Scientists analyze the extent of ocean acidification

Aug 25, 2013
The oceans do not only get warmer with the chaning climate but also more acidic by sinking pH values. Credit: Frank Rödel / Alfred Wegener Institute

Ocean acidification could change the ecosystems of our seas even by the end of this century. Biologists at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), have therefore assessed the extent of this ominous change for the first time. In a new study they compiled and analysed all available data on the reaction of marine animals to ocean acidification. The scientists found that whilst the majority of animal species investigated are affected by ocean acidification, the respective impacts are very specific. The AWI-researchers present their results as an Advance Online Publication on Sunday 25 August 2013 in Nature Climate Change.

The oceans absorb more than a quarter of anthropogenic carbon dioxide emitted to the atmosphere. They form a natural store without which the Earth would now be a good deal warmer. But their are limited and the absorption of carbon dioxide is not without consequence. Carbon dioxide dissolves in water, forms carbonic acid and causes the pH value of the oceans to drop – which affects many sea dwellers. In recent years much research has therefore been conducted on how individual species react to the carbon dioxide enrichment and the acidifying water. So far the overall extent of these changes on has been largely unknown.

In order to gain an initial overview, Dr. Astrid Wittmann and Prof. Hans-Otto Pörtner from the Alfred Wegener Institute, Helmholtz-Centre for Polar and Marine Research (AWI), surveyed all studies so far conducted which dealt with the consequences of ocean acidification for from five animal taxa: corals, crustaceans, molluscs, such as fishes and echinoderms such as starfish und . By the end they had compiled a total of 167 studies with the data from over 150 different species. In order to classify these results they used emission scenarios for carbon dioxide on which the world climate report is also based. These scenarios allow to forecast the impacts of different carbon dioxide concentrations in the atmosphere far into the future.

The results of this new assessment are clear. "Our study showed that all animal groups we considered are affected negatively by higher carbon dioxide concentrations. Corals, echinoderms and molluscs above all react very sensitively to a decline in the pH value", says Dr. Astrid Wittmann. Some echinoderms such as brittle stars have lower prospects of survival in carbon dioxide values predicted for the year 2100. By contrast, only higher concentrations of carbon dioxide would appear to have an impact on crustaceans such as the Atlantic spider crab or edible crab. However, the sensitivity of the animals to a declining pH value may increase if the sea temperature rises simultaneously.

The snail Clione limacina grows up to a length of 70-85 mm. Credit: M. Boeer, Alfred Wegener Institute

Scientists from the Alfred Wegener Institute have determined the consequences of ocean acidification on the fitness of the individual species using physiological features. "For example, we considered whether metabolism, growth, calcification or behaviour change in high carbon dioxide concentrations", explains Prof. Dr. Hans-Otto Pörtner.

The reason for different taxa reacting differently to ocean acidification is that they differ fundamentally in terms of their bodily functions. Whilst fish, for example, are physically very active and are able to balance any initial fall in the pH value very well in their blood, this is more difficult for corals. They spend their entire life in one place and cannot compensate as well for a higher level in their bodies because they lack efficient physiological mechanisms. Failure to compensate the pH value in the body fluids can result for example in lower coral calcification, i.e. its calcareous skeleton does not protect against erosion and it cannot be repaired or developed as well.

The presumption that fish can cope with ocean acidification better than corals also becomes evident on taking a look at the past. "We compared our results with the widespread deaths of species around 250 and 55 million years ago when CO2 concentrations were also elevated. Despite the relatively rough statements we were able to make with the assistance of sediment samples from the past, we discovered similar sensitivities in the same animal taxa", explains Prof. Hans-Otto Pörtner. The spread of the corals and the size of the reefs slumped drastically 55 million years ago whilst fish exhibited a great adaptive capacity and were able to further extend their dominance.

The finding that in the past fish were not highly sensitive to acidic water surprises the scientists because current research results show that fish at the larval stage are quite sensitive to ocean acidification. "Not all effects we are currently measuring are decisive for the destiny of a species possibly in the long term", explains Pörtner.

