Antarctica is Earth’s coldest, driest and windiest continent, but many resilient life forms have adapted to survive the harsh environment. Among them is Earth’s tallest penguin, the largest mammal and the Antarctic icefish – the only bony animal with transparent blood.
The coldest temperature ever officially recorded was on a high snow plateau in Antarctica, at an altitude of around 3.5 kilometers (two miles) – over twice the height of Britain’s biggest peak, Ben Nevis. Around 99 per cent of the land surface is covered with ice and air temperatures can be so extremely cold that atmospheric water vapor freezes to form ice crystals. These crystals catch the sunlight as they fall, and sparkle like diamonds, hence why they’ve gained the nickname ‘diamond dust’.
High altitude renders Antarctica considerably colder than its northern polar counterpart, the Arctic. Air temperature falls by approximately 6.5 degrees Celsius (11.7 degrees Fahrenheit) with each kilometer (0.6-mile) rise in elevation. Antarctica is also Earth’s fifth-largest continent, and the vast interior receives little heat from the ocean, which is warmer than the ice.
If the climate wasn’t extreme enough, Antarctica experiences 24-hour darkness for a couple of months in midwinter. The continent straddles the South Pole and in late June – southern winter – the pole is tilted away from the Sun. Even in summer, most incoming sunlight is absorbed by Earth’s atmosphere before it can warm the ground.
Still, unlikely as it may seem, animals and plants survive in Antarctica’s ice-free regions. In the windswept McMurdo Dry Valleys, the continent’s biggest ice-free area, fungi and algae manage to thrive inside the insulated blanket of sandstone and granite rocks.
The continental coast and Antarctic Peninsula are host to only two flowering plant species. The biggest creatures include mites and primitive insects called springtails. Just one to two millimeters (0.04-0.08 inches) long, they have natural antifreeze in their blood, and they feed on a variety of moss, lichens and other tiny plant life available to them.
In contrast, the Southern Ocean encircling Antarctica is among Earth’s most biologically rich oceans. The melting of sea ice in the spring draws nutrient-rich waters from the depths, feeding phytoplankton. Incredibly, a liter (0.3 gallons) of water can contain more than a million of these tiny life forms.
The phytoplankton are eaten by krill, the powerhouse of Antarctica’s ecosystem. These shrimp-like creatures can grow to six centimeters (2.4 inches) long and form swarms big enough to see from space. They are the food source for most Antarctic predators, including the blue whale – Earth’s biggest animal. During the feeding season, a blue whale can consume 40 million krill on a daily basis!
Most of the world’s seals also live in Antarctic waters. These carnivorous mammals live, hunt and can even sleep underwater. Elephant seals also hold the record for having the biggest relative size difference between males and females of any mammal.
The most common birds in this frozen land are penguins, though of Antarctica’s 17 species, only five breed on the continent itself. Emperor penguins – the world’s tallest, largest penguin – live exclusively in the Antarctic. Males go without food for nine weeks during winter while incubating their eggs, and the females make a long, perilous journey to seek food for when the chicks hatch.
Islands in the Southern Ocean, surrounding Antarctica are wetter, milder and have more varied vegetation than the mainland. Bird Island, South Georgia, for example, has an average summer temperature of four degrees Celsius (39 degrees Fahrenheit). Its dominant coastal vegetation is tussock grass, which can grow to two meters (6.6 feet) tall.
Even Antarctic icebergs can be home to life. Young icefish hide from predators in holes in the ice. Snow petrels also nest on the bergs, which are generally safer than the mainland.
Antarctica was not always an icy desert. Dinosaurs and other megafauna lived in Antarctica when it was warmer. For instance, fossils of a car-sized armadillo, which lived around 45 million years ago, were discovered near the Antarctic Peninsula. Fossilized pollen evidence even shows that rainforests grew on the continent around 52 million years ago, but eastern Antarctica began to freeze over some 34 million years ago, when Earth’s climate cooled dramatically.