Ocean Acidification

[sinimod]

Discussion has been dominated by the grim prospects of global warming. However, there is another topic that is vitally important to the health of this planet, ocean acidification. The importance of this topic cannot be over estimated, and we should be frequently reminded of just what the possible future effects could be.

Due to the rapid increase in the concentration of atmospheric carbon dioxide from the use of fossil fuels, the oceans are rapidly becoming more acidic. Keeping in mind that, in addition to climate change and its many profoundly deleterious effects on the global ecology, the world’s oceans are experiencing dramatic changes in pH levels at rates possibly not experienced since early in the history of the planet when volcanism was far more prevalent. Ocean acidity is increasing at a rate more than 100 times faster than the natural variation experienced over the last two to three billion years, due to a concomitant and proportional increase in the concentration of atmospheric CO2, inadvertently released at the hands of humanity. If, as IPCC emission scenarios and general circulation models suggest, the atmospheric concentration of CO2 reaches 800 ppmv by the end of the 21st century, surface water dissolved inorganic carbon could increase by more than 12% and the carbonate ion concentration could decrease by almost 60%, with a corresponding decrease in pH of 0.4 pH units in surface water (Feely et al., 2004).

Most shallow marine organisms construct their shells with high-magnesium calcite or aragonite, both metastable minerals at earth surface temperature and pressure. If oceanic pH levels reach the predicted values, it could surpass the stability fields for even the biogenically induced precipitation of these minerals, even in tropical oceanic latitudes, where warmer water favors supersaturation with respect to these minerals. This means that biological calcification of the shells of most marine organisms, many of which have already had their physiology deteriorate due to increased shallow ocean water temperatures, might not be chemically possible. As marine ecosystems are extremely sensitive to temperature and pH changes, the prospect of continual deterioration and possible destruction of shell-constructing marine organisms could mean the break down of the entire ocean ecosystem. I don’t think I have to spell out to anyone how utterly disastrous that would be.

[gazelle]

Australia's Great Barrier Reef (GBR) is a great example. The experts see a triple threat: pollution, warming, and acidification. We can also add the usual risk from predators (such as the Crown of Thorns). All together, this means that the GBR will progressively die over the next decade or so, and, being at the start of the food chain, the micro-ecosystem will likely collapse.

I'm worried that if enough of the micro systems collapse, so does the macro system. If enough of the macro systems collapse, so does the global system.

For further reading:
http://www.abc.net.au/rn/ockhamsrazo...08/2207734.htm
http://www.abc.net.au/rn/scienceshow...08/2210916.htm
http://www.abc.net.au/rn/scienceshow...09/2503477.htm


If you want to see one of the world's natural wonders, you'd better book now!

[776281]

http://www.guardian.co.uk/environmen...ans-copenhagen

Carbon emissions creating acidic oceans not seen since dinosaurs

Human pollution is turning the seas into acid so quickly that the coming decades will recreate conditions not seen on Earth since the time of the dinosaurs, scientists will warn today.

The rapid acidification is caused by the massive amounts of carbon dioxide belched from chimneys and exhausts that dissolve in the ocean. The chemical change is placing "unprecedented" pressure on marine life such as shellfish and lobsters and could cause widespread extinctions, the experts say.

Other experts will report that acidification is already affecting marine life in the Arctic and Antarctic. They will also discuss a bizarre finding that acid waters carry sound more efficiently, so the ocean will be a much noisier place in future.

http://www.sciencedaily.com/releases...1124141053.htm

ScienceDaily (Nov. 26, 2008) — University of Chicago scientists have documented that the ocean is growing more acidic faster than previously thought. In addition, they have found that the increasing acidity correlates with increasing levels of atmospheric carbon dioxide, according to a paper published online by the Proceedings of the National Academy of Sciences on Nov. 24.

As usual bad, worse, sooner than expected. Science Daily has heaps of info

[gaiasdaughter]

Coral Reefs May Start Dissolving When Atmospheric Carbon Dioxide Doubles

Rising carbon dioxide in the atmosphere and the resulting effects on ocean water are making it increasingly difficult for coral reefs to grow, say scientists. A study to be published online March 13, 2009 in Geophysical Research Letters by researchers at the Carnegie Institution and the Hebrew University of Jerusalem warns that if carbon dioxide reaches double pre-industrial levels, coral reefs can be expected to not just stop growing, but also to begin dissolving all over the world.

