Icebergs Cause Seabed Disturbance

Marine life calling the Antarctic Peninsula home are being threatened by a common friend, the iceberg. New data suggests this environment along the Antarctic Peninsula is going to get hit more frequently by the icebergs. This is due to an increase in the number of icebergs rubbing the seabed as a result of shrinking winter sea ice.

Nearly 80% of Antarctica's marine life is found on the sea floor and the icebergs are crushing these animals and plant life. Although icebergs do promote biodiversity by creating space for marine wildlife, to much scouring done by these icebergs could cause key species to be moved from their habitats or affect the type and number of animals living in the Antarctic waters.

Scientists from the British Antarctic Survey (BAS) headed by lead author Dr. Dan Smale researched the relationship between the destructive acts of these icebergs and the decrease in water sea ice. Dr. Smale said, “It has been suggested previously that iceberg disturbance rates may be controlled by the formation of winter sea ice, but nobody [has] been able to go out and measure it before. We were surprised to see how strong the relationship between the two factors is."

Dr. Smale went on to say that during periods of long sea ice seasons, lasting up to eight months, the disturbance caused by the icebergs was really low. Unlike when the sea ice season is short, the seabeds are pounded constantly by icebergs causing a lot of disturbance among marine life. Dr. Smale believes this disturbance is caused by the icebergs themselves. "Icebergs are locked into position by winter sea ice, so they are not free to get pushed around by winds and tides until they crash into the seabed.”

Dr. Smale and his team placed markers in a grid pattern on the seabed at three different depths for five years. BAS scuba divers were then able to determine the frequency of any iceberg scraping the bottom by counting the number of damaged or destroyed markers.

Icebergs have long been speculated to be the driving force behind destruction of the seabeds and the displacement of many species in the Antarctic Peninsula. Now, with the knowledge of the special bond between winter sea  ice, icebergs, and the sea floor wildlife, protective actions can now be established and executed to help protect the marine life of the Antarctic Peninsula.