The term “tundra” refers to cold, treeless plains characterized by low temperatures, minimal precipitation, and short growing seasons, often with permafrost. While Antarctica is largely covered by a massive ice sheet, it has small, ice-free areas that resemble tundra ecosystems. These regions support unique life adapted to extreme cold and dryness.
The Harsh Antarctic Environment
Antarctica is the coldest continent on Earth, with average annual temperatures ranging from -10°C along the coast to -60°C in the interior. Temperatures have been recorded as low as -89.2°C. Nearly 98% of the continent is covered by an ice sheet averaging at least 1,500 meters thick, holding about 90% of the world’s ice.
The continent is also extremely dry, qualifying as a polar desert with average precipitation of only about 166 mm per year, primarily as snow or ice. This low precipitation is due to dry, subsiding air over the interior, which limits cloud formation. Strong katabatic winds, formed as cold, dense air flows downhill from the elevated ice sheet, sweep across the landscape, often exceeding 100 km/h and gusting over 200 km/h near the coast. These combined factors create an environment where widespread plant growth is largely impossible.
Life in Antarctica’s Ice-Free Oases
Despite the continent’s harsh conditions, less than 0.5% of Antarctica’s landmass remains ice-free, providing habitats where tundra-like ecosystems can develop. These “oases” are found primarily along the Antarctic Peninsula, parts of continental Antarctica, and various islands. These areas support unique flora, including “micro-forests” of lichens and mosses, which are the dominant vegetation.
Two species of vascular plants, Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis), are also present, with limited distribution. Beyond plants, these ice-free zones host microscopic invertebrates such as tardigrades (water bears), nematodes (roundworms), mites, and springtails. These tiny creatures, along with various algae and microbes, form a simple but resilient food web.
Unique Adaptations for Survival
Antarctic life forms exhibit adaptations to survive the continent’s extreme cold, desiccation, and high UV radiation. Lichens, for instance, can photosynthesize even when frozen at temperatures as low as -20°C and absorb water from a saturated atmosphere or from snow and ice. They endure long periods of drought by entering a dry, inactive state. Their slow growth rates, sometimes as little as 1 cm per 1,000 years, reflect an energy-efficient survival strategy.
Mosses, which are poikilohydric, tolerate being dried and frozen under snow for up to nine months annually, resuming growth during the short summer when meltwater becomes available. They also produce UV-screening compounds and xanthophyll cycle pigments to protect against intense sunlight. Invertebrates like springtails and mites employ cryoprotection strategies, accumulating antifreeze compounds to reduce the freezing point of their bodily fluids, allowing them to survive temperatures below -25°C. Many microorganisms can enter a suspended metabolic state called cryptobiosis or anhydrobiosis, enabling them to survive prolonged desiccation and extreme temperatures, reviving with moisture.