Spatio-temporal Variability in the Phototrophic Chemocline Community at Fayetteville Green Lake (new York)
Open Access
- Author:
- Hunter, Stamatina Elizabeth
- Graduate Program:
- Geosciences
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 06, 2012
- Committee Members:
- Lee Kump, Thesis Advisor/Co-Advisor
- Keywords:
- Green Lake
Meromictic
anoxia
euxinia
biomarkers
pigments
carotenoids. - Abstract:
- Anoxic and sulfidic (euxinic) marine conditions may have been widespread in the Proterozoic, and there is strong evidence for episodic anoxia and euxinia during the Phanerozoic, sometimes tied to mass extinction. Geochemical and microbiological studies of modern analogs (e.g. meromictic lakes) of ancient euxinic environments are essential for furthering our understanding of the stability of euxinic environments and the microbial communities that dominate them. Here, for the first time, we report the seasonal analysis of primary pigments and carotenoids in the microbially dominated chemocline (18-22 m) of meromictic Fayetteville Green Lake (New York) from May 2011 to November 2011. Okenone and BChl-a* are the most abundant pigments in the chemocline in May and June, reaching maximum concentrations at 20 m and 20.5 m depth, respectively. From August through November, the most abundant pigment in the chemocline is BChl-e* reaching a maximum concentration at 21 m in August, September and October, and 20.5 m in November. Our results for the 2011 season reveal a deepening of the chemocline community through time, a shift from a chemocline dominated by PSB pigments to a chemocline dominated by GSB pigments, and finally a slight shallowing of the chemocline community in November. We observed stratification between Chl-a* at 20 m, BChl-a* and okenone at 20.5 m and BChl-e* at 21 m beginning in August and continuing through November. Coupled to physical-chemical data, these results indicate a dynamic relationship between the microbial community and seasonally variable environmental conditions, with subsequent influence on the ambient chemocline environment.