Our oceans are heating up—what does that mean for all the life that lives in the sea...and us?
Today we’re going on a trip to Florida…we’re hanging out in the Keys, and we're going fishing, and scuba diving all to find out what’s going on beneath the surface. Just how bad is hotter water for sea life in South Florida, and for the people that depend on it? And how are scientists leading the charge to save this ocean ecosystem?
This episode was reported and hosted by Jenny Staletovich and co-hosted by Carlyle Calhoun Despeaux. Editing by Johanna Zorn and Carlyle Calhoun Despeaux with additional help from Halle Parker, Eva Tesfaye, and Ryan Vasquez. Carlyle Calhoun Despeaux is the managing producer. Our sound designer is Emily Jankowski and our theme music is by Jon Batiste.
Sea Change is a WWNO and WRKF production. We're a part of the NPR Podcast Network and distributed by PRX. SeaChange is made possible with major support from the Gulf Research Program of the National Academy of Sciences, Engineering, and Medicine. WWNO's Coastal Desk is supported by the Walton Family Foundation, the Meraux and the Greater New Orleans Foundation.
You can reach the Sea Change team at seachange@wwno.org.
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TRANSCRIPT
SHOW INTRO:
CARLYLE: Last summer the ocean temperature just south of Miami was measured at 101.1 degrees. We’re talking Hot tub temperatures. The highest ever recorded. Coral reefs started bleaching and turned a sickly white. Underwater sponges wilted and collapsed. It was scary.
And Sea Change had a lot of questions about what was going on, and how climate change was playing a role. So I got in touch with Reporter Jenny Staletovich who was on the scene last year, covering the impacts. She’s been reporting on the environment in Florida for nearly a decade. Hey Jenny!
JENNY: Hi Carlyle.
CARLYLE: So Jenny, you live in Miami.
JENNY: I do
CARLYLE: And I know you’re a water lover and you’re also an angler.
JENNY: Yep I am. Not necessarily a good one but my enthusiasm makes up for what I lack in skills (laugh).
CARLYLE: You were telling me a story about when you first realized how hot water is getting in South Florida.
JENNY: This spring I’d gone to the Upper Keys to talk to a charter boat captain for this story. I finished by early evening, so headed to one of the little beaches off the Overseas Highway to practice casting. I’d been to this beach a lot over the years. It’s one of the few places with a parking lot and a boardwalk. There were a few cars in the lot when I pulled in. But what was surprising I was the only one dumb enough to get in the water. NO ONE was in the water. As soon as I waded it, I knew why. The water wasn’t just bath tub hot, it felt hotter than the air temps. As I was casting, I saw more people pull in. A few took selfies with the water. But only one guy waded in, and turned around got right back out. There were no fish.
CARLYLE: Is that normal for that time of year?
JENNY: It’s KIND of normal. Summer water is usually hot. But now oceans everywhere are getting hotter. This summer, the Gulf of Mexico has been hotter than the 10-year average. And it’s not just surface waters. That heat extends deep into the ocean. In some places, it’s again breaking records.
CARLYLE: But last year something happened that was really eye opening for South Florida, right?
JENNY: YES! It was a holy crap moment. This was a whole new level stuff. We think of climate change as this slow motion disaster. This was fast and brutal.Starting around March and April last year. scientists started warning that ocean temperatures were warmer than usual. Reefs were hit REALLY hard. That prolonged heat started a massive bleaching event all around the Keys. That’s when the beautiful coral thats usually … turns a ghostly white. Like skeletons.It left some scientists in tears.
CARLYLE: What was happening last summer is known as a marine heatwave, right?
JENNY: Yeah that’s right.
CARLYLE: And they’re Just like we experience on land, right? heatwaves are intensive events bringing higher-than-normal temperatures.
JENNY: That’s right, and atmospheric scientists say as the planet warms, we’re going to see these ocean heat waves more frequently AND they could last longer. And that’s on top of this steadily rising heat.
CARLYLE: So do we know what the consequences of all this hot water are going to be?
JENNY: Yes, some of them… like hurricanes getting super charged…
But then there are surprises…
[Newsreel: Anchor: More endangered sawfish found dead in Florida waters…]
…that leave us wondering WHAT is going on under the surface?
MUSIC
CARLYLE: I’m Carlyle Calhoun and you’re listening to Sea Change.
