NEW YORK – They can bolster the coastlines, break the force of hurtling waves, provide housing for fish, shellfish, and migrating birds, clean the water, store as much as 5 per cent of the world’s carbon dioxide, and pump oxygen into the ocean, in part making it possible for life on Earth as we know it.
These miracle machines are not the latest shiny tech invention. Rather, they are one of nature’s earliest floral creations: seagrasses. Anchored on the shorelines of every continent except Antarctica, these plants – and they are plants, not algae, that sprout, flower, fruit and go to seed – are one of the most powerful but unheralded climate solutions that already exist on the planet.
Restoring seagrass is one tool that coastal communities can use to address climate change, both by capturing emissions and mitigating their effects, which is among the topics being discussed as leaders in business, science, culture and policy gather Thursday and Friday in Busan, South Korea, for a New York Times conference, “A New Climate.”
Around the world, scientists, nongovernmental organizations and volunteers are working to restore seagrass meadows, if not to their original glory, then to something far more expansive and majestic than the barren, muddy bottoms left behind when they are damaged or destroyed.
In Virginia, parts of Britain and Western Australia, among other places, with the helping hands of committed researchers and citizen scientists alike, seagrass meadows are coming back. They’re bringing with them clearer waters, stabler shores, and animals and other organisms that used to thrive there. And yet, seagrass doesn’t get the attention it deserves, its partisans say.
It’s impossible to know exactly how much seagrass has been lost, because scientists don’t know how much there was to begin with.
Only about 16 per cent of global coastal ecosystems are considered intact, and seagrasses are among the hardest hit. It’s estimated that one-third of seagrass around the world has disappeared in the past few decades, according to Dr Matthew Long, an associate scientist in marine chemistry and geochemistry at Woods Hole Oceanographic Institution. “Globally, a soccer field of seagrass is lost every 30 minutes,” Dr Long said, “and we lose about 5 to 10 per cent at an accelerated rate every single year.”
“Seagrasses are adversely affected by global stressors: deoxygenation, ocean acidification and warming temperatures,” Dr Long said. But local stressors also have played a role in their withering, mainly in the form of nutrient pollution, largely from agricultural runoff and wastewater, and subsequent algal blooms and die-offs, which first choke out other plants such as seagrass (a process called eutrophication) and then, as they decompose, take up all the oxygen in the water (hypoxia).
Although the effects of climate change and growing human impacts have accelerated seagrass loss in the past few decades, it’s not a new story.
On the Eastern Shore of Virginia, a strong storm in August 1933 that followed a wasting disease and overharvesting of bay scallops wiped out what remained of once-vast eelgrass meadows. (Eelgrass is a type of seagrass.) For decades, there was no eelgrass on the shore’s ocean side, said Mr Bo Lusk, a scientist with the Nature Conservancy’s Volgenau Virginia Coast Reserve, although some remained on the part of the coast lapped by the Chesapeake Bay.
Mr Lusk, who grew up in the region, heard stories as a child of lush green carpets of eelgrass from his grandmother, who remembered that the shores teemed with life – until they didn’t. But then, in 1997, someone reported seeing some patches of eelgrass on the shore’s oceanside, probably from seeds that happened to drift south from Maryland and settled in a hospitable neighbourhood in Virginia.
After several years of experiments, Dr Robert Orth, a scientist at the Virginia Institute of Marine Science, devised a highly successful method of restoring seagrass, similar to methods used around the world: In the spring, scientists and hundreds of volunteers collect seeds, which they count and process over the summer and plant in the sediment in the fall.
Since 2003, when the restoration effort in the Volgenau Virginia Coast Reserve began, scientists and others have planted around 600 acres (243 ha) of seeds, and seagrass now covers 10,000 acres, according to Mr Lusk. Later this year, the Nature Conservancy is hoping to sell the first validated blue carbon credits for seagrass, based on this restoration effort, said Ms Jill Bieri, director of the reserve.
However, the success of the Virginia project has been somewhat difficult to re-create around the world. “You can’t do this just anywhere,” Mr Lusk said. “If the Nature Conservancy hadn’t started this land protection work 50 years ago, buying up parts of the coast to preserve it, the odds are we wouldn’t have the water quality we have now, and this wouldn’t have been so successful.”
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