0:00:00.5 John Sheehan: The barrier coral reef spanning the Florida Keys, in fact the only barrier reef in the continental US, is vital to the ecosystems and communities of southern Florida. Coral reefs provide crucial habitat and storm protection, not to mention the economic benefits as destinations for diving, fishing, and boating.

0:00:22.0 Jennifer Moore: People call them the rainforests of the sea. They are extremely important in terms of species diversity and for the ecosystem services that they provide to humans.

0:00:30.6 JS: But in recent decades, mostly due to climate change, the reef has been decimated. It had already been in pretty bad shape even before the summer of 2023, when this happened.

0:00:39.1 S3: Soaring ocean temperatures off the coast of Florida.

0:00:41.0 S4: Up to 7° above average.

0:00:44.3 S5: The alarming water temperatures off Florida tonight and what they're seeing in the coral.

0:00:49.5 S6: These waters are hot and corals cannot survive in really hot water.

0:00:54.4 JS: This is Dive In with NOAA Fisheries. I'm John Sheehan. And today we'll hear about Mission: Iconic Reefs, the efforts underway to protect and restore seven key reef sites in the Florida Keys National Marine Sanctuary.

0:01:05.3 JM: Which is basically from a little bit south of Miami through the Dry Tortugas.

0:01:10.8 JS: This is my guest, Jennifer Moore, a Threatened Coral Recovery Coordinator in NOAA Fisheries' Protected Resources Division and a co-lead of Mission: Iconic Reefs. Last summer's heat wave was a major bleaching event and devastating for the reef. And to understand what that means, I kind of had to know what coral bleaching refers to in the first place.

0:01:30.9 JM: Coral bleaching is a response of the coral to elevated temperature in the ocean. It is an animal that also has an algae that lives inside of it that provides food to it to help it grow. And corals live in a very narrow band of temperature. Just a degree or two above that, though, creates oxidative stress. And what the result of that is, is the coral expels their algae. And so what you're now seeing, the reason why it's called coral bleaching is that the algae is what gives the coral their color.

0:02:01.9 JM: And so when the algae leaves the tissue, you're seeing through a relatively clear tissue to the white skeleton that's underneath. Now, the coral is not dead when it bleaches. The animal, the tissue, is still alive and can recover from bleaching when the temperatures go back down if they can reacquire their algae, which does happen very, very often. The problem with some bleaching events, though, is that their temperatures are high for so long that then the corals actually wind up starving to death because the algae is what provides a large portion of their food. And so really, the duration of a bleaching event is what ultimately can cause the corals to die from it because they they slowly starve to death.

0:02:47.3 JS: I see. And that's an unfortunate segue into last summer's heat wave, marine heat wave. Temperatures in and around Florida were pretty extreme. Can you describe what happened?

0:03:01.2 JM: Yeah. So bleaching events have been happening since the late 1980s, but in relative infrequence time, like in between each event, until about the 2000s. Our last major bleaching event was in 2014 and 2015, also related to an El Nino cycle. And we do have elevated sea surface temperatures every August and September, at the warmest part of our summer months, and in some cases, you do get mild levels of coral bleaching every year, and the corals mostly recover from that. What happened this year, though, is that, typically we see that happening in August or September, we started seeing extremely high temperatures above the bleaching threshold, which is about 86 °F in July. In some locations, we had three or four days sustained with temperatures above that bleaching threshold without coming down at night. And so they were basically cooked, those poor corals. And those severe temperatures did not sustain at that same level the entire time, but we were above bleaching thresholds for 20-plus weeks this summer, which is pretty unprecedented.

0:04:13.1 JS: And what was the response like at the time? Because I remember seeing on the news people kind of coming out of the ocean carrying bundles of coral. What was going on?

