Climate change may impact Arctic wildlife

Results from the Norwegian IPY project CLEOPATRA show that climate change can affect the growth conditions of ice algae and copepods in the Arctic. The algae produce omega-3 fatty acids, and the copepods are an important delivery system for these fatty acids to the rest of the marine food chain.

Isalger

Photo: Jørgen Berge / Norwegian Polar Institute

Ice algae

Ice algae; unicellular algae growing within sea ice. Photo: Josef Wiktor / Norwegian Polar Institute

Unicellular algae growing within sea ice, so-called ice algae, form the basis of the marine ecosystem in ice-covered areas. As a consequence of reduced Arctic sea ice cover, growth conditions for those tiny organisms change quite dramatically. In particular, light conditions that regulate algal productivity are strongly dependent on ice thickness, structure and precipitation: snow effectively absorbs light, while rain increases the ice’s transparency. Research results from the Norwegian IPY project CLEOPATRA was recently published in the Marine Ecology Progress Series, showing that light conditions to a large extent determine the food quality of sea ice algae.

- Marine algae are the only source of essential long-chain omega-3 fatty acids that are of prime importance in polar regions, where most organisms store metabolic energy in terms of lipids to survive long periods without sufficient food access, says researcher Eva Leu, who conducted the study.

Leu and her colleagues from the CLEOPATRA project carried out an extensive seasonal study in Rijpfjorden, Svalbard in 2007, where they observed how algal biomass and food quality changes over time dependent on several different factors, amongst others; light. Their results are quite clear: algae that were exposed to high light intensities contain lower percentages of omega-3 fatty acids and therefore represent poorer food for grazers.

The crucial role timing and food quality of ice algal blooms play for the key grazer Calanus glacialis (a copepod) have also been described by the same group in the journal Global Change Biology. Their work have also been featured in the Norwegian research webzine forskning.no.