Land Use Impacts on Microbial Communities in a Coastal Virginia Lake

Background

Microbial Communities play an important role in the ecosystem with impact on nutrient cycling, organic matter decomposition, and water quality. Land use changes like urbanization and agricultural practices significantly affect these microbial ecosystems. Stormwater runoff facilitates the movement of materials which include soil particles, free bacteria and virus, dissolved nutrients and petroleum products. The runoff from areas of high land use tend to carry high levels of pollutants, particularly glyphosate. These conditions are favorable for eutrophication which create harmful algal blooms. To further understand the microbial communities and their interaction with land use, our research used Lake Matoaka and its streams as a model. Each site is the measure of activity and community. This is paired with geochemical and physical variables whch relate to each site. 

Methods 

• Sites were chosen on the basis land use, stormwater retention, runoff zones. 

• Each site recorded Temperature, pH, conductivity, and dissolved oxygen PO4, NO3, NO2 DOC

• For Biological Analysis : 

  • Abundance : Epifluorescence 

  • Richness :  Bacteria -16s RNA amplicon Sequencing, Viral - RAPD

  • Activity : ³H-leucine incorporation 

Results

Bargraph Trends and Diveristy

NMDS Ordination Plots

Discussion

• Similarities between community composition of Proteobacteria with the community composition across all samples.

• Cyanobacteria appears to be greatly influenced by season.

• Greater diversity of species in the Spring/Summer seasons than the Autumn/Winter seasons.

• Greater diversity of species in the forested Patagonia watershed.

• Further research will examine how nutrient abundance influences the microbial diversity of this ecosystem.