Tuesday, October 15, 2013

More Notes on Ocean Acidification

The left side shows the depth of the saturation horizon with regard to the CaCO3 mineral aragonite, and the right side shows the surface ocean pH. The bluer, the deeper and oranger (is that a word?) the closer to the surface. The saturation horizon reaching near the surface means there will be a lack of aragonite mineral in the water which will lead to corrosion of aragonite shells or an extra expenditure of energy for shell growth.  As can be seen the extent and magnitude of low aragonite events off the California coast are projected to increase dramatically over the next few decades.

The pulsing like nature of the aragonite and pH in the images relates to seasonal changes in upwelling which is dependent on northerly winds and duration of the winds. Off of the Washington coast the effect is much more seasonal with more definitive periods of upwelling generally restricted to the summer. Gruber and others (2013) note that coasts such as ours that have weather systems that drive deep water upwelling already have low average pH and will be among the first regions to experience long term under saturation with regard to aragonite.

The video is related to the paper "Rapid Progression of Ocean Acidification in the California Current System," by N. Gruber; C. Hauri; Z. Lachkar; D. Loher at ETH Zurich in Zurich, Switzerland; T.L. Frölicher at Princeton University in Princeton, NJ; G.-K. Plattner at University of Bern in Bern, Switzerland published in Science http://www.sciencemag.org/content/337/6091/220.short.

Climate models project Washington State to fare better than many places with the big Pacific Ocean and weather patterns leading to less dramatic temperature and precipitation changes than other place on the planet. However, it appears that ocean conditions will change off our coast sooner and more intensely than other areas.

There is a tendency to dismiss media reports on science as being a bit hyperbolic and indeed that seems to have been Cliff Mass' angle on the recent Seattle Times articles on ocean acidification (sea-change). Perhaps I can read and edit out hyperbole better than some. Perhaps my past political era helps or sitting through environmental impact statement hearings has allowed me to have a built in filter. On careful look, perhaps a few words here and a story angle with some drama can be a bit much for objective science, but the Times is not a scientific journal. Regardless my take on the Sea Change was it did a pretty good job on a very complex subject. 

The above said, there was a line in the article that I edited in my own mind own hyperbole:

"But all that CO2 is changing the chemistry of the ocean faster than at any time in human mammalian history."

What we are about to do to the ocean chemistry is the sort of stuff that causes hyperbole even in scientific papers.


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