Study: Severe low temperatures devastate coral reefs in Florida Keys – attributed to North Atlantic Oscillation

Temperature from an inshore patch (Admiral Reef) and offshore (Little Grecian) reefs. Dotted line is the average winter (January and February) seawater temperature for Admiral Reef from 2007-2009 (panel a). Photos of Admiral Reef taken in February 2010 show Montastraea faveolata skeletons being overgrown by macroalgae (indicated by arrow, panels b, c). Dead M. annularis (panel d). Tissue necrosis and skeleton of M. cavernosa (panel e). Tissue necrosis from a dead octocoral (panel f). Dead M. faveolata colony with visually unharmed Gorgonia ventalina (panel g). Visually unharmed Siderastrea siderea (panel h). Click image to enlarge

From the University of Georgia, Athens(UGA)

Athens, Ga. – Increased seawater temperatures are known to be a leading cause of the decline of coral reefs all over the world. Now, researchers at the University of Georgia have found that extreme low temperatures affect certain corals in much the same way that high temperatures do, with potentially catastrophic consequences for coral ecosystems. Their findings appear in the early online edition of the journal Global Change Biology.

Lead author Dustin Kemp, a postdoctoral associate in the UGA Odum School of Ecology, said the study was prompted by an abnormal episode of extended cold weather in January and February 2010. Temperatures on inshore reefs in the upper Florida Keys dropped below 12 C (54 F), and remained below 18 C (64 F) for two weeks. Kemp and his colleagues had planned to sample corals at Admiral Reef, an inshore reef off Key Largo, just three weeks after the cold snap. When they arrived, they discovered that the reef, once abundant in hard and soft corals, was essentially dead. “It was the saddest thing I’ve ever seen,” Kemp said. “The large, reef-building corals were gone. Some were estimated to be 200 to 300 years old and had survived other catastrophic events, such as the 1998 El Niño bleaching event. The severe cold water appeared to kill the corals quite rapidly.”

Odum School Professor William Fitt, Kemp’s doctoral advisor and one of the paper’s co-authors, realized that the team had a unique opportunity. “Nearly 100 years ago, Alfred Mayer described the temperature tolerance of different corals in the Dry Tortugas and found very similar results,” Kemp said. “We decided to take the next step and learn how and why the cold temperatures caused the corals to die.”

The researchers took samples of Siderastrea siderea—one of the few reef-building corals to survive—from Admiral Reef. They also took samples of three common Florida Keys corals, Montastraea faveolata, Siderastrea sidereaand Porites astreoides from Little Grecian Reef, a nearby offshore reef that had not experienced the temperature anomaly to the extent of Admiral Reef. Kemp explained that Little Grecian Reef is far enough offshore that the cold-water temperatures were likely buffered by the warm waters of the Gulf Stream, which resulted in offshore coral reefs being less severely affected by the cold air mass that was pushed by an unusual weather pattern over much of the U.S. during that two-week period.

Back in the lab, they simulated the temperatures that had been recorded at Admiral Reef during the cold weather event, testing the different corals’ physiological responses at 12 C and 16 C (61 F), and then, after the corals’ exposure to the cold, returned the temperature to 20 C (68 F). They found that although responses varied depending on the coral species, in general the stress of extended cold temperatures had an effect similar to that of high temperatures.

Kemp explained that corals depend on Symbiodinium, a type of symbiotic algae that lives inside them, for nutrition. Through photosynthesis, the algae produce sugars, which are passed on to the corals. “The cold temperatures inhibited photosynthesis in the algae, leading to a potential net loss of carbon transferred from the algae to the coral,” said Kemp. He said that each coral species had its own unique type of Symbiodinium, some of which were better able to tolerate and recover from cold temperatures than others.

All of the corals experienced a significant decrease in photosynthesis at 12 C. Siderastrea siderea and M. faveolata were able to handle the 16 C temperatures, but P. astreoides was not, and did not show signs of recovery once the temperature was returned to 20 C. Siderastrea siderea was the only coral able to recover.

“Corals and their symbiotic algae have a range of stress tolerance,” said Kemp. “Some can handle moderate stress, some are highly sensitive, and some are in between. But extreme cold is just one stressor among many.” Other threats to coral health include increased seawater temperatures, diseases, ocean acidification, and pollution. “Adding stress from wintertime cold episodes could not only quickly kill corals but also may have long-term effects,” he said. “For corals found in the Florida Keys, winter is typically a ‘non-stressful’ time and corals bulk up on tissue reserves that are important for surviving potentially ‘stressful’ summertime conditions (i.e. coral bleaching).”

