COSMOS MAGAZINE
In midsummer the continent is at its balmiest, with temperatures ranging from -2°C to 8°C, though in recent years new temperature records have been set. Gentoo penguin chicks have usually all hatched, creating bustling colonies noisy with squawking young.
In summer, the Southern Ocean’s abundant krill population – with densities of up to 30,000 individuals per cubic metre – attracts many species of baleen whales: humpback, minke, southern right, sei, fin and blue. Seals and penguins enjoy the krill feast too.
As summer wanes and the nights grow darker and longer, lucky observers may spot the mesmerising displays of aurora australis. These southern lights are the result of charged particles from solar winds hitting the Earth’s magnetosphere.
The fleeting summer is now giving way to the cold of winter. Scientists use this window of changing conditions to wrap up their fieldwork and gather valuable data, before preparing to wind down research stations for the winter – such as at the British Antarctic Survey’s Halley VI Research Station.
As temperatures plummet to lows of around -60°C, the continent undergoes a profound transformation. Research stations retain a skeleton crew, and some people even dive beneath the sea ice during the winter months to collect data on the marine underworld.
As Antarctica enters the depths of winter, female emperor penguins lay their solitary egg, then depart the colony to hunt while males begin the long incubation process on wind-blasted ice shelves. Humans celebrate midwinter with varied traditions. In June 1911 Robert Falcon Scott celebrated his 43rd birthday during the British Antarctic Terra Nova Expedition.
As the polar night extends its grip, the southern lights continue to add a touch of magic to the prolonged darkness. Astronomical facilities such as the South Pole Telescope, located at the Amundsen–Scott South Pole Station, at 2,800 metres altitude, are also looking up. It is the perfect place to observe the universe, due to the cold, dark, high-altitude and remoteness.
As recently hatched emperor penguin chicks shiver through their first days, beneath the ice other creatures thrive. Invertebrates – such as the scallops pictured here – don’t risk freezing internally in the subzero waters, but the notothenioid fish between them needs the antifreeze proteins in its blood and body fluids to prevent ice crystals forming.
Finally, the winter begins to release its grip and the dark-shrouded landscapes are touched once again by the returning sunlight of spring. Penguins and seals return to their breeding grounds, and people begin to return south too.
Though Antarctica’s seasons are dominated by winter and summer, a brief spring arrives in October to herald the coming of the long light. With it come scientists from the 55 different countries that operate research programs on the continent.
Following the return of summer research crews – up to 5,000 scientists and support staff – cruise lines kick off their season in November, while the winter snow is still fresh on the ground. As visitor numbers swell and days lengthen, animal populations get busy: seals are mating while penguins court, build nests and lay eggs.
Summer has now properly begun, and a rich tapestry of life threads its way through the bright landscape. This month is the height of activity for many species: penguin chicks hatch, both baleen and toothed whales begin to return and seal pups make their debut.