Climate Change Seeps into the Sea

Oct 24, 2008
MODIS image showing a plankton bloom off Norway.

(PhysOrg.com) -- Good news has turned out to be bad. The ocean has helped slow global warming by absorbing much of the excess heat and heat-trapping carbon dioxide that has been going into the atmosphere since the start of the Industrial Revolution.

All that extra carbon dioxide, however, has been a bitter pill for the ocean to swallow. It's changing the chemistry of seawater, making it more acidic and otherwise inhospitable, threatening many important marine organisms.

Scientists call ocean acidification "the other carbon dioxide problem." They warn that because it causes such fundamental changes in the ocean, it could impact millions of people who depend on the ocean for food and resources. "The growing amount of carbon dioxide in the ocean could have a bigger effect on life on Earth than carbon dioxide in the atmosphere," says JPL's Charles Miller, deputy principal investigator for NASA's new Orbiting Carbon Observatory, scheduled to launch next January.

The ocean takes in and stores most of the heat from the sun that is deposited at Earth's surface -- heat that would otherwise be melting land ice and warming the atmosphere. The ocean also absorbs about one third of the carbon dioxide that humans now put into the air. The rest is taken up by terrestrial vegetation and soils or remains in the atmosphere, increasing the greenhouse effect.

"The ocean surface acts like a sponge to soak up excess carbon dioxide from the atmosphere," says Scott Doney, a senior scientist in marine chemistry at the Woods Hole Oceanographic Institution in Woods Hole, Mass. Much of the extra dissolved carbon is in the ocean’s upper few thousand feet. However, at high latitudes, surface water quickly cools, becomes saltier and denser and sinks, carrying the dissolved carbon to some of the deepest parts of the ocean.

Mix carbon dioxide with water and the result is carbonic acid. After that first simple chemical reaction comes a slightly more complicated series of changes in seawater chemistry. The final outcome is a lowering of the ocean's pH -- meaning the ocean is more acidic, and, ironically, a reduction in a particular form of carbon -- carbonate ion -- that many marine organisms need to make shells and skeletal material. The lower pH and lack of carbonate ion have serious consequences for life in the ocean.

Carbon, Carbon Everywhere, but Not the Right Kind to Use

Closest to the atmospheric source of excess carbon dioxide, the ocean’s surface waters are the first to show the effects of acidification. Since the beginning of the industrial era, the pH of surface waters has decreased slightly but significantly from 8.2 to 8.1, and it continues to decrease. Scientists project the pH of surface water will decrease by the year 2100 to a level not seen on Earth over the past 20 million years, if not longer.

Likely casualties of ocean acidification are the marine plants and animals that use carbonate to form hard shells or other structures. These include mollusks like clams and oysters, and reef-building corals. Not only does ocean acidification limit their access to the carbonate they need for building material, it could become severe enough to dissolve existing coral structures and the shells of living organisms.

Since most corals live in shallow waters, coral reefs, some of the most biologically diverse places on Earth, are particularly vulnerable. “They are already under assault from warming water, over-fishing and habitat degradation,” says Doney. “Environmental stress is leading to more incidents of ‘coral bleaching,’ which occurs when the symbiotic algae that lives inside the coral leaves or dies, and from which reefs often do not recover. Ocean acidification may push corals over the edge.”

Other sensitive areas are the Southern Ocean and the subpolar North Pacific, where acidification threatens to unravel important food chains by making life difficult for a small marine snail called a pteropod. It’s a favorite food of small fishes, which, in turn, support larger fishes, penguins, whales and seabirds. Ocean acidification strips seawater of the carbonate ion that pteropods need to build new shells, and it also damages their existing ones.

There will be some winners and losers, says Doney, as the effects of growing ocean acidification are felt. “Although we don’t know exactly how many species depend on pteropods, clams, oysters, mussels or other shelled organisms for food, or on coral reefs for critical habitat, it’s clear that ocean acidification will cause a wholesale alteration of some marine ecosystems in ways we can’t predict,” he explains.

History isn’t much of a guide. While there have been times in Earth’s past when the ocean was more acidic than now, most environmental changes occurred at a considerably slower pace than today. “At the rates of climate change and ocean acidification we’re seeing now, many organisms may be not able to keep up,” Doney says.

That Sinking Feeling

Much of the carbon now in the air will find its way into the ocean with predictable results. "Even if we stopped adding carbon dioxide to the atmosphere today, ocean acidification will continue to increase,” says Doney. “What marine fisheries and coral reefs will look like 100 years from now is a big question. We need to know how much carbon dioxide is being taken up, more about the gas exchange between the ocean and the atmosphere, and how this mechanism is affected by climate change.”