Kemp said that researchers at NOAA attribute the record-breaking cold anomaly to a negative trend in the North Atlantic oscillation, an atmospheric pressure pattern that influences the weather in the northern hemisphere. “They speculate that if the trend continues, these kinds of extreme cold events may become more frequent,” he said.

Photographs of coral colonies from Admiral Reef before (panels a, c, e) and after (panels b, d, f) the cold-water anomaly. Photographs were taken in May 2009 (before) and February 2010 (after). Coral species shown are Montastraea faveolata (a, b), Porites astreoides (c, d), and Siderastrea siderea (e, f). “After” photographs of M. faveolata and P. astreoides (panels b, d) show dead colonies, whereas S. siderea (panel f) remained alive. Pigmentation of dead M. faveolata (panel b) is due to overgrowth of the coral skeleton by cyanobacteria and filamentous algae. (Credit: Dustin Kemp/University of Georgia) - Click image to enlarge

Kemp stressed that the study’s findings should not be interpreted to downplay the major role of higher temperatures on corals’ decline. “The study shows that warming may not be the only climate-related problem for coral reefs in the future,” he said.

Kemp also pointed out that it was not only the corals that were devastated by the cold snap. “The corals provide the framework for the entire reef ecosystem,” he said. “The lobster, shrimp, clams, fish—all the creatures that depend on the reef—were affected too. The potential consequences for coral ecosystems are extremely alarming.”

Besides Kemp and Fitt, the paper’s coauthors were Clinton Oakley and Gregory Schmidt of the UGA Department of Plant Biology, Daniel Thornhill of the nonprofit Defenders of Wildlife and Bowdoin College, and Laura Newcomb of Bowdoin College. The research was supported by the National Science Foundation and Bowdoin College.

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68 thoughts on “Study: Severe low temperatures devastate coral reefs in Florida Keys – attributed to North Atlantic Oscillation

  1. erm – after a very quick read – have I deduced correctly that the conclusion is either warmer or colder conditions cause the coral to decline? erm again – isn’t that normal for any delicately balanced ecosystem?

  2. News of the World…………….

    Postdoctoral associate in the Odum School of Ecology, University of Georgia, Athens, discovers that tropical corals are limited by temperature.
    Postulates as to why tropical corals do not grow off the coast of Norway…..

    …receives $48million federal grant to study tropical reef building corals in Baffin Bay…..

    ..film at 11:00

    Does is really get any stupider than this?
    It was also one of the largest fish kills in Florida Bay.

  3. So, in other words, there’s a range of temperatures in which coral thrives; far outside those, it dies. Kind of like every living thing.

    Obviously global warming’s fault. /tinfoilhat

  4. So it seems cold is bad. Who’da thunk it?

    But we also have the obligatory paragraph telling us that Global Warming will be the main problem, this cold thingy is just a minor problem, and warming will get them all anyway (despite warming NOT being proven to cause corals any harm, and cooling has…)

  5. “Kemp stressed that the study’s findings should not be interpreted to downplay the major role of higher temperatures on corals’ decline.”

    Obbligato in the CAGW opéra comique.

  6. Kemp said that researchers at NOAA attribute the record-breaking cold anomaly to a negative trend in the North Atlantic oscillation, an atmospheric pressure pattern that influences the weather in the northern hemisphere. “They speculate that if the trend continues, these kinds of extreme cold events may become more frequent,” he said.

    So recent warming and an impending cooling cycle.

    But there are no natural cycles in climate. The only thing that changes global temperature is changing CO2 concentration.

    The sun is constant, and therefore the climate is constant, although the sun does not affect the climate in any way.

    In fact there are no real cycles anywhere in nature. Day and night, winter and summer, not to mention myths about “ice ages” – these are just artefacts of noise and instrument misreading.

    Even the human heartbeat, rumoured by some to be a nonlinear oscillator, is in fact just pumping in synch with fluctuations in CO2 concentration in the blood. Another instrumental artefact.

    Planets – contrary to popular belief – do not in fact orbit the sun. They move randomly in the vicinity of the sun – their movements can in fact be just as adequately described mathematically as movement relative to a static earth. Orbital movement of the earth (around the sun!) is just as much a myth as cycles in the earth’s climate. In breaking new research, a sophisticated new class of mathematical models called epicycles, well describe the artefact of observed movements of planets and put to rest any outdated notions of planetary orbits or climatic oscillations.

  7. “They speculate that if the trend continues, these kinds of extreme cold events may become more frequent.”

    Then we had better do something about it. Quick, pump out more CO2 to warm up the earth.

  8. So they are now doing “research” on information that was available for 100 years? Why would this kind of regurgitation receive funding?

  9. Yet another reason we’re destined for geoengineering. I doesn’t matter whether the threat is human or natural, or whether the threat is to humans or nature, were going to want to control the system more and more in the future, and have more and better tech/tools at our disposal as time goes on. I think we should get used to the idea.

  10. Latitude says:
    August 8, 2011 at 3:15 pm

    News of the World…………….

    Postdoctoral associate in the Odum School of Ecology, University of Georgia, Athens, discovers that tropical corals are limited by temperature.
    Postulates as to why tropical corals do not grow off the coast of Norway…..

    …receives $48million federal grant to study tropical reef building corals in Baffin Bay…..

    ..film at 11:00

    Does is really get any stupider than this?
    =====================================================
    No, not much. I think this is par for the course of peer-reviewed science. I’m really really sorry to hear of the demise of the entire ecological system in the Keys area. Are we to expect many climate refugees?

  11. “Kemp stressed that the study’s findings should not be interpreted to downplay the major role of higher temperatures on corals’ decline. ”

    They just had to get that money quote in there, didn’t they?

    So, my question is whether the corals were really dead, all dead, Are there plans to come back in 6 months or a year to check on recovery? So much coral bleaching has been reported and not followed up properly. The surprisingly rapid recovery is often missed and not reported (even if detected, I suspect).

    Their assumption that only warm periods are the stressors of coral life is ingenuous. Cold snaps are not all that rare. There were freezing temperatures down to the tip of Florida back in winter 1973. I was sailing a boat down the Intercoastal Waterway and got frostbite in northern Florida. [People wer jumping intheir boats and heading for the Yucutan.] Want to bet that there were probably several cold snaps during those years—and the reefs obviously recovered nicely. We just do not know how long recovery takes.

    They say the effects of the cold snap on the whole ecosystem is alarming. It would be alarming if we had done the damage, but it is not an alarming situation when something totally natural occurs. I would, instead, find it very interesting to watch how the ecosystem reacts and moves back to a new balance.

  12. I wonder what those coral reefs look like today, a year and a half later? Dead? Probably not.

  13. i’ve got alarmist fatigue, but have not outgrown my fondness for laughing at idiots.
    the lab rats who take the money to produce this trash are also fun to laugh at – but they don’t get top billiing as the idiots because they are taking home a paycheck for producing this tripe.
    they got no butthurt to whinge about, so to that degree one can not call them irrational.
    on the other hand, there is a large group of individuals who keep paying for this and crying about what they get – as if they are unable to learn the nature of the game – as if they are, indeed, prey by nature.
    why not take the food out of your kids’ mouths and buy some whine? that makes some ppl whinos, right? and the addiction is so undeniable. they keep doing it and doing it and won’t stop no matter how much damage they do to themselves.
    suicide by climate funding is a new one on me, but the sincerely self loathing just get so creative sometimes. one never knows what they’ll pay for next, only that it will be stupider than the last thing, more expensive, and they will cry about what they got and do it another time presently.
    insanity should be mocked.
    vote on it – reach some consensus. that’s always fun to self “emolliate” in a mob…lol..
    and it’s never too late to immolate!!

  14. “Increased seawater temperatures are known to be a leading cause of the decline of coral reefs all over the world. ”

    …and science [SIC] marches on!

  15. James Sexton says:
    August 8, 2011 at 4:08 pm

    Lat said: Does is really get any stupider than this?
    =====================================================
    No, not much. I think this is par for the course of peer-reviewed science. I’m really really sorry to hear of the demise of the entire ecological system in the Keys area. Are we to expect many climate refugees?
    ====================================================================
    nope, imported new ones from Cuba…………;-) every things fine now

    I could tell you tales on the Bulldogs……;-)
    They are not known for cutting edge marine science………………..

    First off, you would think ….they would have heard of a fish aquarium heater…and have some clue as to why you would need one

  16. I find it worrying that 200 to 300 year old corals could all just die off so suddenly like that. They do seem awfully sensitive to their environment don’t they. Let’s just hope for those chilled-out corals that the record breaking heatwave currently affecting the region will help them survive.

