Coral seems to have its own strategy for adapting to ‘ocean acidification’

From KING ABDULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY (KAUST) and the “don’t worry, nature always finds a way” department

Coral tricks for adapting to ocean acidification

A process that changes the regulation of genes could help corals acclimatize to the impacts of global warming.

Cells commonly control gene expression by adding a methyl group to part of the DNA, changing how the information on the DNA is read without changing its genetic code. Researchers at KAUST wanted to investigate whether DNA methylation could play a role in helping corals adapt to climate change.

They placed colonies of the smooth cauliflower coral, Stylophora pistillata, in seawater aquariums with varying acidity levels for two years. Ocean acidification is a consequence of climate change and hinders the ability of corals to produce the calcium carbonate skeleton they need to maintain their structures. The researchers hypothesized that DNA methylation might allow corals to mitigate these effects by changing the way they grow.

Colonies of the smooth cauliflower coral, Stylophora pistillata, were placed in seawater aquariums with varying acidity levels for two years. CREDIT © 2018 Eric Tambutté

After two years, the team sequenced the genomes of the corals and determined changes in methylation patterns.

“We noticed that corals grown under more acidic conditions had higher levels of DNA methylation,” says geneticist Yi Jin Liew. “Genes with increased methylation were related to cell growth and stress response, but not to calcification as we initially proposed,” he says.

In line with this finding, the team discovered that cell and polyp sizes in the corals also increased with rising acidity. “The coral polyps sit in little cavities called calyxes in which they can retreat for protection,” explains molecular biologist Manuel Aranda. Larger polyps have larger calyxes. “If the calyx is bigger, the coral needs to produce less skeleton to grow at the same pace. I call this the ‘Swiss cheese hypothesis,’ where the coral makes bigger holes so it needs to make less cheese, which allows it to grow at the same speed even though skeletal production is impaired.” This trait would be advantageous in an environment where competition for space and light is an important selective pressure.

The findings indicate that DNA methylation can be used as a marker of coral stress. This epigenetic mechanism might also be harnessed to grow corals under future ocean conditions to prime them for increased temperatures before placing them on reefs, says Aranda. This process is known as environmental hardening.

“We hope our contribution will change the current perception among reef biologists that epigenetics do not contribute much to coral resilience,” says Liew.

The team next plans to investigate whether these epigenetic changes can be passed down to future generations. “The idea is fairly revolutionary,” says Liew.

###

The paper: http://advances.sciencemag.org/content/4/6/eaar8028

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98 thoughts on “Coral seems to have its own strategy for adapting to ‘ocean acidification’

  1. They probably could have given Peter Ridd a bell instead of wasting two years.

    Ah!……Grant funding, I forgot about that.

  2. Just because a gene codes for something doesn’t mean that thing has to happen. In other words, genes can be turned on and off. That’s called gene expression. Gene expression can change relatively quickly. For some lifeforms it can happen in a matter of days. link

    In humans examples are malaria resistance and the ability to digest milk. Malaria resistance doesn’t develop in populations that aren’t exposed to malaria. The ability to digest milk doesn’t develop in populations that don’t practice dairy farming. link

    Because of gene expression, it is wrong to think that creatures are automatically endangered when their environments change. Gene expression is the rule not the exception. Changing DNA is not necessary to adapt to environmental changes.

    • Indeed paper in this post shows that gene expression can be rapidly turned on or off via “epigenetic changes”. There is no very slow lag time of Darwinian evolution via mutation and natural selection for a coral species to adapt.

      In addition the whole coral holobiont must be considered. Lynn Margulis coined the term holobiont in the 1990s to address the well established fact now that the vitality of organisms like coral are determined by all their symbiotic partners. Gene expression in the coral holobiont is very versatile because coral can eject and acquire new photosynthesizing symbionts (each with their different genomes) that may be best adapted to any changing local environment.

      Read http://landscapesandcycles.net/coral-bleaching-debate.html .

      In that essay there are many references to peer reviewed research demonstrating how quickly and effectively the coral holobiont can adapt

  3. There is no such thing as ocean acidification. CO2 can only possibly have a minuscule limiting affect on ocean water acidity.

    It’s the junkiest junk science in this whole muh climate nonsense, ocean acidification is not even science, it’s lies and delusion

    • There is no such thing as ocean acidification…

      Except anthropogenic CO2 has lowered oceanic pH from 8.2 to 8.1.
      That is not even controversial. So what you’ve written is bollocks.

