New concern for California coastal shellfish

California coastal ecosystems can't buy a break.  Abalone is still in big trouble;  sea urchins are wreaking havoc on the seafloor, and the kelp are dying due to that and warming waters to boot;  and now, the ocean waters are experiencing a decreasing pH at twice the global rate, which is not good for much of anything that has a shell.  Plus the usual winter storms, harmful algal blooms,

Tiny shells reveal waters off California acidifying twice as fast as the global ocean

“By measuring the thickness of the shells, we can provide a very accurate estimate of the ocean’s acidity level when the foraminifera were alive,” said lead author Emily Osborne, who used this novel technique to produce the longest record yet created of ocean acidification using directly measured marine species. She measured shells within cores that represented deposits dating back to 1895.

The fossil record also revealed an unexpected cyclical pattern: Though the waters increased their overall acidity over time, the shells revealed decade-long changes in the rise and fall of acidity. This pattern matched the Pacific Decadal Oscillation, a natural warming and cooling cycle. Human-caused carbon dioxide emissions are driving ocean acidification, but this natural variation also plays an important role in alleviating or amplifying ocean acidification."

"The graph shows the decline from 1900 to 2000 in the concentration of carbonate ions in the waters off California. Carbonate ions are the building blocks used by foraminifera and other shelled marine species to build their shells. As carbon dioxide concentrations have risen in these Pacific Ocean waters due to absorbing excess carbon dioxide emissions and upwelling of carbon dioxide-rich waters from the deep, the carbonate ion concentration has declined and acidity has increased, making it more difficult for marine species to build shells. The inset photos show (a) a typical foraminifera shell; (b) cross section of a shell from 1900 showing thickness of the shell; and (c) a shell from 2000 showing a thinner shell wall. Courtesy/Emily Osborne/NOAA"

(from OregonLive)