Coral reefs in Turks and Caicos Islands resist global bleaching event

University of Illinois at Urbana-Champaign, News Bureau

Corals on Turks and Caicos Islands in the Caribbean experienced very little bleaching and recovered quickly from the 2014-17 global coral-bleaching event, researchers report. Credit:photo by Abby Knipp
Corals on Turks and Caicos Islands in the Caribbean experienced very little bleaching and recovered quickly from the 2014-17 global coral-bleaching event, researchers report. Credit:photo by Abby Knipp

CHAMPAIGN, Ill. — A study that relied on citizen scientists to monitor the health of corals on Turks and Caicos Islands in the Caribbean from 2012 to 2018 found that 35 key coral species remained resilient during a 2014-17 global coral-bleaching event that harmed coral reefs around the world. Even corals that experienced bleaching quickly recovered, the researchers found. Some corals appeared healthier in 2017 than they were in 2014.

The researchers report their findings in the Springer Nature journal Applied Sciences.

“Boulder-type corals on the Turks and Caicos Islands demonstrated no significant bleaching as a result of the peak thermal stress in late 2015,” said Abby Knipp, who conducted the research while an undergraduate student at the University of Illinois at Urbana-Champaign. Knipp is the first author of a paper detailing the findings. “Plate-type corals did suffer bleaching, but they quickly rebounded. Their pigmentation levels were back to normal within months of the anomalously high thermal stress.”

Coral bleaching is a common response to extreme heat stress, and global coral-bleaching events are becoming more frequent as the oceans warm. The 2014-17 bleaching event occurred as record-breaking sea-surface temperatures pushed some corals past their physiological limits. Scientists call it “the most severe, widespread and longest-lasting” global coral-bleaching event on record.

Pigmentation in corals comes from photosynthetic algae, on which the corals depend for nutrients, said U. of I. geology professor and study co-author J. Cory Pettijohn.

“The algae colonize the corals and feed on the byproducts of their metabolism,” he said. “When sea-surface temperatures are too high, corals will expel the algae. Corals that experience prolonged bleaching usually die, leaving only a white calcium-carbonate skeleton behind.”

In Turks and Caicos Islands, pigmentation of the boulder corals was darker in 2017 than in 2014, suggesting these corals were even healthier after rebounding from the heat stress, Knipp said.

“We were surprised that apparent healing and darkening could happen so fast,” she said.

The scientists say more studies are needed to explain the unusual hardiness of the corals at Turks and Caicos Islands, but previous research offers clues to factors that promote coral health. For example, some algal types appear to confer added resilience to corals experiencing heat stress. Ocean salinity and acidity likely play a role. Turks and Caicos Islands tend to have lower water temperatures than other, more thermally stressed regions of the Caribbean. And the massive 2017 hurricanes Irma and Maria cooled surface waters and likely contributed to the corals’ recovery, the researchers said.


Knipp conducted this research while studying abroad at the School for Field Studies’ Center for Marine Resource Studies in Turks and Caicos Islands. She graduated from the U. of I. in May 2019.

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Bob in Calgary
March 3, 2020 2:12 pm

More research in the T&C must be conducted due to wrong result and nice location.

Philip Mulholland
Reply to  Bob in Calgary
March 4, 2020 8:15 am

Some colleagues back in the office wouldn’t talk to me for months after I got back from the week-long Carbonates study trip to the Caicos. West Caicos nature reserve, the Cessna flight round the archipelago to see the blue hole; the Z-boat diving trip across the lagoon, the visit to the mangroves, the reef exploration. T&C has it all.

March 3, 2020 2:13 pm

Good news all around.

Reply to  Jack A Simmons
March 3, 2020 2:38 pm

“We were surprised that apparent healing and darkening could happen so fast,” she said.

They should be sacked instantly for spreading such denialistic lies. They should be ostracised and never allowed to work in anything related to climate again.

How can Greta be expected to save the world if so-called scientists are going publish this kind of objective drivel? I will be writing to the dean.

