Archives par mot-clé : Acidification

More Evidence for Rapid Coral Adaptation

by Jim Steele, April 2, 2019 in WUWT


Good news continues to accumulate regards corals’ ability to rapidly adjust to changing climates. The view of coral resilience has been dominated by the narrative of a few scientists. In the 1990s they advocated devastating consequences for coral reefs due to global warming, arguing coral cannot adapt quickly enough. Since the Little Ice Age ended, they believed rising ocean temperatures had brought coral closer to a “bleaching threshold”, a more or less fixed upper temperature limit above which corals cannot survive. Their model predicted the speed of recent global warming “spells catastrophe for tropical marine ecosystems everywhere”. Their assertions that “as much as 95% of the world’s coral may be in danger of being lost by mid-century” was guaranteed to capture headlines and instill public fear. However, a growing body of scientific research increasingly casts doubts on such alarming predictions. Unfortunately, that good news gets much less attention.

A recent peer-reviewed paper titled A Global Analysis of Coral Bleaching Over the Past Two Decades (Sully 2019) compared 20 years of ocean temperatures at which coral bleaching was initiated. From 1998 to 2006, the average sea surface temperature that initiated bleaching was 82.6 °F. But that temperature limit proves not to be “fixed” as earlier researchers incorrectly believed. From 2007 to 2017 the average temperature limit that initiated bleaching was higher, 83.7 °F. This indicates coral have been rapidly adapting to warmer regional climates much faster than once believed.

Coral Reefs in West Hawaiʽi Showing Signs of Recovery

by P. Homewood, February 21, 2019 NotaLotofPeopleKnowThat


Surveys identified 25 coral species in West Hawaiʻi. Lobe coral (Porites lobata), one of the area’s most dominant species, proved to be the most resilient—with only 50% bleaching in 2015. Cauliflower corals (Pocillopora meandrina) were hardest hit—with 98% bleaching—but recent surveys show that they are beginning to recover.

Analysis Finds Oceans Have Become LESS ‘Acidic’ With Rising CO2, Challenging The ‘Acidification’ Narrative

by K. Richard, February 14, 2019 in NoTricksZone


A modest long-term (1800s-present) declining trend in ocean pH values predominantly occurred prior to 1930, or before anthropogenic CO2 emissions began rising precipitously. Since 1930, seawater pH trends have risen slightly, meaning sharply rising CO2 has been coincident with less, not more, ocean “acidification”

 

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Image Source (lower graph): Wei et al., 2015

 

 

CORAL REEFS CAN TAKE THE HEAT, UNLIKE EXPERTS CRYING WOLF

by Peter Ridd, December 26, 2018 in GWPF


Scientists from James Cook University have just published a paper on the bleaching and death of corals on the Great Barrier Reef and were surprised that the death rate was less than they expected, because of the adaptability of corals to changing temperatures.

It appears as though they exaggerated their original claims and are quietly backtracking.

To misquote Oscar Wilde, to exaggerate once is a misfortune, to do it twice looks careless, but to do it repeatedly looks like unforgivable systemic unreliability by some of our major science organisations.

The very rapid adaptation of corals to high temperatures is a well-known phenomenon; besides, if you heat corals in a given year, they tend to be less susceptible in the future to overheating. This is why corals are one of the least likely species to be affected by climate change, irrespective of whether you believe the climate is changing by natural fluctuations or because of human influence.

Corals have a unique way of dealing with changing temperature, by changing the microscopic plants that live inside them. These microscopic plants, called zooxanthellae, give the coral energy from the sun through photosynthesis in exchange for a comfortable home inside the coral. When the water gets hot, these little plants effectively become poisonous to the coral and the coral throws them out, which turns the coral white — that is, it bleaches.

 

Ocean Acidification Background Context

by ‘Guest Blogger’, December 23, 2018 in WUWT


Obiter dictum. We acknowledge that seawater is basic and cannot truly acidify (pH<7). But that is a losing semantic quibble, not a winning skeptical argument. The generally accepted linguistic convention—for better or worse–is that lowering seawater pH means ‘acidification’. There is no doubt that adding dissolved CO2 does lower pH. The relevant questions are how much and whether that amount matters. This post answers both questions (a little, not much) without the two specific false alarms that motivated the ebook version.

