1 00:00:02,033 --> 00:00:03,700 NICK SCHIFRIN: Coral reefs around the world are in growing danger, due in no 2 00:00:03,700 --> 00:00:06,700 small part to rising temperatures connected with climate change. 3 00:00:06,700 --> 00:00:11,033 But, in Florida and throughout the Caribbean, there is now a new mysterious epidemic killing 4 00:00:11,033 --> 00:00:15,266 once healthy corals. Scientists are diving deep to find some answers. 5 00:00:15,266 --> 00:00:19,900 And science correspondent Miles O'Brien recently joined them on their mission to revive the reefs. 6 00:00:19,900 --> 00:00:24,900 MILES O'BRIEN: 7 00:00:26,433 --> 00:00:30,133 I have been scuba diving in Florida and the Bahamas for 35 years, 8 00:00:30,133 --> 00:00:33,500 which makes me an eyewitness to a slow-motion disaster. 9 00:00:35,000 --> 00:00:38,900 Marine biologist Karen Neely is also saddened by what she sees. 10 00:00:38,900 --> 00:00:41,466 KAREN NEELY, Nova Southeastern University: I know what it's like to go somewhere where 11 00:00:41,466 --> 00:00:45,466 you have had old friends and they're not there anymore. That's what we're seeing on the reefs 12 00:00:45,466 --> 00:00:49,866 here. Over the last 20 years, there's just been the continued loss of coral. 13 00:00:49,866 --> 00:00:54,833 MILES O'BRIEN: It's a global problem brought on by pollution, overfishing and the climate crisis. 14 00:00:57,300 --> 00:01:01,733 The Intergovernmental Panel on Climate Change predicts up to 90 percent of 15 00:01:01,733 --> 00:01:06,733 tropical coral reefs will vanish as soon as 2030 unless drastic action is taken to limit 16 00:01:08,633 --> 00:01:13,066 greenhouse gases. Grim as that is, here in Florida, things are worse. 17 00:01:15,100 --> 00:01:19,300 Neely is on a mission to stop a deadly coral epidemic decimating reefs here and throughout the 18 00:01:21,700 --> 00:01:25,533 Caribbean. First identified near Miami in 2014, stony coral tissue loss decide spreads and kills 19 00:01:29,433 --> 00:01:34,433 like wildfire. It strikes more than 20 of the 60 or so species of coral that live here. Mortality 20 00:01:37,266 --> 00:01:42,266 rates range from 66 to 100 percent. The iconic Pillar coral is one of the most susceptible. 21 00:01:44,666 --> 00:01:46,700 VALERIE PAUL, Director, Smithsonian Marine Station at Fort Pierce: It's heartbreaking. 22 00:01:47,466 --> 00:01:50,066 It's just unbelievable. 23 00:01:50,066 --> 00:01:53,933 MILES O'BRIEN: Marine biologist Valerie Paul is head scientist at the Smithsonian Marine Station 24 00:01:55,500 --> 00:02:00,433 at Fort Pierce. She's helping lead the urgent hunt for answers. 25 00:02:00,433 --> 00:02:04,466 VALERIE PAUL: When we started, we didn't know anything. We just knew it was killing 26 00:02:04,466 --> 00:02:09,466 coral tissue, right? We know more than we did a few years ago, but we surely don't know enough. 27 00:02:11,366 --> 00:02:15,000 MILES O'BRIEN: Corals are complex, fragile, and poorly understood animals. They survive 28 00:02:17,333 --> 00:02:22,333 thanks to a mutually beneficial or symbiotic relationship with algae that live in coral tissue. 29 00:02:24,633 --> 00:02:29,633 In this marriage, the coral is the homemaker and the algae brings home the bacon, 30 00:02:32,000 --> 00:02:34,666 actually, nutrients derived from photosynthesis. Many of the vivid colors of coral are actually 31 00:02:36,400 --> 00:02:41,400 created by the algae. So, white patches are signs disease or death. 32 00:02:43,400 --> 00:02:47,300 VALERIE PAUL: So really, this whole piece is diseased at this stage. This is fairly advanced 33 00:02:50,333 --> 00:02:52,166 disease on this coral. 34 00:02:52,166 --> 00:02:56,800 MILES O'BRIEN: But no one know what is sort of pathogen is at work. 35 00:02:58,266 --> 00:03:01,266 It could be viral or bacterial or perhaps some combination. 36 00:03:03,233 --> 00:03:06,866 Here, they isolated a beneficial bacterium that fights offs the disease. 37 00:03:06,866 --> 00:03:11,866 VALERIE PAUL: We started just testing it in the laboratory first in various aquarium studies with 38 00:03:13,466 --> 00:03:16,800 pieces of diseased coral and saw that it would slow down the disease 39 00:03:16,800 --> 00:03:20,133 or stop it entirely. So this was like, wow, this is cool. 40 00:03:20,133 --> 00:03:25,133 MILES O'BRIEN: So they are treating healthy corals with probiotics applied beneath a 41 00:03:27,000 --> 00:03:30,733 weighted bag. It looks promising, but it's still early. Antibiotics are also working. 42 00:03:33,433 --> 00:03:38,433 Karen Neely is part of a small team of researchers applying amoxicillin paste to ailing corals. 43 00:03:40,333 --> 00:03:44,600 KAREN NEELY: We can come back in a month, and that coral has no sign of disease, 44 00:03:46,100 --> 00:03:48,133 it's not dying anymore. And, eventually, it starts re growing. 45 00:03:48,133 --> 00:03:52,633 MILES O'BRIEN: Her team from Nova Southeastern University and others 46 00:03:52,633 --> 00:03:56,066 have collectively saved nearly 15,000 corals. 47 00:03:58,100 --> 00:04:01,700 Still, the researchers are well aware they're only making a small dent in a massive problem. 