M Courtney
Reply to  Greg
March 3, 2020 3:20 pm

But it’s only “apparent” healing.
They are not claiming it’s real. Certainly not.
That would be blasphemy.

Mann would drop his Holy Hockeystick on the foothills of Mt Sinai if he saw such a thing.

Reply to  M Courtney
March 3, 2020 5:01 pm

Apparent is a tricky word. It can mean obvious. It can mean seemingly obvious, but not necessarily so.

Since the article doesn’t seem to be casting doubt on the health of the coral, my guess is that they used ‘apparent’ to mean obvious to the observer.


Reply to  Greg
March 3, 2020 11:46 pm

If the scientists had just added “clearly this must be a case of terminal lucidity”, they would probably have been promoted.

March 3, 2020 2:15 pm

What no crisis. She is clearly not seeking a career in “climate science!”

Reply to  Mohatdebos
March 3, 2020 2:30 pm

Yes, but we will still need to be on site to ensure that the citizen scientists are following the correct protocols. Only in the NH winter, of course.

Reply to  yirgach
March 3, 2020 3:50 pm


In summary, assessing coral health using the CoralWatch health chart methodology as described by Siebeck et al. [20] has proven to be an efficient diagnostic tool in diagnosing coral reef bleaching and recovery in response to regional thermal stress. Results from this study suggest a change in the composition of modern reefs, moving from massive colonies of scleractinian corals to ‘weedy’ scleractinian corals. Future studies in this region should examine the resilient endosymbiont types and life history traits of corals that have assisted in the survival of dominant reef species, representing a key factor for the emerging assisted evolution science as outlined by van Oppen et al. [49]. Further investigations of Turks and Caicos coral habitats are imperative to help understand specific coral response mechanisms and therefore predict how Caribbean region coral reefs may respond to more frequent, and more intense GBEs in the coming decades. This research is important not only to understand the mechanisms behind survival in high stress environments but in order to prioritize conservation efforts, such as establishing effective Marine Protected Areas.

Well, the study is suggesting a change in composition based on a very small sample and time period, so the call for more research is probably justified as no one knows what the hell is happening other than the fact that the corals have managed survive over 100’s of thousands of years of extreme climate change just fine.

James Clarke
Reply to  Mohatdebos
March 3, 2020 3:16 pm

She’s was probably seeking am extended, paid vacation in the Turks and Caicos.

Reply to  James Clarke
March 3, 2020 5:03 pm

I’m glad that people are monitoring the climate, it’s just their obvious preconceived bias which bothers me. Should not be part of any scientific or engineering study.
Anyway, here’s a pic of our intrepid researcher studying the reefs in the Turks.

comment image

Bryan A
March 3, 2020 2:24 pm

Sounds like Adaptation, survival of the fittest style microevolution, to me

Sweet Old Bob
March 3, 2020 2:43 pm

But … but … AOC just told us that 99% of all coral reefs are gonna DIE !

March 3, 2020 2:48 pm

most corals in the Caribbean host clade B zooxanthellae which are not a fast to jump ship…and a lot faster to recruit…
observing is totally worthless without identifying which clade they are hosting

…I hate it when they call zooxanthellae….algae……dinoflagellates

Reply to  Latitude
March 3, 2020 11:50 pm


Isn’t that a very old, obscure Catholic sect?

Henning Nielsen
Reply to  Redge
March 4, 2020 3:58 am

It just goes to show that even simple organisms are able to feel climate shame and guilt and whip themselves in punishment.

Bob B
Reply to  Redge
March 4, 2020 4:01 am

No, that’s what you get from eating bronto burgers.

March 3, 2020 2:56 pm

Citizen science, obviously, has a lot more eyes on the results. That may mean there’s less temptation to cook the books. I take note of a citizen science project on the Great Barrier Reef. link Hmmm. I wonder how Peter Ridd is doing. I’m guessing the citizen science will confirm Peter’s findings and disconfirm the work of the alarmists.

Elsewhere, we have some results that say that equatorial corals are doing OK, link, and some results that say corals are moving away from the equator, link.

