The seakeeper

Two-thirds of the world is covered by oceans, but we're still coming to grips with how they work. CARROLL du CHATEAU meets a New Zealand scientist at the forefront of international studies.

It is almost impossible to get a scientist to say anything rock solid. Ask Dr Julie Hall, the newly appointed secretary of the international Scientific Committee on Oceanic Research (Scor), whether global warming is real rather than scaremongering by scientists, and she hands me a thick report from the United Nations. (Answer, after 20 minutes' reading, yes, very probably.)

When asked if foreign bilge water discharged in our waters causes algal bloom and poisons shellfish, she ducks again. (Answer, maybe, but it's hard to prove.)

She should know. She is a specialist in the study of phytoplankton, which produce more than 50 per cent of the world's oxygen, the dynamics of the ocean's microbial food web and fluctuations of the ocean's carbon cycle, which many scientists believe is the key to global warming.

But Southland-born Julie Hall, BSc (Hons), zoology, PhD (University of Manitoba, Canada), is too much the scientist to give the media an unequivocal statement.

She is also seriously good fun, all 1.27m of her. Despite her lack of height, she gets around on a large but slightly battered Honda 404 bike "with the front let down so my feet can touch the ground."

When she's in New Zealand, she spends weekends and evenings at the Matamata Gliding Club. Her travel schedule, including ocean voyages and international committee work, means she is away from her tiny office in the bowels of the Hamilton headquarters of the National Institute of Water and Atmospheric Research (Niwa) for three months of each year.

At 42, Hall considers her international work as her "public service" work. It encompasses five committees plus the big job as secretary of the Washington DC-based Scor, the world's leading non-governmental organisation for promoting and coordinating international oceanographic activities.

She and her Canadian-born scientist husband, Trevor, decided early not to have children - "my mother tells me I haven't a motherly bone in my body."

But she teaches local Scouts the glories of gliding and helps to attract school students into science careers with projects like her "Sea and Learn" shipboard programme for sixth and seventh formers. This gets them on to the ocean and into Kelly Tarlton's "bathosphere" setup, which mimics the unit used to observe marine life thousands of metres under the sea.

She also gives time and energy to international oceanic research. The first woman committee member, let alone secretary, in this male-dominated area, Hall is upbeat. "It's good for marine science, good for Niwa, good for me and good for women," she says, rolling those wonderful Southland rrs. "Finally beating back the bastions takes a while."

The Scor job comes after 18 years of study and research, plus eight years of international meetings. It started in 1992 with an invitation to Taiwan, where the international scientific steering committee on Joint Global Ocean Flux Studies was looking at carbon fluxes in the area.

Carbon fluxes are one of Hall's specialties. Part of her scientific reputation rests on a 1999 Southern Ocean iron-release experiment designed to test the hypothesis that phytoplankton given extra iron would increase their photosynthesis, gobble up carbon dioxide then sink into the depths, removing carbon dioxide from the water and encouraging its replacement from the atmosphere. Many scientists are convinced that excess carbon dioxide is the major culprit in the greenhouse effect and global warming.

In late January, Hall and a 26-strong team of scientists, plus 10 tonnes of iron sulphate, boarded the RV Tangaroa and sailed 1200 nautical miles into the ferocious Southern Ocean.

The first part of the experiment went as expected. The dissolved iron increased photosynthesis and caused a significant decrease in the concentration of carbon dioxide in the water, removing "approximately 2000 tonnes of carbon from the water inside the patch."

Next, if Hall's instincts are correct, the large carbon-dioxide-rich phytoplankton will drop to the deep ocean, and "be removed from the atmosphere for hundreds to thousands of years, so resulting in a reduction of the carbon dioxide concentration in the atmosphere."

The trouble is, because the Tangaroa couldn't stay around long enough, the final link to the hypothesis "is a question to be answered in future experiments."

Obviously the international scientific community knows a lateral-thinking, relentlessly cheerful and indefatigable woman when it sees one.

In 1993 Hall was appointed to the steering committee of JGOFS, the Joint Global Ocean Flux Study, where for five years she oversaw data from New Zealand scientists working in the Southern Ocean being fed into the international system.

In 1994 she was voted on to the Southern Ocean Planning Group and a year later was asked to head a task force that looked at coordinating international scientific programmes dealing with carbon fluxes.

She is also vice chairman of the Global Ocean Observing System Steering Committee (Goos). "People say Goos is never going to work," she says. "We say it's got to work so people making decisions can make good, informed decisions."

"It's all snowballed," she says. "I think the international stuff is coming to an end. I've got limits and I'm at that stage."

But the offers are challenging and tantalising. At the heart of it all is the task of cajoling a collection of the world's most disparate countries to work together to monitor the world's oceans, which have no boundaries, but swish into each other like one enormous spa pool with all jets working at once.

For this Hall needs to convince countries from the United States through to the most needy African nations that they must work together to maintain their oceans and manage their resources.

Such collective research is also the key to predicting phenomena such as storm surges, "which we can do now," and probably, in future, predicting harmful algal blooms "which we cannot do now."

And yes, this down-to-earth scientist is convinced that global warming is in progress. "But that's only one of the issues. There's a whole range of them - harmful algal blooms, sewage going into our oceans, depletion of fish stocks ...

"Two-thirds of the world's surface is covered by ocean, and we really know very little about how it functions. We've got a great deal of knowledge, but it's all fragmented.

"We now need to fill in the gaps and coordinate new knowledge so we can better manage our marine environment."