BACTERIOPLANKTON DYNAMICS DURING SEASONAL ANOXIA EVENTS IN THE POTOMAC RIVER

Widespread anoxia has been observed in estuaries globally as a combined result of hydrodynamics and eutrophication. During these events, increases in nutrient input drive phytoplankton blooms and subsequent decomposition by heterotrophic bacteria, drawing down oxygen levels. Warm water and stratification also contribute to anoxia as oxygen concentrations are influenced by water exchange and vertical mixing processes. It is expected that anoxia events may increase in size and frequency due to climate change. The Chesapeake Bay is one of the most extensively studied hypoxic estuaries and ecosystems in the world, with drivers being a combination of eutrophication and density stratification. Similar drivers influence anoxic events in the Potomac River Estuary, a tributary of the Chesapeake Bay. However, there is a paucity of data on the dynamics of the microbial community during these events. Seasonal anoxic events have extended further upriver during summer months each year. Here, a long-term fixed monitoring station, Ragged Point (38°10'0.12" N, 76°34'58.8" W), was sampled during anoxia, hypoxia, and oxygenation in 2024. Water samples were collected and filtered from 5 depths to build a vertical profile of the microbial community using metagenomics. The goal of this study is to delve into the relationship between dissolved oxygen, including anoxic events, and their influence on the functional potential of bacterioplankton communities in the Potomac River.

Presentation Preference: Either

Primary Presenter: Alexis Berger, George Mason University (aberge2@gmu.edu)

Authors:

Alexis Berger, George Mason University  (aberge2@gmu.edu)

Jennifer Salerno, George Mason University  (jsalerno@gmu.edu)