Collaborative Research: Using models and historical data to guide effective monitoring and enhance understanding of deep ocean oxygen variability

The ocean is home to larger lifeforms that need oxygen to breathe and smaller lifeforms that produce about half of the oxygen we end up breathing. Concerningly, the observational record indicates that the ocean is losing its oxygen content. State-of-the-art climate models predict this trend will continue through the end of the 21st century. Rates and cause of the oxygen loss are highly uncertain due to sparse data coverage. In recent years, we have learned greatly about the ocean’s salinity and temperature changes from measurements made by the fleet of profiling floats of the Argo program. To date, most of these floats have not measured oxygen. Proposed expansions of the Biogeochemical (operating over the upper 2000 m) and Deep (4000 to 6000 m) components of the Argo program will address this deficit in oxygen measurements. This project will devise an effective sampling protocol for observing ocean oxygen over the full ocean depth. This project will use existing oxygen observations and state-of-the-art numerical tools to provide the first design of a feasible and effective oxygen sampling strategy. The focus is on the role of Deep Argo. This work will calculate the float populations and distributions required to resolve oxygen changes over time and space. At the same time, this work will account for the accuracy and stability of oxygen measuring instruments. Numerical models will be used to determine how historical and additional oxygen data can reduce the uncertainty in understanding of ongoing ocean oxygen loss. Through the course of the project, the researchers will lead several events and create teaching materials to engage the next generation of ocean scientists. They will communicate the importance of ocean oxygen loss, the influence of climate change, and the opportunity to better protect ecosystems through improved oxygen monitoring. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.