      • OOH !! So the oceans became 0.1 pH more neutral ??? Oh, the horror !! ……..D’oh !

      • zazove, There is no proof whatsoever that Co2 lowered pH from 8.2 to 8.1. No One measured pH before the early 1900s. Averaging pH over the entire ocean is near impossible to do with any robust accuracy. The 8.2 to 8.1 drop is based entirely on models that falsely assume that ocean productivity and organic matter sequestration does not increase with increased CO2. The models are simply based on how CO2 effects sea water in a “dead” ocean that remains in a steady state.

        For what ever reasons for the change, since the end of the Little Ice Age upwelling and ocean productivity has increased and deposition of diatoms and fish remains has increased sequestering more carbon for thousands of years. Read Chaves (2011) “Marine Primary Production in Relation to Climate Variability and Change” from which this graph is taken

        http://landscapesandcycles.net/image/122034843_scaled_616x799.jpg

          • I hope such a ridiculously false statement – ” in a world where pH is uniform across 71% of the planet” is a joke. Otherwise Roaddog you join the ranks of ignorant trolls.

      • Start with the basics and then look at the big picture: CO2 absorbed into the oceans reacts with water to form carbonic acid:
        CO2(aq) + H2O H2CO3(aq)

        Carbonic acid disassociates into hydrogen and bicarbonate (until equilibrium is achieved):
        HCO3-(aq) H+(aq) + CO32-(aq)

        Shelled organisms (mollusks, corals, urchins, pteropods, coccolithophores, etc.) continuously remove bicarbonate from the oceans to make their skeletons (shells):
        Ca2+(aq) + 2 HCO3-(aq) CaCO3 + CO2(aq) + H2O

        Without dissolved CO2 in the oceans, there would be no bicarbonate, and without bicarbonate, there would be no shelled organisms, (plain and simple).

        Here’s what’s never mentioned: While CO2 is very soluble in water, its solubility is highly dependent on temperature. Cold water can hold much, much more CO2 than warm water. So as the earth cools during ice ages, tremendous amounts of CO2 get sucked out of the atmosphere and dissolved into the oceans. But as an ice age ends, (like right now), the oceans warm and release that tremendous amount of dissolved CO2 back into the atmosphere. The dissolved CO2 in the cold oceans has to come back out because warm water simply can’t hold as much CO2 in solution as cold water.

        The increase of atmospheric CO2 that we are currently observing (recently from 350 parts per million to 400 parts per million) is due in some part to dissolved CO2 being released back into the atmosphere by the warming oceans. Humans are obviously contributing to this increase in CO2 by burning fossil fuels, making concrete, etc., but the amount of CO2 released to our atmosphere by the oceans vs. contributed by human activities is unknown.

        So to recap, at the end of every ice age as the earth warms, atmospheric CO2 MUST increase; the laws of physics demand it. As the oceans warm, they MUST release dissolved CO2 back into the atmosphere because warm water simply can’t contain as much dissolved CO2 as cold water.

        The idea that warming oceans that are already supersaturated with CO2 can somehow absorb CO2 from the atmosphere to become ‘more acidic’ is complete nonsense.

        • And anyone who ever worked in a Coke plant knows about the solubility vs. temperature relationship.

          • or anyone who ever boiled water in a pot or kettle 🙂 Someone else must cook dinner for alarmists, most of whom have never used a stove it seems

        • “Start with the basics and then look at the big picture: CO2 absorbed into the oceans reacts with water to form carbonic acid:
          CO2(aq) + H2O H2CO3(aq)”

          Indeed and unfortunately for alarmists, there is just not enough carbonic acid created in the first place to back their nonsense theory.

          Alarmists think bicarbonate is a bad thing, true story.

      • Still Alkaline. ” Acidification” is only semantics. It sounds more scary than ”less Alkaline” Meant for the uneducated.

      • Except you cannot support that claim whatsoever.

        The fact that all of the current and historical inputs and outputs in oceans are not even identified let alone quantified, alone makes your comment ridiculous.

        Science, do you even?

        There is NO WAY possible to measure all ocean water to claim to know pH to .1 lol

        The change is so dynamic and of course, historical pH the IPCC uses comes from a model, not observations.

        Over to you, Mr Science illiterate.

        I’ve built and maintained reefs successfully for years, so I know my water chemistry, I understand what buffers are, it seems the climate community intentionally do not want to understand this simple concept.

        There is no possible way atmospheric CO2 at level 0.04% concentration can acidify a water body, in motion with trillions of pH buffering inputs, acidic.

        in fact atmospheric CO2 creates immensely less acidity than sulfur does in the oceans.

