00:00 (dramatic music)
00:02 - Significant severe coral bleaching has been reported
00:04 in at least 54 countries and territories
00:08 around the globe since February, 2023.
00:12 So it's spatially extensive occurring, again,
00:16 in all ocean basins across multiple, multiple countries.
00:20 NOAA is declaring that the world is indeed, in fact,
00:24 experiencing its fourth global coral bleaching event.
00:27 It is unfortunately official.
00:30 Scientists from the National Oceanic
00:32 and Atmospheric Administration
00:33 and the International Coral Reef Initiative
00:36 have formally announced wide swaths of tropical reefs
00:39 have started to expel the colorful algae
00:41 living in their tissue.
00:43 The joint statement comes just weeks
00:45 after NOAA issued a dire warning
00:47 about the risk of a mass coral bleaching event
00:49 following months of record-breaking ocean heat
00:52 and documenting extensive bleaching-level heat stress
00:56 on reefs across the Atlantic, Pacific, and Indian Oceans.
01:00 Joining us now is the man you just heard from,
01:02 the coordinator of NOAA's Coral Reef Watch, Derek Manzello.
01:06 Derek, thank you so much for coming on.
01:08 So for those who might not be familiar
01:10 with the term coral bleaching,
01:12 what exactly is it and what causes it?
01:14 - So corals are an animal,
01:18 very similar to a jellyfish or something like that.
01:21 They're very simple animals.
01:23 They're only about four cell layers thick,
01:26 but they live in a symbiotic relationship
01:28 with a type of algae,
01:30 and this algae provides upwards of 95%
01:34 of the nutritional requirements of the coral animal.
01:37 However, the symbiotic relationship
01:39 is highly sensitive to elevated temperatures.
01:42 And this is because photosynthesis essentially goes haywire
01:46 in the algae at high temperatures and high light,
01:48 causing the coral animal to expel these symbionts.
01:52 So when they expel their symbionts,
01:54 they turn stark bone white,
01:57 and they just have the coral tissue and no algae.
01:59 And essentially what this means is that
02:01 the coral is in a state of starvation.
02:04 So if water temperatures don't decline
02:07 and things don't cool off quick enough,
02:09 the coral may eventually die from this bleach condition.
02:12 - So this is now the fourth worldwide mass bleaching event.
02:15 When was the last one and why is this so significant?
02:18 - So there have been three previous
02:21 global coral bleaching events on record.
02:23 The first was 1998, the second was 2010,
02:25 and the third was from 2014 to 2017.
02:29 So this is the second global scale
02:31 mass coral bleaching event we've experienced
02:33 in the last 10 years.
02:35 And the coral reefs are significant for multiple reasons.
02:38 So one of the big things they do
02:40 is they provide coastal protection from storms.
02:42 Now, healthy coral reefs can block more than 90%
02:45 of the wave energy during things like hurricanes,
02:48 typhoons, and cyclones.
02:51 Coral reefs are also the rainforests of the sea.
02:54 Now, what that means is about 25%
02:56 of every living thing in the ocean
02:58 depends on coral reefs at some point in its lifetime.
03:02 So what that means is one in four of every organism
03:04 that's alive in the ocean is dependent
03:07 on functional, healthy coral reefs.
03:10 - So how does weather play a role in this?
03:12 I assume that El Niño and La Niña both play a part,
03:16 but what exactly is it?
03:19 - So El Niño definitely plays a part.
03:22 Now, the first mass coral bleaching event
03:25 that ever occurred on record
03:27 due to elevated ocean temperatures
03:28 happened actually 40 years ago now.
03:31 So this occurred throughout the Eastern Tropical Pacific
03:34 over 1982, 1983.
03:36 Now, that was at that time the strongest El Niño on record.
03:40 Now, of course, we've broken that record now two times since.
03:44 Now, the reason this is so severe
03:47 and that these mass coral bleaching events
03:50 are happening more frequently
03:51 is because the ocean is warming significantly and rapidly,
03:55 and it's outpacing the ability of corals
03:58 to keep track with these rising ocean temperatures.
04:01 - Is there any hope?
04:02 Can coral reefs rebound?
04:04 - Absolutely.
04:06 So there's absolutely hope.
04:07 One of the things I wanna make clear
04:09 is that all is not lost, right?
04:11 This should be viewed as a global warning.
04:14 The fact that we're seeing this synchronous bleaching
04:17 happening in all three ocean basins,
04:18 I mean, it's so severe,
04:19 you can see coral bleaching from satellites, right?
04:23 So if temperatures cool off quickly enough,
04:26 corals can recover and they can rebound.
04:29 Now, the issue is coral bleaching events
04:31 are becoming more severe
04:33 and they're becoming more frequent.
04:34 So even in the best case circumstance,
04:37 it can take a reef maybe seven to 15 years
04:40 to start recovering coral from upstream sources,
04:44 coral larvae come in from other reefs.
04:46 Now, the issue is we're seeing bleaching events
04:49 happen with much greater frequency than seven to 15 years.
04:52 So what this means is that reefs are now entering
04:54 a state of chronic stress.
04:56 And this is why it's so important that we continue
05:01 to engage in this assistant evolution process
05:04 using cutting edge science and restoration
05:07 to try to breed corals that have higher heat tolerance
05:10 that we can then utilize to restore places
05:13 that have been impacted like the Florida Keys.
05:16 Derek Manziello, thank you so much for coming on
05:18 and for sharing your knowledge with us.
05:20 My pleasure, thank you for having me.
05:23 (upbeat music)
