03 Jun 2008: Analysis

Carbon’s Burden on the World’s Oceans

The burgeoning amount of carbon dioxide in oceans is affecting a lot more than coral reefs. It is also damaging marine life and, most ominously, threatening the future survival of marine populations.

by carl safina and marah j. hardt

When the annual meeting of the American Association for the Advancement of Science (AAAS) convened in Boston this year, a handful of marine biologists and physiologists exposed a whole new side of climate change. They offered no data about the atmosphere. Their focus was not on temperature. Their conversation referred to warming only as a secondary and confounding effect.

Instead, these scientists were talking about chemistry — not just of the ocean water but of ocean animals themselves: their cells, tissues, and body fluids. They were noting the increased costs of living that come as a result of elevated carbon dioxide inside the body and how this added cost stresses marine life and has led to massive extinctions in the past. They were issuing a warning about the potential for unabated elevated carbon dioxide to threaten directly the survival of all marine species.

The direct link between increased carbon dioxide concentrations in oceans and increased internal stress on marine creatures is largely absent from the “climate change” dialogue. It used to be enough to say “global warming” was the problem. But increasing concentrations of carbon dioxide in the atmosphere — and in oceans — have been causing more varied and faster effects than previously imagined. In fact, massive changes underway in the ocean are not captured with the word “climate.”

Certainly, warming itself is a colossal issue. Record world temperatures, melting sea ice, thermally expanding ocean waters, sea level rise, engorged rain clouds in some regions and droughts in others — “climate change” has been used to encapsulate all these effects.

Yet now, that term is beginning to hamper our understanding — and our conversation. Beyond the well-defined relationship between carbon dioxide and temperature lie various chemical reactions that have profound implications for life. These other issues are starving for attention, partly because they are not about warming, the atmosphere, or the climate. But they are about the same carbon dioxide.

Almost half of all the carbon dioxide emitted since industrialization has been absorbed by the ocean. When carbon dioxide reacts with water, it forms carbonic acid, and releases more hydrogen ions into the sea, lowering pH and causing “acidification” of the ocean. Further, these hydrogen ions quickly bind with carbonate ions. This deprives animals like hard corals and certain mollusks and plankton of the raw material for their calcium carbonate shells and skeletons. This may ultimately cause the world’s oceans to become corrosive to such animals, and coral reefs to dissolve.

Calcification rates (think of this as the rate at which a coral, say, can grow, based on its ability to construct its skeleton) decline in relation to carbonate concentrations. Models predict that coldwater corals may lose 70 percent of their habitat by 2100 with some waters becoming corrosive as early as 2020. Calcification rates in tropical waters have already declined by 6 to 11 percent and are expected to decline by as much as 17 to 35 percent by the end of the century. Some models predict concentrations of carbonate ions will be too low for reef growth by as early as 2065.

It turns out that carbon dioxide molecules not only penetrate the ocean; they also infiltrate the bodies of marine animals, permeating cell membranes and disrupting fundamental biological functions. Carbon dioxide is a small, uncharged gaseous molecule that in the ocean environment can rapidly cross cell membranes. Once inside the cell, the same acidification process that happens in ocean water occurs within the cell. Higher concentrations of CO2 alter the acid-base balance within cells and disrupt many cellular functions, from oxygen transport to protein synthesis. The more CO2 inside body tissues, the higher the cost of living for an organism. In its energy budget, the cost of dealing with CO2 comes directly out of energy that would otherwise have gone for other basic functions such as metabolism, growth, immune function, and making babies.

We call this cost “metabolic drag.” It has long-term consequences for survival because even if not acutely fatal, over time reduced growth, disease resistance, and reproductive output threaten the viability and resilience of populations. And they’re going to need resilience.

Too much carbon in the ocean particularly threatens creatures living in the deep sea. The depths of the ocean comprise one of Earth’s most stable environments. Its animals are adapted to that stability. They don’t handle change well. Scientists predict that the pH in the deep sea will be greater than for the ocean’s other regions.

Experiments show that elevated carbon dioxide affects various cellular and bodily functions, such as the ability to make proteins, transport oxygen through the body, or growth rates. But how will the ever-increasing CO2 affect individual animals, populations, and species in coming decades? No one knows. Significant harm appears possible, but evaluating long-term effects will require more work. Research is also critically needed to evaluate large-scale carbon disposal (sequestration) that would cause very high concentrations in deep ocean water (in some experiments, pH declined by more than 1 unit).

Consideration of these known and potential effects of elevated carbon dioxide levels has not been part of the “climate” debate, and it will be difficult to raise or understand these effects if people continue to believe that the problem only involves climate. The language lags behind the science, and needs to catch up.

