As the Arctic warms, light pollution may pose a new threat to marine life

Photograph by Michael O. Snyder
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A research vessel pilots a team of Arctic research scientists through ice north of Svalbard, Norway. Working in the middle of polar night, little light is visible. The team wears survival suits in case the boat capsizes, and they carry rifles in the event they stumble upon a polar bear.


The Arctic Circle in the middle of winter is so dark it's hard to see. Because of the way the top of the Earth tilts away from the sun, the star never appears to rise above the horizon, and dark skies drench the Arctic in what’s known as polar night.

“It kind of feels like you’re working the night shift all the time,” says Finlo Cottier, an oceanographer at the Scottish Association for Marine Science.

Two years ago, Cottier and a team of scientist traveled to the Arctic in the middle of winter to study how light affects the marine critters living in far northern waters. Like us, marine organisms rely on light to guide their daily functions. Light indicates behavior like when to migrate through the water column to find food, when to mate, and where to hunt.

“In June and July, there is this explosion of growth and activity,” says Cottier. “How do we get to that point? What happens in the polar night that sets things up for this spring bloom? We’re trying to understand the complete cycle.”

Understanding that complete cycle will be critical as the Arctic grapples with climate change. Thinner ice means more light will be able to penetrate dark ocean waters. It will also mean more ships will pass, bringing light with it. And warming waters around the world are pushing certain fish species to higher latitudes, disrupting the food web.

What it all means for marine life is yet unclear, but new...

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