How sensitive are systems in the Chesapeake Bay to acidification and nutrient pollution?

Jeremy Testa, University of Maryland

The wild oyster industry has suffered repeated collapses in the Chesapeake Bay due to overharvesting, disease, and declining environmental conditions. How future conditions will affect the Eastern oyster remain uncertain, not only because these conditions such as increased freshwater are difficult to predict , but also because the interactions between stressors such as ocean acidification, temperature, nutrient runoff and sea level rise could lead to unexpected chemical, biological, and economic change. The changes in stressors and their impacts do not always proceed in a straight line.The potential responses of various life stages of the Eastern oyster to stressors like acidification and eutrophication has received little attention. This project will study the impact of different stressors to Chesapeake Bay, a large estuarine system, and the Eastern oyster. The study will bring together different models to understand the relationship between biogeochemical cycling of carbon, oxygen, and nutrients, oyster growth and survival, and oyster economic profitability in the Chesapeake Bay ecosystem. The project will provide insights into future conditions and habitats where aquaculture and wild oyster populations may be most vulnerable to the climate and ocean changes.
Tuesday, October 2, 2018

Can meadows of underwater eelgrass help mitigate the harmful effects of Ocean Acidification on Eastern oysters?

Emily Rivest, Virginia Institute of Marine Science

Submerged Aquatic Vegetation (SAV), such as eelgrass, could mitigate the harmful impacts of ocean acidification on Eastern oysters by reducing the acidity of waters where oysters grow. These underwater grasses take up carbon dioxide and release oxygen into coastal waters, reducing the exposure of marine organisms to increases in acidity conditions that slow or stop oyster growth and reproduction. Oysters, in turn, improve water clarity forseagrasses to thrive by filtering particles out of the water and allowing more sunlight to penetrate. This modeling project will identify the threshold of acidification beyond which the economically important Eastern oyster is negatively impacted and will evaluate the potential benefit of seagrasses in protecting oysters and the ecosystem services they provide. The modeling tool will also identify the acidification conditions in which seagrass restoration is most helpful and when the economic benefits of this restoration to Easter oyster production outweigh the costs. At the end of this project, the final model will be freely available as an online tool and will help scientists, managers and oyster growers assess the potential for both seagrass and oyster restoration.
Tuesday, October 2, 2018
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