There are certainly some ocean related AGW consequences beyond any scientific doubt. Henry’s Law requires that the partial pressures of atmospheric and dissolved ocean CO2equilibrate. Rising atmospheric CO2 must increase dissolved seawater CO2. That is long established simple physical chemistry.

This lowers pH by increasing carbonic acid. NOAA PMEL has documented this in the central Pacific at Station Aloha off Mauna Loa where sea surface pH has declined from 8.11 to 8.07 since 1991, as dissolved pCO2 increased from ≈325 to ≈360μatm while atmospheric CO2 increased from about 355 to 395 ppm. That is Δ0.04 pH in 24 years.

See also here (in French)

Coral Adaptation and Epigenetics

by Rud Itsvan, November 17, 2018 in WUWT


WUWT has posted several excellent articles by Jim Steele on how global warming alarmism uses corals as the poster child for warming and acidifying oceans, none of which is scientifically justified. A brief review follows, calling attention to a recently discovered additional adaptation mechanism not covered AFAIK by Jim Steele’s posts. The motivation for this post was triggered by a recent lunch with newish neighbor Charles the Moderator (CtM), and his sharing many wonderful underwater photographs of the coral reef he now dives frequently off Pompano Beach (same reef system as off Fort Lauderdale, just a few miles further north and more conveniently onshore).

Remember when they told us coral bleaching was a sure result of recent man-made global warming? Never mind.

by Anthony Watts, August 17, 2018 in WUWT


From the “science eventually self-corrects” department, new science showing coral bleaching of the Great Barrier Reef is a centuries-old problem, well before “climate change” became a buzzword and rising CO2 levels were blamed.

Marc Hendrickx writes:

New paper shows coral bleaching in GBR extending back 400+ years.

New Study Shows Some Corals Might Adapt to Climate Changes

by Anthony Watts, August 4, 2018 in WUWT


UM Rosenstiel School-led study exposes two threatened corals to future climate change conditions

MIAMI—New research shows that not all corals respond the same to changes in climate. The University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science-led study looked at the sensitivity of two types of corals found in Florida and the Caribbean and found that one of them—mountainous star coral—possesses an adaptation that allows it to survive under high temperatures and acidity conditions.

“Stressful periods of high temperature and increasingly acidic conditions are becoming more frequent and longer lasting in Florida waters,” said Chris Langdon, marine biology and ecology professor and lead author on the new study. “However, we found that not all coral species are equally sensitive to climate change and there’s hope that some species that seemed doomed may yet develop adaptations that will allow them to survive as well.”

See also (in French) here and  here

Corals use epigenetic tricks to adapt to warmer and “more acidic” water

by JoNova, June 12, 2018 inJoNovaBlog


After half a billion million years of climate change, I’m shocked, shocked I tell you, that life on Earth (and specifically corals) have so many ways to cope with the climate changing. After all, it’s natural (if you are trained by Greenpeace) to assume that corals can only survive in a world with one constant stable temperature just like they never had.

One more tool in the coral-reef-workshop

Corals don’t just have a tool-box, they have a Home Depot Warehouse. h/t to GWPF

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More Proof of a Biological Control on Coral Calcification

by Ross C.L. et al., 2017, June 10, 2018 in CO2Science


The global increase in the atmosphere’s CO2 content has been hypothesized to possess the potential to harm coral reefs directly. By inducing changes in ocean water chemistry that can lead to reductions in the calcium carbonate saturation state of seawater (Ω), it has been predicted that elevated levels of atmospheric CO2 may reduce rates of coral calcification, possibly leading to slower-growing — and, therefore, weaker — coral skeletons, and in some cases even death.

As we have previously pointed out on our website, however (see The End of the Ocean Acidification Scare for Corals and A Coral’s Biological Control of its Calcifying Medium to Favor Skeletal Growth), such projections often fail to account for the fact that coral calcification is a biologically mediated process, and that out in the real world, living organisms tend to find ways to meet and overcome the many challenges they face; and coral calcification in response to ocean acidification is no exception.

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See also in French

Réflexions sur l’acidification des océans

by Prof. Dr. P. Berth, 5 juin 2018, in ScienceClimatEnergie.be


Voici quelques réflexions sur la théorie de l’acidification des océans. Selon cette théorie, le pH des océans diminuerait inlassablement, en raison du CO2 qui ne cesse de s’accumuler dans l’atmosphère.

