As ice thaws on Lake Erie, sediment is re-suspended and phytoplankton change, reflected in the swirling patterns and colours in NASA Earth Observatory's Image of the Day. This image was taken on March 10, one of the sampling and data collection days of Dr. Mike McKay's team at GLIER who are studying how the ecosystem changes from winter to summer. They are looking at populations of diatom algae, and how they use the ice as a substrate to stay near the surface to gather light during the winter.