PACIFIC IMPERILED: An example of life forms attached to the sea floor in shallow seas.
Image: NASA
In Brief
- The pH of seawater worldwide is dropping (acidifying) as oceans absorb ever more carbon dioxide from the atmosphere.
- Experiments show that the struggle by copepods, snails, sea urchins and brittlestars to balance the changing pH inside their bodies impairs their ability to reproduce and grow. Many species are unlikely to genetically adapt to ocean acidification, because the change is occurring too quickly.
- As species wither, the marine food chain could be disrupted; human action is needed to curtail further acidification.
"Slow sperm ... now that’s a problem,” said Jonathan Havenhand, his British accent compounding the gravity of the message. “That means fewer fertilized eggs, fewer babies and smaller populations.” We were sharing a hilly cab ride along the glistening northern coast of Spain to attend an international symposium about the effects of climate change and excess atmospheric carbon dioxide on the world’s oceans. As researchers, we were concerned about the underappreciated effects of changing ocean chemistry on the cells, tissues and organs of marine species. In laboratory experiments at the University of Gothenburg in Sweden, Havenhand had demonstrated that such changes could seriously impede the most fundamental strategy of survival: sex.
Ocean acidification—a result of too much carbon dioxide reacting with seawater to form carbonic acid—has been dubbed “the other CO2 problem.” As the water becomes more acidic, corals and animals such as clams and mussels have trouble building their skeletons and shells. But even more sinister, the acidity can interfere with basic bodily functions for all marine animals, shelled or not. By disrupting processes as fundamental as growth and reproduction, ocean acidification threatens the animals’ health and even the survival of species. Time is running out to limit acidification before it irreparably harms the food chain on which the world’s oceans—and people—depend.
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24 Comments
Add CommentInteresting article. Perhaps a bit biased in the scope of the sample area, a single line of pH sampling over about 17 degrees of Longitude, in the North Pacific Gyre. Also not mentioned are the El Nino/La Nina cycles over the sampling period, and the changes in solubility of CO2 due to ocean temperature differences.
Reply | Report Abuse | Link to thisI would also portend the potential bias of this research based on associations of the authors. Isn't this akin to the "Lard Information Council" espousing on the healthy benefits of eating lard?
I would seriously doubt that plentiful Oxygen, a waste product of phytoplankton, would support ..."the blooming base of the food chain...." (August 2010 article on page 69). Since Sunlight and Carbon Dioxide, not Oxygen, are the chemical resources on which photosynthesis depends, it follows that more CO2 fosters more phytoplankton mass growth and activity, just as it does for terrestrial plants.
I have thought abou this, what happens when the atmosphere goes toward CO2 saturation? But as MensaPE points out the effect should be the same as in forrests. But while doing experiments in forrests (there are huge such going on) have many limitations this could be tested almost in a simple little aquarium!
Reply | Report Abuse | Link to thisThere are so many unproven theories going on "that cannot be proven before it is too late" but here is one that can.
But it is meanignsless to proof that "CO2 kills life", the only meningfull experiment is "what happens?" Like "what happens to eggs in an aquarium when CO2 rises compared to an aquarium that remains the same.
I believe increasing CO2 injection gradually over numbers of generations of small animals should not make too much difference as long as limestone and other buffering minerals are present. I heard of a bit of a test similar wherein small shelled animals were restrained in a small volume, with the idea that increasing CO2 from their respiration would reduce the pH low enough to damage the animals shells, and low and behold, damage was done. However, pH change was mainly due to build-up of ammonia from their waste products.
Reply | Report Abuse | Link to thisIf we look into long-term estimates of paleoclimitology, only in the present epoch and 270 to 320 million years ago, has the atmospheric CO2 been at the low levels we now experience, ~0.05% CO2. During the Jurassic, when the cornucopia of plants allowed the massive dinosaur gigantification, CO2 is estimated to be 0.24%, nearly 6 times today's concentrations. During the Cambrian, 530 MYA, levels were almost 3 times higher than the Jurassic, or about 15 times present levels. We have vast fossil records of the tremendous success of life during those times, compared to today's herbivores which are much smaller. So, we can't say it kills life, but rather CO2 is absolutely necessary for life on earth, and the more the better.
