The presence of oxygen is required for the survival of complex animals in the ocean, e.g. most zooplankton, fish, marine mammals, etc. Oxygen rich environments promote biological and geochemical complexity and healthy ecosystems. However, large areas of the oceans and tremendous volumes of water are impacted by hypoxia, defined as low oxygen conditions where oxygen concentrations are <2 mg/L (see The United Nation’s Global Ocean Oxygen Network) and low oxygen conditions are predicted to spread as a consequence of climate change and eutrophication. Oxygen depleted marine systems occur near shore (e.g. the Gulf of Mexico hypoxic zone along the Louisiana-Texas Shelf) and in the open ocean (e.g. the Eastern Tropical North and South Pacific or the Arabian Sea). Oxygen depletion significantly alters the microbiology of a system and also fundamentally changes the nature of elemental cycling.
Our work on oxygen depleted pelagic environments has focused thus far on the Gulf of Mexico hypoxic zone but we hope to expand in the future to study similar dynamics in other systems.