The study of the biologists from the Alfred Wegener Institute was conducted in the framework of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) and is intended to provide an overview of the current level of scientific knowledge on . "For us, it was important not only to present the research results of recent years but to assess which impacts will have on species", says Pörtner.

It is the first IPCC report to extensively document the consequences of climate change on the ecosystems of the oceans. The report will be published at the end of March 2014 and is prepared by the so-called second working group, which assesses how climate change impacts socio-economic and ecological systems.

Explore further: Baby corals pass the acid test

More information: "Sensitivities of extant animal taxa to ocean acidification" 25 August 2013 Nature Climate Change DOI: 10.1038/nclimate1982

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User comments : 19

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2.1 / 5 (15) Aug 25, 2013
"Ocean acidification could change the ecosystems of our seas even by the end of this century."

As the pH value declines from being so basic (8) more towards a neutral value (7), the term "neutralization" has been cunningly replaced by "acidification." Cue Godzilla movie as the carbon dioxide starved oceans "suffer" an overall double digit boost in productivity. What would the *cost* be of misinforming the public of non-controversial fertilization effects?

"The finding that in the past fish were not highly sensitive to acidic water...."

You don't get to redefine terms like this without suffering extreme ridicule and loss of funding when the Internet allows anyone to point out such deception. "Acidic water" belongs on Greenpeace brochures, not press releases for primary literature results.

"Our study showed that all animal groups we considered are affected negatively...."

Coccoliths which are a central hub of the ocean food chain? A 40% boost in productivity in modern times!
2.1 / 5 (15) Aug 25, 2013
Where are the plots of actual coral, crustacean, mollusk, vertebrate, fish and echinoderm vitality and abundance in recent high carbon fertilization decades? I wonder what those plots really show.

"...over the next century the predicted increase in atmospheric CO2 concentration "will result in about a 15% increase in oceanic HCO3-," and they say that this development "could stimulate photosynthesis and calcification in a wide variety of hermatypic corals."

"... we present laboratory evidence that calcification and net primary production in the coccolithophore species Emiliania huxleyi are significantly increased by high CO2 partial pressures. Field evidence from the deep ocean is consistent with these laboratory conclusions, indicating that over the past 220 years there has been a 40% increase in average coccolith mass."
1.9 / 5 (14) Aug 25, 2013
"...for the Mediterranean zooxanthellate coral, "an increase in CO2, in the range predicted for 2100, does not reduce its calcification rate," and that "an increase in CO2, alone or in combination with elevated temperature, had no significant effect on photosynthesis, photosynthetic efficiency and calcification." However, they report that a 3°C rise in temperature in winter resulted in a 72% increase in gross photosynthesis, as well as a significant increase in daytime calcification rate."
2.6 / 5 (10) Aug 25, 2013
"You don't get to redefine terms like this without suffering extreme ridicule "

Not half the ridicule heaped on Nik for jumping on every climate change article - and making a total joke of himself. The last article - Nik claimed the Antarctic was cooling - 'the rabble' called attention to his little manipulation of the truth. Keep howling at the moon Nik - 'the rabble' will keep pointing out your 'little' inaccuracies.
2.2 / 5 (16) Aug 25, 2013
djr knows in his heart that only tobacco farmer and half billion petrodollar mogul Al "Category 6 Hurricane" Gore is divine, perfect, and not in fact the biggest hypocrite in human history.

How does my real time discovery that the deep cooling of Antarctic trend maps was suddenly re-adjusted in 2007 to alter the past, amount to making a "total joke of myself" when in fact it revealed what a total joke data integrity is in Climatology?

I suggest either Scientology or good old drugged up South American bible churches for you djr, since I'm not gluing any crystals to my forehead to replace your fallen cult leader. I know I profoundly disappoint. Sockpuppet majorities, snide innuendo and regular death threats form the very core of criticism I have received here, for all to see as today's post of primary literature links becomes "howling at the moon." Heavy personal and likely financial investment in doomsday makes you a fair arbiter?
2.9 / 5 (8) Aug 25, 2013
Al Gore has nothing to do with your penchant for spreading untruths on the internet.