A process to remove CO2 from the atmosphere and oceans would be a WMD without equal, by definition of the Organic Cycle of life on earth. Remember Chem 101? Organic = Carbon based chemistry and "Carbon based life forms". How do you like to get your carbon? Eat graphite? I'd rather eat fresh veggies.
The caption "Acid Creation" states that most of this weak acid (Carbonic Acid) dissociates into hydrogen ions(H+).... This is incorrect. By definition a weak acid dissociates to only a very small extent(the ionization constant for carbonic acid is only 4 x 10(-7)which makes it a very weak acid)
Reply | Report Abuse | Link to thisConcerning the first paragraph of the section "Rapid Sea Change", I would like the authors to define for me what is meant by an "average pH". I know of no such number, especially within context of a buffered system.
Reply | Report Abuse | Link to thisConcerning the second paragraph of "Rapid Sea Change", I would like to know the authors' definition of "acidity". As I understand acidity, it is the ability of a buffered system to accept a strong base to a set endpoint. I can surely construct a pair of systems that differ by 0.12 pH units and have exactly the same acidity. However, the fact that the pH scale is logarithmic has nothing to do with a 30 % increase in acidity. Once again, it is easy to construct a pair of buffered systems that have 30% difference in acidity, yet have exactly the same pH.
Concerning the figure "Acid Creation" on page 69, I would wonder why the reverse reactions are not also presented, as this is a pseudo-equilibrium system. Carbon dioxide can and does leave water at any pH. Additionally, limestone (vis. rocks, shells, etc.) are an excellent source of carbonate which is the conjugate base of carbonic acid. Why is this not in the figure?
Are these items considered in the models?
I thought there was a more serious cause of acidification of our oceans. That would be runoff from our farms. That extra fertilizer running into the oceans would create more algal blooms and create more life in the oceans that would eventually die and sink down into the lower levels and decompose back to CO2 raising the CO2 levels in the lower ocean even more than a dilute diffusion from our atmosphere. It may be to our advantage to not raise the fecundity of the ocean if that is the case. We clearly have to address what we wish to grow in our oceans and what would be the best course to follow to achieve that goal.
Reply | Report Abuse | Link to thisBut addressing the problem of excess agricultural runoff may be the most effective way to control excess CO2 in our water in a practical sense. And planting more perennial forests and grasslands would be the best way to fix the excess CO2 in our atmosphere.
However, if we do make certain portions of the oceans more fertile and can harvest a large portion of the biomass produced, it may lower the amount of biomass dieing and decaying in the deeper layers and producing more concentrated CO2 levels there. And removing that fixed carbon in the harvested biomass leaves room for more atmospheric CO2 absorption in the upper ocean levels as well.
Another thing not mentioned is that cooler water absorbs preferentially more CO2 than other gases in our atmosphere. That also means that when water warms up more CO2 is preferentially released than other components of our atmosphere as well. That means cooler water is more biologically buffered as well.
I think that the sample period is also interesting. http://wso.stanford.edu/gifs/Tilts.gif shows this to be an interesting period encompassing 2 solar maximum when lower frequency, deeper penetrating solar radiation may be a factor. Further, the graph on page 69, seems to confirm that during the solar minimum, pH seemed to decline.
Reply | Report Abuse | Link to thisI would love to see these results over a 22 year period, adding 2006-2012. My prediction as a lay person, would be that pH is balanced over that period to a significant extent. Call me a skeptic if you must.
Is atmospheric CO2 buildup happening faster than in prior centuries? How is it impacting surface ocean systems? Will ocean life forms be able to adapt to increased acidification? Article contributes to this important discussion - thank you.
Reply | Report Abuse | Link to thisThe article is based on the premise that pH is dropping throughout the ocean. This premise is not adequately supported by the article or directly by the references at the end of the article. http://en.wikipedia.org/wiki/Ocean_acidification does have an extensive bibliography. That site is referenced by www.oceanacidification.net .
Reply | Report Abuse | Link to thisI think you can almost guarantee that negative comments to an article such as this one are made by people employed to do so to create doubt that these blatant problems even exist so that we continue to buy and use fossil fuels. The existence of these groups employed by oil, coal and even tobacco companies is documented and the mission of these groups is to manifest unfounded doubt. Members of these groups are well paid.