0:04:23.6 JM: Yeah. So we tried to do everything we really possibly could when we saw just how severe this event appeared to be because of it happening so much earlier than we were expecting it to. The reef track is very, very large, about 200 miles long in the Florida Keys National Marine Sanctuary. And so it would be very, very challenging to be able to save the corals on the reef. However, we have a lot of coral restoration activities going on, and we have partners who grow and propagate corals in in-water nurseries. And so it was those corals that you saw people evacuating from their in-water nurseries where the water temperatures were just as hot as on the reef to land-based aquariums in various different facilities around the state because we can control the water temperature there. And it was basically to try to save as much of the stock of these restoration corals as we could so that we would have them to help us restore the reef once the bleaching event passed. But if we lost them, too, we would be really in a major hole that we would have to try to dig out because we knew that a lot of the corals on the actual reef were going to die from this event.

0:05:30.3 JS: And are all of the corals that make up the different reefs the same?

0:05:36.1 JM: No. So in the Caribbean, which Florida's coral reef is part of the Caribbean coral reef ecosystem, there are about 63 different species of corals that grow on coral reefs. And there's maybe a dozen or so that are actually the primary reef builders. So they're the ones that build all the coral reef structure. And then there's a lot of other species, I sometimes call them sprinkle species, that are there and part of the habitat, but they're not necessarily the ones that are building the large coral reef structures that people see.

0:06:06.1 JS: Ah. So there's multiple kinds of corals interlacing on top of existing corals?

0:06:13.4 JM: So basically the way that a coral grows is that it secretes a skeleton, and basically over time that skeleton just keeps building and building and building, and the tissue just keeps rising up and rising up to be at the surface of that. And that's what builds coral reefs. Corals are basically the perfect answer to 20 questions because they are animal, vegetable, and mineral. They're all three. The way that these things grow over time is that, yeah, basically the newest, youngest coral is growing on top of old, dead coral that was maybe growing and alive 100 or 1000 years ago.

0:06:50.0 JS: Got it. And in addition to being many things at once, it also serves many purposes in the environment. It's habitat. It's an essential part of the ecosystem.

0:07:01.3 JM: Absolutely. Yeah. Corals are basically... People call them the rainforests of the sea. They are an extremely diverse ecosystem. So like I said, there's multiple species of corals. But those corals reefs provide habitat for 25% of all marine life in the ocean. And they only occupy about 1% of all of the surface area, the floor of the ocean. So they are extremely important in terms of species diversity. And they're also extremely important for the ecosystem services that they provide to humans. Coral reefs are usually adjacent to coastlines, and they provide a major wave attenuation function. So when you have large storm events like a hurricane or a tropical storm, those big waves crash on the coral reef before it has the opportunity to crash on the shoreline. And so therefore, it actually protects human structures and flood inundation by dissipating that wave energy offshore. Places that have intact healthy coral reefs, up to 97% of the wave energy is dissipated on the reef.

0:08:08.9 JS: In addition to being just environmentally healthy organisms, they're tourist attractions. People go to them to dive and to observe fish of all kinds.

0:08:22.8 JS: Absolutely. There's the shoreline protection component of it, but the economy really depends on healthy coral reefs, both from a tourism standpoint, but also from both commercial and recreational fisheries. Fish like snappers and groupers spend part of their life cycle on coral reefs, and people all over the country like to eat those fish. And so if we have healthy coral reefs, we can have healthy fish populations too.

0:08:44.0 JS: And it's not news that coral reefs have been in decline for decades now. What's going on?

0:08:51.0 JM: So, unfortunately, coral reefs are subject to a multitude of stressors and threats. The disproportionately large ones are related to climate change. So things like coral bleaching from extreme high water temperature, also ocean acidification, but there's also things like diseases. In the early '80s, two of the primary reef builders, elkhorn and staghorn coral, which are on the endangered species list, underwent a huge decline due to a disease. And now Florida's coral reef and the Caribbean is also experiencing stony coral tissue loss disease since 2014. And that is a disease that affects up to 20 different species of corals and has caused significant declines on an already declined system. So when you have very, very low coral cover, when you lose even a little bit more, it has a dramatic effect. There's also things related to land-based sources of pollution; so sedimentation, nutrients. Corals like to live in extremely clear waters with low nutrients 'cause they need to rely on sunlight for the algae within their tissue to photosynthesize and provide the primary source of their foods.

