Microbial Ecology explores the way microbes interact with their environment, and the greater impact it has on their ecosystems both local & global. Aquatic ecosystems are dependent on primary production by algae to fix carbon, which contributes to over 50% of CO2 fixation globally. This is especially the case for microbial communities found within Antarctic Frozen lakes: as lake levels rise due to increased summer streamflow, algae are exposed to varying levels of salinity which would impact algal-bacterial interactions. As part of MBI475: Microbial ecology, we explored the impact of salinity on algal growth, bacterial abundance, and bacterial diversity. Through Enrichment Culturing of environmental samples at varying salinity, measurement of chl-a concentrations, and size fractionation filtering of DNA, we explored the impact of salinity on freshwater Antarctic communities found at 6 meter depths within West Lobe Lake Bonney in the McMurdo Dry Valleys. We found significant differences in bacterial diversity between treatments, Planktonic & Attached bacteria, and algal growth rates. Moderate levels of salt stress seemed to cause more bacterial attachment while higher levels of salt stress led to increased algal growth. Additionally, attached communities seemed to have greater sensitivity to these changes than did planktonic bacteria.
Author(s): Eckhardt Karsten, Microbiology and Environmental Science Major
Gabriel Tonucci, Microbiology Major
Advisor(s): Rachael Morgan-Kiss, Department of Microbiology
Bradley Kryziak, Department of Microbiology
Rochelle Pereira, Department of Microbiology
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