Today we’re going on a trip to Florida…we’re hanging out in the Keys, going fishing, and scuba diving all to find out what’s going on beneath the surface. Just how bad is it for sea life in South Florida, and for the people that depend on it? And how are scientists leading the charge to save this ocean ecosystem?
Jenny takes it from here.
[Ambi of boat zooming out to the Gulf Stream…Start with full sound, then fade under intro]
This summer, on a windy Miami morning, I headed out to the Gulf Stream. The sun was just coming up. I was with Martin Grossell on his fishing boat. We’re with his youngest daughter Camilla. She’s 11.
GROSSELL: Camilla's my, she's my angler today. Yeah. She's born and raised doing this And she's, she's caught a lot more fish than most in South Florida.
Grossell is an avid fisherman but also an ichthyologist -- which is a fancy word that just means he studies fish.
He’s originally from the Netherlands, where he grew up fishing in really cold water.
Now he’s at the University of Miami Rosenstiel School and has spent a good part of his career studying mahi – how they swim, how they make babies and what kinds of water make them happy.
It also happens to be one of his daughter’s favorite fish to catch and eat. So we head offshore to the Gulf Stream. That’s this big fast-moving current that the mahi really like.
[ Boat ambi for bed]
As soon as we hit the Gulf Stream, the waters turn a deep royal blue, the chop settles down.
Grossell gets his rods set up…
[Ambi: rods whirring. This a long chunk]...
…and the two begin hunting for one of the ocean’s most popular fish…
That now, because of rising ocean temperatures – fueled by climate change– are facing an uncertain future.
GROSELL: Help me find either weed or anything that’s floating and also if you see birds let me know. CAMILLA: Alright.
The Gulf Stream was a steamy 88 degrees – too hot for most mahi.
During the six hours we were out, Camilla hooked just two…
GROSSELL: Oh!. There we go! [Reel whirring] GROSSELL: Slow and steady, Mila. Let him run.
One was a schoolie, so too small to keep. The second was not a giant, but big enough to go in the ice chest.
I first started talking to Grossell a decade ago after the Deepwater Horizon oil spill in the Gulf.
Beyond the horrible tarring of sea birds and turtles, he found the oil spill could do widespread damage for years to come.
He’s the principal investigator for a research group funded by BP. BP set up the research as these massive legal battles swirled around them. It was really about damage control. The money pays to study the lasting effects on the Gulf.
From time to time I check in with Grossell about his research, and when I was back in his campus office a little over a year ago…
WLRN: So, let's see, where should we start?
… He told something about the warming waters in the Gulf that was pretty stunning.
Grossell: The warmer it gets, the more northern a southern fish will distribute. They basically leave the tropics.
The fish are leaving the tropics. The most biodiverse part of the planet hugging the equator, where the weather is hotter and more humid.
Until Grossell mentioned it, it hadn’t really occurred to me that such a sturdy fish like mahi, could be impacted by warmer water. And if mahi are being hurt, what about coral, sea turtles, sponges, sharks – and the other sea life in the ocean?
GROSSELL: What we're seeing globally now is that, due to heating, a lot of animals, fish in particular, exhibit poleward migrations. So their sort of geographical distribution is shifting away from the equator and towards the poles.
Grossell says the problem is especially acute for the Gulf of Mexico and the Gulf Stream because waters are heating up faster than in other places.
The National Oceanic and Atmospheric Administration (or NOAA) says the Gulf is warming at twice the rate of the global average.
GROSSELL: We have to be really careful, to not ignore that there could be a lot of negative consequences. This is a shift away from an equilibrium that's been established over the millenia.
And if climate change keeps warming waters, that could leave the tropics as kind of a dead zone as marine life flees or dies. It’s yet another dangerous side effect from drilling and fossil fuel use.
Oceans are absorbing about 90 percent of the extra heat getting trapped in the atmosphere by greenhouse gasses. Our oceans are bearing the brunt of climate change.
We hear a lot about problems on land.
[Newsreel waterfall on hurricanes, wildfire summer heatwave]
But what about the ocean?
Martin Grossell has been studying what stresses fish, and how they react, for decades.
And now when he’s out with his kids…
[AMBI of Camilla catching mahi] GROSSELL: Ooh! Crank on it. [reel whirring] Slow down a little bit.
