Arctic acidification poses risks to crustaceans and fish

A new study has concluded that by 2030 Chukchi and Beaufort seas, in the Arctic Ocean, could reach acidity levels that may negatively affect not only shelled animals but also the fish depending on them.

The research – published in the journal Oceanography -- was conducted by scientists from National Oceanic and Atmospheric Administration (NOAA), University of Alaska, and Woods Hole Oceanographic Institution (WHOI), who raised concern as to the threat these levels pose for the ability of crustaceans to build and maintain their shells.

In the case of the Bering Sea, researchers estimate its water may reach this level of acidity by 2044.

“Our research shows that within 15 years, the chemistry of these waters may no longer be saturated with enough calcium carbonate for a number of animals from tiny sea snails to Alaska King crabs to construct and maintain their shells at certain times of the year,” pointed out Jeremy Mathis, an oceanographer at NOAA’s Pacific Marine Environmental Laboratory and lead author.

“This change due to ocean acidification would not only affect shell-building animals but could ripple through the marine ecosystem,” Mathis added.

For his part, Scott Doney, a coauthor of the study and a senior scientist at the WHOI stressed that a key advance of this study was combining the power of field observations with numerical models to better predict the future.

These researchers, who collected observations on water temperature, salinity and dissolved carbon during two expeditions onboard US Coast Guard cutter Healy in 2011 and 2012, explain that a form of calcium carbonate in the ocean (aragonite) is used by animals to construct and maintain shells.

When calcium and carbonate ion concentrations slip below tolerable levels, aragonite shells can begin to dissolve, particularly at early life stages. As the water chemistry slips below the present-day range, which varies by season, shell-building organisms and the fish that depend on these species for food can be affected.

The region analysed is home to some of the US most valuable commercial and subsistence fisheries.

NOAA’s statistics show that nearly 60 per cent of US commercial fisheries landings by weight are harvested in Alaska, whose fishing landings in wholesale values reached USD 1.9 billion in 2013