Amid rapid declines in fish stocks and fears about the impact of climate change, scientists are nearing the end of the first global attempt to stocktake the astonishing range of life in our oceans.
But alongside the discovery of a hairy "yeti" crab or revelations about the previously unknown migration patterns of the great white shark is the knowledge that these are just a drop in the ocean of what remains undiscovered.
AdvertisementA conference in Auckland this week of around 200 of nearly 2,000 researchers from 80 countries working on the Census of Marine Life have been discussing how to pull together their findings before the census ends in 2010.
So far 17 studies ranging from bacteria to the ocean's largest predators has discovered more than 5,300 new marine life forms.
To put that in context, around 230,000 marine species are known to scientists although estimates of the total number in the world's oceans and seas are between 1.4 million and 1.6 million.
In the 2002-03 year, 1,555 marine species were newly identified, said Dr Dennis Gordon, a principal scientist at New Zealand's national Institute of Water and Atmospheric Research.
Working at that rate, it would take up to 881 years to finish the task of describing the marine species on the planet, Gordon told the conference.
But the principal scientist of the census, Dr Ron O'Dor, a professor of biology at Canada's Dalhousie University, said the census was opening up new areas of research.
"It's as important to know what you don't know as it is to know what you know," he said.
The projects, which include examining life on undersea mountains and under 400 metres (437 yards) of Antarctic ice, are throwing light on previously unknown species and regions.
"The census will provide us an objective robust benchmark by which future change in marine life can be assessed," said Dr Michael Stoddart, chief scientist to Australia's National Antarctic Programme and project leader for the census's Antarctic work.
New technology is allowing researchers to go deeper into the ocean than ever before and to follow large marine animals such as sharks, turtles and seals on their migrations.
A study of 22 Californian sea lions which migrated unusually far out into the Pacific Ocean in recent years due to warmer than normal sea temperatures provides clues to how marine life could respond to climate change.
"By following how these animals respond to the changing oceanography, we will get an idea of how they will respond to a changing habitat in the future," said Daniel Costa a University of California professor and project leader of a census project to tag large Pacific predators.
Tagging of the previously mysterious great white sharks along the Californian coast showed they travelled across the Pacific to Hawaii in spring before returning to the mainland coast in autumn.
Stoddart said climate change is bringing about rapid changes in the Antarctic environment, where 18 expeditions are heading over the southern summer.
"So there is an added impetus and added urgency for us to work in the high latitude southern region," he said.
On the other end of the size scale, even less is known about marine microbes, including bacteria and viruses. Yet they add up to as much as 98 percent of the total biomass of marine life, the conference was told.
To provide some historical context for the census, one study has been looking at how marine life had changed in past centuries.
Researchers have used fossils, archaeological records and historical documents including fishing logs to trace changes in 12 estuary areas, mainly in Europe and North America.
Dr Heike Lotze, also of Dalhousie University, said the project showed about seven percent of species had become extinct globally or locally in the estuary areas and 36 percent had collapsed to less than 10 percent of previous numbers.
"Human exploitation was the most important reason for extinctions, followed by habitat loss and pollution," said Lotze.
But the researchers are also looking to the future, especially as the end of the first census draws near.
They want to ensure that support can be found for funding to ensure there is a second census leading up to 2020 as human and climate threats put mounting pressure on the oceans.
"Can we convey the urgency of continuing our efforts over the next decade?" challenged Rutgers University professor, Dr J. Frederick Grassle, who chairs the census scientific steering committee.
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