The University of Maryland Center for Environmental Science recognizes the value of oysters in the Bay and has a team of experts that focus their research on the benefits, health, and future of oysters in Chesapeake Bay. Keep reading below to learn about some of the key players in oyster research and their discoveries.
Removing nitrogen from the water
“Back when we had vastly more oysters in the 1970s, the Bay had ways to remove nitrogen that no longer exist,” said Cornwell, a research professor at Horn Point Laboratory. “We were able to determine that a square meter of restored oyster reef does 30 times as much as an unrestored area in terms of taking nitrogen out of the Bay.”
Restoring oyster reefs is critical to helping the Chesapeake Bay partners Total Maximum Daily Load (TMDL) requirements, a pollution diet set by the U.S. Environmental Protection Agency in 2010 to restore clean water in the Bay and its watershed.
Graduate Research Assistant Melanie Jackson is working Cornwell to get a better understanding of just how much pollution oysters can remove.
Usually, she needs help from a team of divers that fills trays with sediment and oysters and places them on a restoration site for a month, and then retrieves them. That process takes a lot of time and people however, Jackson said.
“I’ve created a water sampling device where we have over 40 feet of tubing attached to a tripod that sits on the oyster reef. We can see how the water quality changes as the water flushes over the oysters, and we can see that there is nitrogen being removed over the reef.”
Rebuilding an empire of oysters
“The thing that I tell people is when I first got hired in 1973, I was very good at talking to oysters. Then after a while I realized they were talking back to me, and after a little bit more I started to understand what they were saying,” he said. “Oysters, like most animals or plants, will tell you when they’re happy, and they’ll tell you when they’re not.”
Meritt first came to the lab to work on a grant-funded project in the wake of Hurricane Agnes, which inundated the Mid-Atlantic region with heavy rainfall in the summer of 1972. With salinities at record lows, the Bay suffered major losses of oysters and soft clams. Over the years, the oyster culture facility and Meritt’s role there have grown.
As director, Meritt encourages his staff with a mantra: “Do it better this year than we did it last year, do it better next year than we do this year.”
Unlocking new secrets through oyster genetics
Louis Plough is a geneticist whose research is focused on marine animals, such as oysters and blue crabs, at Horn Point Laboratory. Recently, he has been working to develop a line of oysters that excels in low-salinity waters to support the growing aquaculture industry in Maryland.
Oysters typically grow well in high-salinity waters, but they are more prone to diseases that also thrive in higher salinities. Growing an oyster that excels in low salinity could lessen the potential impact of disease.
“I like to say we’re breeding around disease, spatially,” Plough said. “This is also a way to think differently about disease, not just do experiments people are already doing.”
His first step, is to measure the heritability of low-salinity tolerance and make sure he can reach his goal. Then he will identify genetic markers (e.g. genes) of low-salinity tolerance that can aid or accelerate breeding of a low-salinity line with his partners at the Virginia Institute of Marine Science’s Aquaculture Genetics and Breeding Technology Center. In the end, he hopes to provide for Maryland aquaculture farmers something they don’t readily have: more options.
Hatchery-produced oysters used for restoration may alter the genetic diversity of wild populations, but no one has monitored this at restoration sites in Chesapeake Bay. Hornick is using cutting-edge genetic tools to monitor potential changes to genetic diversity during the hatchery production cycle, and the diversity of the planted oysters in the years following planting.
“If the genetic diversity is low, then they are not necessarily unhealthy, but if the oysters that we are planting, or the oyster populations in general, have a very high genetic diversity, then they will have better ability to withstand various environmental stressors that may come their way in the future,” Hornick said.
“It [diversity] is an important parameter to monitor because if you are stocking a population in the hopes of restoring it, it is important to make sure that it is healthy and will be there for generations to come,” she added. “It is a measure of population health.”
Imagining oysters' future in the Bay
Measuring conditions for maximum benefits
Oysters have several ecological and commercial benefits, and increasing populations could maximize oysters’ impact in their local environment.
Matt Gray, an ecophysiologist at Horn Point Laboratory, has spent several years researching the ecological outcomes of restoration and aquaculture to better predict the valuable services provided by oyster species throughout the U.S.
“As these populations grow, so do their effects, which may eventually improve the entire ecosystem,” he said.
Gray’s research seeks to understanding the physiological responses of oyster to current environmental conditions and those predicted for the future and provide relevant information to help inform policy on restoration, fisheries, and the aquaculture industry in Maryland.