Life doesn’t just survive half a kilometer into the rock of the ocean’s crust. It thrives, even in total darkness and with almost no oxygen. According to a report published Thursday in Science, an international team of scientists examined samples from cores that had been drilled into the 3.5 million year old rock found offshore Washington State.
After a painstaking process of sterilizing the samples for two years and then carefully incubating them for another five years, they found genetic traces of both methane-producing and sulfate-consuming microbes.
Nature’s Ed Yong said that it was the first time that scientists had proven that life could exist deep inside of the ocean crust, a thick layer of dark rock at the bottom of the sea that covers 60% of the earth’s surface. That makes it “the largest habitat on Earth.”
That is, if it is in fact a habitat at all.
In the race to discover exotic life in harsh conditions, Russian scientists recently claimed that they’d found an entire new family of bacteria with DNA almost completely unrelated to any known organism in an underground frozen Antarctic lake. While they never acknowledged that the claim was a publicity stunt, they retracted it the next day.
The new study involves an international team from Denmark, Canada, and three other countries, as well as the United States. It is no hoax. However, the researchers were well aware that they might be challenged to prove that they didn’t accidentally contaminate the specimens after they were removed from the deep rock.
Mark Lever, the Danish scientist who is also the lead author for the new paper, said that he had doubts when the project first began in 2004. “I thought it would be impossible to get contamination-free samples,” he told Nature.
A special chemical marker was added to the drilling fluid to see if the cores got contaminated during the drilling process. Once Lever was able to open the first samples and determine that none of the fluid could enter, he gained more confidence that they would be able to successfully complete the research.
If the research stands up, life could be abundant indeed. Science said that the microscopic life in the ocean’s crust could be as dense as 10,000 tiny organisms per square cubic centimeter of water moving through the deep rock.
[ocean floor photo courtesy NSF/USAP photo by Steve Clabuesch]