More algae

I had a question from Granny about the algae trapped in the ice. Here are a couple more pictures. The algal mats grow at the bottom of the lakes (and in the stream beds and practically anyplace where they can find liquid water). They are photosynthetic, so sometimes they get loaded with oxygen gas bubbles. Chunks of the mats get torn off and float up to the ice cover. They get trapped there under the ice. The top photo shows bits of algal mat that have worked their way to the surface of the ice on the moat near Lake Hoare camp. Each little bit of mat is followed by a bubble trail. Maybe the mat melted its way up through the ice by differential heating? It looks very strange.
The botton picture shows more algae chunks on the ice surface. I'm not sure how that happens exactly, but the lake ice acts as a slow conveyor belt moving things up as the ice surface is constantly ablated and new ice forms on the bottom of the ice. It probably takes at least a few years for the algae to make that trip through the ice.