The Arctic Ocean Teems With Activity During the Long Dark Winter

Winter in the Arctic Circle is bleak. In Ny-Ålesund, a Norwegian research town in the Arctic, the noontime sun doesn’t even break over the horizon on some winter days. While you might think that wildlife goes into hiding in the darkness of the polar winter, a new study finds that the Arctic Ocean is anything but dormant during the coldest, darkest time of the year.

The study, in Current Biology, examined ocean activity over three different winters, finding that in some habitats, the winter was an even more active time than the sunny summer. "Biodiversity, abundance, growth, and reproduction in habitats studied were at similar or higher levels” than in warmer months, the researchers write. 

What noon looks like in Ny-Ålesund in the winter

Some birds stuck around for the winter, hunting for fish throughout the dark winter—a previously unobserved phenomenon. Plankton were found throughout the water column. The researchers observed some male crustaceans that are rarely seen during the summer months, indicating that the winter months are an important time for reproduction. While some fish seemed to be fasting for the winter, some cod and haddock species had nearly full stomachs, meaning that those predators feed throughout the season—though the researchers still don’t know how they do it in the darkness.

A black guillemot wades in the dark waters.

All this suggests that vision may not be as important to these animals as previously thought, since they apparently can find food and sustain themselves throughout a season sans sunlight. However, this study took place over the last three years, when the ocean was slightly warmer during the winter and the frozen fjords had melted slightly to allow the scientists to look beneath the surface of the ocean. It’s not clear if this level of activity has always existed beneath the ice, or if there’s been a slight uptick in winter activity due to climate change.

[h/t: BBC]

All images by Prof Geir Johnsen (NTNU)