…. he’s seeing his research play out in real time. That heat wave had fast-tracked what he thought would take years to happen.
GROSSELL: They have a temperature that they very rarely go below and a temperature they rarely go above.
Like a lot of marine life, mahi have a temperature sweet spot. Just like Goldilocks, they need things to be just right. To be able to swim fast and reproduce.
Today, the Gulf of Mexico is nearly 2 degrees warmer than it was a half century ago. Mahi like the water between 77 degrees and about 84 degrees in the Gulf. But now, the average summer temperature is already just over 85 degrees. Just a degree higher and it’s hot enough to be dangerous, even lethal, for mahi. So this has scientists, and not just Grossell, alarmed.
GROSELL: And so we saw that firsthand as anglers that, you know, the mahi behavior was clearly different because of this high temperature. That would definitely, definitely change behavior in these animals. And I'm sure other anglers experienced that also.
Mahi COULD just avoid the heat, and swim deeper. And in fact… that’s what Grossell saw when he was fishing with his daughters during the heat wave.
And in April, the first large scale study of Atlantic mahi also suggested they may already be changing their behavior to escape hotter water.
But that has consequences.
GROSSELL: The problem is now they are entering a different environment where there are different predatory pressures. So it is going to change their circumstances and change their foundation for life.
He says that change is enough to turn their fishy existence inside out.
GROSSELL: So it's not, it's not as simple as saying, well, they can just go to escape the heat. It's like, yes, they can. That's good, certainly in the short term. But, you know, it's very likely that that's going to have consequences.
LIke getting eaten by bigger fish. Or not finding the food THEY need to eat.
[00:16:09] GROSSELL: And I want to say here, we know this for mahi, that’s just an example. Other species are going to have similar limitations and similar problems.
Like sharks and tuna, that are migrating sooner and moving further north because of warmer water. So what’s making the Gulf and waters around South Florida so much hotter?
There’s a couple factors driving that heat, like in oceans everywhere. Radiation from the sun is one. And there’s weather patterns like El Ninos.
But there’s another suspect lurking in the Gulf: this thing called the Loop Current that winds up from the Caribbean and connects with the Gulf Stream.
SHAY1: It transports heat. When it builds up in the tropics, that's what it does. It's one of its functions.
Nick Shay is an oceanographer. Also at the University of Miami Rosenstiel School. Usually I talk to him about hurricanes. Around South Florida, summertime hot water is the magic sauce that can sometimes make or break a hurricane season.
It’s also becoming clear that as the planet warms, these loop currents play a big part in how increasingly hotter water gets spread around. When they come up from the tropics, they move a LOT of warm water.
SHAY1: At some point when you actually look at a map of the Gulf in terms of sea surface temperatures, it's just going to be uniformly warm. Hot. You know, so hot that you can. Take a bath in it, right? I mean, it's, that's how warm the Gulf of Mexico gets.
What’s ironic is currents are usually one way the planet regulates its temperature. But now, they’re like a pipeline for ocean heat.
The Loop Current can also create shallow whirlpools called eddies that can spread that heat even more.
When the Loop Current enters the Gulf, it travels clockwise, sometimes meandering like a snake. It can slither deep into the Gulf and spin off these eddies of swirling hot water.
They’re only about a foot or so deep, but they can stretch more than a hundred miles across. And they can stick around for months.
SHAY1: They move very slowly, a couple, couple of miles per hour And that's why it's like Miami traffic. You just. You're in traffic forever, right?
Shays says to really understand ocean heat, you need to understand these currents and eddies.
SHAY2: This is what we've been stressing for, again, three decades: How important currents are in the giant scheme of things. Currents transport heat. And folks doing careful ocean modeling will tell you they really have to get the currents right in order to understand the heat balances.
It’s not just the ocean that gets hurt if mahi leave South Florida and the Gulf. There are also impacts on land. Mahi are a major player in a sportfishing industry that has defined Florida for decades. In my state, fishing is like a religion
AmericanSportsmanIntro: Music, Narrator:For those of you who love the heartbeat of the hunt, the jolt of the strike, the magic of the wild, join us! For this is the show for you…
That’s next.
