Marine Organisms Threatened by Increasingly Acidic Ocean

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

[cogitator]

I've heard similar news to this before, but this is a fairly detailed press release. I'll have to find the issue of Nature that the actual report is in to read it.

[cogitator]

** ping **

[BadAndy]

"that the ocean's coldest surface waters, such as in the Weddell Sea of Antarctica, will become corrosive to pteropods much sooner than thought. Shells of these marine organisms may simply dissolve as soon as atmospheric CO2 reaches the levels that are expected to occur in about 50 years under the IS92a business-as-usual CO2 emissions scenario. "

Put some pteropods in a tank, lower the pH, see what happens. This should be an easy experiment to do.

[ClearCase_guy]

The amount of acid that humans have dumped into the ocean has altered the Ph of the ocean by 0.0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001%

The ocean is pretty damn big.

[Blueflag]

Basic chemistry tells us that increasing dissolved CO2 increases acidity.

Basic oceanography and biology tells us that increasing CO2 in the photic zone will increase phytoplankton growth, particularly when coupled with rising photic zone mean temperatures. NET: It's a good thing to increase CO2 levels in the photic zones of the world's oceans.

The limiting factor of phytoplankton growth is CO2 (presuming temp and sunlight are constant).

[lilylangtree]

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

[cogitator]

Put some pteropods in a tank, lower the pH, see what happens. This should be an easy experiment to do.

It's been done (read the paragraph starting "As a complement to...")

[cogitator]

It's not the acid, it's the CO2, and the pH change is a lot more than the infinitesimal amount you offered. It's measurable.

[cogitator]

The limiting factor of phytoplankton growth is CO2

CO2 has no significant effect. The main limiting factors on phytoplankton growth are the amount of available sunlight and the concentration of vital nutrients.

[ClearCase_guy]

Measureable, yes. Attributable to humans? Unproven.

[AdmSmith]

Take your gun, hunt a deer and roast it over a fire from some logged trees, deposit the ash in the sea - the pH is 9 - 13.5

Now you have had fun and saved the environment.

http://pubs.caes.uga.edu/caespubs/pubcd/B1142.htm

[cogitator]

Attributable to humans? Unproven.

You may need to read this closely:

How do we know that recent CO2 increases are due to human activities?

[SAJ]

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? Or are we supposed to believe that the addition of carbon dioxide somehow strips out non-hydrogen-bearing compounds, and in that way renders the oceans more acidic?

Now, my chemistry is pretty rusty, so I'd appreciate one of FR's bottomless talent pool correcting me on this if I'm in error. Until then, this article sounds a lot like more Chicken Little horse puckey.

[Old Professer]

Any proposition placed beyond the expected lifespan of the reader is an insult first and specious science second.

If the process of which the autors speak is even somewhat linear then why place the endpoint beyond casual observation?

[Old Professer]

By putting the endpoint beyond the lifespan of the reader and casual observer, the authors have assured themselves that they won't be around to hear a chorus of "atta boys" or a din of "I told you so's."

[SAJ]

Would you please discuss how dissolving carbon dioxide in salt water increases the level of hydrogen ionisation? This seems entirely counterintuitive.

TIA!

[Old Professer]

Doesn't deposited CO2 in water concentrate at the coldest strata?

[AdmSmith]

You may take a look at this http://en.wikipedia.org/wiki/Carbonic_acid

[SAJ]

Look, I know that bubbling CO₂ in a closed water system, say a fish tank, will form some amount of carbonic acid and lower the pH, but only to the extent of free hydrogen ions already present. To increase acidity in a macro NON-closed system, one simply must keep introducing or creating new hydrogen ions. Further, carbonic acid in water breaks down over time under heat (I doubt there's much carbonic acid in the GOM right now...heh heh).

Where does the new hydrogen come from?