The Polar regions: Witnesses to the future
Icebergs destroy life
At 30 metres below sea level, the direct effect of UV-radiation is less noticeable, but Arctic marine life is also suffering from climate change here. Due to warming, more icebergs are released, and move more as well.
"Antarctica is rimmed by miles of ice fields, sliding towards the sea. They form ice shelves, calving icebergs in their turn. This phenomenon has always occurred, but we notice that the ice shelves are breaking up much faster in the last ten to twenty years. Lots of square miles have disappeared completely. This is a major effect of warming: over 50 years the average annual temperature around the Antarctic Peninsula has risen by 2,4°C, which, at about freezing point, means of course a lot.”
Crustaceans: an important link in the ecology chain
As a matter of fact, the team doesn’t directly investigate into the effects of global change. Claude De Broyer has specialized in carcinology, the study of crustaceans, and amphipods get his special attention. During the last years, the deepest zones of the ocean have been searched thoroughly for crustaceans. But these unknown zones have also yielded many new species of fish, sponges, molluscs etc.
"The faunal biodiversity of Antarctica is still largely unknown, and the crustaceans are the most species-rich group of the Antarctic seas. More than 800 new amphipod species are registered so far. Hundreds of unknown species are collected in the deep sea, at more than 1000 metres below sea level. This means that life is rich and diversified there. We are also analysing the crustacean’s role in the ecosystem: once we understand it, we’ll be able to predict more accurately the effects of climate change on the food chain. And, consequently, on all life in the ocean...
The members of the expedition discovered that icebergs scrape the ocean floor, and completely destroy the biocenosis (association of living creatures in the area). Ten percent of the ocean floor dwelling organisms around the continent are likely to suffer the impact of the increase in icebergs. “A priori, it isn’t a problem, since these associations can recover,” explains Claude De Broyer, “but light cycles and ice coverage severely limit the primary production period and the food production in these areas, which makes the recovery last for tens or even hundreds of years”.
In order to assess the long-term consequences of this disturbance, the BENDEX (Benthos Disturbance Experiment) project was set up. For that reason, a floor surface of 1 km by 1 metre has been artificially disturbed. Here, the recovery capacity of benthic associations will be monitored for the next ten years.
In January begins the ANDEEP III expedition, in collaboration with German colleagues. The Polarstern, a German icebreaker, equipped for oceanic research, leaves port for a three month exploration of the southern ocean.
