Antarctic Marine Life Vulnerable to Climate Change

CAMBRIDGE, UK, September 10, 2002 (ENS) - Global warming is changing the life patterns of marine species in Antarctica as fast, if not faster than anyplace on Earth, say scientists from the British Antarctic Survey (BAS). Thousands of Antarctic marine species, adapted to constant temperatures for millions of years, now appear to be uniquely vulnerable in the face of predicted temperature change, new research reveals.

The Antarctic marine environment has the most constant temperature on Earth, with some sites seeing temperature variations of only 0.1 degree Celsius throughout the year, says BAS scientist Dr. Lloyd Peck.


Amphipod crustacean on the Antarctic sea bed (Photo courtesy BAS)
These marine temperature conditions have existed around Antarctica for 10 to 15 million years. As a result, the cold blooded animals living on the Antarctic seabed have developed only limited ability to cope with temperature change.

In a recent paper in the journal Science, Dr. Peck described his work on Antarctica's Signy Island, where temperatures vary more than most places in the Southern Ocean, although by only 1.5 degrees Celsius annually.

Many cold blooded species in Antarctica grow to giant size, because of the high levels of oxygen present in cold water environments. Dr. Peck describes sea spiders over 30 centimeters across, and isopods, the relatives of woodlice, over 13 centimeters long.

"It would thus appear that some of the worlds most exotic and impressive marine species are amongst the most fragile in the face of predicted rising temperatures," he says.

Average temperatures have risen by around one degree Celsius in 15 years, Dr. Peck observes. As a result, open water periods have been extended by around four weeks, and microalgae and nutrients in the water increased by two to 10 times, he reports.

These changes are also associated with what Dr. Peck describes as "a large reduction in ice cover on the island, of around 40 percent in some areas."


British Antarctic Survey research station Signy Island, South Orkney Islands (Photo courtesy BAS)
UK government meteorologists at the Hadley Centre are using one of the world's fastest supercomputers to create environmental climate change models. They predict that global sea temperature will rise by around two degrees Celsius in the next 100 years.

The polar seas are predicted to warm by at least the global average from a current summer temperature of zero degrees Celsius to between two and three degrees above zero, the very temperature at which these species will have trouble surviving.

Dr. Peck says that a rise of two degrees Celsius in Antarctic waters will elevate temperatures to those that "compromise animal capability, at a time when restricted summer food supplies are available and many species need to feed."

There are 750 species of amphipods in the Antarctic that may be affected. "We're talking about thousands of species in total," Dr. Peck said.

"The isolation of Antarctica means that scope for migration in the face of a changing environment is restricted," he said. "Life cycles are long, reducing the ability to adapt biologically to change. The prospects are not encouraging."