0:10:02.7 JM: And so when you have runoff from land that puts sediment and nutrients, which causes blooms of algae in the water column, that all reduces the light and can also... The sediments can actually settle out and smother coral. So unfortunately, there are a lot of global and local threats that are affecting our corals that basically all add insult to injury.

0:10:22.0 JS: And so what's the general process like for restoration of these reefs? How do you go about it? You mentioned these stock corals.

0:10:31.0 JM: Yeah, so coral restoration is actually accomplished in a bunch of different ways. Two of the species that are the main focus of coral restoration are elkhorn and staghorn coral. They are some of the most important ones in helping to build Caribbean reefs. They're branching corals, and part of their regular life history is to fragment, and then a piece of that coral will attach to another part of the substrate and grow into a new colony. Restoration capitalizes on that, and humans fragment those corals and create multiple copies of the same coral, grow them up, and then eventually outplant them. And they do that in in-water nurseries. Imagine like an Iowa cornfield of PVC Christmas trees, and hanging off of each of the branches of the Christmas tree are these corals. And when they grow you can either break them into pieces and put them back on the tree to continue to grow more and more or you can take them and you put them out on the reef and you attach them to the reef using glue or a cement or an epoxy and then they just start to grow and turn into a coral colony out on the reef.

0:11:35.8 JM: There's also sexual propagation of corals where you actually take the eggs and the sperm of individual corals and you cross them and you create larvae and then eventually when after a little while they grow up and we put them out on the reef. So there's lots of different techniques of coral restoration but the whole purpose is to try to grow as many and as much coral biomass as we possibly can because we are in such low coral cover on our reefs right now.

0:12:00.2 JS: Yeah what kind of capacity do you have to grow them?

0:12:03.0 JM: So we're very fortunate that in Florida we have a number of partners who are engaging in coral propagation like the Coral Restoration Foundation, Mote Marine Laboratory, Reef Renewal USA, The Florida Aquarium, Boy Scouts of America, they have a Florida Sea Base, we have partners with I.CARE. There's a ton of restoration practitioners who are engaging in these activities. So we're really fortunate because we have this network already existing that are helping us engage in things like Mission: Iconic Reefs, and that was why it was relatively easy for us to respond to this marine heat wave because we already had these established partnerships and people just jumped in to help. And we, actually, have a very amazing partnership with the Association of Zoos and Aquariums because we do have corals being held on land for conservation, and they helped and jumped in to train the people how to take care of all of these thousands and thousands of evacuated corals on land. So it's amazing network that we have and we're really really fortunate but our capacity is nowhere near where it needs to be to actually grow as many corals as we really need to to restore the reef.

0:13:15.5 JS: Well, that sounded very encouraging, that there was this crowdsourced effort of coral restorers.

0:13:18.2 JM: Yeah. Like I said, we're really fortunate that there is a large community here in Florida, but like I said, it's not enough to really affect the amount of change that we're trying to do. But we're lucky that there has been some pretty large-scale investments from the federal government into these partners. Last year's bipartisan infrastructure law, transformational habitat restoration grants awarded funds to both Coral Restoration Foundation and Mote Marine Laboratory specifically to work at Mission: Iconic Reefs to build up their capacity. Again there's a lot of encouraging activities happening in this space and as I said it's also just not enough, particularly in light of this marine heat wave that we just went through, and we don't know exactly the full extent of the impact yet because we're still conducting surveys and trying to collect the data, but we do know that there was a significant amount of mortality and not only in the wild corals but also in some of our restored corals, our outplanted corals.

0:14:16.8 JS: So you don't know the the scale of the damage yet?

