Ocean Acidification - It's not complicated. Or is it?

The University of Washington's Ph.D. professor Cliff Mass has questioned whether modern civilization's increasing production of CO2 is the primary cause of ocean acidification and of shellfish hatchery failures. He questions if instead those failures may be more closely tied to an attempt at raising non-native oysters in waters colder and at times more "acidic" than where the shellfish are from. He has written a second perspective to the Seattle Times articles. In his second piece he writes:

"The ST suggested that mankind’s emission of CO2 was having profound effects today on shellfish in Northwest waters.   I argued that the ST story was exaggerating the current impacts of CO2 increases and neglected a key point: that the short periods of lowered ph (a measure of acid/base ) were predominantly caused by natural variability.  The truth is that mankind's CO2 emission is actually a very minor player in the current problems at local oyster larvae hatcheries."

Billions lost millions still harvested
Within the shellfish industry there is a belief that the cause of shellfish hatchery failures and the loss of "billions of oysters"* is directly related to increasing levels of CO2 being absorbed by the ocean's waters which in turn are causing a shift in the chemical makeup of those waters. It is believed that the increasing CO2 concentration in seawater decreases carbonate ions. This decrease in carbonate ions affects the saturation state for calcium carbonate, which makes it harder for shelled organisms to grow and maintain shells. As noted, Professor Mass believes the anthropogenic source is a small percentage of the cause.

*As a side note, according to production reports from the Washington Department of Fish and Wildlife, between 2008 and 2012 the pounds of oysters harvested in Washington state have remained relatively steady. From WDFW: 2008-9.7 million pounds; 2009-8.8 million pounds; 2010-9.1 million pounds; 2011-9.3 million pounds; and, 2012-9.4 million pounds. As it takes ~2 years for an oyster to reach maturity, the 2008 numbers include seed produced in 2006.

A complicated web and a chemical soup
It is important to understand that while the shellfish industry may be having problems "hatching" non-native shellfish using Puget Sound's colder waters, where native Olympia oysters and Geoduck appear to have no problems, there may be multiple causes for whatever problems they face, including genetically modifying oysters so they are sterile. The spraying of Willapa Bay tidelands to eliminate species of shrimp considered to be a "pest" by the industry is another example of a self-induced problem. Eliminating these shrimp causes sediments to firm and in turn creates a habitat suitable for Japanese eelgrass to grow in which the shellfish industry now wants to spray with Imazamox. It is little wonder the office of the Attorney General referred to Willapa Bay as a "chemical soup."

Crying wolf is counterproductive
Professor Mass summarizes his position in the following words:

The truth is that anthropogenic increases in CO2 are only having subtle impacts on our regional weather today, the big changes and impacts will occur decades into the future. Both global warming and ocean acidification are very serious issues and by the end of the century their impacts will be substantial.   But exaggerating and hyping the effects today are unacceptable.  Citizens and policy makers deserve the facts, not exaggerations designed to elicit the proper response.  Crying wolf in the end is counterproductive and undermines the credibility of science to promote the proper actions is unacceptable.