redOrbit Staff & Wire Reports – Your Universe Online
Despite immense pressure and a lack of sunlight, an abundance of microbes are thriving in the deepest parts of the Pacific Ocean, claims new research published in Sunday´s edition of the journal Nature Geosciences.
A team of scientists led by Ronnie Glud of the University of Southern Denmark explored the 36,000-foot deep Mariana Trench “unusually high levels of microbial activity in the sediments” of the Challenger Deep region, Colin Barras of New Scientist said.
“Glud’s team dispatched autonomous sensors and sample collectors into the trench to measure microbial activity in the top 20 centimeters of sediment on the sea bed,” Barras added. “The pressure there is almost 1100 times greater than at the surface. Finding food, however, is an even greater challenge than surviving high pressures for anything calling the trench home.”
The amount of bacteria and other microbes discovered by the researchers was more than double that discovered at a site nearly half as deep, explained Reuters Environment Correspondent Alister Doyle. They fed upon dead plants and fish that fell into the deepest parts of the trench, Doyle said, supporting a theory which had suggested that those materials fall onto the trench´s steep sides, slide to the bottom and form a sort of “hot spot” for microbes.
“It’s surprising there was so much bacterial activity,” Glud, an aquatic biogeochemist at the Odense, Denmark-based university, told ABC News Australia. “Normally life gets scarcer the deeper you go — but when you go very deep, more things start happening again. We find a world dominated by microbes that are adapted to function effectively at conditions highly inhospitable to most higher organisms.”
Likewise, Hans Røy, a geomicrobiologist at Aarhus University in Denmark who was not a member of the survey team, told Sabrina Richards of The Scientist that the discovery “shows that microbes are basically able to cope with any conditions on this planet.”
The study could also have implications related to climate change, Richards explained. Ocean-dwelling microbes play a key role in the carbon cycle, and if organic matter falls into the ocean without being eaten and digested, it ultimately turns into fossil fuels. However, if microbes consume those substances, they release carbon dioxide and keep the compound cycling in the ocean where they dwell. The question that remains, the researchers say, is: how effective are microbes at breaking down organic particles at such extreme depths?
Glud told Reuters that it is “likely that more carbon is deposited” in the deepest parts of the trench than previously believed. He added that he and his colleague had discovered “a small exotic piece of the puzzle which has never been studied before” when it comes to the how large bodies of water recycle or bury carbon.
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