48 00:04:03,533 --> 00:04:06,000 KAREN NEELY: We really have to be quite selective. We're figuring out, 49 00:04:07,466 --> 00:04:09,900 what can we save, what might be OK if we can't get to it, 50 00:04:09,900 --> 00:04:13,600 and what are we going to lose regardless, and trying to get the most bang for the buck? 51 00:04:13,600 --> 00:04:16,933 We can't just pretend this isn't happening and not do anything about it, 52 00:04:16,933 --> 00:04:19,733 or the prognosis takes a sharp turn for the worse. 53 00:04:19,733 --> 00:04:24,733 MILES O'BRIEN: At the Florida Aquarium Coral Conservation Center near Tampa, 54 00:04:25,866 --> 00:04:27,833 they are fighting this disease on land. 55 00:04:27,833 --> 00:04:29,900 KERI O'NEIL, Florida Aquarium Coral Conservation Center: So, 56 00:04:29,900 --> 00:04:34,200 this is a tank of corals that are going out into the ocean in a couple of weeks. 57 00:04:35,633 --> 00:04:38,400 MILES O'BRIEN: Keri O'Neil is the senior coral scientist here. 58 00:04:40,200 --> 00:04:43,900 At first, she hoped to participate in a massive effort by a team of scientists to 59 00:04:43,900 --> 00:04:48,900 harvest healthy coral from the reefs to create an ark, a desperate move to avoid extinctions. 60 00:04:50,866 --> 00:04:55,133 KERI O'NEIL: However, they don't stop growing. And if you're keeping them 61 00:04:57,166 --> 00:04:59,266 under happy conditions, then they're just going to keep growing and growing. 62 00:04:59,266 --> 00:05:03,500 MILES O'BRIEN: She wondered if she could make endangered Pillar corals happy enough 63 00:05:03,500 --> 00:05:08,500 to reproduce. Something like that had never been done before with Florida corals in aquariums. 64 00:05:10,400 --> 00:05:14,633 KERI O'NEIL: So you have to get all the seasonal cues right, the change in temperature, 65 00:05:14,633 --> 00:05:19,633 the change in daylight, sunrise, sunset, the moon phase, all of these different 66 00:05:22,133 --> 00:05:25,133 cues have to be just right in order for that one event to occur around the full moon of August. 67 00:05:27,033 --> 00:05:31,633 MILES O'BRIEN: The spawning happened on their first try in August of 2019. 68 00:05:34,166 --> 00:05:37,466 KERI O'NEIL: We were just cheering and yelling and calling everybody, like, come in. We need help. 69 00:05:38,066 --> 00:05:39,733 (LAUGHTER) 70 00:05:39,733 --> 00:05:42,300 KERI O'NEIL: And it's happened like clockwork every year since then. 71 00:05:42,300 --> 00:05:46,800 MILES O'BRIEN: So what started as a gene bank five years ago 72 00:05:46,800 --> 00:05:49,900 is now a huge thriving coral breeding center. 73 00:05:51,933 --> 00:05:55,866 Keri O'Neil occasionally joins divers from the Florida Fish and Wildlife Conservation Commission 74 00:05:57,866 --> 00:06:01,533 as they cement their offspring onto ailing reefs. The team uses little bamboo teepees, 75 00:06:03,600 --> 00:06:07,866 so the young corals don't become fish hors d'oeuvre. So far, they are thriving, 76 00:06:09,866 --> 00:06:13,633 maybe because they're young and strong, or maybe the worst of the epidemic has passed. 77 00:06:15,100 --> 00:06:18,133 Eventually, O'Neil hopes they will find the genes that make 78 00:06:18,133 --> 00:06:23,133 coral resistant and selectively breed animals that are immune to stony coral tissue loss disease. 79 00:06:25,200 --> 00:06:28,866 But, remember, the disease is just one of many threats. 80 00:06:28,866 --> 00:06:33,866 KERI O'NEIL: We cannot save coral reefs without stopping climate change and cleaning up our 81 00:06:35,933 --> 00:06:40,200 environment. That takes time. In the meantime, we need to ensure that we don't lose the diversity 82 00:06:42,866 --> 00:06:47,866 that we have now, so that we can build back the population. Our work here is buying us time. 83 00:06:49,833 --> 00:06:54,833 MILES O'BRIEN: When Karen Neely swims past healthy corals that she has treated, 84 00:06:55,566 --> 00:06:57,000 she feels the same way. 85 00:06:57,000 --> 00:06:59,033 KAREN NEELY: I definitely don't feel like it's 86 00:06:59,033 --> 00:07:02,133 a futile effort. And I do feel like we have to do something. 87 00:07:02,133 --> 00:07:05,266 If you like seafood, you like coral reefs. 88 00:07:05,266 --> 00:07:08,866 If you like vacationing in Florida, you like coral reefs. You might not know it, 89 00:07:08,866 --> 00:07:12,700 but it's super important that we have them, and it's pretty problematic when we lose them. 90 00:07:14,733 --> 00:07:18,400 I think, in my lifetime, we will either start to see the swing back towards more healthy reefs, 91 00:07:18,400 --> 00:07:22,866 or we will see reefs continue to decline into something almost unrecognizable. 92 00:07:22,866 --> 00:07:27,866 MILES O'BRIEN: Imagine that, a world without thriving coral reefs. 93 00:07:29,733 --> 00:07:33,800 Not a pretty thought. It's heartbreaking to watch it happening right before my eyes. 94 00:07:35,833 --> 00:07:40,666 For the "PBS NewsHour," I'm Miles O'Brien 30 feet beneath the surface at Looe Key, Florida.