Ice is overturned as the ship moves through it, exposing the underside of the ice. The brown color and streaks are ice algae that live on the underside of the ice and in the interface between the ice and snow. This time of year, when the sunlight increases, algae bloom in the ice. They absorb visible light, using it for photosynthesis. Excess absorbed energy is transformed to heat, which stimulates the melting of sea ice where the algae accumulate.
Antarctic krill graze the algae along the underside of sea ice.
They, in turn, are the major source of food for whales. Our measurements are collected in two ways. For thin ice measurements , we are suspended over the ice in a cage by the ship's crane. Tom Grenfell, Collin Roesler and Richard Brandt make measurements of spectral albedo over a thick snow covered ice floe. Transmission will be measured subsequently by placing a radiometer underneath the floe.