NASA’s new Orbiting Carbon Observatory will help provide some of the answers after it is launched in January 2009. A NASA Earth System Science Pathfinder mission, it will make precise measurements of atmospheric carbon dioxide on a global scale.

The Orbiting Carbon Observatory will help identify carbon dioxide sources and sinks -- things that absorb and store carbon -- on land and in the ocean and show how they vary over time. Researchers will be able to combine mission data with numerical models to estimate global patterns of the exchange of carbon dioxide from the ocean and atmosphere.

“We’ll have a much better idea about what’s going on over the ocean where measurements have been sparse,” explains Miller. “This is especially true in the Southern Ocean, which we believe is a big sink for carbon dioxide based on existing models.”

While the Orbiting Carbon Observatory may be the newest NASA mission to help address the issue of ocean acidification, NASA has many other projects and missions that provide important information about ocean biology and chemistry that relates directly to this problem. These include NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS), flying on the Terra and Aqua satellites, and the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS). These instruments collect data on ocean color -- a key component of many studies of ocean ecology, plankton and coral reefs. Another example is the recent National Oceanic and Atmospheric Administration and NASA-sponsored Southern Gas Exchange Experiment. During this six-week research cruise, scientists investigated how gases, including carbon dioxide, move between the ocean and the atmosphere in high winds and rough seas.

The really big question is how much longer the ocean can continue to be a sink for atmospheric carbon dioxide before becoming saturated -- a process that may already be under way. The implications for our future climate -- and the ocean -- are immense.

More information about NASA missions that contribute to studies of ocean acidification is available at:

oco.jpl.nasa.gov/
modis.gsfc.nasa.gov/about/
oceancolor.gsfc.nasa.gov/SeaWiFS/
so-gasex.org/media.html

Written by Rosemary Sullivant/Global Climate Change
Provided by NASA

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User comments : 22

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Velanarris
3 / 5 (20) Oct 24, 2008
Seeing as the ocean chemistry has moved from 8.25 in 1751 to 8.14 in 2004, 250 years for an incredibly miniscule change is not that worrisome. Especially seeing as CaCO3 construction, as found in Corals and coccolithophorids, is accelerated by higher CO2 concentration in seawater.

Reference: J. Geophys. Res. Atm., 110, D07302, April 2, 2005.
SteveS
3.4 / 5 (13) Oct 24, 2008
Shouldn't it be read as "less base" or "more neutral" rather than more acidic? After all it has a long way to go before it reaches a neutral PH of 7 only after that can it be said to become more acidic
ryuuguu
3.3 / 5 (15) Oct 25, 2008
Seeing as the ocean chemistry has moved from 8.25 in 1751 to 8.14 in 2004, 250 years for an incredibly miniscule change is not that worrisome. Especially seeing as CaCO3 construction, as found in Corals and coccolithophorids, is accelerated by higher CO2 concentration in seawater.

Reference: J. Geophys. Res. Atm., 110, D07302, April 2, 2005.


A rather misleading quote.
1) PH l is log scale not linear scale. so the difference between 8 and 9 is a factor of 10.
2)Although this change has occured over 250 years, most of the CO2 has been pumped in to the atmosphere in the last 50 years. So the actual current rate of change is much higher than this quote makes this appear.
Soylent
3.2 / 5 (11) Oct 25, 2008
Shouldn't it be read as "less base" or "more neutral" rather than more acidic? After all it has a long way to go before it reaches a neutral PH of 7 only after that can it be said to become more acidic

Going from pH 14 to pH 13 you increase the number of hydrogen ions by a factor of 10; going from pH 0 to pH -1 you increase the number of hydrogen ions by a factor of 10. The only difference is the concentration of hydrogen ions where you start.

There's nothing magical that happens at a pH of 7 that disallows calling it more acidic.
SteveS
3.3 / 5 (12) Oct 25, 2008
My understanding of PH (limited) is that PH 7 is where the concentration of H ions equals that of OH- ions, over 7 is a base under 7 is acid.

My concern is that the use of the word acidic is emotive and potentially misleading. Without any understanding of PH it would be easy for somebody reading this article to come away with the impression that the ocean is an acid. To describe something as becoming more acidic implies that it is already an acid.

