Modest CO2 cutbacks may be too little, too late for coral reefs

Sep 22, 2008

How much carbon dioxide is too much? According to United Nations Framework Convention on Climate Change (UNFCCC) greenhouse gases in the atmosphere need to be stabilized at levels low enough to "prevent dangerous anthropogenic interference with the climate system." But scientists have come to realize that an even more acute danger than climate change is lurking in the world's oceans—one that is likely to be triggered by CO2 levels that are modest by climate standards.

Ocean acidification could devastate coral reefs and other marine ecosystems even if atmospheric carbon dioxide stabilizes at 450 ppm, a level well below that of many climate change forecasts, report chemical oceanographers Long Cao and Ken Caldeira of the Carnegie Institution's Department of Global Ecology in the journal Geophysical Research Letters.

The researchers' conclusions are based on computer simulations of ocean chemistry stabilized at atmospheric CO2 levels ranging from 280 parts per million (pre-industrial levels) to 2000 ppm. Present levels are 380 ppm and rapidly rising due to accelerating emissions from human activities, primarily the burning of fossil fuels.

This study was initiated as a result of Caldeira's testimony before a Congressional subcommittee on Fisheries, Wildlife and Oceans in April of 2007. At that time he was asked what stabilization level would be needed to preserve the marine environment, but had to answer that no such study had yet addressed that question. Cao and Caldeira's study helps fill the gap.

Atmospheric CO2 absorbed by the oceans' surface water produces carbonic acid, the same acid that gives soft drinks their fizz, making certain carbonate minerals dissolve more readily in seawater. This is especially true for aragonite, the mineral used by corals and many other marine organisms to grow their skeletons. For corals to be able to build reefs, which requires rapid growth and strong skeletons, the surrounding water needs to be highly supersaturated with aragonite.

"Before the industrial revolution, over 98% of warm water coral reefs were surrounded by open ocean waters at least 3.5 times supersaturated with aragonite" says Cao. "But even if atmospheric CO2 stabilizes at the current level of 380 ppm, fewer than half of existing coral reef will remain in such an environment. If the levels stabilize at 450 ppm, fewer than 10% of reefs would be in waters with the kind of chemistry that has sustained coral reefs in the past."

For the ecologically productive cold waters near the poles, the prospects are equally grim, says Cao. "At atmospheric CO2 levels as low as 450 ppm, large parts of the Southern Ocean, the Arctic Ocean, and the North Pacific would experience a rise in acidity that would violate US Environmental Protection Agency water quality standards." Under those conditions the shells of many marine organisms would dissolve, including those at the base of the food chain.

"If current trends in CO2 emissions continue unabated," says Caldeira, "in the next few decades, we will produce chemical conditions in the oceans that have not been seen for tens of millions of years. We are doing something very profound to our oceans. Ecosystems like coral reefs that have been around for many millions of years just won't be able to cope with the change."

Source: Carnegie Institution

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Modernmystic
3 / 5 (10) Sep 22, 2008
So at what point can we finally say it's too late and quit writing articles about it?

*crosses fingers and hopes it's soon*
MikeB
3.2 / 5 (11) Sep 22, 2008
The neat thing about this scam is that it is based on computer models. In five years when it is obvious that the computer madels were wrong, guess what? We need more money to upgrade the computer models. We have already been through about five generations of this nonsense.
The computer models will never simulate any part of earth climate very well.
Bazz
2.6 / 5 (10) Sep 22, 2008
Yes everything that contradicts our views is nonsense.

Models are always imperfect especially when it such a complex model as one of our whole atmosphere, noone expects a perfect prediction,exept some people who want it be nonsense so they can discard it.

Thank god we are not all cynical and believe its too late, its never too late for anything.

It makes me smile knowing that you dont have real arguments and resort to these tactics.
Modernmystic
3 / 5 (12) Sep 22, 2008
I think you might have missed the point, it's not that we think it's too late and the sky is already falling. It's that we know that the sky isn't falling at all...we were being "ironical".
Bazz
2.7 / 5 (6) Sep 22, 2008
Yes its all very "ironic" indeed as i "suggested"
Velanarris
2.8 / 5 (9) Sep 23, 2008
The ocean is highly alkaline. CO2 brings the ocean to a more neutral PH balance and creatures like corals take the sunk CO2, (chemically converted to Calcium Carbonate through ocean reactions), and use it to make their shells and produce offspring.