The impact on reefs is a consequence of both ocean acidification caused by the absorption of carbon dioxide into seawater and rising water temperatures. Previous studies have shown that rising carbon dioxide will slow coral growth, but this is the first study to show that coral reefs can be expected to start dissolving just about everywhere in just a few decades, unless carbon dioxide emissions are cut deeply and soon.
----------
"Our fossil-fueled lifestyle is killing off coral reefs," says Caldeira. "If we don't change our ways soon, in the next few decades we will destroy what took millions of years to create."

"Coral reefs may be the canary in the coal mine," he adds. "Other major pieces of our planet may be similarly threatened because we are using the atmosphere and oceans as dumps for our CO2 pollution. We can save the reefs if we decide to treat our planet with the care it deserves. We need to power our economy with technologies that do not dump carbon dioxide into the atmosphere or oceans."

[sinimod]

The calcium carbonates from which organisms construct their shells, are precipitated not from the marine ambient waters, but from the body fluids of the organisms. If the physiology of the organisms is weakened, this affects their ability to continually precipitate calcium carbonate. Therefore, with their physiology already debilitated from increased sea surface temperatures, these organisms have a reduced ability to withstand the increasing acidity of ambient waters (However, this is not the case for coccolithophores). This increased sea surface temperature and decreased pH comes in addition to the huge amounts of pollution in various forms that assault marine organisms on a daily basis, which further reduces their health. All of this does not paint a pretty picture.

[sinimod]

Ocean acidification cuts shell weight

By Anne-Marin Nisumaa

Ocean acidification has reduced the average shell weight of a species of foraminifera single-celled, calcite-secreting plankton in the Southern Ocean by one-third compared to pre-industrial specimens, say scientists in Australia. Their study provides the first evidence of the phenomenon from the field.

Find the article at http://oceanacidification.wordpress....-shell-weight/http://oceanacidification.wordpress....-shell-weight/

[Cliff_Sedge]

Anyone want to double-check my chemistry assumptions?

If ocean acidification is combined with oceanic loss of salinity from melting ice, then the oceans will lose the buffering effect of salts and will become even more acidic..

However, warmer ocean temperatures would yield more release of CO2 from the oceans into the atmosphere and part of the oceans' acidity is from carbonic acid (CO2 dissolved in water).

I've been out of college for several years, but I'm remembering some of this stuff and wondering if it is valid and pertinent to this discussion.

[sinimod]

Originally Posted by Cliff_Sedge

Anyone want to double-check my chemistry assumptions?

If ocean acidification is combined with oceanic loss of salinity from melting ice, then the oceans will lose the buffering effect of salts and will become even more acidic..

However, warmer ocean temperatures would yield more release of CO2 from the oceans into the atmosphere and part of the oceans' acidity is from carbonic acid (CO2 dissolved in water).

I've been out of college for several years, but I'm remembering some of this stuff and wondering if it is valid and pertinent to this discussion.

I am no chemical oceanographer, but I do know that there is an inverse relationship between the temperature of the solvent and the concentration of gas it can dissolve: the higher the temperature of the solvent, the less gas it can dissolve. However, in opposition to that, according to Henry's Law, the higher the partial pressure of the ambient gas, the greater the concentration of that gas that will dissolve in the solvent. And according to Le Chatelier's Principle, a key feature of a system in equilibrium is that when the concentration of one reactant changes, the reaction shifts in the direction needed in order to restore the system to an equilibrium. So in the equation carbon dioxide + water + carbonate yields (reversibly) bicarbonate, if more carbon dioxide is forced into the system, it responds by extracting more ambient carbonate and producing more bicarbonate in order to restore equilibrium. This results in increased production of bicarbonate and hydrogen ions, causing the saturation state of calcium carbonate to decrease. I will caveat this by saying there are several chemical processes occurring continuously which can modify this fundamental equation.