Yes - you repeatedly make a joke of yourself - bragging about your scientific credentials - and then making fundamental cock ups - like repeatedly claiming Antarctica is cooling - when I can use google and know very quickly that this is not supported by the data. Data impresses me much more than your overblown ego driven bragging.
1.9 / 5 (13) Aug 25, 2013
djr refers to the "untruth" of pointing out that prior to 2007, real data produced Antarctic trend maps that indeed revealed that the interior was cooling:


No jumps are to be found in the data after 2006 but suddenly the trend maps turned red, and djr's BS detector didn't even go off when Steig hit the cover of Nature with a textbook case of lying with statistics. He's also still pissed that I pasted his name onto the t-shirt of one of the Manson sisters, to point out that blind faith in rogues defines his lot. He cannot yet even imagine that what he sees as egotism is a simple case of altruism. Alas I live in a big city and not fundamentally on the Internet, so dead thread sniping and Wikipedia link bombing that I don't later see results in the cry of "Victory!"
2.4 / 5 (8) Aug 25, 2013
@NIK, you whine too much for what amounts to BS in a tortilla. If DJR's BS detector goes off reading your horse sh, it's not a malfunction. It's a detector overloaded with bogus BS coming from tainted horse sh.

So from the article here is what the science says; "Our study showed that all animal groups we considered are affected negatively by higher carbon dioxide concentrations. Corals, echinoderms and molluscs above all react very sensitively to a decline in the pH value",

That trumps any BS crap dark money POS website you sight. When you claim "victory" I'm going to laugh as you bake in your own stew.
2.2 / 5 (13) Aug 26, 2013
My after midnight Antarctica project is foiled, as Berkeley's Dr. Richard Muller who bashed the Hockey Stick team and then produced his own hockey stick by the innovation of chopping data up automatically into pieces at every jump and reassembling it like the Human Genome Project, now returns 404 NOT FOUND for the South Pole temperature station:

It's hard to debate when inconvenient data keeps disappearing!

Good old Rimfrost still plots the raw data, and my screen capture has a bonus that shows the Global Warming forgot about Easter Island off the coast of Chile too:


P.S. Hey Howhot, it's *interesting* how you show up in accusations about faux majority sockpuppet campaigns:
2.1 / 5 (11) Aug 26, 2013
Enjoy the porn Howhot, my favorite banner sponsored image host lets me select an "adult" image category to display a screenshot of your nasty dehumanizing hatred of your fellow man, you know, those adults who have naturally progressed from youthful idealism to mature realism that is known as wisdom:

"If you're not a liberal at twenty you have no heart, if you're not a conservative at forty you have no brain." -Churchill

Aggressive hatred is the number one risk factor in heart disease, Howhot. You guys don't upset me though, since us Manhattanites are used to be screamed at by itchy wild eyed fellas who growl a lot about secret societies.
5 / 5 (3) Aug 26, 2013
Nik - "that indeed revealed that the interior was cooling:"

You just conveniently glossed over that one little word 'interior' right? As my google skills point out - Antarctica is a complex place - some areas appear to be cooling, some warming. But on mass - the continent is warming.
2.2 / 5 (11) Aug 26, 2013
djr suggested: "But on mass - the continent is warming."

Temperature stations are scarce and subject to local heating effects due to people being around, and now that satellite data exists long enough back (>30 years) to measure climate instead of just weather, a glance at actual trends shows Antarctica to be dominated by blue cooling:

That data set is run by Dr. John Christy, some background on which is included in the PR firm run site DeSmogBlog, here:

You can see that satellite data confirms NASA's original pre-2007 presentation of Antarctic cooling, found here:
3.3 / 5 (3) Aug 26, 2013
No Nik - your satellite data does not confirm this at all. The picture is pretty - but nowhere in your reference does it discuss the question of the overall balance of Antarctica.