        I would offer that one single chain of volcanoes and vents in the pacific add more acidity to the oceans than global atmospheric CO2 influence.

        carbonic acid resulting from gas exchange at sea level pressure is the most inefficient way possible to alter the acidic nature of ocean water, given the high instability of carbonic acid.

        Lets not forget, in 1896, it was claimed by you know who (who alarmists love to cite as a source, even though everything he claims is proven wrong) that the atmosphere would be saturated with Carbonic acid.. well, where is all this acid in the atmosphere from CO2? I must have missed it.

        Since then we were told sulfides would do it, and acid rain would melt the facades from buildings, during the 80s, well.. seems that was complete nonsense too, just like this is.

        I guess NOAA admitting they have 0 evidence doesn’t float your boat eh 😉

    • Coral reefs depend on photosynthesis. They thrive on more CO2. Seawater pH around coral reefs varies wildly. They won’t notice a little bit of ocean neutralization.

    • In other news
      The Australian Institute of Marine Science reports “The Great Barrier Reef has seen a steep decline in coral cover, a phenomenon that “has not been observed in the historical record,”
      “Survey reefs in the northern section, the worst hit by climate-induced marine heatwaves, have lost about HALF their coral cover.” (my caps)

      • Didn’t they leave out that the corals grow back within a few years once they adapt to the changing environment? And where do they explain how it’s the heat that is the only factor involved in the die out, not that some corals dying won’t be replaced after they respawn? Exactly how long have they looked for regrowth on the record, since we know it is a natural phenomenon? Have you heard of reseeding?

      • zazove you seem intent on spreading ill-informed and biased gloom and doom. Sadly it comes across as just ignorant trolling.

        Read Osborne (2011)”Disturbance and the Dynamics of Coral Cover on the Great Barrier Reef (1995–2009)” to put coral mortality into perspective. Cyclones have the biggest effect on mortality and coral have the ability to rapidly grow, much like land vegetation is adapted to re-growth after a fire. Here is a graph from that paper.

        http://landscapesandcycles.net/image/115377959_scaled_499x240.jpg

        Read about coral rapid adaptations to disturbances at http://landscapesandcycles.net/coral-bleaching-debate.html

      • total spent on climate communications- $150,000,026.25.

        I figure they’re worth $5.25/post. Tops.

      • What global warming might that be Zazov?
        It is not as warm as during the 1930s, and what warming there has been is at high latitudes, in Winter, less cold nights, and fake adjustments to the historical records.
        There is no place experiencing unusual heat.
        Coral bleaching is a natural process, and is how coral survives, not how it dies.
        But you just keep on repeating out of date crap that has already been shown untrue.

        • And you just keep repeating this without bothering to cite nor to take your blinkers off. Good luck.

    • Photosynthesis quickly absorbs CO2 changing it to organic matter that has no effect on ph and thereby raises ocean surface pH. Respiration of that organic matter as well as calcification produces CO2 and lowers pH. Those natural dynamics lower coral reef pH to about 7.8 at night. As a result coral reefs are ventilating more CO2 to the atmosphere.

      As organic matter sinks and is digested by zooplankton and bacteria pH declines with depth. Reports of acidified water is usually caused by upwelling of those deeper waters.

      If organic matter sinks below 1000 meters it is removed for hundreds to thousands of years, and thus has no impact on surface pH or climate. Numerous studies show aggregated bacteria, larvaceans tents, diatoms and fish feces can sink to that critical depth within 2 days.

      Read How NOAA and Bad Modeling Invented an “Ocean Acidification” Icon: Part 1 – Sea Butterflies. http://landscapesandcycles.net/how-noaa-invented-an-ocean-acidification-icon.html

      and How NOAA and Bad Modeling Invented an “Ocean Acidification” Icon:
      Part 2 – Bad Models. http://landscapesandcycles.net/bad-models-how-noaa-invented-acidification-icon.html

      • Jim
        Respiration of that organic matter as well as calcification produces CO2 and lowers pH. Those natural dynamics lower coral reef pH to about 7.8 at night. As a result coral reefs are ventilating more CO2 to the atmosphere.

        Yes the OCO CO2 mapping satellite could find that the GBR emits more CO2 than the city of Sydney.

    • I struggle with the term “acidification.” Seems to me specifically selected to demonize what might more accurately be termed increased neutrality, or ‘less basic”.

      • Roaddog you are exactly correct.
        There has never been a dictionary published that defines the word “acidification” as the process of becoming less basic.
        Acidification is the process of being transformed into an acid.
        The warmista trolls wave their arms around and spew their bland sophistry about how someone might call lowering the pH of a basic solution something it is not, but that is all it is, made up crap and sophistry.
        It aint science.
        And it is not even proper grammar.

  4. I’m no expert on corals but as I understand it, they are symbiotic. One of the main ways they adapt to change is for the host to eject their symbiont to make way for a better adapted newcomer. In the experiment they describe, keeping the corals in separate tanks will obviously negate this possibility and so perhaps cloud the results.

    • Oh Dear ! Bloke !
      You have NOT had ENOUGH TO DRINK yet mate !
      THE RESULT is what counts !
      The METHOD is irrelevant !!
      THINK : RESULT !!
      What RESULT IS NEEDED to ensure that ongoing funding or that EXTRA GRANT ???????
      THEN work or wangle your way to THAT RESULT !!
      Ethics Schmethics !!
      As I said…….drink up ! Have another ONE for me and THINK : RESULT !!

  5. I suggest we don’t need to be told this or spend money on research as the geological evidence of reefs through the current and the earlier 41Ka ice ages is clear over millions of years. The how is interesting, but the facts were already obvious.

    It’s not revolution, it’s evolution.

    A lesson in the blindingly obvious. Corals adapt to their environment, and move elsewhere when it changes. End of. Simples!

  6. This acid acidification is pure nonsense. Coral are living organisms and exhale CO2 creating natural ocean acidification far greater than the greater ocean. Other shellfish have blood that is far more acidic than the ocean and their shells do just fine. Calcium-based bone also has no problem with the acidity of the blood. Lastly, coral first evolved during periods of much higher atmospheric CO2. We are in a geologic draught as far as CO2 goes.

    • Hundreds of millions of years of earth history is meaningless to warmistas and people who know nothing about the history of the Earth…but I repeat myself.

  7. Corals suffer bleaching from heat stress, usually inflicted by el Nino, but this warming of the ocean should raise pH – ie make it less acid, as C02 is ‘exhaled’ ? I guess I must have missed something so could someone please explain

  8. Some kinds of corals have existed through hundreds of millions of years of “climate change”, not to overlook sea-level change.
    Why wouldn’t someone briefly review the history of coral?
    The problem is that there are far too many people who want to be anxious about something. And there are too many who will not just exploit this but will invent new anxieties.
    Mencken has a classic line about the state inventing “hobgoblins”. And then boast about protecting the people from contrived threats.
    Bob Hoye

    • One of the downsides of prosperous western civilisation is the population in general live boring unfulfilled lives and need something to worry about where no problem exists. This is why the climate change nonsense is more successful in the west, and virtually ignored in the east.

  9. Nothing particularly interesting, revealing, or surprising in what they report. It just has the ring of “how can we use this global-warming ocean-acidification lark to leverage funding for our work generally”.

  10. Ah…. So…. they’ve proved that Darwin’s hypothesis of adaptation to the environment works.

    How much did that cost?

    • Darwin thought it happened through genetic mutation. He had no idea the epigenetic system existed. Who knows, maybe there’s an epi-epigenetic system. Maybe it’s epi all the way down (all the way up?)

      (Spell checker isn’t keeping up – flags epigenetic.

      • Darwing, working decades before Mendel works came to be known, had no idea about genes, either, and he didn’t discarded the Lamarkian hypothesis (that is, some transmission of acquired traits to the offspring). This hypothesis was thought wrong with genetics, but resurrected by epigenetics.

        • Darwin thought that random variation plus natural selection could account for all life. Later his theory was modified to random mutations of the genes plus natural selection, the so-called neo-Darwinian Synthesis.

          We now know that randomness plays a more limited role than originally thought.

  11. “The team next plans to investigate whether these epigenetic changes can be passed down to future generations. “The idea is fairly revolutionary,” says Liew.”

    I thought that was already established. Epigenetic traits induced in grandparents who endured a famine in a small Swedish village were discovered in their grandchildren.

    • Fisheries biologists have found the same epigenetic effects with largemouth bass: Those that have been caught on an artificial lure not only become less inclined to hit another one, so do their progeny. DNA didn’t change, but gene expression sure did.

      Another blow to the random mutation school of thought, as this is clearly not random!

      • It’s simply natural selection acting on the epigenetic portion of the genome.

        Randomness comes in because mutations are more or less random, while their selection is the opposite of random.