I do not dispute that any change in ocean chemistry will have an unpredictable effect on both marine life and the oceans ability to absorb heat and CO2, but I do feel that the use of the word acidification is alarmist and emotive.
Ninderthana
3 / 5 (14) Oct 25, 2008
The nitwits that post this article do not know anything about buffer reactions. While it is true
the increased CO2 disolved in the oceans can lead to a lower of the pH they are not taking into account that the oceans are constantly reacting with the rocks and depositions on the ocean floor. These interactions buffer the overall pH of the ocean and so they greatly decrease the acidification.

As ususal they do not want to let real science to get in the way of a simplistic and false word-bite that can be used to scare people.
gmurphy
2.6 / 5 (13) Oct 25, 2008
Ninderthana, your assertion that CO2 will be easily absorbed by the ocean floor is in discord with the observed decrease in PH in the oceans stated in the article. As ryuuguu correctly points out, this will only accelerate in the coming years. I commend Velanarris for providing published scientific work to back up his statement but I disagree with his assertion that it is not worrisome. The one thing we know for certain about the climate is that it is a chaotic system, extremely sensitive to slight changes.Hopefully, it won't have any long term effect but we shouldn't be testing the resilience of our planet to these insults (pollution).
Velanarris
3 / 5 (12) Oct 25, 2008
Ninderthana, your assertion that CO2 will be easily absorbed by the ocean floor is in discord with the observed decrease in PH in the oceans stated in the article. As ryuuguu correctly points out, this will only accelerate in the coming years. I commend Velanarris for providing published scientific work to back up his statement but I disagree with his assertion that it is not worrisome. The one thing we know for certain about the climate is that it is a chaotic system, extremely sensitive to slight changes.Hopefully, it won't have any long term effect but we shouldn't be testing the resilience of our planet to these insults (pollution).
I still have not seen any evidence that our climate system is extremely sensitive to slight changes.

To me it appears to maintain equilibriums rather well.

As for Ninderthana's comment, he's on the money, the cycle does take a rather long time to go full circle though, I thinmk it' currently estimated out to be hundreds of years to reestablish equilibrium. The main factor at play here is heat and pressure over depth as well as composition of the rock.

Velanarris
3.2 / 5 (11) Oct 25, 2008

A rather misleading quote.
1) PH l is log scale not linear scale. so the difference between 8 and 9 is a factor of 10.
2)Although this change has occured over 250 years, most of the CO2 has been pumped in to the atmosphere in the last 50 years. So the actual current rate of change is much higher than this quote makes this appear.


Yes, PH is logarithmic, however the majority of the worlds organisms did not evolve to live in a specifically alkaline environment. You're also ignoring the ability of the worlds oceans to buffer CO2. The ocean acidity could be due to something completely unrelated or it could be a completely natural mechanism. After all there have been reported periods of algal blooms off and on for a long, long time. For all we know this is a completely cyclical change.
Pkatt
3.9 / 5 (7) Oct 25, 2008
Im guessing you ought to contact some of the folks with CO2 ocean sequestration plans. Given your own words: "The one thing we know for certain about the climate is that it is a chaotic system, extremely sensitive to slight changes." The last thing we need is for a bunch of ninnys to start dumping iron filings into the ocean or shooting dry ice bombs to the ocean floor. Oh wait .. theyre already doing that. In our short time here on Earth, man has already exhibited the talent for screwing something up worse by trying to fix it when they dont know all of the variables. Here we go again.
tkjtkj
2.5 / 5 (10) Oct 25, 2008
Dear Ninderthana, i'll ignore the
name-calling and speak to the
issue: Your comment is incorrect.
"The nitwits that post this article do not know anything about buffer reactions. While it is true
the increased CO2 disolved in the oceans can lead to a lower of the pH they are not taking into account that the oceans are constantly reacting with the rocks and depositions on the ocean floor. These interactions buffer the overall pH of the ocean and so they greatly decrease the acidification."

The measured pH's represent values
that exist in the naturally
buffered ocean systems. Were
there no buffering, yes, changes
would be more rapid. But there
IS buffering, as you state. The
pH's are real, their trends are
real, the rates of changes are
real, as will be the
consequences for all earth life-
forms.
You err in your apparent view
that the authors' are speaking
of unbuffered systems. They
are not. In fact, the pH trends
suggest that at some time in
the future, the ability of the
seas to buffer hydronium ion
increases will break down,
tipping the rates to be even
more accellerated in the future.

