Arctic diatoms

This microscope image shows various species of ice algae, magnified 400x. The dominant one you can see, which forms strands of individual algae attached end-to-end, is known as Melosira arctica. This centric diatom is endemic to the Arctic and is often associated with the high Arctic. It can grow into metres-long colonial strands, which resemble algae curtains attached to the ice. 

The sample imaged here by Karley Campbell of the University of Tromsø was scooped from the side of a research ship using a fishing net.