This article is completely backwards. A kindergardener could tell you that the ocean is alkaline.
Bazz
2.7 / 5 (10) Sep 23, 2008
You got it backwards ,altough you are right about that its alkaline, dissolving CO2 will make it less so wich will make it harder for lots of organisms to form some bodyparts.

One of the victims of these extra hydrogen ions could be a type of phytoplankton called coccolithophores, one of the most abundant single-celled algae in the ocean. They are found in the upper, sunlit layers of the sea and play a vital ecological role. Coccolithophores produce a large proportion of the planet's oxygen, sequestering huge quantities of carbon and providing the primary food source for many of the ocean's animals. Coccolithophores use calcite, a form of calcium carbonate, to form tiny plates, or scales, on their exterior. Calcium carbonate starts to dissolve as pH declines: ocean acidification could therefore have a harmful effect on the abundance of coccolithophores and, consequently, on the health of the oceans and the planet.

Further ocean acidification could also be damaging for corals, such as those in the Great Barrier Reef. Corals are constructed with the skeletons of countless generations of small animals called anthozoans, which, in turn, are made largely of calcite. A reduction in calcite in the ocean could limit the formation of new corals, weaken existing corals and could also prompt coral bleaching.

from: http://www.scienc...6key.htm

At least try to make true statements.
agg
3.2 / 5 (9) Sep 23, 2008
computer models from *scientists* are hugely OVERFIT to the preconceived BIAS

Velanarris
3.2 / 5 (9) Sep 23, 2008
You got it backwards ,altough you are right about that its alkaline, dissolving CO2 will make it less so wich will make it harder for lots of organisms to form some bodyparts.

One of the victims of these extra hydrogen ions could be a type of phytoplankton called coccolithophores, one of the most abundant single-celled algae in the ocean. They are found in the upper, sunlit layers of the sea and play a vital ecological role. Coccolithophores produce a large proportion of the planet's oxygen, sequestering huge quantities of carbon and providing the primary food source for many of the ocean's animals. Coccolithophores use calcite, a form of calcium carbonate, to form tiny plates, or scales, on their exterior. Calcium carbonate starts to dissolve as pH declines: ocean acidification could therefore have a harmful effect on the abundance of coccolithophores and, consequently, on the health of the oceans and the planet.

Further ocean acidification could also be damaging for corals, such as those in the Great Barrier Reef. Corals are constructed with the skeletons of countless generations of small animals called anthozoans, which, in turn, are made largely of calcite. A reduction in calcite in the ocean could limit the formation of new corals, weaken existing corals and could also prompt coral bleaching.

from: http://www.scienc...6key.htm

At least try to make true statements.


Ok, I want you to go re-read what I wrote and tell me where I'm wrong.

In case that's tough for you then let me paraphrase:

The ocean is alkaline.

Adding co2 to the ocean brings the ocean from the realm of alkaline to the realm of relative neutrality which is conducive to coral and other organisms that are the subject of the above article.

Adding CO2 to the ocean creates Calcium Carbonate, which is what the shells of coral are made of.

Reducing CO2 leaves the ocean more alkaline and robs coral of calcium carbonate to make their shells.

Now if the ocean was neutrally balanced, then yes, adding CO2 would be bad, but they're not. The seas are rather alkaline, and the amount of CO2 that humans produce will not makes the seas acidic.
Bazz
2.8 / 5 (9) Sep 23, 2008
You argue that the coral,adapted to the alkaline enviroment of the sea ,is better of with the sudden change?

Ocean acidification

Not all the carbon dioxide released into the atmosphere stays there; some of it %u2013 about a third of total human-induced emissions %u2013 has been absorbed by vegetation during photosynthesis and a similar amount has been soaked up by the ocean. We're lucky that it has, or global warming would be happening much more quickly than it is.

The oceans are naturally alkaline, or basic, with a pH of about 8.2. When carbon dioxide dissolves in sea water it forms carbonic acid (H2CO3), which releases hydrogen ions (H ), lowering the pH and making it more acidic. Scientists estimate that the additional carbon dioxide in the atmosphere and the subsequent absorption of some of this by the oceans has lowered oceanic pH by about 0.1 units since 1750. They also estimate that the oceans will continue to absorb the excess carbon dioxide present in the atmosphere and that oceanic pH will fall by a total of about 0.5 units by the end of this century, bringing it down to about 7.7. This is still slightly basic %u2013 so we won't be creating a vast acid bath. But the pH scale is logarithmic, which means that even a decline of half of one unit will mean a several-fold increase in the concentration of hydrogen ions.