  17. DanDaly says:
    August 8, 2011 at 4:34 pm
    I wonder what those coral reefs look like today, a year and a half later? Dead? Probably not.
    ======================================================
    Right back to fine Dan……they are at the limit of their range and cold has always limited them.
    Being where they are, they can get colder in the winter, and also hotter in the summer. The further north you go, the more extremes.

  18. A previous comment called it a “delicately balanced ecosystem”. But if that is presently alive then what does that imply about the ecosystem? Either we’re very lucky to see it alive, or it is not really delicately balanced, or it has ways to recover its balance quickly enough that we’re seeing it as “balanced” rather than “unstable” or “endangered”.

  19. “The potential consequences for coral ecosystems are extremely alarming.”
    Besides Kemp and Fitt, the paper’s coauthors were Clinton Oakley and Gregory Schmidt

    Imagine that, G. Schmidt is involved with alarming research findings, what are the odds?

  20. Latitude says:
    August 8, 2011 at 3:15 pm
    “News of the World…………….

    Postdoctoral associate in the Odum School of Ecology, University of Georgia, Athens, discovers that tropical corals are limited by temperature.
    Postulates as to why tropical corals do not grow off the coast of Norway…..”

    I know you explicitly said tropical corals, but anyhow, just wanted to mention that there are corals off the coast of Norway – deep water or cold water corals.
    http://en.wikipedia.org/wiki/Deep_water_coral

  21. And then the skeletal remains are re-colonized by a myriad of drifting algae and larvae, and the new-old reef reappears. Whether it takes a year or a decade or a hundred years, it’s a blink in the history of such sites.

  22. Can’t we come up with a list of known flora and fauna and their sensitivities to warm and cold so these doctorate candidates can skip the research part and just write an article? Think of all the money we would save as tax payers and we wouldn’t get any better or worse Ph.D.’s than we have now.

  23. I’ll start: Peas won’t grow in hot weather and cabbage will bolt. Pumpkins and toms will not ripen in cold weather. Winter wheat is hardier than spring wheat regarding cold weather. I have a long list. And climate science wannabes interested?

  24. starzmom says:
    August 8, 2011 at 3:07 pm

    Once again, it’s worse than we thought!

    No starz……..it’s worse……

  25. So what did these reefs do during the last ice age (and the one before that, etc.)? Wouldn’t that have wiped the reefs out good and hard?

  26. If said trend in the “NAO” continues, they expect more cold snaps in the future. Hm…that’s a pretty big if. The “NAO” is quite variable, and does not bear any obvious relationship to anything that would suggest a long term trend that “will continue”:

  27. Some environmentalists claim we are in the midst of an extinction. They are misguided. This is no extinction. When the interglacial ends, there may be an actual extinction. If so, it will be ugly.

  28. Heh, breaking news, life that thrives in a subtropical environment doesn’t like cold weather.

  29. Anyone owning a marine fish tank could have told you that but this lot get paid for it!

    John W says:
    August 8, 2011 at 6:05 pm
    “Imagine that, G. Schmidt is involved with alarming research findings,”
    John, I think you are referring to Gavin rather than the one here named Gregory. (Not sure if they are related though ;-) )

  30. “It was the saddest thing I’ve ever seen,” Kemp said.

    Obviously he’s not been paying much attention to the state of peer review, scientific publications, and climatology, lately.

  31. It’s amazing how academia has come up with the justification for monitoring almost everything just to watch for any changes so they can speculate on what’s happening.
    Here in Oregon they used the fabricated AGW link to dead zones and ocean acidification to create 5 Marine Reserves where they are now busy watching everything that happens.
    Piles of papers will be produced reporting on what they have seen with analysis and conclusions limited only by their imaginations. Most of which will have zero value for anything at all.
    Meanwhile all that money they have wasted counting waves, watching sand blow and the little critters scrambling could have gone to real progress.

  32. Can’t find it, but I read somewhere that corals have almost gone extinct at least four times in the last 200 million years, then come back. Maybe someone here can offer a citation. But if that’s true it would indicate that corals are sensitive on the one hand, yet resilient on the other.

  33. Vic said: ” I find it worrying that 200 to 300 year old corals could all just die off so suddenly like that.”

    Not to worry, that’s the topic of the next PhD to be minted at UGA Hokum Odum.