        A gene is a sequence in the genome coding for a protein. Epigenetic sequences control the expression of genes, for example turning them on or shutting them off. But those sequences are still subject to natural selection.

        I wish that people would study or at least think about genetics and biology before presuming to comment thereupon.

  12. Science: CO2 is a problem. Oceans are warmer and more acidic.
    Some: No, it’s not a problem. Not possible. It’s a huge world. Man can’t change things.
    Science: Care to back that up?
    Some: OK, so the oceans are warming, and they are more acidic, but so what? They could rebound.
    Others: I don’t think they are more acidic, and besides CO2 is good for oceans.

    • Slight correction Alley…

      Green Agenda 21′: We pretend that CO2 is a problem because Oceans are warmer than they were during the Little Ice Age and the Oceans are more acidic than soft drinks..!
      Most scientists: CO2 is a benefit to all life GLOBALLY !
      Green Agenda 21: Care to back that up?
      Most scientists: Without CO2 all life on Earth would cease to exist..
      Green Agenda 21: But…Think of the children that will never see snow..in Florida..!
      ..Note…If you don’t like CO2…STOP breathing !…D’OH !

      • “Without CO2 all life on Earth would cease to exist..”

        HA HA HA!!!! Yes, there is a secret science society that wants to rid the earth of CO2!

        This is good stuff.

        • There is a vast global conspiracy against raising vital plant food in the air from near starvation levels.

          Optimum CO2 for C3 plants, which is most of them, is three times the current historically low concentration.

          Present over 400 ppm is better than under 200, as during most of the Pleistocene, but still far below the minimum for C3 plants of 800 ppm and even farther below the optimum of 1200 ppm or more.

          • Over 800 is minimum for healthy growth. Obviously, C3 plants can survive on 200, but can’t thrive. Below about 150, they can’t make seed, and many species can’t even survive.

            C4 and CAM pathways evolved as CO2 plummeted from its Cenozoic high around 2000 ppm in the lush, verdant, equable Eocene to under 200 ppm in the icy, dry, windy Pleistocene.

    • Science: More CO2 in the air is beneficial for plants and other living things. Oceans are warmer thanks to the end of the Little Ice Age Cold Period, which is also a good thing.

    • total cost of climate communications- $150,000,030.25.

      This one is bottom shelf.

    • Hey Alley,
      You might want to familiarize yourself of the difference between the word “science” and the “warmista fearmongering alarmists”.
      Science is a process, a method.
      It does not say anything.
      Your posting is one of the more inane babbling puffballs of idiocy I have seen yet, and that is not easy to do.

  13. I don’t see any measurement of the amount of skeleton created.

    They have measured that the polyps are larger and hypothesize that this is so that the coral can be the same size with less skeleton, but they have not proved that there is less skeleton.

    Perhaps the polyps are larger because the reduced alkalinity is better for them.

  14. Here is a thought about competition vs adaption. I live fairly far north compared to most and there aren’t any palm trees close to here but oddly enough a neighbour planted a palm tree last year and it survived a typical winter, though he did wrap it up.

    That was interesting to me. It told me that we don’t have palm trees not because they can’t live here but because they can’t compete.

    I suspect that most wildlife is far more resilient than we suspect and it is the failure to compete that keeps most animals and plants to specific regions. Alarmists think life is very fragile and tipping points are not far off. Tell that to the palm tree down the street from me.

    • What limits the range of most species is not whether they can survive one Winter, it is whether they can survive all of them.

    • I live in South Florida, about 30 miles inland or so, and where I live I can plant all sorts of palms trees, although even ones that can grow rapidly and thrive ten miles away are rarely seen attaining a large size in my neighborhood.
      Coconuts are an example.
      It takes many years for them to grow large enough for them to bear fruit, and hence to reproduce.
      But they will never get coconuts on them if there is even a little frost every Winter and an occasional freeze.
      Which there is.
      I am not disagreeing with your observation that many plants can grow far from their normal range, and in fact this is well known and much studied, especially as it relates to microclimates, such as occur in large cities.
      Anyway, there are species that some consider tropical which can survive and even thrive in places that get below freezing every year.
      There are some tropical plants living in places like New York and even cities in Canada that are known to be decades old.
      But this has as much to do with the heat retention of concrete and other UHI effects as with the fact that some tropical-ish species are native to locations that get very cold occasionally.

