Activities of subseafloor life more diverse than expected

Washington, DC — December 23, 2004 — Research on cores recovered by the Ocean Drilling Program show that the activity of microbial life beneath the seafloor is far more diverse than expected, scientists report in the December 24 issue of Science. The 35 members of the expedition’s scientific party, who represent more than seven nations, coauthored the article “Distributions of Microbial Activities in Deep Subseafloor Sediments.”

During the expedition, scientists and technicians onboard the JOIDES Resolution recovered sediments that ranged in age from 0 to 35 million years old from up to 420 meters (m) beneath the seafloor at sites in the equatorial Pacific Ocean and on the continental margin of Peru. These sites, which are typical of subsurface environments that exist throughout most of Earth’s ocean, ranged in water depth from 150 m on the Peru Shelf to 5300 m in the Peru Trench and ranged in temperature from 1- to 25 degrees C.

URI geological oceanographer Steven D’Hondt, co-chief scientist of the expedition and lead author on the Science paper, explained the significance of these findings: “We found bacteria to be alive hundreds of meters beneath the seafloor. Their activities are unexpectedly diverse. Some bacterial species recovered and cultured from these sediments were previously unknown. Other species appear to be distributed throughout the entire subsurface world (on land and beneath the sea). Many of their metabolic activities in these sediments ultimately rely for energy on the surface photosynthetic world.”

The Ocean Drilling Program (ODP), an international partnership of scientists and research institutions organized to study the evolution and structure of the Earth through scientific ocean drilling, ended operations on September 30, 2003, and was succeeded by the Integrated Ocean Drilling Program (IODP). ODP was funded primarily by the U.S. National Science Foundation, with substantial contributions from its 21 international partners.

IODP is an international program of basic research that will use multiple vessels and new technology to advance understanding of the Earth and its history through scientific ocean drilling. IODP is guided by its science plan, which encompasses three main themes: the deep biosphere and subseafloor ocean; environmental change, processes, and effects; and solid earth cycles and geodynamics. More information is available online at .

The NASA Astrobiology Institute (NAI) supported postcruise analysis of biogeochemical data and precruise development of shipboard biogeochemical techniques. NAI, founded in 1997, is a partnership between NASA, 16 interdisciplinary U.S. research teams, and five international consortia. NAI’s goal is to promote, conduct, and lead integrated multidisciplinary astrobiology research and to train a new generation of astrobiology researchers. For more information about the NAI on the Internet, visit: