Krill drift with sea ice shelter

Krill under the sea ice.
Sea ice protects larval krill from predators and carries them to food-rich areas. (Photo: Ulrich Freier)
A single Antarctic krill.

13th November 2017

Sea ice protects larval krill from predators and carries them to food-rich areas, according to new international research that involved six Australian Antarctic Division personnel.

The research, conducted in 2013 onboard the icebreaker Polarstern, as part of a German-led multi-disciplinary project, brought together scientists and support people from eight countries to learn more about sea ice and the marine species associated with it.

Led by Dr Bettina Meyer from the Alfred Wegener Institute, and including Australian Antarctic Division sea ice ecologist Dr Klaus Meiners, the study found that the pack-ice zone contains little food, but does serve as an important sheltering ground for developing larvae.

“Until now, winter sea ice has generally been thought to provide critical feeding habitat for overwintering Antarctic krill,” Dr Meiners said.

“However, through our research on the Polarstern, we’ve discovered that sea ice is more important as a refuge against predation during winter, and serves as a drifting platform to transport larvae into more productive waters.”

The leader of the Australian Antarctic Division’s krill research program, Dr So Kawaguchi, said the strong collaboration between the Antarctic Division and the Alfred Wegner Institute in experimental krill biology, had been one of the major driving forces for advancing understanding of Antarctic krill biology in the last decade.

Dr Kawaguchi said the Polarstern campaign integrated behavioural observation using a diving team, under-ice observations using a Remotely Operated Vehicle, and an around-the-clock continuous sampling system.

Australia’s team of six scientists and science support personnel on the voyage played key roles in understanding the day/night migration of krill larvae under ice, as well as their distribution pattern within the under-ice structure.

A number of other Australian scientists contributed to the interpretation of results through their expertise in sea ice habitat modelling for krill larvae.

The research is published today in Nature Ecology and Evolution.