Wednesday, May 7, 2008

Warming Ocean Threatens Sea Life

In more dire news, the earth's warming trend is increasing low oxygen zones in the ocean where much sea life cannot survive. Surprisingly (to me anyway), cold water can hold considerably more oxygen than warm water, so the warmer the seas, the fewer livable zones for the life there:

"Continued expansion of these zones could have dramatic consequences for both sea life and coastal economies, said the team led by Lothar Stramma of the University of Kiel in Germany.

The finding was not surprising, Stramma said, because computer climate models had predicted a decline in dissolved oxygen in the oceans under warmer conditions.

Frank A. Whitney of Canada's Institute of Ocean Sciences said, "As oceans lose oxygen, this will reduce habitat for many organisms."

And before anyone dismisses these changes as trivial, note the extreme differences in oxygen that can occur:

"In cold surface water, oxygen levels can reach as high as 300 to 400 micromols per kilogram, Johnson said. A mol of a gas such as oxygen occupies a volume of just under six gallons and a micromol is one-thousandth of that. A kilogram of water is the amount that would weigh 2.2 pounds.

Dissolved oxygen varies widely in the oceans, and sea life becomes stressed when it reaches between 60 and 120 micromols per kilogram.

The researchers found concentrations as low as 10 in parts of the eastern Pacific and the northern Indian Ocean and larger areas in the Atlantic and Pacific were below 150."

Imagine trying to get by on air that had 1/2 to 1/30th of the oxygen you are used to.
I guess we'd all better enjoy our seafood while we can. And notice that climate models predicted these changes in the ocean's oxygen. What did the denialist's models say? Oh that's right, they don't do any.

1 comment:

Christopher Waldrop said...

Surprisingly (to me anyway), cold water can hold considerably more oxygen than warm water
That's surprising to me too because I understand that oxygen levels are extremely low at the deepest levels of the ocean, where it's also quite cold. Of course I understand the pressure pushes a lot of that oxygen out.
Anyway, this "dead zone" (as I've heard it called) is incredibly disturbing.