Reply | Report Abuse | Link to thisThere's really no bias in this author's biased opinion. The problem is big and becoming bigger in the science lit.
Reply | Report Abuse | Link to thisGood catch, though, on "oxygen" in that sentence. Humbling.
Ah, a little knowledge...
Reply | Report Abuse | Link to thisThe point is, there is not enough buffering and that is why the ocean is getting measurably more acidic, and animals are experiencing growth problems that are already measurable in the ocean. That's data; no conjecture needed.
When atmospheric carbon dioxide was much higher, hard corals vanished for millions of years. I don't want that on humanity's resume.
CS
To, MensaPE.
Reply | Report Abuse | Link to thisI have been thinking of that problem for some years and have
understand that after reading articles from researchers that
phytoplankton and other types of algaes, producing Oxygen, do not stand the acid seawaters, the calciumpart of the body and shell etc. deteriorate as much as they cant stay at the water-surface, but sink, and the production of Oxygen will be less and at risk for ours, and all lives, in need of Oxygen.
They are also a critical part of the ECO-system on the surface in the Oceans, feeding the life of the living forms feeding the next life-forms, at the next stage on the ECO-system at sea.
CO2 create the acidification of the waters, sinking planktons by deteriorate the calcium-structure they need to float. This
disturbing the Eko-system on the sea-surface, badly. And the
large and utterly essential source of Oxygen, for our lives.
regards,
fighter
To, hereticofTruth.
Reply | Report Abuse | Link to thisWell, CO2 could be about the only atmosphere we have, in some time in the future? It is the vast volume of it, that cause us all the trouble.
No one doing anything to stopp the COAL-MAFFIA AND COAL-FIRES! All new plants popping up, at an astronomic speed, thousands of new Coal-plants, every year? In the Year 2040 we can try to survive in a volume of CO2 that sucking us up as easy as anything, no chance to survive.
The extra volume will be;
One-thousand five-hundred millions cubic kilometres of CO2
gas, at one atm. pressure. I.e spread over the entire area of Earth the depth of CO2-gas will be 3 metres. The min concen- tration of deadly CO2 gas will than have a depth of 20 metres.
The volume is that large that nothing can't be done at it? You
can't do anything, or store it any-where or dig it down some- where or put it any-place. It is impossible to take on.
You can only dig your grave. OR? STOP FIRING COAL, NOW!
regards
fighter
To "concerned" and all above. I am a SAH mom, retired BSN RN, with a MA in Clinical Psychology. I do not belong to ANY fossil fuel organizations or any professional organizations. However, I am professionally trained in the protocols of professional research and publications of such. I have subscribed to SciAm for decades as a survey to all things "science" just to grasp current trends promoted to pander to government and the general public.
Reply | Report Abuse | Link to thisSCiAM magazine is not a professional journal. It is a general science magazine that targets the public. The magazine blatantly edits to bias readers. Its editorial board has targeted the general public to promote AGW and all other environmental issues for decades.. Its pages should be synthesized with a "grain of salt". This article is prima fascia evidence of just such "bunk writing" promoted as to mimic a legitimate scientific publication. It doesn't even attempt to mask such biases. EX: this article begins and ends with predertermined emotional and irrelevant statements. These statements are written to create foregone emotional conclusions of fact. Research cited in the article is microscule evidence to make such conclusions as comments suggest from above. I would highlight the use of computer generated models. Most offensive in relevance is the last paragraph that couples any oceanic/marine research citations with the statements about lethal consequences of coal mining and deep-well drilling. (Do you forego cooking, walking, bicycling, drivinig, flying, medicine, surgery, house dwelling, knives, alcohol, etc. because of lethality.) The "slow sperm" opening statement is just as scientifically offensive.
Look at the authors. They are "institute" developers and ruling CEO's of said institute used as evidence of professional status; said institute organized to give themselves salaries from grant money to propagate further grant money. They might have advanced degrees but the institute reference hinders legitimacy of this article.