SPONSOR BREAK
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Saltwater Fishing in Florida is big. Bigger than in any other state. It earns $16 billion – every year. People spend money on fishing guides, restaurants, hotels. They buy boats and tackle.
The biggest fishing store in the Keys even has a life-size replica of writer Ernest Hemingway’s boat, the Pilar, to remind shoppers that they too, can live the dream.
And mahi, this big beautiful deepwater fish, has always been a huge draw. If the mahi go away, It’ll cut a huge hole in the local economy.
[This tape is from the Wolfson Archives, which had the tracks split between Sunshine narrating and scene tape, which is why the tape here is split into two tracks.]
AlSunshine WTVJ1984: The big money fishermen are out in force around South Florida, trying to win some half $1 million in prizes.
This was local TV reporter Al Sunshine covering a fishing tournament in 1984, the start of the Miami Vice days. Back then, we still called mahi dolphin, before chefs and fish markets rebranded them so people wouldn’t think they were eating Flipper.
SUNSHINE: And this is what will get them their money, Dolphin a prized game fish.
[Scene ambi meeting up with Reynonds:] REYNOLDS: It’s gotta run the uh, the air fuel ratio and haaaa. WLRN: Hi there. I snuck up on you. REYNOLDS: How ya doing? WLRN: Good, good. It’s nice to meet you. REYNOLDS: Yeah. You too [cross talk] WLRN: I’m recording if you don’t mind. I just walk in rolling.
I met up with Jon Reynolds this spring at a marina in the Keys, where he was cleaning mahi;
When Reynolds was a kid, there was nothing more he wanted to do than fish.
Reynolds: I started working at a bait and tackle shop called Burt’s Place Bait and Tackle in Cutler Ridge when I was 11 years old.
That was the start of a career that would take him all over the world.
After he got his captain’s license, he started crewing on what’s called the billfish circuit, chasing marlin and sailfish as they migrate around the Atlantic and the Caribbean.
REYNOLDS: It took you away from everything. And you were, it was very remote, especially back then when I was doing it. It was before technology was to the degree that it was now. You had to have a sat phone if you wanted to talk to anyone.
In 2008 he came home and finally got his own charter boat.
[Marina ambi music and gulls]
.the DropBack…
It’s an old Keys boat that was popular with charter boat captains and smugglers for being a smooth ride….
When I asked him to explain the name, he says the Dropback is what you call that magical moment when a giant fish eats a bait and the fish is won or lost by what the crew does.
REYNOLDS: And you are the guy who can't blow it. It's like the world would go away for me and all and everything would get silenced. And those were the moments that I loved, you know, because it didn't matter what else was going on in my life or what else was going on in the world. During the drop back right there, there was no time to think. It was only between me and that fish.
But more than a decade after he christened the Dropback, fishing is changing.
There’s still tuna and sailfish and mahi around, but Reynolds says there are fewer and the BIG mahi -- those trophy fish that helped make him such a successful captain – are disappearing.
REYNOLDS: Historically we'd been pulling up to these schools and there would be 300 to 500 fish. And you would catch, you know, 20 of the biggest fish out of the front and then leave all the rest.
The day we talked, he’d been fishing since early morning with six clients who’d crossed the state to fish with him.
[fade under ambi with fishing clients…REYNOLDS: And you'll be able to tell the snapper. Do you want me to do like a split top or anything? ANGLER: Yeah. If you got something to mark it would be cool. REYNOLDS: Yeah.]
They head off to the bar while I talk to Reynolds.
For the next hour or so, he wields a filet knife like a samurai, cleaning the 25 mahi and half dozen vermilion snapper they caught - slicing, skinning, hosing down the blood - talking and talking, never missing a beat.
Nearly all the mahi are just six or so pounds. Not anywhere close to the 20 to 40, or even 50 pound fish Reynolds says he used to catch.
REYNOLDS: Every recreational angler had an opportunity to catch something giant because the stock was so healthy and there were so many large fish.
But not anymore.
REYNOLDS: A year-old fish is 20 to 40 pounds and you only catch a couple of those a year now, maybe.
Reynolds mostly blames overfishing by the commercial fleet and bad fishing regulations.
He sits on a mahi advisory panel for the South Atlantic Fishery Management Council. But this is how climate change works: when there’s a problem, it gets amplified. So if the population is already struggling, hotter oceans just make things a lot worse.
