At last, the diversity of ocean life has been exhaustively (and expensively) cataloged -- or has it?
The results of a decade-long, first-of-its-kind accounting of the world's oceans were published Monday, revealing the remarkable diversity of life in the world's waters. But scientists say there's much more we don't know about life below the surface of the seas, despite the estimated $650 million the survey has cost.
The Census of Marine Life was conducted by hundreds of scientists around the world, who acted like detectives in search of missing clues as they surveyed 25 different regions from the Arctic to Australia. In the study, teams were charged with finding species through field research and samples brought up from the depths of the ocean.
They also studied existing private and public collections, and pored over material "based on hundreds of thousands or even million of observations of organisms themselves," explained Daphne Fautin, a professor at the University of Kansas who was part of the U.S. group and one of the early participants in the study.
The species discovered or cataloged encompass some of the strangest and most exotic animals on the planet.
From the furtive megamouth shark, discovered decades ago but rarely seen, to the odd-looking dragon fish that has teeth on its tongue, the study proves that Mother Nature has a quirky sense of design. And there's a wealth of stunningly beautiful animals that live miles below the surface, too, such as the deep-sea jellyfish. When threatened by predators, it uses bioluminescence to "scream" for help, creating an amazing light show known as a "burglar alarm display."
The survey found that the number of known, named species contained in the 25 surveyed areas ranged from 2,600 to 33,000 and averaged about 10,750, and they fall into a dozen groups. On average, about one-fifth of all species were crustaceans, which, with mollusks and fish, make up half of all known species on average across the regions. The full breakdown:
* 19 percent Crustaceans (including crabs, lobsters, crayfish, shrimp, krill and barnacles)
* 17 percent Mollusca (including squid, octopus, clams, snails and slugs)
* 12 percent Pisces (fish, including sharks)
* 10 percent Protozoa (unicellular micro-organisms)
* 10 percent algae and other plant-like organisms
* 7 percent Annelida (segmented worms)
* 5 percent Cnidaria (including sea anemones, corals and jellyfish)
* 3 percent Platyhelminthes (including flatworms)
* 3 percent Echinodermata (including starfish, brittle stars, sea urchins, sand dollars and sea cucumbers)
* 3 percent Porifera (including sponges)
* 2 percent Bryozoa (mat or ‘moss animals’)
* 1 percent Tunicata (including sea squirts)
The rest are other invertebrates (5 percent) and other vertebrates (2 percent). The scarce 2 percent of species in the “other vertebrates” category includes whales, sea lions, seals, sea birds, turtles and walruses -- thus some of the best-known marine animals comprise a tiny part of marine biodiversity.
But in counting species around the world, the researchers found that despite 10 years worth of work, they barely scratched the surface.
For example, in the waters around Australia -- some of the most diverse on the planet -- there were 33,000 species listed in official databases, lead researcher Alan Butler told FoxNews.com. Census scientists uncovered an additional 17,000 species that were not listed in the course of the study. However, Butler and his colleagues estimate that there are 250,000 species in the area.
That leaves a lot yet to be discovered.
"We've barely made a dent in this one," admits Ron O'Dor, senior scientist with the Census of Marine Life.
Scientists from the University of Sheffield underscored how little we know about deep-sea life in particular. Most of our knowledge about what lives in the ocean covers either the shallow fishing waters or the ocean floor. We know little about the waters between, the so-called deep ocean.
"The deep open ocean is in fact teeming with life," Tom Webb, the lead scientist on the Sheffield report, told FoxNews.com. "Our research shows that we have barely started to explore the deep ocean. Remember, this is by far the largest habitat on Earth."
Webb and the scientists responsible for the Census of Marine Life agree about one other thing: The state of current research indicates that we need to learn more.
"To better predict the long-term effects of things like oil spills, climate change, and overfishing, this habitat needs more attention," said Webb.