Plankton at risk

One of the victims of these extra hydrogen ions could be a type of phytoplankton called coccolithophores, one of the most abundant single-celled algae in the ocean. They are found in the upper, sunlit layers of the sea and play a vital ecological role. Coccolithophores produce a large proportion of the planet's oxygen, sequestering huge quantities of carbon and providing the primary food source for many of the ocean's animals. Coccolithophores use calcite, a form of calcium carbonate, to form tiny plates, or scales, on their exterior. Calcium carbonate starts to dissolve as pH declines: ocean acidification could therefore have a harmful effect on the abundance of coccolithophores and, consequently, on the health of the oceans and the planet.

Further ocean acidification could also be damaging for corals, such as those in the Great Barrier Reef. Corals are constructed with the skeletons of countless generations of small animals called anthozoans, which, in turn, are made largely of calcite. A reduction in calcite in the ocean could limit the formation of new corals, weaken existing corals and could also prompt coral bleaching.

from: http://www.scienc...6key.htm

Thats going against scientific knowledge about ocean acidification.

Get your facts right.
Velanarris
2.6 / 5 (10) Sep 23, 2008
You argue that the coral,adapted to the alkaline enviroment of the sea ,is better of with the sudden change?

Ocean acidification

Not all the carbon dioxide released into the atmosphere stays there; some of it %u2013 about a third of total human-induced emissions %u2013 has been absorbed by vegetation during photosynthesis and a similar amount has been soaked up by the ocean. We're lucky that it has, or global warming would be happening much more quickly than it is.

The oceans are naturally alkaline, or basic, with a pH of about 8.2. When carbon dioxide dissolves in sea water it forms carbonic acid (H2CO3), which releases hydrogen ions (H ), lowering the pH and making it more acidic. Scientists estimate that the additional carbon dioxide in the atmosphere and the subsequent absorption of some of this by the oceans has lowered oceanic pH by about 0.1 units since 1750. They also estimate that the oceans will continue to absorb the excess carbon dioxide present in the atmosphere and that oceanic pH will fall by a total of about 0.5 units by the end of this century, bringing it down to about 7.7. This is still slightly basic %u2013 so we won't be creating a vast acid bath. But the pH scale is logarithmic, which means that even a decline of half of one unit will mean a several-fold increase in the concentration of hydrogen ions.

Plankton at risk

One of the victims of these extra hydrogen ions could be a type of phytoplankton called coccolithophores, one of the most abundant single-celled algae in the ocean. They are found in the upper, sunlit layers of the sea and play a vital ecological role. Coccolithophores produce a large proportion of the planet's oxygen, sequestering huge quantities of carbon and providing the primary food source for many of the ocean's animals. Coccolithophores use calcite, a form of calcium carbonate, to form tiny plates, or scales, on their exterior. Calcium carbonate starts to dissolve as pH declines: ocean acidification could therefore have a harmful effect on the abundance of coccolithophores and, consequently, on the health of the oceans and the planet.

Further ocean acidification could also be damaging for corals, such as those in the Great Barrier Reef. Corals are constructed with the skeletons of countless generations of small animals called anthozoans, which, in turn, are made largely of calcite. A reduction in calcite in the ocean could limit the formation of new corals, weaken existing corals and could also prompt coral bleaching.

from: http://www.scienc...6key.htm

Thats going against scientific knowledge about ocean acidification.

Get your facts right.


Crazy people like you are out there sticking iron ore into the ocean because they think it's good for the acidic balance of the ocean.

You realize how much CO2 compared to how much ocean water there is?

If you increase a natural resource in an environment, any biological organisms in that environent that utilize said resource will thrive. For instance:

"Previously, the fact that carbon dioxide made the oceans more acidic was thought to be harmful to all organisms that produce calcium carbonate - for example, corals and coccolithophores (a group of calcium carbonate-producing phytoplankton). However, observations in the laboratory and the deep ocean have shown that the calcification of coccolithophores increases significantly with rising carbon dioxide (CO2) levels, produced by human activity."

http://www.soton....71.shtml

Get your facts up to date.
Slioch
3 / 5 (1) Sep 24, 2008
Velanarris

The http://www.soton....71.shtml

article to which you link is interesting, but it appear to include a major error. The article states, "When coccolithophores make plates of calcium carbonate they also release carbon dioxide."

