Team will collect samples in the Antarctic to prove role of mammal in function of the oceans

Most people go out of their way to avoid even the faintest whiff of excrement, but a team of scientists is now preparing to voyage for seven weeks to the Antarctic so they can collect blue whale faeces and examine its impact on biodiversity and climate change.

“The most detailed whale poo expedition ever,” as the participants have dubbed it, aims to test a theory that waste from the world’s biggest mammal plays a far more crucial role in maintaining the productivity of southern oceans than previously believed.

“I want to show that whales are ecosystem engineers,” said Lavenia Ratnarajah, a marine biogeochemist at the University of Liverpool. “Conservation campaigns are usually focussed on their beauty, but that doesn’t convince everyone. If we can show how much these animals contribute to the functions of the ocean, then it will be easier to save them.

Facebook Twitter Pinterest The study will look at how blue whale faeces contributes to nutrition levels in Antarctic waters. Photograph: Franco Banfi/Biophoto/Alamy

Blue whale numbers plunged by 95% in the early 20th century, but they have stabilised and partially recovered since the introduction of a global ban on catches in 1966. There are now thought to be between 10,000 and 35,000, mostly in the Antarctic.

Until now, most research has focused on the breeding and migratory habits of these giant creatures, which can grow to more than 30 metres in length and weigh 200 tonnes – more than even the largest dinosaurs. But the new research will consider how they contribute to nutrition levels in Antarctic waters.

Whale excrement acts as an iron-rich ocean fertiliser that stimulates the growth of marine bacteria and phytoplankton – tiny plants that form the base of the Antarctic food chain and act as the greatest biological source of carbon sequestration. Without the biological recycling of iron, the relatively anaemic Southern Ocean would not be able to sustain as much phytoplankton, which is the main food for krill.

The new study will try to quantify that fertilising impact and test theories that the whale is irreplaceable in the polar ecosystem because the other major predators – penguins and seals – tend to defecate on the ice rather than in the water so they cannot provide the same nutritional benefits.

The team – along with dozens of other scientists – on 19 January from Hobart, Tasmania on the Research Vessel Investigator, which is is funded by the the Commonwealth Scientific and Industrial Research Organisation and Australian Antarctic Division. They will first deploy sonar buoys to identify the location of the whales and then, when close, use drones to fly above them and wait for telltale orange plumes. It can take days.

The faeces, which is mainly composed of digested krill, initially floats on the surface before dissipating and then sinking to the floor of the ocean. On previous missions, researchers have had to collect samples by hand, but this time they are relieved that they can get drones to do the dirty work.

“You don’t want to fall into it. It’s liquid and smells awful,” said Ratnarajah, who plans to tweet about the voyage.

“Sometimes I think I have the worst job in the world and sometimes I think I have the best.”