San Diego

Big rig: researchers on the Resolution hope to find out more about elusive marine microbes. Credit: ODP

Microbes that live beneath the sea floor are the core issue for the latest expedition in the Ocean Drilling Program (ODP), which set sail from San Diego on 27 January.

The research ship will spend eight weeks drilling for sediment samples from the Pacific Ocean, mainly off the coast of Peru.

This is the first time that an ODP cruise has been dedicated to sedimentary biomass, says Steve D'Hondt, an oceanographer at the University of Rhode Island and co-director of the project.

Microbes living in seafloor sediment are thought to make up between one-tenth and one-third of all the living organisms on the planet, but very little is known about them. One of the expedition's goals is to find out how the microbes manage to survive in such an unpromising environment.

The international crew of 25 researchers and a similar number of technicians on board the JOIDES Resolution will recover sea-floor sediment and study the biomass it contains.

Better understanding of the microbes' metabolism should help to explain the interaction among biomass, ocean chemistry and carbon sequestration — a natural process by which carbon is stored in the deep ocean, and which could possibly be tapped artificially to absorb greenhouse gases from the atmosphere.

The Resolution has been fitted with a new laboratory where researchers will initiate their study of the respiration of microbes found in the samples.

Previous, smaller-scale studies have found very little respiration — five to six orders of magnitude less than anticipated — from microbial life in the sediment, scientists say. “If one-third of life is in the sea floor, why is there so little respiration?” asks D'Hondt.

The expedition, costing about US$8 million, is occurring as the ODP — which is supported by the US National Science Foundation and 21 partner agencies around the world — prepares to close down in 2003 after 18 years of operation. A new Integrated Ocean Drilling Program is to take its place, involving a broader international scientific and funding effort.

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