11 680.1 -23.40 10.40 1.43
(24-26) 65.2 4.96 684.5 -23.38 10.50 1.34
(26-28) 50.0 3.91 523.5 -23.25 10.47 1.32
S42 (0-2) 80.9 5.54 749.9 -23.68 9.26 2.48
(2-4) 109.5 5.50 1021.9 -23.76 9.33 2.46
(4-6) 78.9 5.19 719.8 -23.77 9.12 2.13
(6-8) 84.3 5.15 786.7 -23.81 9.33 2.43
(8-10) 82.3 5.21 757.3 -23.80 9.20 2.00
(10-12) 79.6 4.62 772.0 -23.78 9.70 1.95
(12-14) 72.1 4.70 713.2 -23.74 9.89 1.99
(14-16) 58.8 4.46 588.2 -23.70 10.00 1.95
(16-18) 82.98 4.64 845.50 -23.64 10.19 1.62
(18-20) 60.1 4.21 611.0 -23.62 10.17 1.75
(20-22) 54.3 5.09 540.4 -23.50 9.94 1.98
(22-24) 70.7 4.04 749.9 -23.50 10.60 1.95
(24-26) 78.2 4.08 867.6 -23.45 11.09 1.90
(26-28) 70.1 4.07 749.9 -23.47 10.70 1.99
(28-30) 75.5 6.35 808.7 -23.26 10.71 1.85
(30-32) 56.8 3.43 621.3 -23.47 10.94 2.02
S50 (0-2) 64.9 4.66 585.3 -24.86 9.03 3.53
(2-4) 81.0 4.70 700.2 -24.26 8.65 3.55
(4-6) 68.4 4.35 640.1 -24.29 9.36 3.44
(6-8) 85.6 4.53 776.8 -24.09 9.07 3.11
(8-10) 75.7 4.53 689.3 -24.07 9.11 3.22
(10-12) 75.7 4.18 749.5 -23.97 9.90 3.10
(12-14) 89.6 4.50 820.6 -24.03 9.16 3.14
(14-16) 64.3 4.36 601.8 -23.81 9.36 3.10
(16-18) 77.0 4.23 776.8 -24.08 10.09 3.04
(18-20) 83.6 4.60 804.2 -24.41 9.61 3.12
(20-22) 59.8 4.36 618.2 -24.19 10.34 3.15
(22-24) 66.2 4.62 634.6 -23.85 9.59 2.64
(24-26) 60.6 4.73 585.3 -23.72 9.66 2.65
(26-28) 69.0 4.60 716.6 -23.79 10.38 2.70
(28-30) 75.7 4.73 744.0 -23.79 9.83 2.81
(30-33) 59.5 4.40 629.1 -23.74 10.57 2.68
(33-36) 63.3 4.28 623.6 -23.81 9.86 3.02
(36-39) 63.1 4.02 678.3 -23.77 10.75 3.07
(39-42) 80.3 3.90 798.7 -23.73 9.94 2.96
(42-45) 80.3 3.82 853.4 -23.55 10.63 3.16
159
Site Interval Micro g N Delta Air Micro g C Delta PDB C/N %OC F/NF
S50 (45-48) 89.6 4.04 864.3 -23.42 9.65 2.60
(48-50) 79.7 3.94 847.9 -23.50 10.65 2.62
S59 (0-2) 77.7 4.51 754.9 -23.86 9.72 2.14
(2-4) 88.3 4.57 891.7 -23.92 10.10 2.14
(4-6) 77.7 4.41 782.3 -23.73 10.07 2.31
(6-8) 85.6 4.44 891.7 -23.71 10.41 2.11
(8-10) 73.0 4.19 771.3 -23.77 10.56 2.15
(10-12) 69.03 4.00 754.93 -23.65 10.94 2.09
(12-14) 68.4 4.09 754.9 -23.51 11.04 1.98
(14-16) 67.7 3.92 744.0 -23.52 10.99 2.22
(16-18) 69.0 3.98 749.5 -23.46 10.86 1.94
(18-20) 60.9 3.87 645.5 -23.32 10.60 2.00
(20-22) 67.7 3.62 705.7 -22.79 10.42 1.21
(22-24) 66.4 3.70 678.3 -22.80 10.22 1.00
(24-26) 63.3 3.88 634.6 -22.82 10.03 1.24
(26-28) 69.7 3.84 694.8 -22.73 9.97 1.52
(28-30) 63.7 3.78 640.1 -22.66 10.04 1.80
(30-33) 71.7 4.09 711.2 -22.68 9.92 1.66
S60 (0-2) 73.7 4.58 629.1 -24.01 8.54 2.33
(2-4) 92.3 4.50 809.6 -24.23 8.77 2.46
(4-6) 98.9 4.72 864.3 -24.33 8.74 2.67
(6-8) 79.0 4.74 733.1 -24.44 9.28 2.68
(8-10) 93.6 4.82 826.1 -24.35 8.83 2.35
(10-12) 88.3 4.94 787.8 -24.10 8.92 2.22
(12-14) 85.63 4.76 787.76 -23.82 9.20 2.08
(14-16) 90.9 4.54 902.6 -23.86 9.93 1.98
(16-18) 81.6 4.58 820.6 -23.65 10.05 1.84
(18-20) 62.2 4.36 656.5 -23.33 10.55 1.82
(20-22) 67.7 4.39 700.2 -23.25 10.34 1.68
(22-24) 62.4 4.04 640.1 -23.27 10.26 1.64
(24-26) 61.8 4.13 645.5 -23.30 10.45 1.63
(26-28) 76.3 3.80 809.6 -23.28 10.61 1.67
(28-30) 68.4 3.78 716.6 -22.74 10.48 1.72
(30-33) 60.7 3.72 640.1 -22.45 10.54 1.81
S61 (0-2) 78.3 4.63 700.2 -23.69 8.94 2.31
(2-4) 85.0 4.68 776.8 -23.62 9.14 2.09
(4-6) 68.4 4.63 651.0 -23.51 9.52 2.11
(6-8) 73.7 4.52 727.6 -23.56 9.87 2.07
(8-10) 75.0 4.58 754.9 -23.43 10.06 1.94
(10-12) 73.7 4.52 760.4 -23.42 10.32 2.03
(12-14) 49.2 4.22 497.3 -23.26 10.11 2.12
(14-16) 70.4 4.30 733.1 -23.42 10.42 1.98
(16-18) 65.8 4.37 689.3 -23.31 10.47 1.92
(18-20) 56.6 4.14 596.3 -23.10 10.54 1.59
(20-22) 58.1 4.11 618.2 -23.01 10.64 1.37
(22-24) 54.5 4.05 612.7 -22.81 11.24 0.87
(24-26) 50.4 4.06 563.5 -22.64 11.17 1.04
(26-28) 44.3 3.99 495.1 -22.50 11.17 1.15
(28-30) 54.6 4.13 612.7 -22.57 11.22 1.20
(30-33) 53.2 4.12 596.3 -22.56 11.20 0.68