  34. Huge coral reefs would have been killed during the last glaciation. The Great Barrier Reef would have been hundreds of feet above sea level. There should be rather extensive dead reefs in areas that are now submerged too deep to sustain growth since the Holocene raised water levels. Has anyone looked for these?

  35. Well finally after millions of years, the water got colder in the Florida Keys.

    Gee! why does all of ths mayhem seem to happen, while I am down fishing in Baja, where it is nice and toasty.

  36. These kind of studies in ecology all point to life being unusually sensitive to their environments, It’s almost like they are trying to prove that life just existed when and where they found it in it’s current form and did not evolve by adapting to extremes or to the environment.
    If some of the coral survived the colder temperatures then obviously the next batch of coral that came from the survivors would be more hardy (how ever slightly) to the cold and so on, where’s the study that explains this process in coral? maybe corals evolve and adapt to their environments a lot quicker than they understand, what effect does an Ice age have on corrals?

    Extremophiles shouldn’t even exist on the fantasy planet they are studying because I don’t honestly think they are describing this planet realistically for it to be called science.

  37. Cross patch – 8/8 9.27 pm. You are right there. After the sea level rises post glaciation, and the monsoon area up top end arrived, (The big wet known as this time) Aborigines started to move onto estuary and coast areas. However, I read somewhere that the oil spill last year or was it the year before (time flies eh?) was affecting the gulf stream. In fact one article said it had stopped. And they were thinking of putting
    giant fans under the sea to stimulate this. (I wonder what type of electricity if any they would use, LOL) to keep the warmer water circulating. I wonder how Bermuda is faring.

  38. The longer term North Atlantic Oscillation (NAO) has entered strongly into the negative territory, but it takes time for all relevant effects to take place. Likelihood is that it could last for few years to come. Origin of it is to the south of Greenland and Iceland, some experts consider it to be self-sustaining feedback between the ocean (subpolar gyre) and the atmosphere (Icelandic low pressure system diverting the jet stream) but they are uncertain about underlying causes, but one thing appear to be certain, it is nothing to do with the anthropogenic warming and CO2. Here are few basic details as I see them:
    http://www.vukcevic.talktalk.net/NAOn.htm

  39. Corals die in extreme temperatures…….. Omigod!!!!! Call a Marine Biologist and give them a life time government grant!!!!!

    Sorry if my sarcasm has overwhelmed my intense concern….. Yawn. ;-)

  40. “..leading to a potential net loss of carbon transferred from the algae to the coral..”

    Fools! It’s the algae that’s killing the coral with evil, poisonous carbon. Why can’t they see it?

  41. Several people have mentioned that the corals dying off have been 200 to 300 years old.

    Does this mean that they are the survival/regrowth after the Little Ice Age. No evidence, just asking.
    Please can I have some funding to travel somewhere nice, do some diving and write up an opinion?

  42. Timetochooseagain: The winter seasonal NAO mean does indeed have a strong long term oscillation. I have to state this again. All such cryospheric, atmospheric and temperature measurements should be done, including land and SST metrics, on a three month year round running mean and three month seasonal means so that oscillations, correlations and teleconnections can be more easily detected.

    http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/JFM_season_nao_index.shtml

  43. If corals have such a hard time surviving in suboptimal temperatures, why have they persisted for so long in the geologic record? Those kiddies need to go outside of their air conditioned offices and look at the real world. No, wait. They have a model for doing exactly that.

  44. “It was the saddest thing I’ve ever seen,” Kemp said.
    If that is the saddest thing Kemp has ever seen, he is living a charmed life…. Maybe he should go do some aid work in Africa for a few months.

  45. This was not all Keys reefs….
    Just one, inshore shallow reef.

    The next closest reef, Grecian (so close you can underhand a rock and hit it), was fine.

    Inshore shallow reefs, growing this far north, are always vulnerable to weather.
    This had more to do with wind, and the way the cold front came in, settled, and the wind died. Wind drives the currents in shallow water, the cold water just sat there.

  46. Jeff in Calgary says:
    August 9, 2011 at 7:26 am

    “It was the saddest thing I’ve ever seen,” Kemp said.
    ============================================
    That has more to do with money…..
    They are permitted to collect only on certain reefs, this was their major cash cow. They have build courses around their ability to collect, and they’ve been milking that one reef for years.
    The fact that it’s not considered an important reef was figured in to their ability to get permits to collect.

    If it was such a wonderful reef, how is it that a school is allowed to take corals off of it and kill them?

