Welcome to the bottom of the deep-sea food chain. The rock bottom, that is.
In the current edition of Geochemistry, Geophysics, Geosystems, a team of researchers uncovers and characterizes a process that is commonplace below the ocean bottom. In the upper 300 meters of the earth’s oceanic crust, microbes were found to have literally eaten their way through rock. Traces of this process are preserved in the glassy margins of underwater lava flows (scientists call super-cooled lava spewed by undersea volcanoes "glass," which is similar to material used to make stone-age axes and knives). Glass samples were recovered by drilling as deep as four miles below sea level.
"We’ve documented how extensive these microscopic organisms are eating into volcanic rock, leaving worm-like tracks that look like someone has drilled their way in," said one of the paper’s co-authors, Hubert Staudigel of Scripps Institution of Oceanography at the University of California, San Diego. "Our study has confirmed that there’s no place in the oceans that doesn’t have these features."
The process of volcanic rock changing from one state to another has traditionally been seen as a purely chemical-physical process, rather than biological. These rock alterations lead to chemical interactions between the oceanic crust and seawater, influencing important chemical cycles on the earth, including the carbon cycle that is important to the earth’s climate.
Staudigel says the microbes may tunnel their way into rock to derive chemical energy from the glass and to find protection from larger grazing organisms. He calls the glass-eating microbes the rock bottom of the food chain.
"We’ve basically determined the depth of the biosphere," said Staudigel.
The study is featured as an "Editor’s Choice" selection in the September 28, 2001 edition of the journal Science.
Co-authors include Harald Furnes, Ingunn H. Thorseth, and Ole Tumyr, Geological Institute, University of Bergen, Bergen, Norway; Terje Torsvik, Department of Microbiology, University of Bergen, Bergen, Norway; Karlis Muehlenbachs, Department of Geology, University of Alberta, Edmonton, Canada.
# # #
Journalists may request a copy of the paper from Harvey Leifert at email@example.com. Please indicate whether you prefer PDF or fax and provide your contact information.
Scripps Institution of Oceanography at the University of California San Diego, is one of the oldest, largest, and most important centers for global science research and education in the world. Now in its second century of discovery, the scientific scope of the institution has grown to include biological, physical, chemical, geological, geophysical, and atmospheric studies of the earth as a system. Hundreds of research programs covering a wide range of scientific areas are under way today on every continent and in every ocean. The institution has a staff of more than 1,400 and annual expenditures of approximately $195 million from federal, state, and private sources. Scripps operates oceanographic research vessels recognized worldwide for their outstanding capabilities. Equipped with innovative instruments for ocean exploration, these ships constitute mobile laboratories and observatories that serve students and researchers from institutions throughout the world. Birch Aquarium at Scripps serves as the interpretive center of the institution and showcases Scripps research and a diverse array of marine life through exhibits and programming for more than 430,000 visitors each year. Learn more at scripps.ucsd.edu and follow us at Facebook, Twitter, and Instagram.
About UC San Diego
At the University of California San Diego, we constantly push boundaries and challenge expectations. Established in 1960, UC San Diego has been shaped by exceptional scholars who aren’t afraid to take risks and redefine conventional wisdom. Today, as one of the top 15 research universities in the world, we are driving innovation and change to advance society, propel economic growth, and make our world a better place. Learn more at www.ucsd.edu.