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Along a 540-square-foot patch of the Southern California shoreline, a tiny restoration project is trying to accomplish a big goal: show that oysters can play a key role in revitalizing sea life along the coast.
The native Olympia oysters, which once were plentiful and even harvested along this section of Long Beach’s Alamitos Bay, are being nurtured back to play their natural role as ocean engineers that protect against storms and sea-level rise while also cleaning polluted water and providing key habitat to other marine life.
Oyster larvae that previously could only find scattered rocks to cling to now have a relatively wide bed made of oyster shells on which to grow.
“We created what we think is the best real estate in the area” for oysters, said Danielle Zacherl, the project leader and a marine biology professor at California State University, Fullerton.
The experiment will wrap up in June, when the last data-collecting tools are removed and the nearly three-year-old oysters are left to sink or swim, so to speak.
A key factor is whether free-floating oyster larvae will find that bed -- and not random rocks.
If she could give the larvae advice, Zacherl said, it would be this: “It’s the most important real estate decision in your life, so choose where you settle carefully.”
The scientists monitoring the oyster nursery are not deterred by the fact that their manmade reef is surrounded by some of the most urbanized shoreline in the world, not to mention the Los Angeles and Long Beach ports –- the world's largest shipping complex.
"We saw dramatic increases in oyster density and organisms that use the oyster shell itself," said Christine Whitcraft, a marine biology associate professor at California State University, Long Beach.
Those other organisms include marine worms, sea snails and barnacles that found prime habitat in the shells.
The Long Beach oysters are still too young to work their engineering magic. But the project is among dozens started in the last six years thanks to an unusual mix of science and economic recession.
The East Coast, particularly Chesapeake Bay, has a long history of trying to bring back oysters, but efforts really spread after a 2009 study by The Nature Conservancy showed an 85 percent decline in oyster reefs globally.
At the same time, the Great Recession led to federal government attempts to jump start the economy with stimulus money. Some of those funds even reached the sciences –- for marine restoration that meant $150 million, a piece of which went to oysters, said Boze Hancock, a scientist with The Nature Conservancy who helped run a federal program that found community partners for oyster restoration.
New projects started popping up from the West Coast to the Gulf of Mexico and even New York Harbor, home of the Billion Oyster Project.
But why bring back oysters? For a spineless, limbless life form, oysters are amazing. A single large oyster can filter upwards of 50 gallons of water a day, removing nitrogen from fertilizer and other runoff that kills fish by reducing oxygen in the water. An acre of oysters can filter 24 million gallons of water a day.
They also provide nutrients "that make beautiful habitat, especially for newborn fish … so you are pumping more fish into the oceans from this habitat," said Hancock. "It's not that the oysters are important," he added, "it's what the oysters do as environmental engineers that's the key."
The engineering works like this: Oysters take in sediment like nitrogen runoff, digest what they want to eat and then spit the rest out in a mucus string that stays on the seafloor. That does two things: it cleans the water so light can get further down, allowing seagrass to grow. And it allows nutrients to settle in between the bed of shells.
The Long Beach partners include community groups, California's Coastal Conservancy and the National Oceanic and Atmospheric Administration, which administered the stimulus grants.
But expanding across Southern California requires more money and that, said Whitcraft, has been "piecemeal.”
The dozens of projects along U.S. coastlines should be seen as blueprints for those communities to go out and fully restore their areas within a bigger ecosystem context, said Hancock.
That bigger picture includes what NOAA and others call "living shorelines" -– using oyster reefs, eel grass and marshes to build up ocean sediment that deflects wave action from storms and sea-level rise.
This "green infrastructure" can be used in place of, and often at lower cost, than "gray infrastructure" like concrete sea walls, said Hancock. The goal is to "reduce wave energy as it hits the shore," he said, and a strong marine ecosystem does that by "increasing the friction on the bottom and creating living barriers that reduce energy."
San Francisco Bay is the focus of a living shoreline project that's restored four acres so far, and San Diego is interested in learning from the Long Beach researchers to do the same there, said Natalie Manning, NOAA's manager for marine restoration in California.
Figuring out how and where to restore takes time and money. But, said Manning, "we're on the verge of knowing exactly the places we want to go and dedicate the funds to."
And oysters are there to do their part. "They are pretty tough," Hancock said. "They'll handle a lot of environmental insults.”