Velanarris
3.7 / 5 (9) Oct 25, 2008
The
pH's are real, their trends are
real, the rates of changes are
real, as will be the
consequences for all earth life-
forms.
You err in your apparent view
that the authors' are speaking
of unbuffered systems. They
are not. In fact, the pH trends
suggest that at some time in
the future, the ability of the
seas to buffer hydronium ion
increases will break down,
tipping the rates to be even
more accellerated in the future.



Pray tell what is that rate of change?
Trippy
3.8 / 5 (5) Oct 25, 2008
While it's true that the Ocean has the ability to buffer the Carbon dioxide levels, think about if for a moment.

The Carbon Dioxide is being absorbed at the surface of the ocean, but the carbonate deposits that are available for buffering are (largely) on the ocean floor, so it's going to take some time for the Ocean to move back to a new equilibrium point.

As for the use of the word 'Acidic' it's a completely accurate descriptor, and it is used appropiately.

Although still Basic, a pH of 8 is more acidic then a pH of 9, it really is that simple.

As has already been pointed out, there's nothing magical that happens at pH 7 that one base can't be described as being more acidic then another one.
Ashibayai
1 / 5 (3) Oct 25, 2008
". Much of the extra dissolved carbon is in the ocean%u2019s upper few thousand feet."

So this supports the idea that, if this starts to become an increasing issue, we could take measures to remove this dissolved carbon from the oceans most easily at the equator?
Solar powered carbon filtering barges anyone?

It's not an ideal solution, but I was thinking if the ocean absorbs so much of the carbon, could it be useful to filter the ocean rather than the air? Granted it's not a replacement for stopping it at the source, but if the carbon collection of the oceans and the atmosphere are mutually dependent then it would be best to go to the source of highest concentration. (Accounting for economic viability of course.)
RAL
3.3 / 5 (12) Oct 26, 2008
Looks like the climate thing isn't working out too well so they had to come up with a new boogeyman. Any excuse to raise taxes and turn the world economy over to the UN.

The first pH meter was developed in 1934, although the glass pH electrode dates back to 1906.
http://www.ph-met...-history

I wonder what the accuracy and representation of the samples were that determined the pH "of surface waters" in the 1700s. For example, the pH of ocean water today varies /- 0.3 (http://royalsocie...id=13314 page 6). This would indicate that the "signal" increase of 0.1 is exceeded by the "noise" of natural variation by 600%. How certain then, is the number from the 1700s? How was it measured and where? How many samples were involved?

I don't know the answer, but it seems reasonable to remain skeptical before plunging into another boondoggle like Gore style AGW. The answer is more research, a lot more research, and then more on top of that before anything approaching a panic button need be pushed.
Velanarris
3.4 / 5 (10) Oct 26, 2008
Looks like the climate thing isn't working out too well so they had to come up with a new boogeyman. Any excuse to raise taxes and turn the world economy over to the UN.

The first pH meter was developed in 1934, although the glass pH electrode dates back to 1906.
http://www.ph-met...-history

I wonder what the accuracy and representation of the samples were that determined the pH "of surface waters" in the 1700s. For example, the pH of ocean water today varies /- 0.3 (http://royalsocie...id=13314 page 6). This would indicate that the "signal" increase of 0.1 is exceeded by the "noise" of natural variation by 600%. How certain then, is the number from the 1700s? How was it measured and where? How many samples were involved?

I don't know the answer, but it seems reasonable to remain skeptical before plunging into another boondoggle like Gore style AGW. The answer is more research, a lot more research, and then more on top of that before anything approaching a panic button need be pushed.


Agreed RAL. Very much agreed.
GrayMouser
3.3 / 5 (7) Oct 26, 2008
The one thing we know for certain about the climate is that it is a chaotic system, extremely sensitive to slight changes.


Your missing the corollary, chaotic systems are also extremely insensitive to large changes. You have to know the initial state and the precise change introduced to even start predicting the results.

Since humans are incapable of knowing the initial state of the climate to that degree we make models that approximate what we think is happening. Garbage-In=Gospel-Out.
jeffsaunders
3.4 / 5 (5) Oct 26, 2008
I do not dispute this article but it does not seem to be any different from one reporting the same thing, that I read about a year ago.

Wait maybe the last paragraph is new. It is good to remind people from time to time that higher CO2 in the atmosphere will result in higher CO2 in the ocean.

It seems to me that some eminent people that tell us they are experts yet they do not know this? Do we believe them about being experts or do we believe them when they tells us they don't know about the Oceans CO2 increase?

What to believe and when seems to be a problem and maybe we should not accept anything we are told about the problem or the solution except the numbers themselves.

