LoTSHMiR 2028 Spring

Coastal hypoxia occurs when dissolved oxygen decreases below 2 mg/L (~62.5 µM), impacting marine animals, including valuable fisheries species. One of the largest hypoxic zones occurs along the Louisiana-Texas continental shelf, where bottom water dissolved oxygen depletion can cover tens of thousands of square kilometers, with substantial impacts on fisheries and the local and regional economies. The majority of marine dissolved oxygen consumption results from microbial metabolism, however, the relative contributions of different microbial metabolisms to oxygen consumption remains unknown, limiting our ability to link microbial community composition and abundance with oxygen dynamics. The overarching question addressed by our work is: how is total oxygen consumption partitioned across different microbial groups with unique oxidative metabolisms? We will quantify rates of metabolic activity from the most abundant dead zone microorganisms using a combination of in situ measurements, shipboard incubations and collections that lead to single cell-sorting, advanced multi-omics, culturing, and metabolic modeling. This research will quantify the energy sources and oxygen consumption rates of the most important coastal microbes responsible for oxygen drawdown and model the microbial guilds responsible for the most critical metabolisms associated with the seasonal cycle of coastal hypoxia.