Marine Organisms Threatened by Increasingly Acidic Ocean

Woods Hole Oceanographic Institution ^ | September 29, 2005 | Shelly Dawicki

[SAJ]

Agreed, see post 19. However, carbonic acid is not stable in an open system, and especially with the introduction of heat to the system. Also, rainfall will decompose any carbonic acid on the surface of a body of water, right back into CO2 and H2O.

My original post was poorly phrased; the question is why acidity increases in an OPEN system, not a fish tank or a glass of water.

[SAJ]

Agreed, except that at any point in time there are X available ions in a given quantity of water. Introduce some CO2, make some carbonic acid, but sooner or later the process stops dead, for there are no more free ions with which to combine.

I just phrased the question very poorly, sorry.

And, there are other factors to consider, too. If a body of water is rich in dissolved minerals, say calcium, introducing CO2 is going to form relatively more calcium carbonate, and a good deal less carbonic acid. pH might actually rise in this case, depending on mineral concentration.

[Gorzaloon]

This doesn't pass the smell test of Chem 101. To form an acid, you must have hydrogen ions. CO2 has none, and so is adding no hydrogen in any form to seawater. Are we supposed to believe: H2O.NaCl + CO2 ==> something acidic?

CO2 hydrates to Carbonic Acid, H2CO3. This is the key to the stalactite-forming process in caves. CO2 dissolved in water percolates through limestone, CaCO3, dissolving it. When CO2 is lost upon evaporation or diffusion into the air because of k, the CaCO3 precipitates out.

The role of the carbonate ion is also linked to the formation rate of kidney stones. The body is very effective at PCO2 regulation, as a person can "blow off" CO2 when needed.Metabolic defects such as occur in Renal Tubular Acidosis were at one time (1970's) treated with bicarbonates. Now, citrates are used because RTA is one result of a genetic citrate metabolic defect- And the citrate is a very effective chelating agent for Group IIA metals.

Still, I HATE agreeing with enviro stuff!! :-)

[cogitator]

Where can I find some real numbers? I want to know more than just the trend.

Probably in the September 29 issue of Nature. But wait...

Google finds:

http://www.ipsl.jussieu.fr/~jomce/acidification/paper/Orr_OnlineNature04095.pdf

This is the referenced Nature paper, and now you and I don't need to go to the library to read it!

[Blueflag]

cogitator -- review the carbon cycle and photosynthesis.

CO2 + H2O ------> sugar
+ light
+ heat

Without CO2, there is no growth. CO2 IS an essential "vital" nutrient. ;-)

[Bloody Sam Roberts]

Coming from the movie "Day After Tomorrow", eh.

Exactly. This article is a well crafted, steaming double coiler.

[Blueflag]

Simply put, the hydrogen ions come from water, H2O. Carbonic acid is the result as shown by a prior post. When the vapor pressure ( of dissolved CO2 ) changes, more CO2 enters or leaves the water, and the amount of carbonic acid correspondingly changes.

This is NOT an open system, it is a closed loop system. CO2 enters and leaves the oceans all the time. The oceans are not just a carbon sink.

[Blueflag]

As the other poster mentioned, it varies by local and depth and composition as to what THE specific limiting factor is. My point is that in the core reaction of photosynthesis, -- combining CO2 and H2O to make sugar, CO2 can be the limiting factor. This is true in hot house tomato farming and corn fields. I don't have the citation, but this was demonstrated IN DEPTH by the University of Southwestern Louisiana in the 1908s.

[SAJ]

Excellent explanation, and thanks!

[SAJ]

Ok, thanks. I'll take your word for it, certainly, but I've some trouble imagining the oceans as merely an overlarge fish tank, in terms of characterising the system as open or closed.

;^)

[Blueflag]

Fair enough. When I speak of a closed system, I mean the carbon cycle. Carbon's trip into the oceans is not a one way trip, like dumping mining slag into a pit would be.

[Gorzaloon]

cogitator -- review the carbon cycle and photosynthesis.

CO2 + H2O ------> sugar

+ light

+ heat

Without CO2, there is no growth. CO2 IS an essential "vital" nutrient. ;-)

True as far as it goes, but in the context of biology, that is only half the cycle.

The other half is:

Sugars*-------Metabolism---> CO2+HOH+Energy, and around it goes, plants to animals to plants..

*(Including oligomers like starches)

When someone runs a propane CO2 generator in a tomato greenhouse, they are cycling the plant-produced O2 through another redox reaction to produce CO2 back to the plants, and the plants love it.

[dennisw]

I doubt we can impact on the oceans in such a way. They are much too big. We can over fish the ocean. We can over exploit fisheries. But the oceans are too big for mankind to turn acid. But perhaps some scientists can get research grates and employment from this non-issue

[Blueflag]

Absolutely. U R correct. That's why it's called the carbon cycle, not the carbon drain.

[Sir Francis Dashwood]

Marine Organisms Threatened by Increasingly Acidic Ocean

Maybe we should start adding DRANO to the oceans???

[GOPJ]

bump

[cogitator]

Without CO2, there is no growth. CO2 IS an essential "vital" nutrient. ;-)

It's essential, but not limiting.

[cogitator]

I doubt we can impact on the oceans in such a way.

It's fine to be skeptical, but in this case, the science is very strong, so your doubts are trumped by data. I invite you to read the paper linked in post 44.

[cogitator]

Maybe we should start adding DRANO to the oceans???

Powdered limestone. Might take a bit, though. (This works in acidified lakes, by the way.)

[Bernard Marx]

If C02 is the enemy, I'm sure this group of scientists will be at the forefront of a movement to replace fossil fuels with clean nuclear energy -- NOT!

Reading between the lines it's clear the only solution they have in mind is a drastic reduction in the number of human beings. Let them volunteer to be the first to go.