I cannot see how that can possibly be correct. The overall equation for the production of calcium carbonate is,

Ca (aq) CO3--(aq) goes to Ca CO3--(s)

This clearly consumes carbonate ions ( CO3--(aq) ), which are themselves produce by the reaction of CO2 with water. Thus, calcium carbonate production indubitably consumes CO2.

That aside, the evidence that coccolithophores may be able to respond to increasing CO2 levels by increasing their production of calcite (calcium carbonate) plates is interesting (and hopeful). The reason appears to be that coccolithophores produce calcite internally, where they are able to regulate the pH more effectively than corals, which produce calcite externally. The article thus provides no good news for corals, which will suffer from increased CO2 levels in the ocean.

The reason this is complex is that I surmise that each species of calcite forming organism will have a level of dissolved CO2 at which calcite production is at a maximum. One would expect that most organisms would have evolved such that that maximum is at the CO2 levels to which they have become accustomed in past ages. In this respect coccolithophores appear to be an exception.

The reason a maximum is reached is that two opposing reactions are occurring: The calcite producing reaction:

Ca (aq) CO3--(aq) goes to Ca CO3--(s)

clearly increases (shifts to the right) as CO2 (and hence CO3--(aq) ) concentrations increase.

However, since since increased CO2 levels also increase H (aq) levels (ie. water becomes more acidic), then the calcite dissolving reaction also increases:

Ca CO3--(s) goes to H (aq) Ca (aq) HCO3-(aq)

This sequence of events can easily be observed by bubbling CO2 through limewater (calcium hydroxide solution), and is the classic school chemistry test for CO2. The limewater is alkaline and when CO2 is first bubbled through it, the previously clear liquid becomes "milky" due to the production of solid calcium carbonate. With further passage of CO2, the liquid clears as, with increasing acidity, the calcium carbonate dissolves. This simple experiment is a parable for the future of our oceans, but the above article suggests that some lifeforms may be more resilient than simple limewater.
Slioch
not rated yet Sep 24, 2008
Unfortunately the software is unable to cope with chemical equations and plus signs, so the equations in the above post have been mangled. I hope it is still reasonably clear.
Velanarris
3 / 5 (6) Sep 24, 2008
It's not an error. When the cells are creating the Calcium carbonate they're working, like animals' mitochondria would create CO2 and H2O (and other things) from O2 and whatever sugars it's breaking down to release the energy necessary to create cell growth. The CO2 is produced from the chemical energy expenditure required to create the Calcium Carbonate, not in the reaction creating calcium carbonate itself.
Bazz
2.6 / 5 (5) Sep 24, 2008
velenarris ,if you would have read a bit more carefully you would have understood the relevancy of the article.It does not in the slightest way contradict what i have said.

The article says that a group of singlecelled are not expected to be hurt by increased CO2.

The main conclusions of this work are:

* Ocean acidification remains one of the most important environmental and societal concerns of the 21st century

* Contrary to previous suggestions of decreased calcification under high CO2 levels, which could potentially act as a negative feedback on atmospheric CO2 levels, the observed increase in both calcification (CO2 outgassing) and photosynthesis (CO2 ingassing) suggest that future coccolithophore populations will neither greatly ameliorate nor exacerbate atmospheric CO2 rise.

* These results have important implications in palaeoreconstruction and in forecasting the future marine carbon cycle and climate.

* This work *does not* suggest that the observed increase in calcification will be followed by a positive feedback of CO2 to the atmosphere.

* The present work shows the physiological response of an important component of the food chain but the response of the natural communities remains an open question. There is an urgent need to conduct these studies in the most vulnerable ecosystems to ocean acidification, such as Antarctic waters.

* This work is in agreement with the observed resilience of coccolithophores in the geological record. However other important marine calcifiers, such as corals, remain vulnerable to the increasing CO2 levels. The coccolithophores are unusual among cacifiers in that they calcify inside the cells, and therefore there is a strong biological control compared to corals that calcify externally. Concern about the fate of corals and other calcifiers in high CO2 scenarios still remains.

Its says that this study does not mean corals wont be affected and even points out why.
It has no agument inside for skeptics or doomsayers,its very moderate in its conclusions strengthening already made observations and refining other facts.

