Hunting facts in icy depths
Herald science reporter Jamie Morton is profiling a series of new studies taking place in Antarctica, before his return to the frozen continent next month. Today, he talks to the University of Waikato’s Professor Ian Hawes
Back when Professor Ian Hawes began researching the colourful life on Antarctica’s seafloor, our scientific understanding was almost as sparse as the frozen continent itself.
Four decades later, the questions that he and his colleagues are grappling with are much more refined, yet even tougher to answer.
They now can’t focus on just one part of Antarctica in isolation, but many, and all at once.
For some time, the Waikato University ecologist and other scientists have been studying the dynamics of those coastal communities that could be reached from New Zealand’s Scott Base outpost. This gave indications about their vulnerability to the effects of climate change and other impacts, and how best to monitor them over time.
But they found a much better picture could be formed if they expanded their study area from the McMurdo Sound region to the whole of Victoria Land, from Scott Base to Cape Adare, 750km away.
“After all, McMurdo Sound is the most southerly piece of open ocean on the planet, and we can perhaps expect a slower response to gradual change there than at more northerly locations,” Hawes said.
It was a tough ask for New Zealand to do the job alone: the sheer logistics of setting up research camps far from base was difficult and expensive.
When South Korea’s programme built a station at Terra Nova Bay, halfway up the Victoria Land coast, to capture year-round observations of temperature, light and water quality, Hawes saw potential to collaborate.
As luck would have it,
South Korea’s station Jang
Bogo was opened at the same time the
Ministry of
Business, Innovation and Employment opened a grant fund for research between New Zealand and South Korea.
This summer, Hawes and his colleagues will reunite with another group led by the Korean Oceanographic and Polar Research Institute’s Dr Sanghee Kim to survey invertebrate species living at sites near Scott Base and Jang Bogo.
Hawes described South Korea’s site at Terra Nova Bay as a similar “bio-region” to McMurdo Sound, which Scott Base overlooked.
“By that we mean that the marine benthic fauna is similar, though more diverse at Terra Nova Bay likely due to its more northerly location. We know that somewhere a little way north of Terra Nova Bay, there is a substantial change as large brown seaweeds begin to appear, with a corresponding change to food webs and habitat structure.
“At Terra Nova Bay and southwards, such algae do not occur and the persistence of sea ice limits the types of algae that can grow.”
Despite being relatively close to the two bases, their study would still offer challenges. As his team needed to get beneath the sea ice, they first needed to punch holes large enough for divers to enter through.
In the McMurdo Sound, they planned to borrow a powerful drill from the United States programme, but at Terra Nova Bay they’d use simpler methods. That involved flying up a “hole melter” — effectively a modified steam cleaner used to pump heated seawater through a series of jets.
“Once the holes are made we place a hut or tent over them for divers to operate out of, and then the only challenges relate to operating in clumsy dry suits under the ice.” Their sampling is a mix of highdefinition videography and collection of sediment cores, animals and seaweeds.
Over the longer term, as part of the new Antarctic Science Platform, the scientists will look more widely at these crucial indicators of change across the Ross Sea region.
“One of the questions that we find hardest to answer at the moment is whether the flora and fauna of the Ross Sea is responding to, or threatened by climate change. In other parts of Antarctica, where change has been more evident, then significant effects through food chains have been recorded.”
The Antarctic Peninsula had seen considerable warming in recent decades, with major implications.
“To date there has been less obvious environmental change in Victoria Land, so we have a chance to investigate what is natural variability, which will allow us to identify when change exceeds this natural threshold.”
Many Antarctic animals and plants grow relatively slowly to large sizes and have long lives, making small changes harder to pick up.
“This year’s work was part of an initiative involving scientists from New Zealand, Korea, Italy and other countries,” he said.
“In future research we hope to determine the demographics of key species across environmental gradients provided by the Victoria Land coast, monitor their environment and examine its effects on growth and reproduction.
“We can then develop ways to combine these decipher the history of populations using markers contained in the annual growth of their shells, and set the stage for a comprehensive understanding of the consequences of climate change on coastal marine communities.”