New paper finds prior claims about effects of ocean "acidification" may be overblown

A paper published today in Global Change Biology finds that prior papers about the alleged effect of ocean "acidification" on marine organisms are overblown because prior research has failed to consider that organisms can adapt over time to pH changes. According to the authors, "nearly all of this work [on the alleged effects of "acidification"] has focused on the effects of future conditions on modern populations, neglecting the role of adaptation."

Natural variation, and the capacity to adapt to ocean acidification in the keystone sea urchin Strongylocentrotus purpuratus

Morgan W. Kelly et al

Abstract: A rapidly growing body of literature documents the potential negative effects of CO2-driven ocean acidification (OA) on marine organisms. However, nearly all of this work has focused on the effects of future conditions on modern populations, neglecting the role of adaptation. Rapid evolution can alter demographic responses to environmental change, ultimately affecting the likelihood of population persistence, but the capacity for adaptation will differ among populations and species. Here, we measure the capacity of the ecologically important purple sea urchin Strongylocentrotus purpuratus to adapt to OA, using a breeding experiment to estimate additive genetic variance for larval size (an important component of fitness) under future high pCO2/low pH conditions. Although larvae reared under future conditions were smaller than those reared under present-day conditions, we show that there is also abundant genetic variation for body size under elevated pCO2, indicating that this trait can evolve. The observed heritability of size was 0.40±0.32 (95% CI) under low pCO2, and 0.50±0.30 under high pCO2 conditions. Accounting for the observed genetic variation in models of future larval size and demographic rates substantially alters projections of performance for this species in the future ocean. Importantly, our model shows that after incorporating the effects of adaptation, the OA-driven decrease in population growth rate is up to 50% smaller, than that predicted by the “no-adaptation” scenario. Adults used in the experiment were collected from two sites on the coast of the Northeast Pacific that are characterized by different pH regimes, as measured by autonomous sensors. Comparing results between sites, we also found subtle differences in larval size under high pCO2 rearing conditions, consistent with local adaptation to carbonate chemistry in the field. These results suggest that spatially varying selection may help to maintain genetic variation necessary for adaptation to future ocean acidification.

Key points from prior posts on ocean "acidification":

• Doubling of atmospheric levels would only increase dissolved CO2 in the oceans by .48%
• There is no reliable evidence that ocean pH is falling
• Increased CO2 dissolution in the oceans increases calcification of shellfish and coral
• Corals evolved at a time when CO2 levels were 15 times higher than the present
• Laboratory experiments on sealife in which hydrochloric acid is added to the water (not CO2) and without the natural buffers present in the ocean is meaningless to determine effects of increased CO2 levels on sealife.

Other recommended resources on "Ocean Acidification":
http://nipccreport.org/articles/2013/may/8may2013a1.html
Global Warming Science
Ocean Acidification: How bad can it get?
Acid Test
SeaFriends
Ocean Acidification: Another Failing Scare Story
Acid in the oceans fraud
Ocean acidification: a non-problem
Dying Shellfish Larvae: Story of a Scam
Corals & the Great Barrier Reef
Monterey Bay pH 1995-2004
South China Sea pH
Ocean Acidification: the evil twin of global warming?
'Ocean Acidification' is the new climate scare
Testimony of Dr. John Everett
Speculations beyond the pale of reality
CO2 & pH

Effects of Ocean Acidification on Marine Ecosystems