What's Behind the Arctic's Mysterious Green Ice?

It should be dark under the ice cover of the Arctic, and yet in 2011, scientists were perplexed when they discovered phytoplankton blooming beneath it, giving the ice a greenish hue.A large bloom of phytoplankton, which is algae, was first found growing under the Arctic sea ice in 2011.New research has shown, however, that the thinning sea ice allows enough light to pass through for the phytoplankton to bloom.