Niveen Ismail, Stanford University
Bivalves, like these California floater mussels, could be used to filter pollutants from waterways.
The month of June honors both National Ocean Month and World Ocean Day (June 8). What better time, then, to check out photos of undersea life and be reminded that things "down there" are just as important as things up here on land. Here, a manatee goes about its day. The manatee, also known as a "seacow," is an air-breathing herbivore listed as a federally endangered species. Manatees are slow moving and can't swim quickly away from boats. This often results in collisions that can kill or injure them.Whales Counted With Space Satellites
Life's a beach. Mom and her baby elephant seal roll around in the sand in Ano Nuevo Island, Calif.Elephant Seal Calls Tell Rivals Who's Boss
Robert Schwemmer, NOAA National Marine Sanctuaries
A humpback whale breaches in the Gulf of the Farallones National Marine Sanctuary, off the coast of California.Distinct Humpback Whale Populations Found in North Pacific
A blue rockfish fans for the camera in Monterey Bay National Marine Sanctuary, in California.200-Year-Old Fish Caught Off Alaska
A Southern sea otter, aka,
Enhydra lutris nereis
, wonders what all the fuss is about, at South Harbor, Moss Landing, Calif. The World Ocean Day Photo Contest entrant was Submitted by Dr. Steve Lonhart.PHOTOS: Otter vs. Gator: Otter Wins
A white-lobed sponge brightens up the scenery. It's one of several images of rarely seen deep-sea animals that were captured on camera in Olympic Coast National Marine Sanctuary during a NOAA expedition. Researchers used a NOAA remotely operated vehicle in waters 328 to 656 feet deep off the Olympic Peninsula in Washington State. The research was funded by NOAA's Coral Reef Conservation Program.Strange, Carnivorous Sponge Found In Deep Sea
This image brimming with colorful marine life is from the Pearl and Hermes Atoll. It's a huge oval coral reef within several internal reefs and is the second largest among the six atolls in the Northwestern Hawaiian Islands.PHOTOS: Sharks, Marine Mammals Hang in Paradise
Having no backbone isn't always a bad thing! Just ask any octopus. These boneless invertebrates know how to squeeze into (and out of) many a tight spot. They have three hearts, nine brains and blue blood. (Two hearts send blood to the gills, while the third pumper sends it to the rest of the body.)VIDEO: Octopi Have a Brain in Every Tentacle
Rapture Reef sits within the Northwestern Hawaiian Islands Marine National Monument. The monument encompasses more than 140,000 square miles of ocean and coral reef habitat.PHOTOS: Life in Australia's Great Barrier Reef
This seal is eager to wriggle its way back to freedom, as divers release it from fishing nets. Marine debris -- such as these nets -- makes a serious impact on its surroundings. From being an eyesore on a beach to injuring marine life or stopping a 400-ton vessel at sea, it causes problems that are difficult to ignore.Seal Pup Found in Forest
They might not have feather dusters, brooms or even arms and legs, but bivalves — such as clams, mussels and oysters — make good underwater maids, a new study suggests.
These useful creatures serve as tiny water filtration systems, constantly sieving the water around them in their hunt for a meal of bacteria or microscopic algae known as phytoplankton. As they filter water, the bivalves' tissues absorb some of the chemicals and pathogens that are present — things like herbicides, pharmaceuticals and flame retardants — according to researchers at Stanford University in California.
To see just how good the bivalves are at cleaning up toxins in their environment, the researchers put California floater mussels and Asian clams into a tank with treated wastewater that contained various levels of contamination. Within 72 hours, the bivalves had removed up to 80 percent of some of the contaminants from the water, according to the researchers. [In Photos: World's Most Polluted Places]
Observing these shellfish soaking up harmful chemicals got the Stanford researchers thinking about how they might put the cleansing clamsand mussels to good use. They decided to assign some of these underwater maids a new job: cleaning up a dirty lake in the middle of San Francisco.
Mountain Lake is a body of water that researchers say is heavily polluted with harmful bacteria and other contaminants. The researchers are still deciding how many clams and mussels they'll need to introduce into Mountain Lake to get the job done, and they're also trying to decide how to best deploy the bivalves.
"We are considering using a raft carrying caged native bivalves, which will allow us to monitor the health of the bivalves and also protect them from predators," study lead author Niveen Ismail, a Stanford graduate student in environmental engineering, said in a statement.
This method of deploying oysters and other shellfish, which involves placing the bivalves in a tray or cage and suspending them in water from an anchored raft, has been used before in places such as the Bronx River and Long Island Sound, according to Ismail and his colleagues. In those locations, Eastern oysters are used to control nutrients and excessive algae, but the researchers hope that in Mountain Lake, the bivalves will also help cleanse the water of pollutants.
"Each native mussel filters about two liters of water a day, so it doesn't take a whole lot to improve water quality," study co-author Richard Luthy, the Silas H. Palmer Professor of Civil and Environmental Engineering and a senior fellow at the Stanford Woods Institute for the Environment, said in a statement.
Detailed findings of the study were published online July 13 in the journal Environmental Science and Technology.
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