Oceans in Crisis - Ocean Worlds: The Story of Seas on Earth and Other Planets - page 180

Life in a Warmer Ocean
The warming of the last century has produced changes in life on land
as plants and animals have migrated to follow the climate belt that
best suits them. On land, temperatures naturally vary from day to
night and from day to day, and living plants and animals must adapt
to such conditions. The ocean waters, though, because of their bulk
and their capacity to store heat, are much less prone to such short-term
fluctuations. Marine organisms, therefore, are used to living in more
uniform temperature conditions, and are more sensitive to changes
in temperature. The results of even slight temperature changes can
look scary.
Take, for example, the television pictures beamed, in 2010, up from
a remotely operated vehicle that was trundling along the sea floor off
the Antarctic Peninsula to its mother ship, the research icebreaker
R.V. Nathaniel Palmer . The crew huddled around the screen were per-
plexed, for something strange was happening down there, almost a
kilometre and a half beneath them. They were used to seeing the typi-
cal life forms of the Antarctic sea floor—sea lilies, brittle stars, and
peculiar forms of sea cucumber, stumping around the sea floor on
short legs. These are archaic faunas, more like throwbacks to the far-
off Palaeozoic age than the typical denizens of the modern deep sea.
But there was a bare patch there. Then, the watching scientists saw
why. A red crab, its legs spanning the diameter of a large dinner-plate,
walked into view. Then another. And another. They were looking for
food, and the long-isolated creatures of the Antarctic sea floor were
easy prey.
The crabs had arrived with the warmer water that is now imping-
ing ever deeper into the normally frigid Antarctic bottom regions. 103
It is the beginning of a classic biological invasion. If it continues, as
seems likely, it will devastate the pristine ecology of the deep polar