Scientists explore role of algae in climate change

The Arctic Ocean could be a sink for carbon dioxide, a greenhouse gas linked to global climate change, say scientists studying the marine ecosystem. Researchers from Canada and nine other countries are on board the Amundsen icebreaker off Baffin Island. They're studying the exchange of carbon dioxide between the ocean and the atmosphere, which they say is key to understanding climate change.

As part of the research, an instrument called a rosette is raised from the seabed of Lancaster Sound, stopping at different depths to add water into each of its 24 bottles. It's just 4 a.m. – as Jean-Eric Trembly of Montreal's McGill University prepares to study the samples to learn more about phytoplankton. The tiny photosynthetic algae are an important food source in the Arctic marine ecosystem. They also absorb carbon dioxide from the atmosphere. As sea ice shrinks from warming, the algae could play an important role in slowing climate change, said Tremblay.

"The more open water there is, the more the phytoplankton are able to consume carbon dioxide and limit the effect of the greenhouse gas over the Arctic Ocean," he said. "This is one of the loops that we are looking at, but the net effect of all these processes is not known at present."

Scientists are also looking at the full cycle of carbon as it moves through the food chain, said Karine Lacoste of the Ocean Science Institute in Rimouski, Que. She explained that they're trying to determine what the capacity of the ecosystem is for taking out extra carbon dioxide from cars and industry. Lacoste and Tremblay say they're working to understand if there is more carbon dioxide going into the ocean than coming out, and how melting sea ice may effect the cycle.