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Coastal Deoxygenation: An Impact of Global Warming
Bala Krishna Prasad
Mathukumalli, University of Maryland, mbkp@umd.edu
(Presenter)
Climate Change induced warming of temperatures can reduce solubility of atmospheric oxygen in water and enhance biospheric respiration, leading to deoxygenation in coastal waters. Oxygen depletion may disrupt the structure and function of the coastal ecosystem and biodiversity. Long-term records of air temperatures in conjunction with in-situ water temperatures and dissolved oxygen (DO) levels of the two important estuaries of North America, viz., the Chesapeake Bay and the San Francisco Bay are analyzed to delineate the potential relationships between temperatures and DO responses. The annual mean air temperatures and water temperatures increased by 0.023-0.051˚C yr-1 in the Chesapeake Bay and 0.0001-0.0149 ˚C yr-1 in the San Francisco Bay. Long–term increases in water temperatures are typically correlated with air temperatures. Negative correlations between increased water temperatures and DO suggested that rising temperatures may impede the kinetic exchange of oxygen across the air-water interface in coastal waters. Various climate circulation models predict significant increases in the global air temperatures with regional specificities and a dependence on CO2 emission scenarios. Rising temperatures can be expected to interact with nutrient loadings, which themselves are increasing along most of the coasts, to influence future DO dynamics in coastal waters. The interactive effects of eutrophication and rising temperatures represent multiple stressors with a potential for nonlinear cascades or even irreversible tipping points for the associated ecosystems. Any adaptive or mitigative efforts will require enhanced process understanding of these biophysical-biogeochemical interactions and feedbacks to extract predictive understanding leading to reliable and skillful ecological forecasting. Presentation Type: Poster Session: Global Change Impact & Vulnerability (Tue 11:30 AM) Associated Project(s):
Poster Location ID: 228
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