Oysters: more than what meets the eye

By Courtney Cox | gargoyle@flagler.edu

Marine mammals like dolphins, whales and other large aquatic species receive most of the attention when it comes to favorites of the sea. However, a smaller, harder and completely motionless “rock” is responsible for sustaining the lives of such large, and popular, marine life. This “rock” is known as the oyster.

Oysters are a keystone species, meaning they keep the ecosystem thriving through their filter feeding. It’s their filtration of the water that keeps it clean and sustainable for sea life.

Matthew Monroe, a biologist for Guana Tolomato Matanzas National Estuarine Research Reserve, works in the field closely with oysters.

“They’re the building blocks of our estuaries. Without oysters your ecosystem is not going to function,” Monroe said. “When you don’t have enough oysters filtering the water, you have increased nutrients and you’ll reach what’s called eutrophication where there is too much oxygen in the water and it can turn into a hypoxic zone: an area where there’s no oxygen in the water– where nothing is going to live.”

Monroe has recently been collecting data alongside the boat ramp of the St. Augustine Lighthouse where he and other field biologists have worked on an oyster mitigation project.

“Mitigation we do whenever there is something being purposely removed or destroyed or changing. They wanted to put a boat ramp through the middle of the oyster reef. So to mitigate that, instead of putting a seawall in or anything like that, we came through and hand moved every oyster out of the way. We used some bags and other techniques to try and control them,” Monroe said.

The oysters’ role in the ecosystem is crucial. Monroe said that him and other biologists have even relocated oysters to unhealthy and unfiltered water so that they can clean it.

Oysters may not move around much, or at all, but they do provide the environment with a large number of sustainability services. Dr. Melissa Southwell, an associate professor in the natural science department of Flagler College, has worked closely with the oysters as well and said that oysters really don’t get the credit they deserve.

“They filter the water and actually improve the clarity of the water. There’s improvement of water quality, there’s habitat, there’s protection of the shoreline against wave energy– so protection against erosion for example,” Southwell said. “And my work is focused on the potential for oysters to be storing carbon which can help that carbon stay out of the atmosphere. It’s like a whole portfolio of services that oysters provide.”

Without the oysters, whales, dolphins, manatees, turtles, sharks and every other marine species that fills people’s lives with entertainment, education and food won’t exist. They’ll merely become stories, just like the dinosaurs. Their legacy of charismatic interactions with humans will have to be told by people because marine life won’t be here to tell it themselves.

“If you care about seafood, if you care about the ocean, the dolphins, the turtles, you should care about the oysters because without them we wouldn’t have any of the other stuff,” Monroe said. “If it wasn’t for the little guys we wouldn’t have the big guys.”