0:14:20.9 JM: We don't know the scale of the damage yet, and that's for two reasons really. So one is we did conduct, at least for the Mission: Iconic Reefs sites, there's seven of them in the Florida Keys, we conducted a research cruise in August, so basically in the middle of the event, to see what the effect of the heat wave was on those corals. Looking again at those outplanted corals that were the restored corals as part of Mission: Iconic Reefs. So that information was happening during the event. That's not going to give us the information of afterwards, after the temperatures have cooled, which really they didn't cool down until October. So we're going to repeat that same type of cruise in February and that will give us enough time to see, not only what may have died, but what may have recovered. So like I said before when a coral bleaches, it's not dead, it's not necessarily the death knell for them. So if they were able to recover that will give us enough time to see that recovery, and anecdotally we are seeing recovery and some of the corals are ready in other surveys that are being conducted. So we have hope that when we go back in February that we will get a picture of both the impact but also the recovery.

0:15:26.9 JS: Has coral restoration improved over these last few years? Has this crisis led to greater understanding and how to rebuild these reefs faster, stronger, better?

0:15:38.8 JM: Absolutely. Coral restoration started in its infancy in the late '90s, and has grown exponentially in terms of techniques and learning how to do things better. There's a very robust research community that's looking into, not only the propagation techniques, but how do we actually grow corals that are better, able to deal with all these multitude of threats, particularly, related to ocean warming and extreme temperatures? So there's promise there. We haven't been able to take the leap from the research in the laboratory and actually bring it to scale operationally in restoration activities, but I think we're getting closer and closer to that. And I think this year's marine heat wave really is shining a spotlight on the fact that we need to put the pedal to the metal and really enhance the speed at which we translate that promising research to actual restoration on the reef.

0:16:33.3 JS: So in light of continuing surveying of the damage, and you mentioned how you're still not totally sure of the scale of last summer's heat event, where do you go from here?

0:16:46.3 JM: So while we all kind of expected there to be a marine heat wave this summer, there were predictions again because it was an El Nino year, we were still caught off guard. The thing that we have to learn is that these types of events are going to happen and probably happen more frequently. And how exactly do we incorporate that knowledge so the next time we're not responding in an emergency but we just are enacting what we know we're supposed to do? For example, aquariums all have a emergency procedure. If there's gonna be a hurricane or a snow storm and the power is likely to go out, they know exactly where every single one of those animals is gonna be evacuated to, and they just turn that on when the threat is near. So we need to do things like that. We also need to... While we knew that we need to invest in research on how to make corals more resilient, we really need to incorporate that more wholesale into restoration activities like Mission: Iconic Reefs and we really need to amplify that research and get it into the restoration, and how do we do that as fast as possible? Because we need to give the corals that we're putting out on the reef the best chance of survival.

0:18:02.0 JM: And we'll be re-evaluating our plan for Mission: Iconic Reefs and we're going to look at that and say, "Okay, in light of what we just experienced, do we need to re-evaluate some of our targets and our timelines?" Because we have to adaptively manage knowing that we are going to have these types of events really hit our stock and what we put out there over and over again. So we need to figure out how do we on a day-to-day basis operate in the fact that we're going to have these booms and busts along the way.

0:18:31.2 JS: Jennifer Moore, thanks so much.

0:18:33.0 JM: Well, thank you so much for having me. It's really important to get this information out because coral reefs are so important to, not just those of us who study and work on them, but really the entire country. So I'm glad that we had the opportunity to talk about this today.

0:18:46.5 JS: Jennifer Moore is co-lead of Mission: Iconic Reefs and a Threatened Coral Recovery Coordinator in NOAA Fisheries' Protected Resources Division. More than 25 coral species are listed as threatened or endangered under the Endangered Species Act, which is marking its 50th anniversary this month, December, 2023. The goal of the act is to recover listed species, including corals, so that they can be taken off the land through conservation efforts such as Mission: Iconic Reefs. You can read all about the efforts to restore the reef at floridakeys.noaa.gov, or get updates about all sorts of restoration efforts at fisheries.noaa.gov. I'm John Sheehan and this has been Dive In with NOAA Fisheries.