Ancient Adélie penguin sites may reveal whether birds’ diets changed in the past, and investigations continue into the effects of carbon dioxide on marine microbes during the 2013/14 Antarctic season, which begins today with the departure of the research and resupply ship, Aurora Australis, from Hobart.

Australian Antarctic Division seabird ecologist, Dr Barbara Wienecke, will head a ‘penguin archaeology’ project on abandoned Adélie sites in a bid to determine whether the birds’ diet may have changed over the past few thousand years.

“We will be digging down into the old soils formed from bird waste and looking for the remains of prey, such as otoliths (fish ear bones) and squid beaks.

“It is the first time this type of work has been done in the Davis region and we are hopeful of finding out whether Adélie diets changed in the past, for example, from krill to fish-based diets,” Dr Wienecke said.

“Gaining this knowledge can help manage Southern Ocean fisheries to avoid disrupting the Antarctic food chain.

During her five months at Davis station, Dr Wienecke, who is a recent Australian Antarctic Medal recipient, will also monitor snow petrels and collect scat samples of various flying birds for genetic analysis.

“Cameras that we have installed over the past seven years will help determine if the birds have returned to the area, if they have new partners, if they are breeding and if their eggs are hatching and chicks surviving.

“The scat analysis will tell us what the birds are eating,” Dr Wienecke said.

In a separate project at Davis, Australian Antarctic Division microbial ecologist, Dr Andrew Davidson, will continue investigations into the effects of ocean acidification — caused by increasing levels of atmospheric carbon dioxide (CO₂) dissolving in the Southern Ocean – on microbes such as phytoplankton and bacteria.

Dr Davidson’s team will grow natural communities of Antarctic marine microbes in six 650-litre tanks or ‘minicosms’, set up in a shipping container, and observe the effects of different CO₂ concentrations on those communities.

“Microbes are the base of the marine food web, directly or indirectly supporting all life in the Southern Ocean. They also drive the ‘biological pump’, the process by which marine life transfers CO₂ from the atmosphere to the deep ocean storing it for hundreds to thousands of years” Dr Davidson said.

“However, the concentration of CO₂ predicted in seawater by the end of this century may dramatically change the composition of these communities by altering food webs, having an impact on iconic Antarctic wildlife — such as whales and seals — and reducing the efficiency of the ‘biological pump’ with consequences for global climate.

“This season’s work will help to refine our understanding of the effect of ocean acidification on microbial communities and, in turn, assist in predicting future responses and informing policy development to protect the Antarctic ecosystem,” Dr Davidson said.