MELBOURNE, Sept. 8 (Xinhua) -- Larval Antarctic krill could be carried far from their birthplace by drifting sea ice, linking distant ecosystems in ways conventional ocean-current models may miss, new research finds.
The study, published in Global Change Biology Communications, modeled how ocean circulation, sea ice drift and vertical migration influence the overwinter transport of Antarctic krill in the southwest Atlantic sector of the Southern Ocean, according to a statement released Tuesday by the Australian Antarctic Program Partnership (AAPP).
Antarctic krill are a key part of the Southern Ocean food web and are also the target of its largest fishery, the statement said.
"Krill are spending time sheltering in sea ice and use the ice as an extra transport system that moves and connects populations more widely than ocean currents alone," said lead author Aditya Sharma, a PhD student with the AAPP at Australia's University of Tasmania.
Using 32 years of high-resolution ocean current and sea ice simulations, researchers found that greater exposure to sea ice drift reduced krill retention near the Antarctic Peninsula while increasing northward transport toward the Scotia Sea and South Georgia.
Using a particle-tracking model, researchers released virtual "krill" and tracked their movements from April to October. The model indicates a strong tendency for krill to move eastwards away from the Antarctic Peninsula, largely due to the prevailing Antarctic Circumpolar Current.
With ocean currents alone, 17 percent of simulated krill moved east into the open ocean, but when particles spent all available time associated with sea ice, 48 percent moved east away from the peninsula.
The researchers said declining Antarctic sea ice could change the pathways transporting young krill across the Southern Ocean, potentially reshaping connectivity between krill populations and fishing regions. ■
