KEY POINTS:
Scientists have been literally scratching the surface of the ocean bed around New Zealand to try to discover its secrets.
While New Zealand's 266,000sq km of land are well explored, little is known about the four million square kilometres of Exclusive Economic Zone which surround the country.
For
the past two years National Institute of Water and Atmospheric Research vessel Tangaroa has taken teams of scientists from NIWA, the Ministry of Fisheries, Department of Conservation and Land Information New Zealand to the Challenger Plateau - off the West Coast - and Chatham Rise.
On those voyages the sea has been dredged at various depths to examine the biodiversity of the two areas. Sediment cores have also been taken by drilling into the seabed, samples which scientists hope will give clues to how the undersea landscape was formed, and details of climatic changes in recent centuries.
"We have very, very little information," Dr Mary Livingston, MFish principal scientist, said.
"We have quite a lot of information from satellite imagery about what is going on in the surface water.
"We also know where our fisheries are, but there has been a lot of interest in trying to zone the ocean in terms of its sensitivities and biodiversity."
Scientists brought back 3400 samples from the Chatham Rise, made up of about 450 different types of organisms and weighing about 3.5 tonnes. From the Challenger Plateau, which Dr Livingston said had as diverse an environment as the Chatham Rise but fewer numbers of species, Tangaroa brought back 1.5 tonnes of material: about 2000 samples comprising about 200 different organisms.
Teams of taxonomists are now scouring the voyage's finds and trying to identify each species. It is expected that several species either not found before in New Zealand or totally new to science will have been discovered.
The project also hopes to assess the impact of dredging and bottom trawling on marine environments.
However, with fishing a well-established industry in New Zealand, trying to find an unfished environment to compare with well-harvested waters was problematic, Dr Livingston said.
"Within the Chatham Rise it's hard because its been pretty much gone over at least once in the last 15 years, particularly within trawlable depth," she said.
"Once you get to deeper water where trawlers can't reach down there, there's not necessarily evidence of large numbers of fish down at those greater depths. We don't know if the animals from those greater depths can necessarily repopulate an area that has been disturbed at a shallower depth. We're looking at how depths work in terms of biodiversity."
The ministry is about to issue tenders for eight research projects stemming from the project's findings, including producing ecological maps of the seabed.
The ministry hopes to expand the project in future years to encompass waters south of Stewart Island, and around the Kermadecs.
