Ocean census reveals how little we know.

New data from a global survey of the world's oceans is revealing how little is really known about marine ecosystems. In November, scientists with the 10-year Census of Marine Life announced the discovery of 106 new species of fish in 2004 alone. This brings the total number of known marine fish species to 15,482. Scientists believe there may be over 20,000 such species.

The census, which began in 2000, is a huge scientific undertaking and the most extensive of its kind. Researchers are probing the depths of virtually every ocean, studying everything from large predators to tiny microbes, in habitats ranging from shallow coastal waters to the deep sea. The goal is to significantly enhance the understanding of life in these vast and mostly unexplored waters, which may rival terrestrial rainforests in species diversity.

Within the past year, the census has grown from 10 to 13 projects and now involves some 1,000 scientists in 70 countries, up from 300 scientists in 53 countries in 2003. Most are conducting their studies in poorly known habitats, from geyser-like deep sea vents to undersea mountains that host a remarkable range of unique species. Of the estimated 14,000 sea mounts that have been discovered, only about 250 have been studied.

In addition to new fish, the survey is turning up hundreds of previously unrecorded species of other animals and plants. Among the creatures identified are two types of octopus that lurk in the frigid waters off Antarctica and a burrowing 20-centimeter worm that lives in the depths of the mid-Atlantic. The total number of known life-forms in the world's oceans is now about 230,000, but scientists suspect the actual number may top two million.

By late 2004, the census database contained more than 5.2 million records and mapped the distribution of 38,000 marine species, a significant increase over the previous year. Entries include more than 6,800 species of zooplankton, tiny invertebrates that drift with the ocean currents and serve as a vital link in the marine food chain.

Researchers are also documenting the wide diversity of marine microbes--the smallest single-celled organisms and associated viruses--which account for more than 90 percent of the ocean's biomass.

[ILLUSTRATION OMITTED]

Not surprisingly, most new species are being found at the ocean's depths. The census's $9.5 million database (the Ocean Biographic Information System) reveals that up to 95 percent of existing observations of marine life have been made at or near the surface, with less than 0.1 percent coming from the lower half of the water column. As a result, specimens collected below 2,000 meters are about 50 times more likely to be new to science than those found at 50 meters.

The high rate of discovery will likely continue as the "information seaway" becomes increasingly sophisticated. Marine scientists now rely on everything from unmanned submarines that observe deep-sea life to electronic tags that track the movements of large open-ocean species such as leatherback sea turtles and bluefin tuna. In 2004, data conveyed by some 700 Atlantic bluefins revealed that individuals from vastly different regions commingle during their migrations--overturning the belief that tuna populations never mix and suggesting that intense harvesting in one region could in fact harm stocks elsewhere.

The census project is expected to cost participating governments and other funders as much as $1 billion by 2010. It grew out of a concern that human activities could permanently affect oceanic diversity, and comes at a time when the world's oceans are increasingly beleaguered by pollution, climate change, and over-fishing. Scientists hope that the survey will not only shed new light on the effects of environmental change on oceanic diversity, but also help conservationists identify threatened species as well as locations for protective marine parks.

For more information: www.coreocean.org/Dev2Go.web?id=205703&rnd=750