Our general field of research is Microbial Ecology, and we sought to answer the question of how Antarctic microbial communities grow and change under oxidative stress. Antarctica is a perfect resource for studying microorganisms, as the ice-covered lakes are one of the few places where there is an entirely microbial food web. This simplified food web allows for easier interpretation of the different relationships between microbes at each food chain level. It may not be realized, but microbes play an important role in all aspects of life. The first step to developing methods in which to prevent damage to important microbes is understanding how microorganisms deal with harmful oxygen species. Lake water samples were taken from Lake Fryxell, Antarctica, and grown in enrichment cultures. Three experimental groups were grown under conditions of oxidative stress by introducing hydrogen peroxide, while three cultures were grown under control conditions. We took measurements of cell density, photosynthetic efficiency (energy-creation), and cell count while also sequencing the diversity of bacteria (16S rRNA) and eukarya (18S rRNA). We found that when comparing physiological data to that of the control groups, the cell density and count increased while the photosynthetic efficiency was relatively the same. This suggests that the communities present may have the capacity to mitigate damage and stress caused by the reactive oxygen species present in their environment, whether that be from interactions among each other or their own stress responses. We also found that both bacterial and micro eukaryal diversity was lost between control communities and those impacted by ROS. Further research could involve proteomics or transcriptomics to measure expression of enzymatic response to ROS exposure. Overall, this experiment has expanded our knowledge of laboratory techniques and given us an understanding of how microbial ecology research is conducted, preparing us for our future careers.
Authors: Rocco Huston, Maddy Spencer
Faculty Advisor: Rachael Morgan-Kiss, Microbiology
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