Marine microbial ecology
Marine microbes - single celled plants and animals (phytoplankton and protozoa), bacteria and viruses - comprise most of the living matter in the sea. Photosynthesis by phytoplankton takes up CO2, producing the food that supports, directly or indirectly, the wealth of marine life for which Antarctica is renowned. However, only a small proportion of the carbon taken up flows directly on to organisms such as krill, fish and whales. Most of this carbon is cycled by microorganisms in the so-called microbial loop.
Marine microbes also have major effects on the world's climate. By absorbing carbon dioxide, they contribute to the uptake of CO2 from the atmosphere, thereby moderating the global Greenhouse Effect. The Southern Ocean is one of the world's important 'sinks' where carbon is transported to the deep ocean by sinking particles. Some microorganisms also produce chemicals which, when ventilated to the atmosphere, form aerosol particles that can trigger the formation of clouds.