A host of hardy microbes may be living miles beneath the ocean floor, new research suggests.
Complex chemical compounds found in the rocks spewed from oceanic mud volcanoes suggest microbial life-forms may be dwelling some 32,800 feet (10,000 meters) beneath the seafloor. Though scientists have not yet found a smoking gun proving that life exists in these subterranean depths, similar chemical compounds have been found in other places where hardy microbes cling to life.
"Although we cannot pinpoint the exact origin of the organic matter, chemical analysis of the constituents resembles molecular signatures that could be produced by microbial life deep within or below the mud volcano," the researchers wrote in the study.
For more than two decades, scientists have known that life lurks beneath the Earth's crust. For instance, in 2010, scientists found microbes nearly 0.75 miles (1,391 m) beneath the planet's surface, in the mysterious gabbroic layer of Earth's crust, the deepest portion of the crust that lies above the oozing mantle. The mucky sediment in the ocean's crust may also teem with microbes that live in a thriving community, according to a 2013 study. Still other work has shown that microbes live in the watery portions of the Earth's mantle, which lies even deeper. The deeper that scientists have looked, the deeper life has seemed to go. [Photo Timeline: How the Earth Formed]