Splash. A Weddell seal weighing almost 500 kilograms lands inside the tent and blocks the hole laboriously sawn out by researchers in the two-meter-thick ice to launch drones under the sea ice.
The tent is lovely and warm. Small petroleum ovens provide heat to keep the hole free from ice. Outside, the Antarctic sea ice stretches for miles around, and the thermometer shows -15 degrees. The seal finally glides back into the water foraging for more fish, and the researchers have access to the open water. The advanced technology drone is carefully lowered into the icy cold sea.
Working here (right next to the old hut used by polar explorer Robert Falcon Scott in the Antarctic winter) are researchers Lars Chresten Lund Hansen, Brian Sorrell and Ph.D. student Bibi Ziersen from Aarhus University, along with their colleagues from Australia and New Zealand. They are developing and testing a new method to map the distribution of ice algae on the underside of the sea ice in Antarctica.
The tent covers a hole in the ice measuring 3 m x 1 m, and the researchers send their torpedo-shaped underwater drone down through the hole to map the underside of the sea ice. Making the hole takes most of a day and requires a major equipment package with an oil burner and steam drill.
“The drone was actually designed to study the sea bed and map factors, such as sediment types, but our Australian colleagues modified the drone so that it now looks up towards the bottom of the sea ice and measures the light coming through the ice with a radiometer,” says Associate Professor Lars Chresten Lund Hansen, Aarhus University.