IN THE UNITED STATES AND OTHER COASTAL NATIONS,
ocean acidification has quickly become a common topic of scientific research. Ocean acidification also has become a public concern as news headlines warn of this potentially threatening byproduct of global climate change. Global climate change studies have revealed that the rate of increase in atmospheric carbon dioxide (CO2) concentration has increased substantially since the
industrial revolution (mid-1700s). The world's oceans
have absorbed between 30% and 50% of that new
CO2.
The increase in oceanic CO2, when incorporated into the carbonate system, has resulted in an average decrease of surface ocean pH by 0.1 units, the equivalent of a 30% increase in acidity. The increased acidity
reduces the saturation of calcium carbonate, making it more difficult for some calcifying organisms to sequester
calcium and carbonate to build shells. In the North
Pacific Ocean, the saturation depth of calcium carbonate
is already shallow (<200 m) relative to the North
Atlantic (~2,000 m). Therefore, the marine organisms
in Alaska are particularly at risk to effects associated
with ocean acidification. In addition, some species such
as golden king crab (Lithodes aequispinus) in Alaska
already inhabit undersaturated environments; understanding
how they cope with this environment will
help us evaluate the effects of ocean acidification on
Alaska species.
Megalops crab larva.
Scientists at the Alaska Fisheries Science Center (AFSC) have worked locally, nationally, and internationally
since 2007 to address the potential impacts of
ocean acidification on scales from individual organisms
to ecosystems. This research currently receives funding support from NOAA's Ocean Acidification Program and the North Pacific Research Board. In 2008, AFSC scientists developed
a research plan to test the hypotheses that reduced
ocean pH and the resultant reduction in availability
of calcium carbonate would have wide-ranging effects,
including reduced growth, survival, and reproduction
of commercially important fish and shellfish,
ecologically important prey of those species, and cold
water corals. Species-specific physiological responses to
ocean acidification were not well understood, so a broad
research effort was considered for several taxa including
shellfish, calcareous plankton, coldwater corals, and fish.
Prioritization was given to the larval and juvenile stages of
commercially and ecologically important taxa more likely
to be directly affected by ocean acidification in Alaska.