No term in use captures the full array of issues from warming and climate to the chemistry changes throughout the ocean and inside every marine creature. Not “climate change,” certainly not the almost-quaintly catastrophic “global warming.” Those aren’t even the problem; they’re symptoms. Behind all these symptoms is the root of the problem. We call it “the carbon burden.”

So hear this: It is not just about climate. It is, and always has been, about the carbon. We need to place carbon back in the center of the equation. From atmosphere to ocean to cell, the carbon burden is the problem. It’s the heaviest load anyone’s ever placed on an unsuspecting planet, and the more we learn, the more its dimensions appear ever more staggering.

POSTED ON 03 Jun 2008 IN Biodiversity Climate Climate Oceans Science & Technology Antarctica and the Arctic Europe North America 


have you ever heard of the devonian period?That is where the corals first built coral reefs. Any idea what the atmospheric co2 concentration was? APPROX TEN TIMES WHAT IT IS NOW.Of course its not about "global warming " anymore,as with the 0.6 degree C decrease over the last 10 years the temperature of the globe is right back where it was in 1900! And we now know [from the Vostok ice core] that co2 rise follows temperature rise by between 300 and 1000 years,so the current co2 rise MAY well be due to the temperature rise of the medieval warm period [800 to 1200 AD].Incidentally, have you seen NASAs latest release on massive climate change...on Jupitor!
Posted by ian aitken hilliar on 06 Jun 2008

An interesting fact - raise the temperature of a CO2 carrying media, and the level of retained CO2 decreases - chemistry 101. The pH level will increase - initially until the dissolved CO2 (in the form of carbonic acid) reaches a point of equilibrium, at which stage the media will once again, release the CO2 back into the atmosphere. Chemistry 101 again.The Earth is carbon neutral, as mass cannot be created nor destroyed. So we are merely releasing carbon fixed during the carboniferous period, which will once again be fixed by the oceans and the forests. Perhaps the researcher should look more into the effects of run-off (phosphoric acid, fluoric acid, sulphuric acid etc., that have much more of an effect on calcium fixation (shellfish and corals) than increased CO2 levels.
One has to wonder who this guy is sponsored by....
C Caudwell MSc., ATPL
Posted by Clark Caudwell on 07 Jun 2008

"The Earth is carbon neutral, as mass cannot be created nor destroyed."

That is 100% true but unfortunately irrelevant.

When life first appeared on earth around, say, 3.5 bya the atmosphere was >90% CO2, it was that CO2 blanket that allowed a surface temperature of 15 C due to the greenhouse effect. By some remarkable alchemy life processes have been removing CO2 continuously from the atmosphere ever since and storing it in carbonate rich rocks removing the blanket in the face of the ever increasing out put from the sun's evolving nuclear furnace, which has increased solar radiation by at least 25% and maybe 40% since 3.5 bya. This process reached an especially high rate of carbon storage during carboniferous times when carbon was stored directly as coal and other very carbon rich sediments, which under favourable conditions reacted to produce oil and gas. We are currently releasing this stored carbon thtrough exploitation of fossil fuels.
The above information is irrefutably accepted, basic, (unponsored!!) geological and atmospheric fact.

"That is where the corals first built coral reefs. Any idea what the atmospheric co2 concentration was? APPROX TEN TIMES WHAT IT IS NOW"

Hmmm.... and any idea what the average planetary surface tempertaure was in the Devonian? Well it just happens to have been within +/- 5C of 15C, which is the ideal for carbon based life forms. A significant demonstration of the result of the removal of the CO2 blanket since 3.5bya. That excess of CO2 probably prompted the evolution to carbonate use in shells and eventually skeletons. Since then of course marine life has also evolved to live with a much lowered CO2 content and has also adjusted to changing oceanic chemistry, so direct comparisons are not appropraite.

Wonderful to see so many splendid Red Herrings (Clupea bosfaeces)swimming about though!!
Posted by Lucie Bell on 09 Jun 2008

"The Earth is carbon neutral, as mass cannot be created nor destroyed." How is talking about increasing the carbon mass in the Earth? Just not bend the carbon equilibrium to extreme biotic absortion .. quite simple.
Posted by Giancarlo Raschio on 23 Jun 2008

Comments have been closed on this feature.
carl safina and marah j. hardtABOUT THE AUTHORS
Carl Safina, a marine biologist, is president of the Blue Ocean Institute and author of the award-winning books Song of the Blue Ocean and Eye of the Albatross. Marah Hardt is a post-doctoral research fellow at the institute.



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