Except that we had mention of CO2 levels in the ocean from the 1700's and it has been pointed out that there is quite a bit of variability in dissolved CO2 so how much can we believe about that?
goldengod
2.3 / 5 (9) Oct 26, 2008
So, where in extracting millions of years of pollution and pumping it into the atmosphere in the space of a couple of hundred years do you see a disconnection with global warming?

If you burned a bag of coal in ten seconds things the room would get very hot. On a global scale we are not doing any different.

Clean energy is our childrens only hope. Anyone who is not seriously trying to do their part is condemning the health of future generations.

Roach
5 / 5 (7) Oct 27, 2008
I'm going to start extemely against my own idiom and lash at the people talking about the buffering capacity of the oceans first. Buffering capacity changes take place prior to pH changes, sounds strange I know, but go talk to a wastewater treatment plant operator about anaerobic digesters, you can have a complete volitile acid to alkalinity upset before oyu ever see a change in pH.

Ok, that's out, now onto the panic people, if you truely want a stagnant system that makes no changes in Temperature, pH, CO2 concentrations, ice structures, seasons, weather, etc, then the solution is simple if we could just block out all extra terestrial energy sources and drop the temperature to about -273.15C. Then we can stop worring about changes.

That being said a rise in acids takes place much faster than the neutralizing biological activity, this is in part due to the hearty nature of acid consuming microbes which wouldn't stop just because they reached equilibrium, if the gas formers ran of on themselves, they could quickly turn the oceans basic. I promise this stuff isn't new, I'm sure some of you even have home scale vesions with septic tanks or compost heaps.

Now I'll harp on accuracy of results, yes pH is logarithmic and small numerical changes represent a larger real world change, that being said do any of you know someone who can tell the pH of a Coke off hand, or tell the difference between the pH of household bleach versus shampoo just by touch, or heck, lets make it easy, a 5.3 versus a 5.4 on the Richter scale? Guess what before the industrial revolution they did not have post industrial revolution measureing instruments.

Lastly, though it pains me do do so I'll go ahead and cite a Wiki page, http://en.wikiped...wiki/PH, at least it's well referanced, not the line,

"In practical terms, the three seawater pH scales differ in their values by up to 0.12 pH units, differences that are much larger than the accuracy of pH measurements typically required, particularly in relation to the ocean's carbonate system.[10]"

Granted the referance may not apply to modern equipment(last 7 years), but I'm sure a book from 2001 would include data from any magical instrument from the 1900s that could measure pH down to miniscule changes.

Again, I'm all for clean energy, and between Smog and acid rain, you don't need to convince me, but quit trying to make up problems that don't exist, instead how about making an electric car that doesn't create more harmful emmisions in manufacturing the battery than my car ever could, or a hybrid that doesn't cost $40K and doesn't look like a Pinto on pot?

If I am wrong and the oceans are infact becoming acidic, this could be good for boats by reducing the ion exchange on metal parts though:)
Trippy
4.3 / 5 (3) Oct 29, 2008
I'm going to start extemely against my own idiom and lash at the people talking about the buffering capacity of the oceans first. Buffering capacity changes take place prior to pH changes, sounds strange I know, but go talk to a wastewater treatment plant operator about anaerobic digesters, you can have a complete volitile acid to alkalinity upset before oyu ever see a change in pH.


For the most part I agree with this statement, however there's two points that I want to make about it.

1. This might be true for a well mixed system, but in this respect the Oceans are not well mixed* - hence the point I made about the Carbonates being on the Ocean floor, and the carbon dioxide being absorbed at its surface.

2. Most Buffer solutions allow a small change in pH in response to the addition of a disproportinately large amount of acid - the amount of acid required to make a change of say 0.1 pH units to a buffered solution might make a change of pH of 1 or 2 pH units to a non-buffered solution.

*Yes, in general the oceans are well mixed, but the mixing takes place on a scale of hundreds of years - thousands of years, it's a question of perspective. If the Oceans were well mixed in the way that a lab sample is, or an anerobic digestor is, we wouldn't have problems with Eutrophication of the sea floor.
GrayMouser
5 / 5 (4) Oct 31, 2008
What I don't understand is the statement "The ocean takes in and stores most of the heat from the sun that is deposited at Earth's surface".

The oceans are getting colder by absorbing heat? How?

Another point is that a warmer ocean will absorb less CO2 (or any other gas for that matter.)

Buffering capacity changes take place prior to pH changes

This isn't true, buffering says that you add so much H to a solution and the measured response is less than the same amount added to pure water. The various ionic species exist in a dynamic equilibrium.

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