In N. Pacific Ocean @ Specific Depths, Acidification Already Outpacing Shell Growth For Marine Life

[hatrack]

Global warming has increased acidity levels of the oceans by 30 percent and in the decades ahead will create new risks for coral, zooplankton and other creatures that help support the North Pacific fisheries, according to researchers who gathered Monday at the University of Washington. In a two-day workshop that ends today, these scientists are reviewing what is known about this grim corner of climate change and brainstorming ways to measure and assess the threats to a marine ecosystem that yields North America's largest seafood harvests.

The acidification is caused by the ocean's absorption of carbon dioxide produced by fossil-fuel combustion. Currently, this is about 2 billion tons of the gas each year. As this gas dissolves, it sets off a chemical reaction that produces carbonic acid, which in high-enough concentrations can erode protective shells and other structures of some sea creatures. "We have significant changes in chemistry," said Richard Feely, a Seattle-based National Oceanic and Atmospheric Administration oceanographer who helped to organize the conference. "And if we project over time ... we are talking about massive changes that will take place."

Some of the most acidic waters are found in the North Pacific, which has absorbed more carbon dioxide than tropical oceans. The North Pacific appears to be more acidic because it is colder than tropical oceans, which enables it to absorb more carbon, and because it has older, more carbon-rich water than the North Atlantic. In some areas of the North Pacific — at depths ranging from about 300 to more than 1,000 feet — researchers already have detected a kind of saturation point where acidity causes shells to disintegrate faster than they can grow. This contrasts to the North Atlantic, where the saturation point typically is at depths that exceed 7,500 feet, according to Feely.

By the end of the century, these North Pacific saturation zones are expected to expand and extend into much shallower waters. Last year, Feely helped measure the acidity in these zones, and in the years ahead he will start to check the acidity levels of the most productive fishing zone: the Bering Sea.

EDIT

http://seattletimes.nwsource.com/html/localnews/2003678459_acidocean24m.html

[hunter]

1. Damn.

Damn. The ocean we know won't exist.

Everything will be different.

[poverlay]

2. Looks like soylent green will be on the table a bit quicker than anticipated... nt

[GliderGuider]

3. I attended a talk by an oceanic scientist who covered this

Dr. Denman is a scientist who works for the Canadian Department of Fisheries and Oceans. He was a lead coordinating author on the IPCC chapter devoted to oceanic effects of GW. He talked about this and showed maps of current and projected saturation point depths in the North Pacific. The Bering Sea is going to be hugely affected.

He showed us a microphotograph of a gorgeous filigree ball of exoskeleton around one particular organism that he said was going to disappear within the next 50 or 75 years. Then he asked, "If the ocean acidity is too high for calcium carbonate to form, how do fin-fish get the calcium they need to make bones?" Loooong silence...

[hatrack]

4. Seriously long-ass silence, I'd wager

Sounds like an, uh, interesting conference.

[phantom power]

5. Hey Mister Grumpy-gills -- just keep swimming!

[necso]

6. Acidification has the potential

to be a serious problem in the oceans (it's already known to be a problem in fresh-waters (eg, acid rain)). Anything that negatively affects zooplankton (acidification; pollution; etc), phytoplankton (less sunlight making it to where they habitate; etc) or other "feedstocks" (etc) has the potential to disrupt the food-web. And then there's the role marine organisms and sediments play in locking-up CO2 long-term.

To lock-up CO2 long-term (not just store it in a reservoir, like the ocean waters), (some) organisms need to (be able to) build calcareous (carbonaceous) shells. And when carbonaceous organisms die, their calcareous shells (carbonaceous bodies) need to be deposited on the sea floor and get buried (or get "buried" in reefs, etc).

Normally, calcareous deposition happens in a "band" of seafloor above a certain depth. But this depth can rise if CO2 increases in the water-column above the (potential) sedimentation site.

Of course, there are complications. For example, ocean waters aren't homogeneous, and distinct layers (with different solute levels) are commonly to be found. And as water temperatures rise, CO2 is generally less soluble (although it isn't a given that this will stop acidification damage).

Moreover, in general the rate of change is critical. Given sufficient time, many species can be expected to adapt (where possible* -- or to be replaced relatively gracefully); given little time, fewer can.

And if the change is too abrupt, you can get cataclysmic extinction, and radical changes in the floral and faunal (etc) environment -- to accompany other environmental changes (degradation).

Pumping huge amounts of CO2 into the atmosphere (and as a result the oceans; along with other "pollutants" (toxins; things not normally present in those proportions, changing at those rates)) isn't a good idea.

Indeed, it's a bad idea of global proportions. (Pollution is typically an unaccounted-for cost (on the books), but it's potentially very costly. And frequently it's a good example of privatized/localized (monetary) profits -- with socialized/widespread risks and costs (monetary and otherwise).)

*: Some changes are of a threshold nature, resulting in (particular) processes becoming no longer practical or even possible. In particular, above a certain level of acidity, it may be impossible to produce a calcareous exoskeleton fast enough to keep up with the effects of dissolution. (Of course, it may also just be impossible for many organisms to live above a certain acidity level.)