Early life stages of one Arctic copepod not impacted by OA

Results of a new independent study of copepods show that the copepod Calnus glacialis, one of the most abundant surface copepods in the Arctic, may feel less impact than other critters from changing ocean conditions.

Researchers in this new study, have found no maternal or direct effects of ocean acidification on egg hatching in the copepod Calanus glacialis.

The peer-reviewed article published in the online journal PLOS One on Feb. 7 said a research team led by Peter Thor of the Norwegian Polar Institute in Tromse studied maternal and direct effects of ocean acidification predicted for the Arctic shelf seas on egg hatching time and success in the keystone copepod species Calanus glacialis in a highly replicated experiment.

They incubated female copepods of that species in present day conditions of pH 8.0 and possible year 2100 extreme conditions of pH 7.5 during oogenesis, or development of the ovum, and subsequently reciprocally transplanted laid eggs between these two conditions. Statistical tests showed no effects of maternal or direct exposure to ocean acidification at that level, they said.

The researchers hypothesized that the Calanus glacialis may be physiologically adapted to egg production at low pH since oogenesis can also take place at conditions of potentially low pH of the mother during hibernation in the deep.

The full study is online at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0192496

These tiny crustaceans are endemic to Arctic waters and according to the Research Council of Norway this herbivorous Arctic zooplankton species is specially adapted to melting sea ice and the blooming of a few small algal species. This lipid-rich zooplankton is the primary food source for Arctic cod, marine birds and bowhead whales, Arctic cod, in turn, are the main course for seals, which are the favorite meal of polar bears.