Skating on thin ice

His job title is 'physical oceanographer' but the description fails to capture the reality of Craig Stevens' extraordinary world.

In the past year he's visited Antarctica twice, battled six-metre seas and endured -45°C temperatures in the process.

He has sat above internal waves 80 metres high off Norfolk Island, used giant kelp to work out how to extract electricity from ocean currents, and stood within a few metres of a floating melting glacier.

If you put him in front of a classroom of high school students still undecided about their career path in life, there's no doubt he would change their perceptions of science - in a very positive way.

"I'm constantly discovering that science is behind the solution to so many of the world's pressing problems, such as climate change, population pressure and food security," Craig said.

For the past decade he's been a leading figure in the New Zealand marine science scene, involved in five projects supported by the Marsden Fund, the premier source of investigator-driven, blue-sky research in that country.

Based at the National Institute of Water & Atmospheric Research (NIWA) in Wellington, Craig's research is centred on small scale ocean physics, or "environmental fluid mechanics".

"We are all familiar with large scale processes in the ocean - things like tides and solar warming of the surface - but all this energy needs to be dissipated somewhere and this happens in a smaller space and time scale, he said."

The 44-year-old physicist works across disciplines as diverse as marine ecology, climate, aquaculture, oceanography and energy.

His work informs our knowledge in unusual ways: the purpose of "that green slimy stuff" called seaweed, which actually plays a vital role in the marine ecosystem; how giant kelp manage to hold fast under crashing waves and what this tells us about extracting energy from the ocean; and how ice sheets actually melt, helping us to map future climate models.

Craig graduated from the University of Adelaide in 1987 with a Bachelor of Engineering (Honours) before completing his PhD in environmental fluid mechanics at the University of Western Australia.

He undertook his postdoctoral research at the University of British Columbia in Canada and then migrated back to the southern hemisphere in 1996, accepting a job with the Marine Physics Group at NIWA.

"Although my undergraduate degree was in engineering, I have crossed over into applied science, marrying my interest in technical things with my love of the ocean," he said.

"I spend time on ships, boats, Antarctic field camps and in the process get to work with a range of really interesting people."

In November 2009, he was part of a crew conducting under-ice turbulence measurements in Antarctica, tackling some extreme physical and mental challenges. The data collected were some of the first looking at the turbulence within a few metres of the face of (and underneath) a melting glacier.

His team also researches the ocean-to-atmosphere exchange of carbon dioxide and how ice platelets form beneath the sea ice. In ecosystem programs he looks at how plants, animals and humans are transported along in ocean currents, and how waves influence the behaviour of objects such as baby seaweed.

"My research crosses over from physics to chemistry, biology and all the inter-related processes," he said.

"Arguably, the greatest challenge facing the human species is population pressure," Craig said. "Our group at NIWA works on understanding, predicting and mitigating climate variability, feeding the population and powering the planet. They all feed into this challenge.

"There's nothing quite like being in the field, retracing the steps of Scott's first Antarctic voyage (albeit using skidoos). It beats sitting in front of a plasma screen in the lounge, that's for sure." ■

STORY CANDY GIBSON