  47. This paper is obviously written by someone with limited knowledge of coral reefs. Here is a news flash. Corals die all the time in response to local heating and cooling, and are re-colonized by polyps better adapted to the new temperatures. Come back in 5 years and look at these same reefs and they very likely be healthy again. After the panic over bleaching in the Great Barrier Reef it was discovered it is simply a part of the life cycle of coral.

    This years dead coral is an idea colonization site for next years coral polyps. All that is required is for fish (parrot fish usually) to graze the algae that overgrows the dead coral, leaving a bare patch for the still floating juvenile polyps to colonize. One large danger to corals is over fishing of the reefs, which interferes with this process. Humans are killing reefs, but not through CO2.

  48. Pamela Gray-Thanks for finding a more easily understood chart. As readers can no doubt tell, there is variability, but no long term negative trend. The article this post is about seems to be referring to a short term trend toward negative values. It is rather silly, I think, to speculate about that continuing, given the history of the NAO that suggests, in fact, that one should not expect it to continue to decline indefinitely.

  49. True we have only seen one potentially complete cycle from neutral to negative then back up to positive and now back to neutral (though a bit noisy it looks almost like a sine wave). Will it continue its downward trend and start another complete oscillation, if indeed it oscillates? Maybe. Not enough data to pin this one down. Your skeptical view is the more appropriate one. I will tone mine down a bit from yes it oscillates to maybe it does.

  50. Looking at the 6 – 14 day prog’s for the leading edge of North America, the Pacific High may start to wind down as early as next week opening the storm door 2 months early. Maybe these are the warning waves of a Bond Event. I would even wonder about “the Great Heat Wave” of the Southern Plains and Northern Sierra Madre Occidental – sometimes there is a last blast of heat before the serious cold.

  51. timetochooseagain & Pamela Gray

    The NAO is assumed to have variations in the decadal band between 15 and 20 years.
    http://www.vukcevic.talktalk.net/NAOn.htm
    I have also some NAO longer term graphs from 1970-2005 (subject I am interested in at the moment) you can see here:
    summer- http://www.vukcevic.talktalk.net/PD-ICprs_dif_s.gif
    winter – http://www.vukcevic.talktalk.net/PD-ICprs_dif_w.gif
    annual – http://www.vukcevic.talktalk.net/PD-ICprs_dif_a.gif
    correlation with CET summer/winter

    http://www.vukcevic.talktalk.net/CET-winter.htm

  52. ferd berple says:
    August 9, 2011 at 8:19 am

    This paper is obviously written by someone with limited knowledge of coral reefs. Here is a news flash. Corals die all the time in response to local heating and cooling, and are re-colonized by polyps better adapted to the new temperatures
    ===============================================================
    Not necessarily better adapted ferd……
    …just whatever is down stream, tends to be the same old same old

    The ones better adapted just crowd them out over time, which limits the settlement of the new lesser adapted because of less clean surfaces for them to settle on

    Most of what people consider corals, are actually the weeds, acropora, etc. They are fast growing and over-grow the true reef building corals, killing them.

  53. So as the Little Ice Age ended, these corals moved into the newly warmer areas and started growing. Let me guess, the 300 year old corals were the ones that more cold tolerant than the 200 year olds. When cold returns, these corals die off.

    Hey, these are coralometers!

  54. “The ones better adapted just crowd them out over time, which limits the settlement of the new lesser adapted because of less clean surfaces for them to settle on”

    Makes sense to me. Without the parrot fish to clean the reef the new corals are out competed by sponges and similar.

    What doesn’t make sense to me it the concern for coral reefs in the face of warming. Coral is only abundant in the tropics. Thus, the only effect to be expected from warming is to expand the range of habitat of corals into what are currently temperate zones. Yes, there are cold water corals, but nothing like what we find in the tropics.

    The idea that warm water is dead for corals simply makes no sense as from my personal experience they thrive in the hottest ocean waters on earth. Whenever I see someone say that warmth is bad for corals I can’t help but thinking the person hasn’t spent much time on the tropical oceans of this planet.

  55. Serious question: A researcher has found a coral reef that died due to cold temperature. Has any researcher found a coral reef that died due to warm water? Not speculation, but rather a specific reef that is no longer alive because temperatures got too warm.

  56. Increased temperatures do not lead to coral death. They lead to algal symbiot change during which whitening can occur. The process can take several weeks.

    The real foe in the coral reef is the Crown of Thorns starfish.

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