Scientists have known for 20 years of microorganisms that thrive in the acidic iron-, sulfur- and heavy-metal-rich fluid environments in areas where seafloor is being created at mid-ocean ridge spreading centers. These areas are subject to frequent volcanic eruptions and can have fields of hydrothermal vents that pour superheated water as hot as 750 F into the oceans. As visually spectacular as such newly formed active areas can be, they represent only a tiny area of the seafloor. Most of the seafloor is tens of millions of years old.

Now fifteen-foot-long hypodermic needles – strong enough to penetrate the volcanic rocks that make up the Earth’s crust – were used to collect subsurface water samples from sites on the Juan de Fuca plate 200 miles off the coast of Washington and Oregon. As reported in the March 25 in the American Geophysical Union’s publication Eos, microbe samples have been cultured from these water samples originating within the “normal” seafloor. Cell counts obtained from most of the sites are higher than cell counts from normal seawater, a strong indication the scientists were sampling a true crustal environment and that their samples were not contaminated with bottom seawater. Laboratory work by University of Washington scientists shows bacteria extracted from seamount flanks grow best at hot temperatures, 190 F, which is considerably higher than the 68 F fluid they were collected with and the 140 F temperature of the rocks in that area. This implies that the fluid and microbes are coming from deeper within the ocean crust, perhaps as deep as half a mile below the seafloor.

“The types of seafloor environments we sampled last summer are found everywhere in the ocean. This argues, although it doesn’t prove, that oceanic crust may be a microbial incubator of global proportions,” says University of Washington oceanographer H. Paul Johnson. “The chances are good that there is a global-scale biosphere living within the upper oceanic crust. This oceanic crustal biosphere would live at a wide range of temperatures…It’s like finding an undiscovered world.”

Update [2003-3-23 10:26:16 by rickyjames]: Turns out that China is working to genetically engineer sub-surface organisms to increase its oil production…