With the rising concentration of CO2 in the atmosphere, the partial pressure of CO2 in the atmosphere increases. Apparently, the partial pressure of CO2 has been increasing at a fast enough rate to cause the concentration of dissolved CO2 in the oceans to continue to rise, despite the increase in sea surface temperatures. Obviously, if there were no anthropogenic forcing of the equation caused by an abnormal rise in the atmospheric concentration of CO2 from the burning of fossil fuels, this situation wouldn't occur. That is, if sea surface temperatures rose under natural conditions, oceanic concentration of CO2 would decrease as ocean temperatures rose, and CO2 would be expelled into the atmosphere causing a rise in atmospheric temperatures. That's the way things happened during transitions from glacial epochs to interglacials. And more CO2 was absorbed in the oceans when interglacials transitioned back to glacial epochs. In this way, CO2 acted as a natural amplifier of climate change caused by Milankovitch Cycles and/or shifts in the thermohaline circulation.

As far as CO2 dissolving in sea water versus fresh water, it dissolves more easily in seawater compared to fresh water because seawater naturally contains more carbonate ions.

[Nick Palmer]

Originally Posted by sinimod

If the physiology of the organisms is weakened, this affects their ability to continually precipitate calcium carbonate. Therefore, with their physiology already debilitated from increased sea surface temperatures, these organisms have a reduced ability to withstand the increasing acidity of ambient waters (However, this is not the case for coccolithophores).

Sinimod - does this mean that coccolithophores are less affected by rising acid levels? It is their "bodies" that sequester a lot of chalk/limestone...

[sinimod]

Originally Posted by Nick Palmer

Sinimod - does this mean that coccolithophores are less affected by rising acid levels? It is their "bodies" that sequester a lot of chalk/limestone...

Nick, the first difference between coccolithophores and other calcifiers is that they are floral organisms: phytoplankton, Protists. Corals, mollusks, bryozoa, echinoderma, and other calcifying organisms are faunal. Therefore, coccolithophores are more likely to process greater amounts of CO2 than faunal organisms.

Coccolithophores thrived during the Cretaceous Period during which the oceans were much warmer than today. The concentration of atmospheric CO2 was also much higher during the Cretaceous, probably engendering somewhat lower pH oceans. Modern coccolithophores are not significantly different than Cretaceous coccolithophores. Since they do not appear to have evolved much, perhaps they have a greater tolerance to increased ocean warmth and acidification. Work by Debora Iglesias-Rodriguez, a biological oceanographer at the National Oceanographic Centre in Southampton, UK has shown that modern coccolithophores can thrive at CO2 partial pressures equivalent to atmospheric concentrations of 750 ppm.

Another difference of note is that the plates they produce, called coccoliths, are composed of nearly stoichiometric calcite. That is, the composition is nearly identical to CaCO3 formula with magnesium "impurities" in the hundreds of parts per million. Calcite is more chemically stable than aragonite or high magnesium calcite. The greater the magnesium content, the lower the saturation state of the calcite.

Chalk is made up of the coccoliths, or platlets surrounding the coccolithophore, that disaggregate upon the death of the organism. Evidence that coccolithophores thrived during the Cretaceous can be seen in the Cretaceous aged "white cliffs of Dover." Coccolith plates are typically the largest component of chalk.

[sinimod]

Scientists have warned that ocean acidification could lead to widespread extinctions of marine animals.

Ocean acidification was high on the agenda of the Climate Change Congress in Copenhagen in March, where scientists predicted that the rate of future ocean acidification would be unprecedented in the last 65 million years.

from

http://www.divemagazine.co.uk/news/article.asp?uan=5139

Dive Magazine

[sinimod]

Originally Posted by sinimod

Nick, the first difference between coccolithophores and other calcifiers is that they are floral organisms: phytoplankton, Protists. Corals, mollusks, bryozoa, echinoderma, and other calcifying organisms are faunal. Therefore, coccolithophores are more likely to process greater amounts of CO2 than faunal organisms.

Coccolithophores thrived during the Cretaceous Period during which the oceans were much warmer than today. The concentration of atmospheric CO2 was also much higher during the Cretaceous, probably engendering somewhat lower pH oceans. Modern coccolithophores are not significantly different than Cretaceous coccolithophores. Since they do not appear to have evolved much, perhaps they have a greater tolerance to increased ocean warmth and acidification. Work by Debora Iglesias-Rodriguez, a biological oceanographer at the National Oceanographic Centre in Southampton, UK has shown that modern coccolithophores can thrive at CO2 partial pressures equivalent to atmospheric concentrations of 750 ppm.

