Climate downscaling projections of estuarine acidification and hypoxia in Chesapeake Bay in the 21st century

Ming Li1, Yijun Guo2, Wei-Jun Cai3, Jeremy M Testa4, Chunqi Shen4, Wenfei Ni5 and George Gerard Waldbusser6, (1)University of Maryland Center for Environmental Science Horn Point Laboratory, Cambridge, MD, United States, (2)University of Maryland Center for Environmental Science Horn Point Laboratory, Cambridge, United States, (3)University of Delaware, School of Marine Science and Policy, Newark, DE, United States, (4)University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, Solomons, MD, United States, (5)University of Maryland Center for Environmental Science, Horn Point Lab, Cambridge, MD, United States, (6)Oregon State University, College of Ocean, Earth and Atmospheric Sciences, Corvallis, OR, United States
Abstract:
Climate change is expected to have more pronounced effects on acidification in estuarine and coastal systems than in the open ocean, but the coupled eutrophication-acidification processes in a changing climate need to be better understood. Using a coupled hydrodynamic-biogeochemical-carbonate chemistry (ROMS-RCA-CC) model, we conducted climate downscaling projections for ocean acidification and dissolved oxygen in Chesapeake Bay in the 21st century. ROMS-RCA-CC was forced by regionally downscaled and bias-corrected projections from regional and global climate models. The model showed that pH decreases by ~0.3 between 2000 and 2050 and experiences larger reductions in early summer (0.4) than in late summer (0.2). This variation of the pH reduction appears to be related to the earlier initiation and earlier termination of hypoxia in a warming climate. The hypoxic volume is projected to increase by 20-30% while the acidic volume is projected to increase by 50-60% by the mid-21st century. Examination of pH-O2 relationship reveals large and abrupt pH decreases in anoxic waters in the future climate.
Back to: Advances in Coupled Physical-Biogeochemical Modeling: Continental Shelves, Estuaries, and the Coastal Ocean I