Oxygen minimum zones (OMZs) in the world's oceans typically occur below regions of high productivity where oxygen is utilized in the remineralization of sinking detritus by bacteria. The Arabian Sea OMZ is one of the most intense such zones in the world ocean with near-total depletion of oxygen in the eastern-central Arabian Sea at a depth from 100-1000 m. Remarkably, the zone is shifted well to the east of the most productive regions of which are located in the western basin.
In this project, scientists from the University of Hawaii and the University of Maryland will collaborate with international partners from India and Japan in order to understand the processes that determine the strength and location of the Arabian Sea OMZ. Their working hypothesis is that physical, and not biological, processes shift this zone to the eastern basin through eddy processes. A hierarchy of physical models will be utilized for this study, each will be coupled to a biological model (NPZD) with an oxygen package.
The research aims to understand basic biophysical processes of the Arabian Sea oxygen minimum zone and the results should be applicable to other such regions in the world's oceans. Because of its intensity, understanding the dynamics of the Arabian Sea OMZ is of global importance. Because of its "reducing conditions," the zone impacts the global nitrogen inventory and hence the degree of nitrogen limitation and carbon export. In addition, through the production of N2O, the zone also influences greenhouse gas accumulation in the atmosphere. Finally, the zone is known to have varied considerably on geological time scales which suggests that it may be affected by modern climate change.
The research also contributes to international programs including the development of the CLIVAR/GOOS Indian Ocean observing system and Integrated Marine Biology and Ecosystem Research (IMBER).
