The first study to ever explore biological activity in the deepest layer of ocean crust has found bacteria with a remarkable range of capabilities, including eating hydrocarbons and natural gas, and "fixing" or storing carbon.
"This is a new ecosystem that almost no one has ever explored," said Martin Fisk, a professor in the College of Oceanic and Atmospheric Sciences at Oregon State University. "We expected some bacterial forms, but the long list of biological functions that are taking place so deep beneath the Earth is surprising."
Rock from deep beneath this undersea mountain in the Atlantic Ocean was recently studied to reveal some of the microbial life interactions going on in the deepest ocean crust ever explored. Image Credit: PLoS One; study number E15399
The research, just published in the journal PLoS One, showed that a significant number and amount of bacterial forms were present, even in temperatures near the boiling point of water. The study provides new information about evolutionary mechanisms and the limits of life on Earth. This can help astrobiologists identify environments on other worlds that might be habitable for life as we know it.
â€śThis is a new ecosystem that almost no one has ever explored,â€ť said Martin Fisk, a professor in the College of Oceanic and Atmospheric Sciences at Oregon State University. â€śWe expected some bacterial forms, but the long list of biological functions that are taking place so deep beneath the Earth is surprising.â€ť
Oceanic crust covers about 70 percent of the surface of the Earth and its geology has been explored to some extent, but practically nothing is known about its biology â€“ partly because itâ€™s difficult and expensive, and partly because most researchers had assumed not all that much was going on.
Potential sources and sinks of methane on Mars. Credit: Atreya, Mahaffy and Wong, Planetary Space Science, 55 (2007) 358â€“369.
A research expedition drilled more than 4,600 feet into this formation, into rock that was very deep and very old, and found a wide range of biological activity. Microbes were degrading hydrocarbons, some appeared to be capable of oxidizing methane, and there were genes active in the process of fixing, or converting from a gas, both nitrogen and carbon.
The findings are of interest, in part, because little is known about the role the deep ocean crust may play in carbon storage and fixation. Increasing levels of carbon dioxide, a greenhouse gas when in the atmosphere, in turn raise the levels of carbon dioxide in the oceans.
Microbial processes in the seafloor could play a role in cycling carbon on Earth. Image Credit: PLoS One; study number E15399
The researchers also noted that methane found on Mars could be derived from geological sources, and concluded that subsurface environments on Mars where methane is produced could support bacteria like those found in this study.
â€śThese findings donâ€™t offer any easy or simple solutions to some of the environmental issues that are of interest to us on Earth, such as greenhouse warming or oil spill pollution,â€ť Fisk said. â€śHowever, they do indicate thereâ€™s a whole world of biological activity deep beneath the ocean that we donâ€™t know much about, and we need to study.â€ť
Story Source: The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Oregon State University.