In bays along the coast of Antarctica, thick shelves of floating ice extend tens or hundreds of miles out from the shoreline. Hidden beneath those shelves are sheltered waters that until recently had been almost entirely unexplored. Now that is changing.
In 2002 a 1,250-square-mile chunk of the Larsen Ice Shelf disintegrated in a matter of weeks. The event became a symbol of a warming globe, but it also presented a sudden opportunity. In January of this year, the German research vessel Polarstern settled in where the Larsen shelf had crumbled, and researchers on board conducted the first detailed biological survey of one of the most inaccessible ecosystems on Earth.
15 new amphipod species including Eusirus
was found beneath Larson B Ice Shelf.
Image courtesy of C. D'Udeken,
Royal Belgium Instit. for Natural Sciences, 2007
The expedition was part of a 10-year research project called the Census of Marine Life, a loose collaboration of more than 2,000 researchers from 80 countries who are organizing dozens of expeditions to all corners of the planet. They are motivated by the humbling realization that our knowledge of undersea life as a whole is only slightly less sketchy than our knowledge of life under those Antarctic ice shelves: Even where the water is not covered by ice, its sheer volume—not to mention the difficulty of seeing and moving through it—means that it is nearly all aqua incognita. The ocean contains 320 million cubic miles of water covering 140 million miles of seafloor, more than twice the area of all the continents combined, and we’ve only had a look at tiny bits of it. “If you ask, ‘What lives in the middle of the Atlantic?’ nobody knows,” says Jesse Ausubel, an environmental researcher at Rockefeller University and at the Alfred P. Sloan Foundation, which launched the $650 million Census of Marine Life.
By 2010 the census aims to deliver the best answer yet to that question. One should not picture it as a fleet of ships steaming up and down the ocean in a regular grid, counting every fish, crab, and worm—even $650 million won’t buy that. Instead the census consists of 17 separate subprojects, each one a well-organized raid on a huge but well-defined realm of ignorance. There is a census of coastal waters and a census of the abyssal plains, a census of coral reefs and a census of seamounts. There is a census of microbes, of drifting animals small and large—the zooplankton—and of large swimmers like tuna and blue whales.
The ocean probably harbors millions of species of organisms, but right now only 230,000 have names. When the census is completed, it will have added thousands more to that list. Although the overwhelming majority will be nameless still, we will have a much better idea of how many there are, where they live, and how abundant the major groups are.
Amphipod, Epimeria was found beneath
Larson B Ice Shelf.
Image courtesy of C. D'Udeken,
Royal Belgium Instit. for Natural Sciences, 2007
Ship by ship, voyage by voyage, ocean scientists will taste the pleasure that in January 2007 welcomed Julian Gutt of the Alfred Wegener Institute in Bremerhaven, Germany, as he sat on the Polarstern watching video images of the seafloor transmitted by a robot dangling from the ship: the joy of seeing what no one has seen before. In this case the researchers weren’t expecting to find much that was alive. Organisms tend to grow and move slowly on the ocean floor, where food is scarce and temperatures hover just above freezing. Moreover, it seemed likely that large parts of the Larsen seabed would have been scoured by icebergs from the collapsing shelf. “I was crossing my fingers that there would be any animals there at all,” Gutt says.
In fact, Gutt saw a vibrant scene: hundreds of sea squirts, the kind of animal—so characteristic of the deep—for which analogies invariably seem strained. They resemble gelatinous tulips, except that they happen to be chordates, animals distantly related to us. Gutt and his colleagues also saw herds of sea cucumbers—imagine sluglike water balloons crawling en masse over the seafloor. The sea squirts, he thinks, are recent colonizers from open water, but the sea cucumbers are probably remnants of the original ecosystem from before the collapse of the Larsen Ice Shelf. Why these creatures have flourished in forbidding conditions where others could not survive, Gutt does not know.