Another difference of note is that the plates they produce, called coccoliths, are composed of nearly stoichiometric calcite. That is, the composition is nearly identical to CaCO3 formula with magnesium "impurities" in the hundreds of parts per million. Calcite is more chemically stable than aragonite or high magnesium calcite. The greater the magnesium content, the lower the saturation state of the calcite.

Chalk is made up of the coccoliths, or platlets surrounding the coccolithophore, that disaggregate upon the death of the organism. Evidence that coccolithophores thrived during the Cretaceous can be seen in the Cretaceous aged "white cliffs of Dover." Coccolith plates are typically the largest component of chalk.

Work by Hassenkam et al., 2011, Tracking single coccolith dissolution with picogram resolution and implications for CO2 sequestration and ocean acidification, challenges some assertions I made earlier about coccoliths. This from Science Digest:

"We know that the world's oceans are acidifying due to our emissions of CO2 and that is why it is interesting for us to find out how the coccoliths are reacting to it. We have studied algae from both fossils and living coccoliths, and it appears that both are protected from dissolution by a very thin layer of organic material that the algae formed, even though the seawater is extremely unsaturated relative to calcite. The protection of the organic material is lost when the pH is lowered slightly. In fact, it turns out that the shell falls completely apart when we do experiments in water with a pH value that many researchers believe will be the found in the world oceans in the year 2100 due to the CO2 levels," explains Tue Hassenkam, who is part of the NanoGeoScience research group at the Department of Chemistry, University of Copenhagen.

Using an Atomic Force Microscope (AFM), Hassenkam was able to weigh coccoliths before and after immersing them in water of differing acidities, thus measuring how much and how long these solutions took to dissolve coccolith shells. It's hard to argue against direct observation.

[sinimod]

The Monaco Declaration:

http://scrippsnews.ucsd.edu/Releases...eclaration.pdf

[Cliff_Sedge]

Thanks, Sinimod, that sounds about right.
Ha, I think I'm actually motivated to pull out my old university text books on aquatic chemistry now!

[sinimod]

The Federal Ocean Acidification Research and Monitoring (FOARAM) Act passed in the House of Representatives and Senate respectively on 3rd and 19th March 2009.


The Act authorizes appropriations for ocean acidification research for fiscal years 2009, 2010, 2011, and 2012, at $14 million, $20 million, and $27 million, and $35 million per year, respectively (this is broken down for NOAA and NSF below). Note that these funds are authorized but not yet appropriated.

More information: http://www.govtrack.us/congress/bill.xpd?bill=h111-146

[sinimod]

With creative kids like the ones who made this video growing to adulthood and to positions of responsibility, there is yet hope for humanity and the world:

http://oceanacidification.wordpress....problem-movie/

[sinimod]

Bryozoans are highly sensitive to ocean acidification and could be the canaries of shallow carbonate shelf environments in the temperate southern ocean:

http://www.publish.csiro.au/nid/10/paper/MF08321.htm

...increasing dissolution pressure in cool temperate environments dramatically reduces sediment accumulation rates. Bryozoan shelf carbonate sediments, which blanket the southern shelves of New Zealand and Australia, may serve as biological saturometers, monitoring the effects of acidification over shelf depths.

[sinimod]

Maybe a slight reprieve:

http://www.biogeosciences-discuss.ne...6781-2009.html

[776281]

http://www.guardian.co.uk/world/2009...s-turn-to-acid
Arctic seas turn to acid, putting vital food chain at risk

Carbon-dioxide emissions are turning the waters of the Arctic Ocean into acid at an unprecedented rate, scientists have discovered. Research carried out in the archipelago of Svalbard has shown in many regions around the north pole seawater is likely to reach corrosive levels within 10 years. The water will then start to dissolve the shells of mussels and other shellfish and cause major disruption to the food chain. By the end of the century, the entire Arctic Ocean will be corrosively acidic.

