Today we were able to have a look underneath the sea ice surrounding Scott Base. We would have never expected to see this amount of life just a couple of meters below our feet.
Sea ice is just frozen ocean water, growing in winter and melting in summer. At its bottom it is exposed to the cold, relatively low-salinity water flowing out from beneath the Ross Ice Shelf. It is here where parts of the supercooled meltwater coming from the Darwin glacier meet the ocean surface and are recrystallizing again. These tiny ice crystalls are growing slowly to the size of a hand while they rise towards the surface and get stuck beneath sea ice. This layer is called “plateled ice” and is home to a large variety of organisms.
Sea ice is thin enough to let sunlight through which allows algae to grow. This algae forms the beginning of the food chain, feeding crill, fish and eventually seals and killer whales. The “observation tube” let us climb below the sea ice, where glass windows allow an insight into this fascinating underwater world. It was the most colourful place we have seen during the last month and its surreal inhabitants made us feel like “sea-icetronauts “.