Oyster Aquaculture Could Significantly Improve Potomac River Estuary Water Quality plus 1 more

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Oyster Aquaculture Could Significantly Improve Potomac River Estuary Water Quality plus 1 more

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Oyster Aquaculture Could Significantly Improve Potomac River Estuary Water Quality

Posted: 09 Apr 2014 07:00 AM PDT

Summary: Oyster aquaculture in the Potomac River estuary could result in significant improvements to water quality, according to a new NOAA and U.S. Geological Survey study published in the journal Aquatic Geochemistry.

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Contact Information:

Ben  Sherman ( Phone: 301-713-3066 ); Karen Rice ( Phone: 434-243-3429 );

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Oyster aquaculture in the Potomac River estuary could result in significant improvements to water quality, according to a new NOAA and U.S. Geological Survey study published in the journal Aquatic Geochemistry.

All of the nitrogen currently polluting the Potomac River estuary could be removed if 40 percent of its river bed were used for shellfish cultivation, according to the joint study. The researchers determined that a combination of aquaculture and restored oyster reefs may provide even larger overall ecosystem benefits. Oysters, who feed by filtering, can clean an enormous volume of water of algae which can cause poor water quality 

The study is based on data modeling and an ecosystem-wide scientific evaluation, which examined how activities in the watershed affected the river estuary’s water quality. The research team evaluated nitrogen flows from the Potomac River headwaters and the nutrient-related water quality conditions of the estuary, called eutrophication.

Eutrophication takes place when a body of water becomes enriched in dissolved nutrients that stimulate the growth of aquatic plants, causing nuisance algal blooms. These blooms often result in the depletion of dissolved oxygen and the loss of seagrasses.

The team sought to assess how shellfish aquaculture – specifically oyster aquaculture -- could be used to remove nutrients directly from the water, complementing traditional land-based measures.

Although the estuary bottom area needed to grow oysters to remove the nutrients exists, it is unlikely that such a management measure would be implemented because of conflicting uses. However, a smaller area could still provide great benefits if aquaculture leases were approved. According to the study, if only 15 to 20 percent of the bottom was cultivated it could remove almost half of the incoming nutrients.

“Our study looked to see just how much impact oyster aquaculture could have in restoring some balance to the system,” said Suzanne Bricker, physical scientist in NOAA’s National Centers for Coastal Ocean Science and the paper’s lead author. “Eutrophication conditions in the Potomac River estuary are representative of conditions found in the Chesapeake Bay and many other U.S. estuaries. Historically, waters of the Potomac and other Chesapeake region estuaries were filtered by oysters, but as their populations declined so did their filtration capabilities. This resulted in increased concentrations of nutrients and related water quality concerns, such as algal blooms and low dissolved oxygen.

“The most expedient way to reduce eutrophication in the Potomac River estuary would be to continue reducing land-based nutrients complemented by a combination of aquaculture and restored oyster reefs. The resulting combination could provide significant removal of nutrients and eutrophication impacts directly from the water column, and offer innovative solutions to long-term persistent water quality problems.”

This alternative approach to water quality management has the potential to address legacy pollution, provide a marketable seafood product if there are no other contaminant issues that would prevent human consumption, and enhance local economies with additional income to growers through the possible development of a program -- similar to those being considered in other parts of the country -- where growers would be paid for the water cleaning services done by their oysters.

Flowing into the Chesapeake Bay, the Potomac River is the fourth largest river on the Atlantic coast, with more than six million people living in its watershed. The NOAA and USGS research about human influences on water quality found that the effects of high nutrient levels have not changed overall since the early 1990s. There are, however, some signs of improvement, such as decreased nitrogen loads from the watershed, increased dissolved oxygen and decreased algal blooms in the upper estuary, and continued regrowth of seagrasses.

While scientists have seen signs of improvement, they remain concerned with eutrophication. Dissolved oxygen, a key measure of water quality, is something fish and other aquatic species can’t survive without.