Just as an acid descaler breaks apart limescale inside a kettle, so the shells that protect molluscs and other creatures will be dissolved. "This will affect the whole food chain, including the North Atlantic salmon, which feeds on molluscs," said Gattuso, speaking at a European commission conference

"

Scientists have proposed all sorts of geo-engineering solutions to global warming," said Gattuso. "For instance, they have proposed spraying the upper atmosphere with aerosol particles that would reduce sunlight reaching the Earth, mitigating the warming caused by rising levels of carbon dioxide.

"But these ideas miss the point. They will still allow carbon dioxide emissions to continue to increase – and thus the oceans to become more and more acidic. There is only one way to stop the devastation the oceans are now facing and that is to limit carbon-dioxide emissions as a matter of urgency."

Related?
http://au.news.yahoo.com/thewest/a/-...obster-limits/

He said the catch target was set to protect the sustainability of the western rock lobster fishery, smooth the catch and reduce the economic impact of the record low baby rock lobster (puerulus) count in the past three years.

"Poor puerulus settlement in recent years means the number of lobsters available to the fishery is expected to be significantly reduced in seasons 2010-11 and 2011-12," Mr Moore said.

At this stage some other factor is probably responsible. However, wouldn't the effects of ocean acidification first affect the early shell formation of juvenile shellfish?

[sinimod]

In an interview by Yale Environment 360 (http://www.e360.yale.edu/content/feature.msp?id=2194) with eminent oceanographer Sylvia Earle, she outlines some of the ways humanity can begin to restore the ocean's health. It is now very clear that the ocean's ecosystems, like their terrestrial counterparts, are now in serious trouble. Dr. Earle provides advice as to how humanity can save the oceans before it is too late. She has written a book on the matter, "The World is Blue," where she describes the changes she has witnessed in the oceans and a blueprint on how to eventually bring back to health ocean ecosystems.

In The World is Blue, Earle describes the two-pronged assault on the seas: what we are pulling out of the oceans, through unfettered industrial fishing, and what we are putting into the oceans through pollutants, fertilizers, and growing amounts of carbon dioxide that are leading to a dangerous acidification of the sea.

Dr. Earle is still hopeful:

The world’s oceans, Earle concludes, can still be redeemed, but only through swift and decisive action.

But she is clear that we must change our ways and do it quickly.

We should have learned with wildlife on the land that we have the power — through both our numbers and our technologies — to be able to find, kill, extract and market, to decimate, anything that swims in the ocean.

And she is very clear on what effects our actions are having.

Fish, every living thing, is a carbon container. By extracting millions of tons of ocean wildlife, it’s like clear-cutting forests. You have removed the carbon-based units.

...this destruction of the great ocean food web, the destruction of the habitats in the sea, the dredging, the trawling, that [alters] these finely tuned systems that have developed over literally hundreds of millions of years... We call it the great green engine that generates oxygen and takes up carbon dioxide at a point that is just right for life. But our actions in just a little slim period of time have so altered the nature of nature.

And what we must do:

We have about 4,500 protected areas in the sea, but it’s a fraction of one percent of the ocean. So we’ve got to step up to the plate while we have time, and seriously support protected areas in the sea. To do it as if our life depends on it, because it can.

If you want tuna to prosper, for heaven’s sake, don’t go to the places where they are breeding and attack them, which is what the fishermen are now doing in the western Gulf of Mexico, or where they aggregate off the coast of North Carolina.

At the same time in our own backyard, by giving up a lawn that is heavily dependent on chemical fertilizers and pesticides and herbicides — [you can] turn them into your own little areas of hope, where you can plant native trees and wildflowers, and let them be a substitute for a green rug out there. Do your part, or do your part by not consuming the ocean wildlife that is seriously in trouble.

And finally:

If we want to have livelihoods, to feed families and communities, we have to cut back on the large industrial-scale exploitation of ocean wildlife and ocean systems. Because it’s not working and in fact it’s undermining health, undermining security, undermining the economy, undermining the capacity of the world to work at all.

We get to choose. We either get to choose by conscious action or by default because we are complacent — that we just let things slide, to continue the way they are at present, thinking somebody else will look after this. But nobody else will take care of these issues.