Researchers URI: Deep-sea microorganisms live on the by-products of a radioactive process

NARRAGANSETT, RI – February 26, 2021 – A team of researchers from the University of Rhode Island Graduate School of Marine Science and their colleagues have revealed that the abundant microbes that live in old sediments beneath the seabed maintained mainly by chemicals created by natural molecular irradiation of water.

The team found that the formation of these chemicals is greatly increased by minerals in marine sediments. In contrast to the conventional notion that sediment life is stimulated by photosynthesis results, a water-induced irradiation ecosystem begins just meters below the seabed in much of the ocean. open. This world fueled by radiation is one of the largest ecosystems on Earth.

The research was published today in the journal Nature Communication.

“This work provides an important new perspective on the availability of resources that microbiological communities can use to sustain themselves. This is fundamental to understanding life on Earth and to prevention. on the potential of other planetary bodies, such as Mars, “said Justine Sauvage, lead author of the study and a graduate of the University of Gothenburg who conducted the research as a doctoral student at URI.

The process that guides the decisions of the research team is water radiolysis – the separation of water molecules into hydrogen and oxidants as a result of exposure to naturally occurring radiation. Steven D’Hondt, professor of marine science at URI and co-author of the study, said the resulting molecules become the main source of food and energy for the microbes that live in the sediment.

“Marine sediments increase the production of these useful chemicals,” he said. “If you have the same amount of irrigation in pure water and in wet sediment, you can get a lot more hydrogen from wet sediment. The sediment makes hydrogen production much more efficient. “

It’s not clear why the process is augmented in wet sediment, but D’Hondt points out that minerals in the sediment could “behave like a semiconductor, making the process more efficient. ”

The findings came as a result of a series of laboratory experiments conducted at the Rhode Island Nuclear Science Center. Sauvage irradiated vials of wet sediment from various locations in the Minch and Atlantic Ocean, collected by the Integrated Ocean Drilling Program and by U.S. research vessels. She compared the production of hydrogen with filters similar to seawater and sediment water. The sediment increased the yields by as much as 30 factors.

“This study is a unique combination of solemn laboratory experiments linked to a global biological context,” said co-author Arthur Spivack, URI professor of marine science.

The decisions have a big impact.

“If you can support life in subterranean marine sediments and other subterranean environments from natural radioactive water seepage, then perhaps you can support life in the same way in another world, “D’Hondt said. “Some of the same minerals are present on Mars, and as long as you have those wet catalytic minerals, you will have this process. If you can produce radiolytic chemicals at high levels in a wet substrate Martian, you could keep life at the same levels as it is maintained in marine sediments. “

Sauvage said, “This is particularly relevant as the Perseverance Rover has just landed on Mars, with the mission of collecting Martian rocks and identifying their arable environments.”

D’Hondt said the findings of the research team have an impact on the nuclear industry, including how nuclear waste is stored and how nuclear accidents are managed. “If you store nuclear waste in sediment or rock, it may create hydrogen and oxidants faster than in fresh water. Such natural catalysis can make these storage systems more polluting than those produced in the world. space, “he said.

The next steps for the research team are to study the impact of hydrogen production through radiolysis in other environments on Earth and beyond, including oceanic, continental and subspecies. Mars. They will also seek to understand how underground microphone communities live, interact and evolve when their main source of energy comes from radically leaking water.

###

This study was supported by the U.S. National Science Foundation and the U.S. National Aeronautics and Space Administration. The project is also affiliated with the Center for Dark Energy Biosphere Research.