Robot gliders probe iceberg’s impact on penguins

For the next four months, robotic submersible vehicles will swim the frigid, choppy waters around South Georgia island, gathering evidence to determine whether a massive Antarctic iceberg might have harmed wildlife there, scientists said Wednesday.

The iceberg, known as A68a, approached the South Atlantic island as a single block of more than 4,000km² in December, then began breaking into enormous chunks that have since swirled around the island on counter-clockwise currents.

Even broken up, A68a and its baby bergs could still disrupt the local environment, said Geraint Tarling, an ecologist with the British Antarctic Survey (BAS). The largest chunk now covers almost 900km², about the same size as the Scottish island of Mull.

“Many of these icebergs could still go in and scour large areas of the seabed,” he said. “They could become lodged in bays or obstruct routes of penguins out to their feeding grounds.”

Scientists with the BAS and Britain’s National Oceanography Centre said they were launching two 1.5-metre-long submersible gliders to gather evidence of how the freshwater melting off the ice is affecting the surrounding seawater.

The battery-powered robots will measure water salinity, temperature and chlorophyll content, periodically popping out of the water to transmit data and receive instructions by satellite from Britain. The gliders will also observe any impact on ocean plankton, which could ripple up the food chain, the scientists said.

“We are almost nannying these things, watching over them all the time,” Tarling said.

Debate is ongoing over whether A68a’s initial split from the Antarctic ice shelf in 2017 was due to rising global temperatures.