Effects Of Nutrient Availability And Disturbance On The Composition And Diversity Of Soil Microorganisms
Thigpen, Joshua C.
Determining how factors such as disturbance and nutrient availability affect species diversity in a community has been a major goal of community ecology. The purpose of this study was to look at how species diversity and composition of soil bacterial communities are affected by nutrient addition and disturbance. I characterized soil microbial communities at the long-term ecological research site at the West Research Campus (WRC) located in Pitt County, NC. Briefly, DNA extracted from soils was analyzed using amplicon sequencing of the 16S ribosomal RNA gene. The Illumina Platform was used to sequence the bacterial DNA from each sample, and the Mothur Pipeline was used to analyze the DNA sequences. I hypothesized that changes in nutrient availability and disturbance would impact soil microbial community composition and diversity through direct and indirect effects mediated by plant-soil interactions. My research complemented previous work carried out in the WRC determining the effects of nutrient addition and disturbance on plant communities. Analysis of 2013 plant data showed that mowing increased plant species richness, and fertilization decreased plant species richness significantly. The experimental treatments as well as the proximity of the blocks to a drainage ditch all had significant effects on plant community composition. Analysis of the microbial community data showed that both fertilization and mowing significantly increased mean species richness. Relative abundance microbial community composition varied significantly due to the proximity of the blocks to the ditch. Presence/absence microbial community analyses showed significant effects of the treatments, as well as ditch proximity on microbial composition differences. Also, unknown microbial communities showed significant variation of the communities due to the treatments. The results of the presence/absence analysis and the unknown microbial community analysis show the importance of rare taxa and unknown microbial communities to the differences in composition of our soil microbial communities. Analysis of the soil chemical and physical data showed very little variation due to the treatments. This study will contribute to our understanding of how both plant and soil bacterial community diversity are affected by anthropogenic nutrient addition and disturbances. Maintaining diversity is important for ecosystem stability and functioning.
Thigpen, Joshua C.. (January 2015). Effects Of Nutrient Availability And Disturbance On The Composition And Diversity Of Soil Microorganisms (Master's Thesis, East Carolina University). Retrieved from the Scholarship. (http://hdl.handle.net/10342/5040.)
Thigpen, Joshua C.. Effects Of Nutrient Availability And Disturbance On The Composition And Diversity Of Soil Microorganisms. Master's Thesis. East Carolina University, January 2015. The Scholarship. http://hdl.handle.net/10342/5040. December 13, 2018.
Thigpen, Joshua C., “Effects Of Nutrient Availability And Disturbance On The Composition And Diversity Of Soil Microorganisms” (Master's Thesis., East Carolina University, January 2015).
Thigpen, Joshua C.. Effects Of Nutrient Availability And Disturbance On The Composition And Diversity Of Soil Microorganisms [Master's Thesis]. Greenville, NC: East Carolina University; January 2015.
East Carolina University