Researcher dedicates life’s work to ocean’s secret weapon against climate change

June 7, 2021 at 12:51pm

Around the golden hour of a summer’s evening, the shallow seagrass meadows of South Biscayne Bay transform, appearing almost magical. James Fourqurean can tell you all about it. How those seagrasses are so full of oxygen they burst, releasing endless streams of bubbles that rush upward through the waving canopy. Swimming through it is like swimming through champagne, he says.

To recognize the beauty of seagrasses, to be completely taken by them, comes from a sense of deep appreciation. For Fourqurean — an FIU professor of biological sciences and director of the Institute of Environment’s Coastlines and Oceans Division — that appreciation stems from nearly 40 years spent researching seagrass ecosystems around the world.

He started in 1982. Fourqurean was an undergraduate at the University of Virginia. One day, his professor asked for a volunteer to join him on a trip to map the distribution of seagrasses in Florida Bay. There were two requirements. Availability that summer and to know how to drive a boat. Fourqurean was in the front row and immediately raised his hand. He already had two jobs lined up and didn’t have a clue how to drive a boat. But that boldness got him to the Everglades, and that summer spent with the seagrasses changed everything. Fourqurean has not spent more than nine months away from South Florida since.

Fourqurean’s extensive knowledge makes him one of the foremost experts on seagrass ecosystems and Blue Carbon — the term used to describe carbon captured by the world’s oceans and coastal ecosystems. He’s one of the lead scientists in the International Blue Carbon Working Group, as well as scientific representative to the International Blue Carbon Policy Working Group. These teams initially set out to have seagrasses recognized as a valuable resource in climate change mitigation, critical to helping slow the rise of C02 in the atmosphere. They’ve helped to include these coastal ecosystems into national greenhouse gas inventories.

This story appears in the College of Arts, Sciences & Education magazine issue on Life Below Water.

One of the foremost experts on seagrass ecosystems, Fourqurean samples the pristine seagrasses of Shark Bay, Australia (right).

The first Blue Carbon paper in 2012 was groundbreaking. Fourqurean and his collaborators showed seagrasses store tremendous amount of carbon. But were also rapidly disappearing. Their loss meant more C02 being released into the atmosphere — at a rate equal to or greater than other carbon dense ecosystems like forests.

This triggered more research. Fourqurean and his students are currently focused on South Florida, which is one of the largest seagrass ecosystems in the world. Their work has an added layer of complexity when it comes to calculating how much C02 is being stored versus released, and it all has to do with limestone.

From coral reefs to the marl deposited in the Everglades, limestone is made by different organisms. It’s a little bit of a math equation. When an organism makes limestone, it takes two units of dissolved inorganic carbon to make one unit of limestone and also one unit of C02. For every ton of carbon in the limestone, a ton of C02 is released, and about 60 percent enters the atmosphere.

Fourqurean’s students are looking at these fluctuations. Former Ph.D. student Jason Howard tested whether Florida Bay released more carbon, because of the limestone accumulation over the years, than was taken out by seagrasses. He’s analyzed data and is looking to publish the results. Meanwhile, Christian Lopes, a current student in Fourqurean’s lab, is measuring carbon fluctuations in the atmosphere.

A monitoring tower is set up above seagrass beds in the Everglades. Among the first projects measuring the C02 coming out of seagrass ecosystems, it is also a part of the Institute of Environment’s Florida Coastal Everglades Long-term Ecological Research (FCE-LTER) Program. The tower takes real-time measurements of CO2 concentrations in the wind and then streams the data back to the lab.

This kind of data will help paint a picture of what’s happening with the seagrasses in South Florida, and will hopefully provide the scientists with answers.

Regardless of what they find, Fourqurean knows seagrasses are desperately needed.

Even after all these years and all the research, Fourqurean said he still gets emails from resort owners asking how they can remove seagrasses so tourists don’t have to walk through them. His reply remains the same. Don’t do it. It would trigger a cascade of devastating impacts.

The existence of so much life is tied to those underwater meadows. They are home to economically important seafood, like sea trout, red fish, black grouper, conch, lobster, shrimp, and also to endangered manatees, green sea turtles and smalltooth sawfish. They are filters, keeping mud out of the water. They defend coastlines, dampening the impacts of damage from powerful hurricanes. If they vanish, so does all of this.

Most people will never experience the golden hour when seagrasses turn the water to champagne. Most people simply don’t think about seagrass. If they see a sandbar, they probably won’t know it was once a place where seagrasses grew.

But Fourqurean is keeping watch.

Sometimes, when he’s out on the water doing his research, it’s like that first time in 1982. There’s not another boat on the horizon. Dolphins and sea turtles swim by. The water is crystal clear. Other times, it’s not. But, Fourqurean finds a way to stay hopeful. He’s seen the seagrasses die off. He’s watched them recover. He’s watched them start dying again. As he tells his students, the seagrasses can recover. It all comes down to stewardship. And that stewardship begins with a recognition of all the benefits seagrasses bring to our coastal communities — and beyond.

“Here in South Florida, we are sitting in the middle of one of the largest seagrass ecosystems in the world,” Fourqurean said. “We might not see it, but we are sure made richer by it.”