Under the Arctic sea ice, fish and plankton live in complete darkness, even in midsummer. Ice floes stop the sun's rays, especially if they are covered by snow. As the ocean heats up, the sea ice thaws, and new regions are exposed. A recent study warns that climate change will create trouble for cold water fish species in this century. Paired with higher temperatures, changes in the light conditions will make less food accessible when the fish need it the most. The work is published in the journal Nature Communications.