I don't fault SciAm magazine; they are what they are. But the public and policy become SciAm victims. IMO, SciAm is part of the LSM simply because of their artful aim to bias its readers to "the AGW science is settled" conclusions. Scientists never utter "the science is settled" phrase because that premise is unscientific, by scientific standards. Such was hammered into my brain during under/graduate studies. Evidence of unsettling the "settled science " is found on pg. 59, bottom left in same issue.
Aloha all. Thank you for your thoughtful responses. I will address each of the issues you raise in this response. Please search for your name to find the specific response to your question/points raised:
Reply | Report Abuse | Link to thisHERETICOFTRUTH
Thank you for your reply and concern regarding the role of fertilizer run-off threatening ocean life. You are correct that this is a big concern, but from my understanding, ocean acidification is not a result of this process. Instead, the threat from run-off is often a draw-down of oxygen levels in seawater. As bacteria work to decompose the phytoplankton, they use up large quantities of oxygen, creating what are known as dead zones areas where there is too little oxygen to support other organisms, such as crabs, shrimp and fish. While some CO2 is released in the decomposition process, I have not heard of nor seen any studies that have documented acidification due to this phenomenon. If you know of any research on this, please share!
Surn
I am not sure I understand why deeper solar radiation would be a factor? How does radiation affect the carbonate chemistry equilibria? We know that the carbonate buffering system of the oceans cannot keep pace with the rate of CO2 absorption currently occurring (http://www.realclimate.org/index.php/archives/2005/07/the-acid-ocean-the-other-problem-with-cosub2sub-emission/ ) , and thus, the CO2 is affecting the basic chemistry. The declines in pH as a result of this shift have occurred over the last 150 years. The figure you refer to on page 69 also shows that the declines in pH occurred from 1991 to 2006 which, if I understand the graph you refer to, encompass a period of a solar minimum (1995-6) and maximum (1999-2001)?
Wrmelgaard
Reply | Report Abuse | Link to thisLike any physical parameter, there are high levels of variability in surface ocean pH across space and time. We were careful not to claim that pH is dropping throughout the ocean (in fact, the figure on page 69 shows the spatial heterogeneity in pH values in space and time across the largest transect studied to date)—instead, we wrote that the “average pH of the ocean’s surface layer” had decreased. Being an average, this means some regions will not have changed, and some areas will have changed more than others. Depth, temperature, carbonate chemistry, and other factors all play a role in how much change a specific amount of CO2 will cause in ocean chemistry in any particular region. However, what this article shows (supported by numerous independent research studies) is that predicted decreases in ocean pH, based upon known carbonate chemistry system of the ocean, are manifesting in many places around the globe. And, because of the basic chemistry involved, additional CO2 will continue to push the system towards lower pH. For a detailed description of how this happens, please see:
http://www.realclimate.org/index.php/archives/2005/07/the-acid-ocean-the-other-problem-with-cosub2sub-emission/
for the chemistry involved.
Bfseverin
Reply | Report Abuse | Link to thisMeasurements of past ocean pH are based on the air bubbles trapped by glaciers. Scientists can measure the CO2 trapped in these air bubbles and because much of the surface ocean remains roughly in equilibria with the atmosphere, the surface ocean CO2 can be calculated. From this, the pH of surface ocean waters is also determined. Modern day estimates are based on direct measurements from the field, and models that look at atmospheric CO2 levels. Please see the FAQ section of EPOCA for more details on this question.
As noted on the EPOCA project website, the term “acidification” to refers to lowering pH from any starting point to any end point on the pH scale. It is similar to temperature verbage: when it is -40 C outside, and moves to -20C, it is still cold outside. But we say it has “warmed.” You are correct that “acidity” refers to the quality or degree of being an acid. However, in terms of the acidification process, any increase in ocean hydrogen ion concentration (a lowering of pH) is referred to as an increase in “acidity”, even though the pH of the seawater remains basic.
In the context of acidification as a process, governed by a change in hydrogen ion concentration, it is true that because of the logarithmic nature of the pH scale, for every 1 unit drop in pH, the hydrogen ion concentration increases by 10 fold (all other factors being equal). So, a 0.1 unit decline in pH equates with a 26% increase in ocean hydrogen ion concentration (we rounded to 30% to keep things simple).
