Award: OCE-1153295

This project funded the technical development and testing of new techniques to study relatively small (by volume) but important and poorly studied regions of the ocean called Oxygen Deficient Zones (ODZs). Centered on the eastern side of most ocean basins close to the continental shelf and at a few hundred meters below the sea surface, ODZs have very low dissolved oxygen (O2) concentration and natural microbial communities that remove nutrients and produce nitrogen gas (N2) in a process called denitrification. Expansion of ODZs through ?Ocean Deoxygenation? may be a response to global warming that has already resulted in more intense ocean nutrient loss over recent decades. Knowing nutrients, phytoplankton production and fisheries are closely related, we developed a new oceanographic sensor to measure N2 concentration and N2 production rates in seawater on robotic profiling platforms that transmit the data via satellite. We can now, for the first time, use these autonomous oceanographic sampling platforms to remotely measure N2 in ODZs and track temporal and spatial variability in denitrification rates in near real-time. The new sensor is commercially available and can be used more widely in environmental research and monitoring (e.g., to study the rate of exchange of gases between the atmosphere and ocean, the causes and consequences of coastal hypoxic ?dead zones?, the impacts of aquaculture on seawater quality, and the effects of upstream dams on juvenile salmon mortality rates in rivers and estuaries via ?gas bubble disease?). Last Modified: 09/05/2018 Submitted by: Craig Mcneil