On the return of the Polarstern vessel of the Alfred Wegener Institute (AWI) for Polar and Marine Research in the German-based Helmholtz Association, scientists reported that organisms found in the Atlantic region of the Southern Ocean were not adapting quickly to changes in the environment.
“An initial evaluation of the measurement data shows that the temperature down to great depths of the Weddell Sea continues to rise,” explains Dr Fahrbach, who was in Antarctica on the Polarstern from November 2010 to February 2011.
The Weddell Sea is a favourite haunt for German polar researchers, located near the Antarctic Peninsula and part of the Southern Ocean itself. There is already an existing network of moorings and floats that measure temperature, sea ice thickness and salt concentration, and each time the Polarstern heads back out, more measurements are taken using floats and satellites to transmit their information.
One of these measurements was the temperature of the Weddell Sea, which saw rising temperatures in the deep water of the region. But while the waters warmed, the organisms found therein were not adapting quickly to the change in temperature.
According to the researchers on board the Polarstern vessel, the data collected help our understanding of the role that the Atlantic sector of the Southern Ocean plays in large-scale climate events.
According to Dr Fahrbach, the temperature in the Weddell Sea has increased by six-hundreds of a degree on average across the entire water column in just a little over a quarter of a century.
“This temperature rise seems small,” says Dr Fahrbach, “but because it extends down to great depths, it entails a considerable heat volume that is stored in the ocean. This contributes to the fact that the atmosphere heats up less than expected as a result of the increase in the greenhouse effect. According to the World Climate Report (IPCC), more than 80% of the heat that Earth has additionally absorbed thus far due to the altered greenhouse effect is stored in the upper ocean layers down to a depth of 1 500 metres. Now we have been able to show that the deep ocean with its enormous volume is also involved in this process.”