By Often by Hand, Scientists Work to Turn the Tide of Oyster and Seagrass Decline in Chesapeake Bay
The Chesapeake Bay, despite massive setbacks, has continued to revert to something like a healthy estuarine ecosystem, in large part thanks to the dedicated scientists who study it.
As the most studied estuary on Earth, the Chesapeake’s 11,000-mile coastline is home to a family history of competition between short-term economic and long-term ecological interests.
There may have been a time when the two most important species, oysters and seagrasses, would have ceased to exist if pollution continued as it had, but regulation reduced dead zones and brought in fish, oysters, and seagrasses. . back to the bay.
Now teams of scientists are working to accelerate the recovery of these keystone species, often by hand, reasoning that as ecosystem engineers, oysters and seagrasses can start doing scientists’ work for them if they can only be propagated in the required amount.
As the main pollutants were nutrient runoff from farms into surrounding states and pollutants flowing from cities, regulating storm drains and incentivizing farmers to reduce runoff resulted in a 316% increase in runoff. seagrass beds between 1984 and 2015.
Oysters are also recovering thanks to the diligent work of people like Romuald Lipcius, professor of fisheries science at the Virginia Institute of Marine Sciences. He has worked in the Bay for more than 16 years, helping oysters recover, live longer, and perform more of their all-important filter feeding.
Use fossil oyster shells, safe artificial substrate, or concrete “Oyster Castles” Lipcius and his colleagues are creating a safe and optimal habitat for them to grow and, as a result, they are seeing three-dimensional oyster beds.
In Baines Creek, a tributary of the Elizabeth River in Virginia, oysters are reaching the age of five, once thought impossible due to the diseases that pollution made so common in the bay.
“All these oysters that look out over the water are a beautiful sight,” said the geology professor Rowan Lockwood at William & Mary College. “It’s a glimpse of what the bay looked like 6,000 years ago.”
Slowly
On the Rappahannock River, also in Virginia, a retired naval officer had used oyster castles to farm millions of oysters that regularly reached the age of seven. Between five and seven is when oyster fertility is highest and they release the most larvae.
In the bay, his continued interest in restoring the oyster revealed some “relic reefs” that had survived from pre-colonial times.
“Relict reefs and artificial reefs tell us beyond a doubt that oyster restoration can be successful,” says Lipcius.
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“I have always believed that we know how to restore oysters; we are simply choosing not to, ”Lockwood adds.
Oysters aren’t the only species that are getting a helping hand. In 2018, after the prolific increase in seagrass acreage in the bay, record rains washed away huge amounts of sediment from surrounding farms. Nitrogen and phosphorus were absorbed by algal blooms that prevented the sun from reaching the seagrasses, and 38% of seagrass species were lost as a result.
“Seagrass is one of the key critical habitats in the Chesapeake Bay and shallow coastal marine systems around the world,” says Chris Patrick, also of the Virginia Institute of Marine Sciences. “It anchors the sediment, it clarifies the water, it allows the small particles to slide and creep.”
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Patrick and his team are looking to speed up the seagrass recovery process by manually planting seagrass seeds and collecting the seedlings of two different species, eelgrass and widgeon, in May.
By filtering the sediment from the seeds, they take the best quality seeds and plant them in the fall. Compared to last year, Patrick estimates that his planting operations will produce four times more grass next year.
Patrick and Lipcius work hard for small profits, but luckily for them, the species they are working to save are better at cleaning up and protecting the bay than even the most staunch marine biologists, and for every blade of seagrass or every oyster. Happy to add to the Chesapeake, they add one more dedicated worker to the project of restoring the bay to its glorious and abundant heritage.
(LOOK the PNAS video about this story below).
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