"Long before it's in the papers"
January 27, 2015


Deep-rock microbes found to be similar worldwide

Dec. 10, 2013
Courtesy of Michigan State University
and World Science staff

Sci­en­tists are dig­ging deep in­to the Earth’s sur­face col­lect­ing cen­sus da­ta on the mi­cro­bi­al denizens of the hard­ened rocks. What they’re find­ing is that, even miles deep and half­way across the globe, many of these com­mun­i­ties are some­how quite sim­i­lar.

The re­sults, pre­sented at the Amer­i­can Geo­phys­i­cal Un­ion con­fer­ence Dec. 8 in San Fran­cis­co, sug­gest that these com­mun­i­ties may be con­nect­ed, said Mat­thew Schrenk, Mich­i­gan State Uni­vers­ity ge­o­mi­cro­bi­ol­o­gist.

“Two years ago we had a scant idea about what mi­crobes are pre­s­ent in subsur­face rocks or what they eat,” he said. “We’re now get­ting this emerg­ing pic­ture not only of what sort of or­gan­isms are found in these sys­tems but some con­sist­en­cy be­tween sites glob­ally – we’re see­ing the same types of or­gan­isms eve­ry­where we look.”

Schrenk leads a team stu­dy­ing sam­ples from deep un­der­ground in Cal­i­for­nia, Fin­land and from mine shafts in South Af­ri­ca. The sci­en­tists al­so col­lect mi­crobes from the deep­est hy­dro­ther­mal vents in the Car­ib­be­an Ocean.

“It’s easy to un­der­stand how birds or fish might be si­m­i­lar oceans apart,” Schrenk said. “But it chal­lenges the ima­gin­ati­on to think of nearly iden­ti­cal mi­crobes 16,000 km [10,000 miles] apart from each oth­er in the cracks of hard rock at ex­treme depths, pres­sures and tem­per­a­tures.”

Cat­a­loging and ex­plor­ing this regi­on could lead to break­throughs in off­set­ting cli­mate change, the dis­cov­ery of new en­zymes and pro­cesses that may be use­ful for bio­fuel and bi­o­tech­nol­ogy re­search, he added. En­zymes are com­pounds that speed up spe­cif­ic chem­i­cal reacti­ons.

For ex­am­ple, Schrenk’s fu­ture ef­forts will fo­cus on un­lock­ing an­swers to what car­bon sources the mi­crobes use, how they cope in such ex­treme conditi­ons as well as how their en­zymes evolved to functi­on so deep un­der­ground.

“In­te­grat­ing this regi­on in­to ex­ist­ing mod­els of glob­al bi­o­geo­chem­istry and gain­ing bet­ter un­der­standing in­to how deep rock-hosted or­gan­isms con­trib­ute or mit­i­gate green­house gas­es could help us un­lock puz­zles sur­round­ing modern-day Earth, an­cient Earth and even oth­er plan­ets,” Schrenk said.

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Scientists are digging deep into the Earth’s surface collecting census data on the microbial denizens of the hardened rocks. What they’re finding is that, even miles deep and halfway across the globe, many of these communities are somehow quite similar. The results, presented at the American Geophysical Union conference Dec. 8 in San Francisco, suggest that these communities may be connected, said Matthew Schrenk, Michigan State University geomicrobiologist. “Two years ago we had a scant idea about what microbes are present in subsurface rocks or what they eat,” he said. “We’re now getting this emerging picture not only of what sort of organisms are found in these systems but some consistency between sites globally – we’re seeing the same types of organisms everywhere we look.” Schrenk leads a team studying samples from deep underground in California, Finland and from mine shafts in South Africa. The scientists also collect microbes from the deepest hydrothermal vents in the Caribbean Ocean. “It’s easy to understand how birds or fish might be similar oceans apart,” Schrenk said. “But it challenges the imagination to think of nearly identical microbes 16,000 km [10,000 miles] apart from each other in the cracks of hard rock at extreme depths, pressures and temperatures.” Cataloging and exploring this region, a relatively unknown biome, could lead to breakthroughs in offsetting climate change, the discovery of new enzymes and processes that may be useful for biofuel and biotechnology research, he added. Enzymes are compounds that speed up specific chemical reactions. For example, Schrenk’s future efforts will focus on unlocking answers to what carbon sources the microbes use, how they cope in such extreme conditions as well as how their enzymes evolved to function so deep underground. “Integrating this region into existing models of global biogeochemistry and gaining better understanding into how deep rock-hosted organisms contribute or mitigate greenhouse gases could help us unlock puzzles surrounding modern-day Earth, ancient Earth and even other planets,” Schrenk said.