Life in a cold environment - Antarctica: Global Science from a Frozen Continent - page 189

Figure 6.18 Kelp beds around the coast of

Iles Crozet, which are important spawning
grounds for many Antarctic fish. (Credit:
D.W. H. Walton)

are most sensitive to UV in the littoral zone, but most species also occur in the
sublittoral. It seems that UV sensitivity, along with ice scouring, is an important
factor in uencing the zonation of these macroalgae along the coast. Dispersing cells

are also adapted to function in low light conditions, with photosynthesis further
depressed by exposure to UV radiation. Even with the possession of chemical
defence mechanisms against invertebrate grazers, macroalgae are centrally
important primary producers - given their often remarkable abundance they are

likely to play a signi cant role in mediating energy and nutrient transfer in the

nearshore Antarctic environment. For many benthic animals, e.g. echinoderms,
molluscs, peracarid crustaceans and fish, macroalgae are important not only as a

food source, also providing shelter and space to hide for the offspring.

Terrestrial ecosystems

At first sight, the terrestrial ecosystems of Antarctica appear to provide a direct

and striking contrast to those of the surrounding benthic and pelagic ocean realms.
While the latter are extensive, diverse, include great biomass and have an undeniably
long evolutionary history, habitats on land are sparse and visually barren, biota
are miniscule, their diversity is low and, at least until recently, any historical signal
they provide was thought to be insigni s Antarctic terrestrial

ecosystems are isolated from other continents and from each other. Only about
0.34% of the continental area is not permanently covered by snow or ice, including
nunataks, cliffs and seasonally snow and ice-free areas. Most terrestrial habitats are
found in coastal regions, primarily the Antarctic Peninsula, along with a series of
isolated oases along the coastline of continental Antarctica, and in major mountain
ranges such as the Transantarctic Mountains. Most of these terrestrial ecosystems

cant. Today '