Integrating Coastal and Oceanic Perspectives on Deoxygenation: Introduction to the Session

Deoxygenation of coastal and oceanic waters is one of the major manifestations of global change. Historically, eutrophication-induced hypoxia in coastal ecosystems and naturally occurring oceanic hypoxic zones (including oxygen minimum and limiting zones, and their shoaling into coastal habitats) have generally been viewed as distinct phenomena. Both forms of deoxygenation are, however, predicted to worsen with increasing temperatures, are affected by surface layer productivity, and affect physiological processes, animal movement and fishing practices. Processes relevant within oceanic or coastal waters are translated across water bodies by the movement of organisms and their dependence on multiple habitats to complete life cycles, as well as by spatial shifts in human pressures as local environmental and fishery resources degrade.

As researchers, we risk missing insight that can be gained by considering similarities and differences in processes that occur across a range of hypoxic habitats. Parallels in eutrophic and oceanic systems range from the potential for fish to become more susceptible to fishers because of predictable avoidance of oxygen-depleted habitat, to the importance of acidification as a co-stressor with hypoxia, to the effects of rising temperatures on deoxygenation through multiple mechanisms. In addition, questions, tools and approaches developed for one realm may provide pathways to new knowledge when applied in other kinds of systems. We provide examples in this talk, and papers presented in this session will flesh out the potential for forging stronger scientific linkages among researchers studying deoxygenation in estuarine, coastal and oceanic ecosystems.