Reply to  commieBob
March 3, 2020 3:29 pm

Prevalent trains of thought from researchers at James Cook University, Townsville, Australia (ex campus of Prof Peter Ridd) –

“Lemme see- we are the go-to source for the msm for news about coral bleaching outbreaks on the Great Barrier Reef. It’s what hey have come to expect from us. My bosses bring in lotsa grant $$$$s based on the papers we publish about coral bleaching (always worse than we thought). Sooo, I better get my ar5e into gear and find some more of that coral bleaching, quick. Hhmmm, maybe I can use some left over from last time – some I prepared earlier, as the celeb tv chefs are wont to say ??”

Think I’m joking?

March 3, 2020 3:00 pm

Don’t corals not exchange their algae ?

March 3, 2020 3:18 pm

re. Peter Ridd

Holy Smokes! James Cook University is a bleeping cesspool. There is serious fraud by one of its star graduates and things don’t look so good for her co-authors at JCU. And wait, there’s more. Jo Nova has this.

Rod Evans
Reply to  commieBob
March 4, 2020 3:53 am

I am wondering is JCU will be offering Michael Mann a visiting professor role, he seems to share all the same characteristics the University seems to value….

March 3, 2020 3:18 pm

Observations are used to form testable hypotheses:

1. Coral bleaching is a common response to extreme heat stress, and global coral-bleaching events are becoming more frequent as the oceans warm.
– Aside from the hype that this is “unprecedented” (nonsense) as the oceans warm and cool all the time over multi-decadal ocean cycles and centuries, the observation is that during a warm-up phase coral bleaching occurs as one type of critter is expelled and another replaces it.

2. Observation: In Turks and Caicos Islands, pigmentation of the boulder corals was darker in 2017 than in 2014, suggesting these corals were even healthier after rebounding from the heat stress, Knipp said.

Coral bleaching is a healthy response that drives coral reefs that leads to resumed, and then accelerated growth. Thus not only does occasional coral bleaching lead to vigorous regrowth, it is necessary to the long-term health of the reef system.

Rationale: I liken this reinvigoration of coral response to bleaching to that of pruning back my roses every February. Anyone who has roses knows you have to prune them aggressively to get the best regrowth, because it is from the new growth from the pruned branches that the April-May buds will come.

Coach Springer
Reply to  Joel O'Bryan
March 4, 2020 5:24 am

Also forest fires, flood plains, winter/spring, desert dry spells, …

March 3, 2020 4:06 pm

While on Okinawa in 1998 and witnessing bleaching during the strong El Nino that year, I noted that areas with the greatest amount of bleaching weren’t as well circulated by ocean currents as others that showed little to no bleaching. My thoughts were that the moving water provided cooling as well as more bits of nutrients to the coral. Just an observation. Am not a scientist nor have I ever played one on TV.

March 3, 2020 4:19 pm

Clearly this is impossible. They need to send the guys from James Cook University. They can kill any reef just by looking at it! We know that reefs have been around for a zillion years but who would’ve guessed 1 degree of warming will destroy them ( or maybe that only applies in Australia).

Philip Mulholland
March 3, 2020 4:29 pm

“The scientists say more studies are needed to explain the unusual hardiness of the corals at Turks and Caicos Islands”

More field work diving the Caicos lagoon? Its a tough assignment, but someone has to do it.

The Oceanic Central Heating Effect : Report of a Carbonates field study trip to West Caicos in June 1991.

Philip Mulholland
March 3, 2020 5:21 pm

Its It’s

Ron Long
March 3, 2020 5:23 pm

If these research scientists say “Ocean salinity and acidity likely play a role.” they should be reprimanded and sent to remedial chemistry class. The oceans are alkaline, not acidic, with rare exceptions like directly above black smokers and a few isolated tannic acid discharge rivers. When a scientist says “acidity” in relation to oceans they are either not properly educated or are exposing their political agenda, and I think we can guess which.