REYNOLDS: Basically what's going on is these fish are being treated like and I'm going to use the exact terminology that they're using in these federal meetings, that everyone started using. As an annual crop.
A crop, and NOT a wild animal that Reynolds clearly thinks should be treated with more care than a field of corn or soybean.
Reynolds worries a lot about the future of Florida’s fishing industry, and a career that he’s spent building— tying one fishing knot, in one fishing line, at a time.
So what does the future of fishing look like for Reynolds and Florida’s fishing industry? To find out, I talked to Matt Damiano. He’s a NOAA fisheries biologist who models fish populations to help set U.S. fishing rules. He’s studied the WHOLE Atlantic mahi population. And he found that Reynolds is right: the number of mahi HAVE declined.
DAMIANO: In many of the places like Florida and the Caribbean, where we've heard anecdotal reports of there being a lot fewer dolphinfish available, there was a declining trend overall.
Remember mahi are also known as dolphin or dolphinfish.
DAMINAO: But if you go north to areas like North Carolina and Virginia, a lot of those folks have said the population seems stable. And if you go even further north of that, folks up there have said that during certain parts of the year, they have more dolphinfish than they know what to do with.
That suggests mahi are fleeing hotter waters in the south and moving to cooler places. And remember what Grossell said: that alters an ecoystem that’s been around for millenia.
So where does that leave Florida? That’s a question that scientists are taking very much to heart. They are getting out of their labs and working hard to wake up the public to what’s going on. and into wetsuits. They’re trying to restore reefs, one coral at a time, with squads of eco-volunteers by their sides. We tag along, next.
BREAK
Since 1970s, the Keys have lost about 90 percent of their coral, but there are still pockets that are stunningly beautiful. You can find blue tangs, yellowtail snapper and swirling clouds of glass minnows along ledges or stacks of boulders. Barracudas skulk over fields of yellow and purple sea fans.
There also used to be a rainbow of sponges in all different shapes – pale pink vases and red and purple ropes. But like coral, sponges are in trouble, which is why I joined about a dozen divers headed to a reef called Rocky Top in the Keys.
[Ambi from dive boat…divers jumping into water] DECK CREW: Ready? Here we go. [Splash!]
Today’s dive was organized by sponge scientist Bobbie Renfro. She’s in her early 30s and gives off the vibe that there’s nothing she can’t do.. Other researchers fondly call her SpongeBobbie.
RENFRO: So you're gonna come over here? So we're going to go over to the mooring buoy here okay?
She’s also part of a growing number of scientists who are stepping outside their labs to work directly with volunteers trying to figure out what’s going on.
For this project, Renfro and some students work with volunteer divers who’ll be cutting off pieces of green finger sponges to grow in an underwater nursery. It’s a little like taking cuttings from a garden. Later they’ll be transplanted back on the reef.
They’re loaded down with big orange Home Depot buckets for the sponges.
RENFRO: It’s just a little added challenge for keeping your buoyancy and making sure that you're not, you know, tipping the bucket over and dumping everybody back out [laughs].
Renfro’s sponge project is the latest chapter in the Keys eco tourism side hustle that’s been going on for a while. Diving, boating and fishing have always drawn nature lovers. But impacts from climate change are fostering this new wave of volunteerism with a new sense of urgency.
SIMON: It only helps what I enjoy: scuba diving. So, you know, I get to see the fruits of my labor.
David Simon was on his second dive with Renfro. He’s a retiree who tries to do a volunteer dive at least once a week..
SIMON: The coral that we plant, you go back and see that wow, they’re doing good, or look how big this one got. You can see the progression of your labors, you know, of all their labor, the combined effort.
This feel-good volunteerism can also provide a deeper connection for tourists that they may not get from riding the Conch train through Key West. Ask doctors and they’ll tell you trying to save a reef is actually good for you.
It’s also good for the scientists, especially after last summer’s heat wave left so many feeling helpless. At the time we heard mostly about coral dying. But the heat also hammered Renfro’s sponges.
RENFRO: I had worked at a reef that we call Lion's Lair here in the Keys for several years, and and it was hard, but we dropped down earlier this week. It's going to affect me. [pause] …
RENFRO: And most of the animals were dead.
It was the first time she’d visited the reef since the heat wave.