You are correct that the chemistry of the ocean is governed by a series of reactions forming an equilibrium system. We did not present the full equations in order to simplify the description and show the dominant reactions that are currently taking place (but the models of all studies do incorporate the full set of reactions). The oceans continue to absorb CO2 from the atmosphere and it is accumulating in surface waters—thus while some CO2 continues to off-gas into the atmosphere, the dominant force is increased CO2 in seawater. Because of the nature of the carbonate chemistry reactions, the equilibrium are driving towards increased bicarbonate, which reduces overall the amount of available carbonate, and does drive dissolution of compounds such as limestone. This is why acidification is such a problem for corals and other organisms whose shells contain calcium carbonate. However, there is not nearly enough of this material to serve as an adequate buffer for the system. This natural buffering capacity of the ocean operates on time scales of thousands of years, while the CO2 increase is on the order of years/decades. That is one of the biggest reasons for concern. Please see:
http://www.realclimate.org/index.php/archives/2005/07/the-acid-ocean-the-other-problem-with-cosub2sub-emission/
and
http://www.epoca-project.eu/index.php/what-is-ocean-acidification/faq.html
for a detailed description of the chemistry and explanation for the buffering systems and time scales involved.
Jtyrrel
Reply | Report Abuse | Link to thisCarbonic acid is a weak acid, as you say, meaning it does not dissociate all the way. However, it does dissociate into H+ and bicarbonate, and the bicarbonate is much more stable at the range of ocean pH in current times. Thus, much of the carbonic acid does eventually dissociate, even though it is over longer time scales. Please see the following link and check out the Graphic Results section to see how bicarbonate dominates at this current pH level:
http://www.chem.usu.edu/~sbialkow/Classes/3650/Carbonate/Carbonic%20Acid.html
Thanks for your interesting response. There are a few points I’d like to respond to. First, the major problem with ocean acidification today is that the rate at which it is occurring— 100 times faster than animals have experienced in the surface oceans for tens of millions of years. It is too fast for the natural geological buffering mechanisms to keep up, and likely too fast for many marine organisms to adapt. In regards to “the more the better” I would just call attention to the fact that too much of anything is never a good thing. That reasoning could lead people to think more oxygen is better too, but we know that too much oxygen is toxic and deadly.
Reply | Report Abuse | Link to thisAt the end of the day life exists as it does today as a direct result of billions of years of modification—physical and biological processes interacting and adjusting, reacting and responding, until we reached the current conditions. Life and the physical earth continues to change, but the question of whether we can keep up with this change (or will want to) is another matter. This article attempts to show the types of change we are, and will continue to bring, if we do not adjust our behavior. The choice to do so or not, and live with the consequences either way, remains not one of science, but one of values.
In terms of the bias you refer to, the single transect across the Northwest Pacific is only one of many research projects gathering data on changing ocean pH (the importance of this study was that it showed pH declines across such a large swath of coean). For example, data monitoring stations with 20-30 years of semi-continuous recording of carbon dioxide levels in the ocean and ocean pH exist from Hawaii, Bermuda, and the Canary Islands and all show rising ocean CO2 mirroring rising atmospheric CO2 (and ocean pH declining).
In terms of author bias, I am not sure I understand your reasoning here. As scientists and communicators we work to translate science into stories that can be understood and accessible to non-scientists. We had no connection whatsoever to any of the research reviewed in this study, nor the funding sources for it.
I am pasting here a response from Chris Langdon, a world renowned ocean acidification researcher, where he addresses the issue of past change (you can see more FAQs on the EPOCA website):
How is today’s change in ocean chemistry different from those of previous geological periods?
