Tuesday, April 21, 2009

Oceans and Plimer

Most Australian readers would probably know already of the global warming skeptics excitement about a new hefty book by geologist Ian Plimer that (apparently) sets out with lots of footnotes his opinion as to why the great majority of climate scientists are wrong.

While we are waiting for some climate scientist types to review it in detail, I am curious as to whether he makes any attempt at addressing ocean acidification. As remarked here many times, this is an issue skeptics just like to wave away with a few dismissive snorts, and that's about the extent of their analysis. (Yes, I am aware of Plimer's previous short contributions to the issue, such as this one noted last year at Marohasy's blog. Anyone who has bothered to read about the issue can readily spot that this was a disingenuous attempt at dismissing it, and does not address the reasons why it is believed to be a serious problem regardless of the oceans surviving past periods of high atmospheric CO2.)

In fact, I haven't posted anything new about ocean acidification for a few weeks, but there have been quite a few papers of note, such as:

* some new calculations indicate that ocean "dead zones" will increase:
increases in carbon dioxide can make marine animals more susceptible to low concentrations of oxygen, and thus exacerbate the effects of low-oxygen "dead zones" in the ocean.

Brewer and Peltzer's calculations also show that the partial pressure of dissolved carbon dioxide gas (pCO2) in low-oxygen zones will rise much higher than previously thought. This could have significant consequences for marine life in these zones.
* (if I am reading this right) some lab tests indicate that phytoplankton in nutrient poor ocean areas (such as the Southern Oceans, which will be affected first by lower .pH) don't do well with increased CO2.

* A paper notes the wildly conflicting results of different lab tests on whether a certain type of phytoplankton will get heavier or lighter with more ocean acidification. However, even if they do in nature get heavier, they will not make a significant reduction in CO2 levels in the atmosphere:
...it should be recognized that the direct impact of calcification changes on atmospheric CO2 through the remainder of this century is relatively small compared to anticipated annual emissions as well as to other carbon cycle feedbacks.
(Hence, if AGW is true, you can't expect the carbon incorporating phytoplankton to save you.)

* more research indicating pteropods (which feed a lot of fish) don't do well with increased acidfication. The researchers note:
A decline of their populations would likely cause dramatic changes to the structure, function and services of polar ecosystems.
Not exactly cheery news.

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