Detective work through poo analysis

A Cawthron Institute scientist has just come back from an unusual Antarctic mission where he was constantly in the poo.

Jonathan Banks specialises in faecal DNA and has spent three weeks collecting samples from seal and penguin colonies spread over 40 kilometres. With eight other researchers he also ice-fished for fish samples that he can compare with faecal DNA.

"I'll match the DNA sequences from the poo, with the DNA sequences from the fish samples and then we'll know what they're eating," he said.

The project, funded by the New Zealand Antarctic Research Institute, is looking at the impacts of climate change and commercial fishing on Antarctica's top predators.

"As fishing pressure is increasing we need to understand what these species are eating and how fishing activity will affect them," Dr Banks says.

The year-long study is examining the diets of killer whales, Weddell seals and Adelie penguins to help understand critical food resources needed for their survival.

The team's research will also provide reference points for detecting future changes, and allow for responsible management of the Ross Sea.

While in Antarctica, Dr Banks extracted DNA from the samples to bring back to Cawthron's laboratories for analysis.

Working from a small laboratory at Antarctica New Zealand's Scott Base, he extracted approximately 5 millilitres, or one teaspoon, of DNA in total from about 50 different animals. The DNA samples were transported back to New Zealand in separate vials each containing about 0.5 millilitres of faecal DNA.

Scientists from the Smithsonian Institution, University of Tasmania, NIWA, Landcare Research, University of Auckland, Lincoln University and University of Canterbury are all working on the project. Its principal investigator is Regina Eisert from Gateway Antarctica at the University of Canterbury.

"Climate change and commercial fishing are two potential drivers of change in the Ross Sea, but our ability to predict or manage impacts is limited by lack of information," Dr Eisert said.

"Antarctic top predators integrate complex changes in the physical and biological conditions affecting their food resources, making them ideal sentinels for the state of the Ross Sea ecosystem."

It was Dr Banks' eighth trip to Antarctica. Previously, he has studied penguin lice to understand their evolution, and used genetics to identify the faecal bacterial communities of seals, penguins and skuas.

At Cawthron, he works on faecal source tracking, working with councils throughout New Zealand to identify the sources of faecal contamination in marine and freshwater environments. His methods are so precise that, through DNA fingerprinting, he is able to identify the source of faecal contamination in a river, lake or sea, down to the species responsible.

Before Antarctica, he was in Edmonton, Canada. "I was walking to work in minus 25 degrees and was looking forward to my trip to Antarctica so I could warm up in minus 5 degrees," he said.