March 3, 2020 6:02 pm

How much thermal stress even happened in the Caribbean in 2015? The global thermal.spike of 2015-2016 was due to an El Nino, whose effects are greatest in the Pacific. The main coral bleaching that I heard about was in the Great Barrier Reef.

Janet Holden
March 4, 2020 12:30 am

Oh yes that global temperature spike around 2016 caused by a strong El Nino

shortus cynicus
March 4, 2020 3:34 am

Ocean level moves 140m up and down because of glaciations.

In that context, any talk about survival problems of coral reefs (or beaches) is primitive manipulation.

Jeremiah Puckett
March 4, 2020 4:36 am

I’m not even going to bother reading more than the headline. It isn’t a “global” bleaching event. Many reefs around the world are THRIVING. And, it isn’t an “event.” Each reef is independent of the others. Some have been bleaching longer than others. We have record of dead reefs that bleached long ago. Nothing to see here. It happens.

Coach Springer
March 4, 2020 5:45 am

Something tells me that there wasn’t a lot of attention paid to actual temperature change over this period on these reefs. Otherwise, they’d have their answer as to whether those hurricanes cooled those waters enough to make a difference. Or at least a mention in their press release.

What is “anomalously high thermal stress” ? Exactly how long is the record used to define the anomaly? So sea surface temperatures are dangerously high? How high are they? Dangerous to what and how?

March 4, 2020 6:21 am

A “global bleaching event” in 2014-2017? Really, EVERY SINGLE CORAL ON THE PLANET BLEACHED OUT FOR THOSE THREE YEARS???

Well, coulda fooled the world of swimmers, snorkelers, divers, and fishermen who did not report such a massive catastrophic occurence.

Of course, if such a thing really did happen, and then corals are now stronger than they were before the global catastrophe, then gee, guess it wasn’t a catastrophe to begin with, huh?


March 4, 2020 9:04 am

My son sailed through the Turks and Caicos area just weeks ago and reported marvelous coral reefs with no signs of damage or die-back.

I was last through this area in 2015 (northbound) and found the reefs in the T&C a real treat … though spearfishing is not allowed anywhere in the country. T&C has a wide-ranging series of protected marine areas and parks which help preserve the reefs from over-fishing.

Philip Mulholland
Reply to  Kip Hansen
March 4, 2020 10:51 am

The Caicos lagoon produces warm dense saline surface water by evaporation. This is why the Caicos islands used to produce sea salt. It’s also the reason for the white cones of salt on the former colonial flag.

T&C is also a great place for free diving. World Champion Freediver, Tanya Streeter Shatters Both Men and Women’s World Records at Club Med Turkoise, Turks And Caicos

Warm surface water pours out the Caicos lagoon in the gap between Providencilaes and West Caicos at the western end of the archipelago. This lagoon water is denser than the open waters of the surrounding Atlantic and so, as it flows down over the reef edge it drops away into the ocean depths (personal experience). This helps create the possibility for an assisted descent. Imagine swimming down the flow of a submarine waterfall. Tanya’s achievement is a record to be admired, as is her choice of location to achieve her feat.

Citizen Smith
March 4, 2020 11:37 am

So this coral bleaching event is unprecedented because it’s not worse than we thought.

Philip Mulholland
Reply to  Citizen Smith
March 5, 2020 3:38 am

“Turks and Caicos Islands tend to have lower water temperatures than other, more thermally stressed regions of the Caribbean”
Really? Their study location of South Caicos is on the eastern side of the archipelago, located in an exposed seaward location on the outside of the lagoon.
Had they bothered to travel to West Caicos they would have found naturally higher sea water temperatures. What is most obvious is the expectation by the researchers that warm surface water in the Caicos lagoon would be an environmental catastrophe for the corals. This is a location where the environment is so dry that it is possible to produce sea salt by coastal solar pan evaporation. Have they not realised that in such a semi-desert location the shallow waters of the Caicos lagoon will naturally be warm in summer and that the corals that live around this lagoon will be robustly adapted to these extremes of the natural environment?

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