Deep Sea Surprise
Electron micrograph of foraminifera. Image courtesy of NOAA
In the deepest part of the ocean, 10,896 meters below the surface, scientists have discovered communities of organisms mostly made up of delicate, soft-walled, single-celled species, most of them new to science, according to an article in the 4 February 2005 issue of the journal Science.
Much to the surprise of researchers Yuko Todo and colleagues, these populations of organisms known as foraminifera were found to inhabit the sediment of the Challenger Deep, in the Pacific's enormous Marianas Trench. Foraminifera are single-celled protists, typically with hard shells, found primarily in the oceans. They are rare in deep-sea environments and are of crucial importance to geology and biology.
The lineage to which the new soft-walled foraminifera belong includes the only species to have invaded fresh water and land, and analysis of the new organisms' DNA suggests they represent a primitive form of organism dating back to Precambrian times from which more complex multichambered organisms evolved.
The depth of the Challenger Deep may have developed during the past 6 to 9 million years, the authors say, adding that the organisms recently found there probably descended from populations that were able to adapt to steady increases in pressure as the depth increased.
3 February 2005