Antarctica is probably the Earth’s most important continent for influencing global climate and ocean ecosystem function. Winds descending off the continent cool the surrounding seawater, causing an annual formation of sea-ice stretching up to 20 million km2 (about 2½ times the area of Australia). The cooling has two effects: it causes seawater to become more dense, and salt precipitates from the sea-ice as it forms, so the sea-ice essentially becomes fresh water. As a result, a downward force is generated that drives global ocean currents.
The cold Southern Ocean surrounding Antarctica also supports the growth of phototropic microbes that harvest the sun’s energy and fix CO2 from the atmosphere. These microbes, and others that recycle nutrients, represent the beginning of a marine food web that feeds krill and all other ocean life.
As one of the tiniest forms of microbes, viruses play essential roles in all of the Earth’s ecosystems. Viruses may cause about 20% of the cellular microbes in oceans to lyse and die each day, causing nutrient turnover and further microbial growth (http://tinyurl.com/abmjhtf). Viruses play particularly important roles in the Antarctic because its waters harbour fewer larger predators, so viruses can contribute even more to the natural turnover in these...