Les mesures directes de pH sont récentes et nous n’avons aucun recul. Selon les médias et les ONG écologistes, qui se basent sur le GIEC et sur certaines publications (e.g., Caldeira & Wickett 2003), le pH des océans aurait été de 8.25 en 1750. Cependant, il faut savoir que personne n’a jamais mesuré le pH des océans en 1750, puisque le concept de pH n’a été inventé qu’en 1909 (par le danois Søren P.L. Sørensen), et que les premiers appareils fiables pour mesurer le pH ne sont apparus qu’en 1924… Nous ne sommes donc pas certains de cette valeur de 8.25 pour 1750… La valeur de 8.25 est donc obtenue par des mesures indirectes et n’est donc pas certaine.

A l’heure d’aujourd’hui, tous les pH sont possibles. Lorsqu’on dit que les océans actuels sont à un pH de 8.1, de quel océan parle-t-on? S’agit-il du pH moyen global? Si c’est de cela qu’on parle, quelle est l’incertitude sur la mesure? (i.e., l’écart-type?). Ceci n’est jamais indiqué. Il faut savoir que si l’on prend un jour de la semaine, tous les pH sont possibles dans les océans, comme l’illustre très bien la figure suivante.

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The Total Myth of Ocean Acidification

by David Middleton, June 5, 2018 in WUWT


The Fable of Chicken Little of the Sea

Guest essay by David Middleton,

When if comes to debunking Gorebal Warming, Chicken Little of the Sea (“ocean acidification”) and other Warmunist myths, my favorite starting points are my old college textbooks.

Way back in the Pleistocene (spring semester 1979) in Marine Science I, our professor, Robert Radulski, assigned us The Oceans by Sverdrup (yes, that Sverdrup), Johnson and Fleming.  Even though it was published in 1942, it was (and may still be) considered the definitive oceanography textbook.  I looked up “ocean acidification” in the index… It wasn’t there.

The notion that CO2 partial pressure influences the pH of seawater isn’t a new concept, *surely* ocean acidification must have been mentioned in at least one of my college textbooks.

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Evidence for the Thermal Bleaching of Porites Corals From 4.0 ka B.P. in the Northern South China Sea

by S. Xu et al., December 2017, in AGU1000Biogeosciences


Coral bleaching is becoming a serious issue for coral reefs under the stress of global warming. However, whether it has occurred in the past in times of thermal stress remains unclear. Moreover, an understanding of historic coral bleaching events would greatly improve our insight into the adaptive capabilities of corals under such stresses. It is known that Porites corals, a massive coral, have relatively high levels of symbiotic zooxanthellae and a strong thermal tolerance when compared with most other corals (and particularly branched corals). Thus, growth hiatuses and/or mortality surfaces of fossil Porites may be used to indicate past ecological or environmental stress events, such as severe bleaching. In this study, monthly geochemical and isotopic environmental proxies of four fossil Porites corals with well‐preserved growth hiatuses and mortality surfaces (aged 3,800–4,200 years before 2013 A.D.), collected from Wenchang fringing reef, Hainan Island, Northern South China Sea were analyzed. Specifically, the Sr/Ca, δ18O, and δ13C were measured with a monthly resolution for each sample.

CORALS CAN WITHSTAND ANOTHER CENTURY OF CLIMATE CHANGE

by Kate Wheeling, April 19, 2018 in PacificStandard


Coral reefs are facing no shortage of threats including ocean acidification, overfishing, plastic pollution, and rising temperatures. Sea surface temperatures have been climbing on average for over a century, and ocean heat waves—which can trigger coral bleaching events—are becoming more common and severe. Scientists have long worried that as coral-killing spikes in temperature become more frequent, corals won’t have enough time to recover between bleaching events and will ultimately go extinct. But a new paper, published today in PLoS Genetics, suggests that corals might be able to adapt to another century of warming.

The Resilience of a Coralline Red Algae to Ocean Acidification

by  Donald et al. 2017, in CO2Science from Géochim.Cosmochim.Acta


The influence of pHsw on both pHcf and the calcification rate of Neogoniolithon is plotted in Figure 1 below. As indicated there, this coralline algal species is able to elevate its pHcf so as to increase its rate of calcification under moderate levels of ocean acidification (pHsw of 7.91 and 8.05), which increase the authors say is “most likely due to CO2-fertilization of [algal] photosynthesis” that is limited in Neogoniolithon at these lower pCO2 conditions. (….)