Even a year later it was still upsetting to her. She’s worried it won’t be a one-off event.
RENFRO: The temperature over my long term data is, is frightening.
It shows temperatures climbing from an average of just above 82 degrees to around 88 degrees just in the last six years she’s been working on getting her doctorate.
And THAT can be daunting to a scientist.
I’ve been reporting on climate change for about a decade and I can feel overwhelmed and burned out. So I wondered… how do scientists cope? How do they keep doing the work? .
Beyond all the harm to dying coral, harm to sea turtles, and wilting seagrass, SPONGES and other sea life I already knew about, reporting this story had led me to discover yet another casualty of a warming ocean – mahi. declining and fleeing to cooler water.
That puts Florida’s fishing industry at stake.
Even after talking to the scientists and volunteers, I kept coming back to that question: how do people keep going in the face of climate change and what seems like such an insurmountable problem – we’re talking about a whole planet afterall.
That’s why I reached out to Nikki Traylor- Knowles. She’d discovered some pretty important findings by not giving up in the face of some tough odds.
[The Knowles interview is from a Zoom call]
KNOWLES: When you sent me the message about this, I was like: How do we stay positive? Also, how do we take care of ourselves?
Traylor-Knowles is a cell biologist who does some really complicated stuff, like stem cell therapy for coral and investigating their immune responses to disease and warming water. After my conversation with Renfro, I wanted to ask her how she keeps treating what seems like a dying patient.
KNOWLES: I hate to say this because I don't like to be like, there's a silver lining for this because it's terrible. But sometimes when we're faced with really, really horrible situations, kind of like the pandemic, right? It was this horrible situation for everybody. But there were a lot of amazing things that came out of that time.
When she was in graduate school in the early 2000s, Traylor-Knowles says there was hardly any talk of climate change. Science was about discovery, not tri-aging an unfolding disaster.
KNOWLES: It was like, we can work on corals to understand their biology, because there were a lot of things about their biology and about their genes and their immune systems that we didn't understand. And so we could just look at it for the sake of looking at it.
The idea of engineering nature to deal with climate change would NOT have even been a consideration.
KNOWLES: Really the thought was, we're observing. We don't want to manipulate the ecosystem. But now [laughs] it's a very different world.
It’s very different because it is CLEAR that nature isn’t just changing the planet. We are. And while she prefers spending long days hunched over a microscope, Traylor-Knowles says that is NO longer enough.
KNOWLES: I got into science because I didn't want to deal with people. But all I do is deal with people. [laughing] As a graduate student, I was like, I just want to save corals. But it's like, it's a people issue. I can show them all the coral cells in the world. But that isn't going to solve saving corals. People's actions and political will are what are going to save corals.
Like the Keys tourist council turning reef restoration into a destination vacation. Or Jon Reynolds sitting through fishery management meetings after long days on the water catching mahi a fraction of the size they used to be. Or SpongeBobbie Renfro growing sponges for a reef expected to die if the planet heats up much more.
These things can make people feel better. But we need to be honest. We’re really just BEGINNING to untangle what happens in the oceans as we continue to burn fossil fuels and the world heats up faster than ever before. This summer, the planet endured its hottest day on record, for the SECOND year in a row. Our fish here in Florida have been hammered by a lot over the years - pollution, wilting reefs, oil spills, invasive species, hurricanes and on and on. But will climate change trump them all?
That’s something we wonder a lot about at our house. An entire wall in our kitchen is covered with pictures of us catching fish in Florida. We’re still adding to the wall. And I’d like to think we’ll run out of space before climate change chases/takes away our fish.
OUTRO
Thanks for listening to Sea Change. This episode was reported and hosted by Jenny Staletovich. Editing by Johanna Zorn and me, Carlyle Calhoun with additional help from Halle Parker, Eva Tesfaye, and Ryan Vasquez. I’m the managing producer. Our sound designer is Emily Jankowski and our theme music is by Jon Batiste.
Sea Change is a WWNO and WRKF production. We're a part of the NPR Podcast Network and distributed by PRX. SeaChange is made possible with major support from the Gulf Research Program of the National Academy of Sciences, Engineering, and Medicine. WWNO's Coastal Desk is supported by the Walton Family Foundation, the Meraux and the Greater New Orleans Foundation. We'll be back in two weeks!
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