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Hypoxic waters: Researching beyond the surface to understand the impact on fisheries

Friday, March 19th, 2010

Two summer interns in a boat measuring the water's dissolved oxygen.

Two summer interns measure the water's dissolved oxygen concentrations. Water is typically considered hypoxic if oxygen concentrations are below 2mg/L. Photo: Courtney Richmond

Habitat destruction comes in many forms. The obvious include the clear-cutting of forests and the removal of mountaintops. Then there is the damage that’s less visible, like hypoxia.

In coastal waters around the world there are more than 500 hypoxic zones. These are areas where dissolved oxygen concentrations are so low that they threaten fish, invertebrates and aquatic food webs. Some fish manage to escape hypoxic areas, but oysters, clams and other sessile creatures are simply stuck.

Hypoxia makes the evening news when there’s a noticeable fish kill. However many of its effects are more subtle. Individuals that fail to escape low oxygen zones can suffer mortality or reduced growth and reproduction. Creatures that flee can become easy targets for fishermen and predators.
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Posted in Ecology, Fisheries, Interns, Publications | 1 Response »
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Climate change may drastically alter Chesapeake Bay, scientists say

Thursday, December 3rd, 2009

Smithsonian researchers Lori Davias and Jenna Malek collect oysters on an intertidal reef in the Chesapeake Bay. It is difficult to predict the effect of climate change on oyster populations because increasing temperatures will likely have at least two opposing effects. On one hand, intertidal oyster populations may be able to expand northward as winter temperatures rise. On the other hand, increasing summer temperatures are likely to worsen the problem of low oxygen concentrations and may reduce the extent or suitability of some subtidal habitat currently used by oysters. At this point, scientists are unable to predict whether the combination of these two factors will result in a net increase or net loss of habitat. Photo: Sean Fate

Smithsonian researchers Lori Davias and Jenna Malek collect oysters on an intertidal reef in the Chesapeake Bay. It is difficult to predict the effect of climate change on oyster populations because increasing temperatures will likely have at least two opposing effects. On one hand, intertidal oyster populations may be able to expand northward as winter temperatures rise. On the other hand, increasing summer temperatures are likely to worsen the problem of low oxygen concentrations and may reduce the extent or suitability of some subtidal habitat currently used by oysters. At this point, scientists are unable to predict whether the combination of these two factors will result in a net increase or net loss of habitat. Photo: Sean Fate

It is one of the largest and most productive estuaries in the world, yet dramatic changes are in store for the Chesapeake Bay in coming decades if climate change predictions hold true, say a team of scientists from the Smithsonian Environmental Research Center, the University of Maryland, Pennsylvania State University, and other research organizations in a recent paper published in the journal “Estuarine, Coastal and Shelf Science”

Using forecasts of atmospheric carbon dioxide production for the coming century, the scientists predict the water of the Bay will see rising levels of dissolved carbon dioxide and higher water temperatures. As a result, climate change is expected to worsen problems of low dissolved oxygen concentrations in the Chesapeake’s water and cause sea levels to rise.
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Posted in Climate Change, Fisheries, Publications, Water Quality | No Responses »
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$5 million grant from NOAA funds Chesapeake Bay research

Tuesday, November 10th, 2009

If the Chesapeake Bay could drive, it would have a severe case of road rage. The nation’s largest estuary is stressed out. That’s putting it mildly.

The Chesapeake Bay Watershed. Landsat imagery courtesy of NASA Goddard Space Flight Center and U.S. Geological Survey.

The Chesapeake Bay Watershed. Landsat imagery courtesy of NASA Goddard Space Flight Center and U.S. Geological Survey.

Nutrient runoff, shoreline development and invasive species are just a few of the factors contributing to the Chesapeake Bay’s poor health. For decades, scientists at the Smithsonian Environmental Research Center (SERC) have been teasing out how these “stressors” impact the Bay’s plants and animals. A new $5 million grant from the National Oceanic and Atmospheric Administration (NOAA) will help bolster their efforts.
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Posted in Fisheries, Invasive Species, Land Use, Water Quality | 1 Response »

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