Atmospheric deposition—where gases and particles are released into the atmosphere from combustion of fossil fuels and return to the land as contaminants—also plays a role in polluting the estuary.

“Less attention has been paid to monitoring the effects of atmospheric deposition in headwater streams now that acidic emissions have declined because of the Clean Air Act and Amendments going into effect,” said Karen Rice, USGS research hydrologist. “Nevertheless, monitoring of forested, headwater streams that reflect changes in atmospheric inputs should be continued, if not expanded, so that changes in stream-water quality as related to atmospheric deposition can be tracked.”

The researchers believe the results of the study may be useful on a broad basis, as there are other river-dominated estuaries in the Chesapeake region and elsewhere along the U.S. coastline that could support shellfish aquaculture.

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Sea Otters Can Get the Flu, Too

Posted: 08 Apr 2014 09:45 AM PDT

Summary: Northern sea otters living off the coast of Washington state were infected with the same H1N1 flu virus that caused the world-wide pandemic in 2009, according to a new U.S. Geological Survey and Centers for Disease Control and Prevention study

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Human H1N1 Pandemic Virus Infected Washington State Sea Otters

Contact Information:

Gail Moede Rogall, USGS ( Phone: 608-270-2438 ); Marisa Lubeck, USGS ( Phone: 303-526-6694 ); CDC Media Relations ( Phone: 404-639-3286 );

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Northern sea otters living off the coast of Washington state were infected with the same H1N1 flu virus that caused the world-wide pandemic in 2009, according to a new U.S. Geological Survey and Centers for Disease Control and Prevention study. 

During an August 2011 health monitoring project, USGS and CDC scientists found evidence that the Washington sea otters were infected with the pandemic 2009 H1N1 virus, although the exact date and source of exposure could not be determined. The findings suggest that human flu can infect sea otters.

“Our study shows that sea otters may be a newly identified animal host of influenza viruses,” said Hon Ip, a USGS scientist and co-author of the study. 

The researchers discovered antibodies for the 2009 H1N1 flu virus in blood samples from 70 percent of the sea otters studied. None of the otters were visibly sick, but the presence of antibodies means that the otters were previously exposed to influenza. Further tests concluded that the antibodies were specific to the pandemic 2009 H1N1 flu virus, and not from exposure to other human or avian H1N1 viruses. 

“We are unsure how these animals became infected,” said Zhunan Li, CDC scientist and lead author on the paper. “This population of sea otters lives in a relatively remote environment and rarely comes into contact with humans.” 

An unrelated 2010 study showed that northern elephant seals sampled off the central California coast had also been infected with the 2009 pandemic H1N1 virus. This elephant seal exposure is the only other known pandemic H1N1 influenza infection in marine mammals, and similar to sea otters, it is unclear how the seals were exposed.

“Our new study identifies sea otters as another marine mammal species that is susceptible to influenza viruses and highlights the complex interspecies transmission of flu viruses in the marine environment,” said USGS scientist LeAnn White.

The 2009 H1N1 virus has spread globally among people since 2009 and was the predominant flu virus in circulation during the 2013-2014 flu season. This study is the first time that evidence of influenza infection has been detected in sea otters, although these viruses have previously been found in many different animals, including ducks, chickens, pigs, whales, horses and the elephant seals.

The study is published in the journal Emerging Infectious Diseases and is available online.

Sea otter sampling was performed by a collaboration of the USGS National Wildlife Health Center, USGS Alaska Science Center, USGS Western Ecological Research Center, Monterey Bay Aquarium and Seattle Aquarium. 

The USGS and the Interior Department work with CDC and other state and federal partners on research related to zoonotic diseases – diseases that can be passed between animals and humans – to help provide an early warning to the agriculture, public health and wildlife communities, as well as to the public. For more information, please visit the USGS National Wildlife Health Center or CDC websites.