IN THE SPOTLIGHT: Dr. Jim Fourqurean

Renowned seagrass expert visits Cape Haze

Dr. Jim Fourqurean is one of the world’s leading seagrass scientists, a pioneer whose decades of research at Florida International University have shaped how scientists – and policymakers – understand and protect coastal ecosystems. A professor and director of the Coastlines and Oceans Division of the Institute of Environment at Florida International University, where he has been on the faculty since 1993, he has also been an international leader in advancing understanding of the importance of carbon sequestration in marine ecosystems. He is a past president of the Coastal and Estuarine Research Federation, the world’s largest association of coastal scientists and resource managers.

Fourqurean will present “Saving Seagrass to Save the World” at the Lemon Bay Conservancy’s Coastal Seminar Series on Thursday, Feb. 5. Ahead of his visit, he spoke with the Beacon about why seagrass matters globally, and especially here in Southwest Florida. The following is an excerpt from a conversation with Dr. Fourqurean, lightly edited for clarity.

Q: For readers who may not realize it, how important is our local region – Gasparilla Sound, Charlotte Harbor, and the Greater Cape Haze Peninsula – in the context of Florida’s seagrasses?

A: Florida is surrounded by seagrasses, and your part of the coast is no exception. Historically, there were a lot of economic activities supported by those seagrass meadows in your area – scallop culture, clam culture – and early on, economic activity was really explicitly linked to seagrass and the fish that live in them. Later, the explicit link became less obvious, compared to the links that most people don’t think of. Things like the fact that seagrasses are out there knocking down storm surge, slowing coastal flooding, slowing erosion, fixing carbon out of the atmosphere and storing carbon to keep our temperatures from continuing to rise.

Q: Seagrasses are sometimes referred to as the “lungs of the sea.” From a scientific standpoint, what does that really mean?

A: I didn’t write that. I think they’re a lot more like the liver. Years ago, when a new field called ecological economics was being born, there was an attempt to figure out the dollar value to humans of all of the world’s ecosystems. That first paper came out with the unexpected result that seagrasses and estuaries are the most valuable ecosystems on Earth in terms of goods and services to humans – more important than tropical rainforests, more important than coral reefs, if you believe the monetization.

Seagrasses are incredibly important because of what they do for us. I already talked about erosion control and storm surge abatement. We also have a lot of fisheries directly related to seagrass. On your coast it’s the offshore shrimp fishery, recreational fishery and many others.

One of the other really important things seagrasses do – and this is why I think they’re more like the liver than the lungs – is that they process pollutants that cause environmental harm. They remove nitrogen from the water, which is a plant nutrient that leads to harmful algal blooms like red tide. They bring particles out of the water and cause them to settle. They stabilize sediments so they don’t get mixed up. They really purify the water that runs over them.

Now, the lungs comparison works too. Seagrasses are very productive. They photosynthesize a lot. When light shines on them, they produce a lot of oxygen. At night, they and the organisms that live within them use up oxygen. That oxygen production is important for preventing nighttime hypoxia – low oxygen levels that can lead to fish kills.

So between water purification, fisheries support, erosion control and oxygen production, there are a lot of reasons people should care about seagrass. Clean water. Lots of fish. Less erosion. Less storm damage.

Q: How do seagrass meadows support the coastal food web here in Southwest Florida?

A: This time of year, down here in South Florida, we’re thinking a lot about manatees because they’ve escaped the cold up north and they’re here. Manatees depend on seagrass. Sea turtles, especially green sea turtles, depend on seagrass, as well as black grouper, queen conch, pink shrimp and smalltooth sawfish. There are lots of charismatic big species and important seafood species, and then emblematic South Florida species like manatees and sea turtles that are all dependent on seagrass. It’s really the base of the coastal food web.

Q: You’re one of the leading scientists working on “blue carbon.” What does that mean?

A: Blue carbon is, in a sense, a marketing gimmick – but a useful one. Carbon in most forms we think about is black. Coal is made of carbon, oil is made of carbon. There was a United Nations program called REDD, which stands for the Reduction of Emissions from Deforestation and Forest Degradation. That program created a way to reward landowners for not turning the carbon in their forests into CO₂ and putting it into the atmosphere.