Present conditions differ from the past largely because the rate of change of atmospheric CO2 does not match the rate of mitigating geological processes. If CO2 is added slowly over hundreds of thousands of years, as it was during the Ordovician by volcanic and plate tectonic activity, the CO2 that enters the ocean has time to mix throughout the ocean from top to bottom. As a result, even though the amount of CO2 that is taken up by the ocean is large, it is spread out over a very great volume of water and the resulting decrease in pH is small. At the same time, as the CO2 level in deep oceans increases over millennia, carbonate sediments lying on the seafloor begin to dissolve and release carbonate ions that neutralize some of the acidity, further minimizing the decrease in pH. Past oceans also contained higher calcium and magnesium ion concentrations, which helped stabilize calcium carbonate minerals in marine animals’ skeletons. Today, the CO2 in the atmosphere is increasing much faster than the ocean mixes. During CO2 releases like this over “short” (<10,000 year) timescales, the ability of sediments to regulate ocean chemistry is overwhelmed and both pH and saturation state decline. Even though the amount of CO2 that has entered the ocean in the last 200 years is smaller than that added during the Ordovician, the CO2 has built up to a much higher concentration in the surface ocean. As a result, upper ocean pH has decreased more rapidly and by a greater amount than in the geological past. Both the rate of change of pH and the magnitude of the change present problems for organisms that evolved in an ocean that experienced smaller, slower pH changes in the past. — Chris Langdon, Associate Professor, University of Miami, USA; Andy Ridgwell, Royal Society University Research Fellow, Bristol University, UK; Richard Zeebe, Associate Professor, University of Hawaii at Manoa, USA; Daniela Schmidt, Senior Research Fellow, University of Bristol, UK
Jarmo
Reply | Report Abuse | Link to thisI would like to refer you to the FAQ section of the EPOCA website where they go into details of how ocean acidification experiments are conducted:
http://www.epoca-project.eu/index.php/what-is-ocean-acidification/faq.html
You will find that aquariums are indeed used to test many of these effects. Field measurements are also a big part of the data collection process.
This article is one of countless in the last few decades on the degradation of Planet Earth. As usual the authors and editors refuse to mention that the fundatmental cause is the gross over population for the planet with six to seven thousand million people and growing by 70 million every year. People who know the facts of environmental destruction and refuse to acknowledge the cause and refuse to advocate for policies to limit and reduce population are more guilty than all the corporations, governments and other selfish exploiters of the earth.
Reply | Report Abuse | Link to thisI appreciate the well thought out comments on this topic. I've seen adequate information regarding the coincidence between CO2 increase and pH change in the Oceans.
Reply | Report Abuse | Link to thisI fear the bias of anyone studying "Ocean Acidification", as compared to studying "Ocean pH Change". Sort of predicts the outcome of the research without having to spend all the R&D funds, doesn't it? Sort of like studying "Damage to the Earth by Humans", rather than studying "The Effects of Humans on the Earth". The Moon doesn't care about it's condition and the Earth doesn't either. Only Humans care about what is good or bad for Humans, or what is good or bad for what Humans like.
My thoughts lead me to another pH changer which has massively increased due to the availability of 'cheap' energy, that of nitrates used in Agriculture. Ammonia and oxides of nitrogen have many many orders of magnitude greater efficiencies in changing pH than CO2, and, these things have increased all over the world at the same time as has CO2, due to cheaper fertilizers, more pigs and other animals upstream of most burgeoning high population areas, vastly more human and other animal wastes, and indeed greater discharge of other pH changing things from manufacture all over the world. Yet I see no mention of these things. Similar to the coincidence between CO2 and natural climate change. I guarantee global cooling would get a similar response. Find the witches, and punish them. Why do no scientists address or even mention the massive nuclear furnace internal to our planet, and the internal Earth heat.....The skin of the earth is after all only 0.075% thick, yep, it's only 1/130 th of the distance to the center. Roiling molten rock is below. If it's only heat left over from formation of the Earth, it would be a cold rock like the moon in 100 million years. Go down into the Earth only 1/4000 th the way to the core, and there is NO energy shortage there....Why is Earth temperature we measure only 55F a foot or two deep? The surface of the Earth is emitting peta-joules of heat into space. Cloudy nights stay warmer, but on a clear night, you can feel the energy being sucked right out of your body.
CO2, by the way, is such a poor pH changer, that we can drink carbonated drinks, which have pressurized 100% CO2 atmosphere over them, not the ambient 0.05%, in our atmosphere, over our Oceans and lakes.
I do agree with you about the many comments I have read. My daughter is doing an experiment on Ocean Acidification and it is real. National Geographic magazine has some pictures that will help explain our science experiment results coming this November 2012.
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