Ocean census reveals how little we know.

• Author: Mastny, Lisa
• Position: ENVIRONMENTAL Intelligence

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...