It looks like decent research built on previous knowledge.
Slioch
4.3 / 5 (3) Sep 24, 2008
Velanarris

The emission of CO2 during respiration (or its absorption during photosynthesis) obviously both occur, and will influence CO2 level during the coccolith's lifetime, but if, upon death and decay, the calcium carbonate (calcite) falls to the sea bed and accumulates, then that represents a net removal of CO2 (and calcium ions) from the sea water. That is not a matter of debate, it is a simple matter of fact, (if necessary verified by reference to the Law of Conservation of Matter!!). The only uncertainty (that the article does NOT address) is the extent to which the calcite skeleton from the cocolithophores will indeed accumulate. As the CO2 content of the oceans increases, the skeletons become more likely to dissolve rather than accumulate. The statement in the article only make sense if it is assumed that no such accumulation occurs, but no evidence or statement to that effect is made in the article.

My conclusion is that the confusion arises from the journalist who wrote the article, but as I don't have access to the original paper, I am unable to confirm that.

Whilst the evidence that coccolithophores increase their calcite skeleton with increased CO2 is interesting and important, the crucial question, not addressed by the article, for the long term effect of that on the carbon cycle is "will their skeletons accumulate?"
Velanarris
2.6 / 5 (5) Sep 24, 2008
Slioch that's pretty easy to guess.

Answer is yes, where else do you think limestone comes from?
Slioch
4.5 / 5 (4) Sep 24, 2008
Velanarris

Well at least we now agree that the process has the potential to remove CO2 from the sea, and thus the atmosphere...

But the extent to which that will occur is not "easy to guess". There are currently large areas of the ocean floor where no calcium carbonate accumulates - it redissolves as it falls through the water column before reaching the sea floor. The increase in CO2 content of sea water will increase that tendency to dissolve.
Velanarris
3 / 5 (5) Sep 24, 2008
Velanarris

Well at least we now agree that the process has the potential to remove CO2 from the sea, and thus the atmosphere...

But the extent to which that will occur is not "easy to guess". There are currently large areas of the ocean floor where no calcium carbonate accumulates - it redissolves as it falls through the water column before reaching the sea floor. The increase in CO2 content of sea water will increase that tendency to dissolve.


Yes but don't neglect the effects of pressure and temperature on the ability of carbonic acid to dissolve calcium byproducts.

BTW: we never disagreed, that was Bazz.
Bazz
2.3 / 5 (6) Sep 25, 2008
Nice try to spin.

I havent commented on Slioch,only on your dishonest interpretation of the article you linked to that if you had read it doesnt do any good for your arguments.

Better luck next time, tell me some more about the big conspiracy.

Modernmystic
3 / 5 (6) Sep 25, 2008
Nice try to spin.


Indeed since it's painfully obvious here who's doing that.
Bazz
2.6 / 5 (5) Sep 26, 2008
So why are you spinning?
Velanarris
3 / 5 (5) Sep 26, 2008
So why are you spinning?


Gravity.

But seriously, what are you talking about spinning?
Bazz
1 / 5 (2) Sep 26, 2008
i havent disagreed with slioch yet, unlike you suggested.

He didnt say anything conclusive i believe.
CWFlink
4.3 / 5 (4) Sep 27, 2008
Now add to all the debate above the mix of organisms in the ocean. The flora and fauna thriving in the oceans today include creatures that would prefer warmer oceans, and cooler oceans, creatures that would prefer more acidic oceans and creatures that would prefer less acidic oceans, etc. I bet any studies done to date have been done by looking at the impact upon species that are dominant "now" and not the full mix of creatures competing for the top spot.

In our myopic view of what is "right", we have a tendency to wax romantically about those who fell from positions of dominance: dynasours, mamouths, and buffalo. A true study of nature teaches that change is essential, basic and fundimental to life.

Thank goodness we don't worship the "dominant" politician election after election.... or we would not need elections!

Note: I'm not saying that creatures evolve quickly enough to address the variability we've observed over the last 20,000 years, but that there are very likely members of all so-called threatened populations that are already adapted, and in fact NOT dominant because the environment does not favor THEM. THEY are no less worthy of life in our oceans than the specific organisms currently most dominant. To properly model the impact of climate change on the order of hundreds of years, the impact on the over-all population of creatures need to be considered, not just that change may mean one species may be impacted negatively. Also consider what species may be impacted positively.
Velanarris
4 / 5 (4) Sep 27, 2008
CWF, that is spot on. After all, we're the most dominant species on the planet and technically, we'd stand to benefit rather greatly by a small increase in teperature.
GrayMouser
5 / 5 (2) Sep 27, 2008
But the extent to which that will occur is not "easy to guess".


Why should they have to guess? They've got their computer model. It should already cover this.
Bazz
1 / 5 (4) Sep 28, 2008
These personal theories are very amusing indeed.Imagination is a great thing to have.