Turns Out, Oysters Are An Unlikely Ally In The Fight Against Climate Change

mbg Sustainability Editor By Emma Loewe
mbg Sustainability Editor

Image by KatieDobies / iStock

When Hurricane Sandy hit New York City in 2012, it showed just how powerless waterfront cities are against the elements. In the years since, NYC has investigated how to protect its coasts for a future when storms are only expected to get worse. Strategies include raising shorelines, restoring wetlands, lowering emissions that contribute to climate change, and...introducing more oysters?

Yep, beyond being a decadent appetizer, the almighty oyster can help coastal areas negate the effects of climate change.

The awesome way oysters can protect us from the effects of climate change.

The Billion Oyster Project, a nonprofit based on Governors Island, just south of Manhattan, is on a mission to strengthen and repair New York's notoriously dirty waterways by introducing 1 billion live oysters back into the ecosystem by 2035.

Over 75 NYC restaurants have agreed to donate their empty oyster shells to the nonprofit instead of just tossing them out after service. The Billion Oyster Project now brings about 8,000 pounds of discarded shells to their island home base every week. "We just had a big shell dump earlier this morning," Helene Hetrick, the team's communications manager, tells me over the phone. Before being returned to the ocean, this mountain of shells has to stay on land for about a year to be cleaned off by bugs, birds, and the elements. Next, the Billion Oyster team and students from the nearby New York Harbor School will bag them up, place them in tanks filled with Harbor water, and expose them to oyster larvae, which are also hatched on the island

Then comes the cool part: The larvae will latch onto the empty shells and use them as a platform on which to grow their own shells. About 20 new oysters can take root on one empty shell, and when combined, they form a reef of sorts.

An adult oyster can filter up to 50 gallons of water per day.

These oyster reefs are then strategically placed around New York Harbor to do what they do best: filter water and protect shorelines. "An adult oyster can filter up to 50 gallons of water per day," Hetrick explains. Like other filter feeders, oysters naturally trap excess nitrogen and phosphorous, as well as potentially dangerous pathogens, in their gills as they search for food. If the nonprofit reaches the goal of a billion oysters, they would be able to filter the entire harbor every 72 hours.

Beyond being mini water filters, oysters are also known as ecosystem engineers. When waves come in contact with an oyster reef, they lose some of their power. The hard shells act like little soldiers against storm surges that can cause coastal damage and erosion. They also provide a habitat where other marine species can set up shop and therefore lead to healthier underwater ecosystems overall.

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How we can filter our way to a brighter future.

It may be hard to believe, but New York City actually used to be the oyster capital of the world. Its waterways were clean and swimmable, full of seals, whales, fish, and half of the world's oyster population. The New York Public Library records show that long before pizza and bagels, the city's menus were overrun with local, fresh-caught oysters. By the time the 20th century rolled around, though, city dwellers had gobbled up all the oysters and started dumping trash and sewage into surrounding waters.

The Billion Oyster Project is hoping their work will help turn back the clock to cleaner days. "We already know that these oyster reefs were meant to be here in the first place," says Hetrick. "We know it's possible."

So far, the organization has returned 30 million oysters to the harbor, and we'll need every last one of them to help clean increasingly polluted water and combat the extreme sea level rises that the U.N. predicts could go from happening once a century to once a year by 2050.

And New York isn't the only place using bivalves for a brighter future. "All coastal cities are in for adverse effects... Oysters are a good option [for them]," says Hetrick. The Chesapeake Bay is another hot spot for reef restoration; the Nature Conservancy is working to introduce more oysters to the Gulf of Mexico; and a number of European cities have expressed interest in doing something similar, according to Hetrick.

It's important to note that the oysters placed in the wild for restoration aren't meant to be eaten—especially the ones in New York's waters. (A Hudson River oyster is not something to be enjoyed raw.) So to support efforts like these in your area, keep on eating oysters, but opt for ones that are farmed, and leave the wild ones to do the hard work of cleaning. Consult the Monterey Bay Aquarium's list of 18 farmed varieties that are raised responsibly the next time you're looking to order oysters in a restaurant and if you're buying them in a store, the seafood watchdog recommends looking out for ones that have the CO (Canada Organic) or ASC (Aquaculture Stewardship Council) certification.

Beyond buying responsibly, we can all help this important species thrive by living as sustainably as possible. "While oysters are very good at helping us adapt to the effects of climate change, they're also vulnerable themselves," Hetrick says, explaining that ocean acidification from climate change can make it more difficult for oysters to grow their shells. Yet another reason to pay attention to your carbon emissions, live as low-waste as possible, and vote with your dollar (and your ballot) for companies and candidates that are committed to helping the planet.


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