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NOAA awards grant to study impacts of oxygen depletion, acidification in fish and oyster habitat

NOAA awards grant to study impacts of oxygen depletion, acidification in fish and oyster habitat

The National Oceanic and Atmospheric Administration (NOAA) has announced it will award a five-year, $1.6 million grant to University of Delaware Prof. Timothy Targett and colleagues at the Smithsonian Environmental Research Center (SERC) and Louisiana State University (LSU).

The award, through NOAA's Coastal Hypoxia Research Program, will support research to predict the impact of daily cycles of hypoxia and pH in shallow estuarine waters on ecologically and economically important finfish and shellfish.

Results of this study will help environmental and fisheries managers pinpoint key areas for habitat and fisheries restoration, and better protect shallow water estuarine habitat that serves a critical nursery function.

Hypoxia is a condition of low oxygen levels in the water. Hypoxic waters can become insufficient to support growth, reproduction, and even survival of fish and shellfish. Although hypoxia can occur naturally, it is often worsened by excess nutrients from human activities such as coastal development and agriculture.

The deep waters of Chesapeake Bay, for example, experience hypoxia and even anoxia (no oxygen) during summer. However, as continuous oxygen monitoring has increased in shallow tributaries and near-shore areas of estuaries worldwide, it has become apparent that many of these habitats experience day-night “swings” in oxygen concentrations that result in hypoxia and anoxia during night and early morning hours.

The study will examine how daily cycles of hypoxia impact growth, reproduction, and survival of fish and shellfish in these productive shallow water nursery areas. It will focus on species with significant commercial value for the region, including summer flounder, striped bass, weakfish, white perch, and the eastern oyster, as well as important prey fish such as the mummichog.

The researchers also will study the effects of acidification (decline in pH) that is linked with hypoxia and may exacerbate its impact on fish and oysters.

Laboratory experiments will be conducted in Targett's laboratory at UD's Hugh R. Sharp Campus in Lewes and at Senior Scientist Denise Breitburg's laboratory at SERC; field sampling will be conducted in Chesapeake Bay; and ecological modeling to predict how daily hypoxia and pH cycles affect abundance and production of fish and oysters in Chesapeake Bay will be done at LSU and at the NOAA Chesapeake Bay Office.

“Daily hypoxia and pH cycles are a common feature in shallow estuarine waters throughout our region,” said Targett, who is professor of marine biosciences in the College of Earth, Ocean, and Environment. “This will be the first time the potentially compounding effects of acidification are investigated in conjunction with hypoxia and the first time results from controlled laboratory experiments and extensive field sampling are combined with predictive models to study hypoxia effects on the productivity of these shallow water nursery habitats.”

The research team will collaborate closely with state and federal management agencies, including NOAA's Chesapeake Bay Office, EPA's Chesapeake Bay Program, and Maryland's Department of Natural Resources.

Numerous Sea Grant-supported projects led to the proposal for this project. To learn more about Delaware Sea Grant, visit its website.