Krill are widely recognised as the linchpin of the global ocean food web. Remarkably, very little is known about the diet of krill themselves.

The mystery of the krill diet has led Molly Jia, a PhD student at the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS), to embark on at least two unexpected research journeys.

The quest for an ecosystem model giving shape to the beginnings of a Southern Ocean food web in winter has brought Molly to the business end of her thesis, due in December. Building such a model requires an understanding of the diet of Antarctic krill and other lower food chain species. Molly identified a clear gap in the research, particularly in the underpinning influences of winter diets. She joined the 2012 SIPEX-2 (Sea Ice Physics and Ecosystem eXperiment) voyage into the Southern Ocean to collect winter samples. The voyage was funded by the Australian Antarctic Division and the Antarctic Climate & Ecosystem Cooperative Research Centre.

Molly’s field work involved deploying special fine nets to a depth of 100m. When the nets were retrieved, the captured krill and other planktonic life were frozen in liquid nitrogen for later chemical analysis of their diet.

The scheduled month-long voyage blew out to six weeks when the ship became ice-bound. It was a special chance for Molly, 29, whose research quest brought her from her home city of Huhhot, in Inner Mongolia, to Tasmania.

The opportunity to learn from the strong research teams aboard the ship as it drifted in pack ice just outside the Antarctic Circle was not wasted.

Molly’s thesis will contain comparisons with planktonic analyses from a similar late-winter voyage in 2007. The data from both voyages led to the food web ecosystem model that has filled the gap in scientific knowledge.

This research will also be used in management and planning at the Commission for Conservation of Antarctic Marine Living Resources, the international management secretariat representing 30 nations and based in Hobart. Guiding Molly have been her five supervisors from the key Hobart-based research institutions – Dr Patti Virtue and Dr Kerrie Swadling from IMAS; the ACE CRC’s Dr Klaus Meiners, who was chief scientist on the 2012 Aurora Australis voyage; and Dr So Kawaguchi and Dr Simon Jarman, from the Australian Antarctic Division.

The University of Tasmania is the primary funder for Molly’s research, with top-up funding from the ACE CRC, while laboratory analysis was made possible by support from the Holsworth Wildlife Research Endowment.

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