That was really targeted at green carbon – forests on land. But almost all the carbon on Earth cycles through the ocean, and the oceans are blue. So blue carbon is a way of calling attention to the fact that coastal ecosystems – especially seagrasses and mangroves, which we have an abundance of down here – are hotspots for carbon storage and are pulling huge amounts of carbon out of the atmosphere. They’re also hotspots for coastal development and destruction. We’re losing them really fast, which means we’re losing the carbon that’s stored in them really fast. That carbon goes right back into the atmosphere and directly contributes to global warming.

South Florida has more seagrass than almost anywhere else in the world. In the areas I map, which stop just south of you, there are about 18,000 square kilometers of seagrass. That’s a huge amount. The currently well-documented global extent is only about 172,000 square kilometers. Even if those numbers aren’t perfect – and I don’t think they are – this region is clearly one of the most important seagrass regions on Earth.

Q: What are the biggest threats?

A: In Florida, our biggest problem is water quality. Seagrasses photosynthesize, so they need light. Light gets absorbed very quickly by algae-laden water. Pollution cuts down the amount of light that reaches the bottom. Seagrasses have to grow on the bottom because they’re rooted. They’re also rooted in soils that have no oxygen, so their own oxygen production is critical for keeping their roots alive.

So when we cut down on the amount of light that can reach the water because of pollution, because of our leaky septic tanks, because of mismanagement of water in Lake Okeechobee, you name it – we dump more nutrients in the system. We give a kick-start to the really fast-growing things that can float up in the water, like harmful algal blooms. And those harmful algal blooms then rob the seagrasses of all their light. So really, in Florida, nutrient pollution and poor water quality management in the watersheds feeding into the coast are the largest threats to seagrass.

Q: Are storms a major threat to seagrass?

A: Seagrasses evolved during the time of the dinosaurs. They evolved in a world with hurricanes. Most of the plant is below ground. The growing tips are protected from the sheer stress of waves and currents. Hurricanes can tear off leaves, pile them on beaches and people think everything is gone. But if you go back six months later, there’s often very little long-term change in distribution. There can be erosion at the edges of meadows and deposition elsewhere. On average, hurricanes are not the biggest threat to seagrass. As long as water quality is good and light returns, seagrasses recover. 

Q: What can local residents actually do?

A: Individual actions matter – reducing fertilizer use, maintaining septic systems – but the biggest impact comes from supporting long-term policy initiatives.

The great success story is Tampa Bay. In the 1970s, seagrasses were almost gone. Scientists knew nitrogen pollution was the problem. The region committed to massive investments in sewage treatment and stormwater management. It took 30 to 40 years, but the seagrasses came back.

We need that same long-term perspective. As voters, we need to support policies that improve water quality, even if they cost money. We need to think in decades, not weeks.

If we want our grandchildren to have manatees, we need to fix what we’re doing now.

Q: What can attendees expect to learn?

A: Seagrasses are the Rodney Dangerfield of marine ecosystems – they get no respect. They’re as important, or more important, than ecosystems that do get the respect like coral reefs or rainforests, but nobody talks about them. And South Florida has more seagrass ecosystems than almost anywhere else in the world. There are very few places on Earth where seagrasses play such a large role over such a large area as they do here.

Making the world better for seagrasses makes the world better for people. We like clear water. We like blue water. We like fish that don’t get killed from red tide. A lot of those things are symptoms of the same cause as the loss of seagrass, and that is poor water quality management in the watersheds that lead into the coastal systems. If we want our grandchildren to have manatees, we need to fix what we’re doing now.

The talk is “Saving Seagrass to Save the World,” part of Lemon Bay Conservancy’s Coastal Seminar Series on Thursday, Feb. 5 at the Cape Haze Community Center, 180 Spyglass Alley, Placida. Refreshments will be served at 5:30 p.m., followed by the presentation at 6 p.m.