Life in a cold environment - Antarctica: Global Science from a Frozen Continent - page 161

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Life in a cold environment

PETER CONVEY, ANGELIKA BRANDT AND STEVE NICOL

The ship was stopped to take soundings and to dredge, and a good haul
was brought up from the bottom of the most beautiful things imaginable.
The bottom of this sea must be covered with the most wonderful collection
of star sh, sea urchins, Polyzoa, crustaceans, etc. All fairy-like delicate
things that reminded one much more of the Tropics but all living at a
temperature of 29 F.

Edward Wilson, Diary of the Discovery Expedition

Antarctica is a good place to study both evolution and adaptation. Despite the low
temperatures and lack of liquid water on land, and the effects of sea ice and
temperatures just above freezing in the sea, Antarctic organisms have found ways
not only to survive but to thrive in what to us seem very dif cult environmental

conditions. Its unusual evolutionary history, from Gondwana supercontinent to the
present day, together with a climate that has now been cold for at least 25 million
years, gives Antarctic biodiversity some unique features, whilst the survival
techniques that its plants, animals and microbes have developed can provide
important insights into the physiological and biochemical ways in which organisms
function. It is on land that physical environmental extremes are perhaps most
obvious, and the continent

s terrestrial habitats include some of the coldest, driest,
windiest and most abrasive to be found anywhere on Earth. Less than 0.4% of the
Antarctic is ever free of ice or snow cover, and even then this may be for as little as a
few days or weeks during the height of the summer. In this respect Antarctica is
strikingly different to the Arctic. The latter experiences a similar radiation
(daylength) regime, determined by latitude, which means that both polar regions
face similar thermal stresses during their winter months when the input of solar
energy is absent. In summer, the almost complete ice cover of Antarctica gives it a
very high albedo, re

'

ecting virtually all incoming solar radiation back up through