      http://www.hardytropicals.org/

      https://youtu.be/tHGnaikMZ74

    • Let me say this another way which is more relevant to the discussion at hand: Nearly every species of plant and animal and everything else on Earth, is very resilient and adaptable to varying conditions precisely because of the huge range of natural variability in all sorts of parameters, such as the temperature, humidity, pH of the soil and of aquatic habitats, etc.
      Temperatures normally vary tremendously from day to day, season to season, year to year, and over timescales of decades, centuries, and millennia, and on up the scale (and down).
      If the people who seem to be so alarmed by the prospect of anything ever changing really wanted to understand what might be dangerous or worrisome, a great place to start would be to get a very good understanding of the natural variability of these and other parameters.
      But a funny thing is noted when one considers that: Alarmists do not want to ever talk about natural variability.
      They make up completely inane jackass lies about the stability of climates and weather and pH and everything else, and start off by assuming that every living thing is existing in some fragile state that cannot tolerate any changes at all.

      Very peculiar, eh?
      Surely people worried about such things should start off by gathering information, no?
      Instead these nitwits start off by purposefuilly and systematically excluding huge libraries of existing information.
      This is one of the reasons that after all the trillions spent on this phantom menace, less is known now that before it all started.

  15. Corals have survived all the climate change since the Precambrian. Of the extant three subclasses of Anthozoa, the youngest dates at least from the Ordovician, and probably the Cambrian.

    Even in today’s frigid climate, they can live far into high latitude temperate waters. They are found north of Scotland and in the Aleutians. Clearly, though generally thought of as tropical, corals are adaptable creatures, thanks to many mechanisms, including their ability to move if need be.

    • The one thing that coral reefs can’t handle are too many SCUBA divers and dynamite fishing… The two things that coral reefs can’t handle are too many SCUBA divers and dynamite fishing and too much agricultural runoff… The three things…

      Kind of a coral reefs version of No one expects the Spanish Inquisition!

      🤣

      • And too much suntan lotion on the divers.

        Yet they survived all the mass extinction events of the Phanerozoic Eon, ie the past 541 million years. They have survived ice ages and hot houses, indeed every climatic change since the Precambrian.

      • And the higher the CO2 and hotter the temperature, the happier they are.

        As noted elsewhere, they loved the Cretaceous, helping lend it its name. When crocodilians thrived in the Arctic, corals were happy as clams at high tide.

  16. That the coral are able to alter in this way to cope with lowered pH is a sign that in their evolution they have encountered a significanty range of pH. Long-enduring corals are perhaps the most successful creatures in life’s domain. The GBR, a polar-bear like icon of climate Gang-Green activists, which has lived through a number of glacial cycles over 100s of thousands of years is not in existential danger. Like the polar bear, these tough creatures are a poor choice to point to in terms of extinction.

    • If nothing else, alarmists have a near perfect record when it comes to choosing the wrong hill to fight and die on.
      And yet they march on, a zombie army with their precious chestnut of a zombie hypothesis.

  17. Fascinating. Could this be more evidence indicating nature is dynamic and organisms adaptable, as everyone seems to know except the self-appointed “environmentalists” and climate hysterics?

    Coral husbandry. An interesting concept. Get along li’l polyps! Heeeeyah!

  18. This study is meaningless if they kept the CO2 constant and only changed the pH.

    If they claim that CO2 is causing the pH decrease, they must accomplish this using higher concentrations of CO2. If it was done thus, they would find that the increased CO2 forces the extended equilibrium from CO2/carbonic acid to bicarbonate to carbonate to calcium carbonate would be pushed toward more calcium carbonate deposition. Higher CO2 encourages coral deposition.

    The protons (H+) from carbonate cannot affect this equilibrium, as an equilibrium cannot affect itself.

    Only an outside source of protons can push this equilibrium toward carbonic acid and CO2 production.

    Also, corals are much more physiologically powerful than even many biologist think, as they forget that these organisms have been around for 600 million years and have been there-done that when it comes to climate change. Actually, coral reefs and tropical rainforests are two of the most stable ecosystems in the world. Their complex speciation could not have occurred as they have without being ridiculously resilient, which is another word for stable.

    • This study is meaningless if they kept the CO2 constant and only changed the pH.

      If they claim that CO2 is causing the pH decrease, they must accomplish this using higher concentrations of CO2. If it was done thus, they would find that the increased CO2 forces the extended equilibrium from CO2/carbonic acid to bicarbonate to carbonate to calcium carbonate would be pushed toward more calcium carbonate deposition.
      No, addition of CO2 would reduce the CO3^2- concentration and increase the bicarbonate, there is no change in alkalinity.

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