Let me give you a quick quote from a well supported Wiki article.

"There is no similar controversy within the scientific community, as the small observed changes in Antarctica are consistent with the small changes predicted by climate models, and because the overall trend since comprehensive observations began is now known to be one of warming."

1.6 / 5 (9) Aug 26, 2013
djr: I concede that overall Antarctica is not cooling as far as recent abrupt data adjustments are concerned. However, it gives me a chance to point out that peer review in climate science is broken since it took skeptics a mere week or two to reveal the bad math behind Steig's Nature journal cover story map that smeared *very* geographically localized Antarctic peninsula heating across the whole damn continent, and show what a peer reviewed correction by O'Donnell of that curiously incompetent math lead to:

On Steve McIntyre's blog, the paper's math was indeed exposed as being *only* sensitive to peninsula data variation yet immune to interior data:

The corrected map helps explain why nearly all of the Antarctic "global" warming articles I've seen here on are about the hot spot peninsula.

But *skeptics* are accused of dishonest "cherry picking"?!
3.7 / 5 (3) Aug 26, 2013
Nik - might I point out that on at least 2 occasions recently - you have gone on a science web site and claimed that the Antarctic is cooling. YOUR claims regarding this issue were wrong. YOU now have no credibility, and no right to question others motives. I am not interested in dissecting individual papers, and playing your game of looking for a conspiracy that is not there. How do you not understand the fundamental point? YOU have been caught at least twice making a false claim. YOU have no right to now set yourself up as judge and jury of others. I am comfortable going with the consensus - that makes the conspiracy boobs uncomfortable - but when YOU are proven to not know what you are talking about - it is time to put the keyboard down.
2.3 / 5 (3) Aug 26, 2013
In the pH range of 6.37 to 10.36, in which nearly all sea water falls, the most abundant carbonate species is bicarbonate - HCO3(-) - which is used by marine invertebrates (plankton, mulloscs, corals, etc.) to form their skeletons.
As the animals remove bicarbonate from the sea water, the pH is kept above 6.37 and below 10.36, as LeChateleir's Principle informs us.
Bottom line: CO2 in the air is GOOD for the coral reefs.
3 / 5 (4) Aug 26, 2013
As the pH value declines from being so basic (8) more towards a neutral value (7), the term "neutralization" has been cunningly replaced by "acidification."

Don't you claim a PhD in chemistry? Then you must know that a pH of 12 is more acidic than a pH of 13, even though both are alkaline. Using the term acidification to refer to the direction of change is legitimate, especially when the term neutralisation would give the misleading impression that the process must stop when reaching neutral pH. Trying to see a conspiracy in the more accurate term acidification looks rather desperate.
4 / 5 (1) Aug 26, 2013
This is a response by Steig to the McDonnell paper:
"In summary, even if their results are taken at face value, O'Donnell et al. 2010 doesn't change any of the conclusions reached in Steig et al. In West Antarctica where there is disagreement, Steig et al, 2009 is in better agreement with independent data, and O'Donnell et al.'s results appear to be adversely affected by using procedures known to underestimate trends. Thus while their results may represent an improved estimate for the trends in data rich regions — East Antarctica and the Peninsula — it is virtually certain that they are an underestimate for West Antarctica. This probably means going back to the drawing board to write up another paper, taking into account those suggestions of O'Donnell et al. that are valid, but hopefully avoiding their mistakes."

4 / 5 (1) Aug 26, 2013
djr refers to the "untruth" of pointing out that prior to 2007, real data produced Antarctic trend maps that indeed revealed that the interior was cooling:


Re first Link:
"(Editor's note: This image was first published on April 27, 2006, and it was based on data from 1981-2004. A more recent version was published on November 21, 2007. The new version extended the data range through 2007, and was based on a revised analysis that included better inter-calibration among all the satellite records that are part of the time series.)"

2nd Link
Where is that from?