Deep Sea Microbes Hold Secret to Earths Early Life

These tough microbes survive under extreme oxygen -free conditions.
Jessica Miley

New research has detailed how a group of deep-sea microbes thrive in the hot, oxygen-free fluids that flow through Earth's crust. Understanding these hardy microbes provides clues to the evolution of life on Earth, says the research papers authors. 

Hydrothermarchaeota, are a group of microbes that live in such extreme conditions that they have never been able to be grown inside labs. But now a collaborative research team from Bigelow Laboratory for Ocean Sciences, the University of Hawai'i at Manoa, and the Department of Energy Joint Genome Institute have overcome this problem by creating genetic sequencing methods called genomics. 


Unusual metabolic strategy helps microbes thrive

They discovered that Hydrothermarchaeota may obtain energy by processing carbon monoxide and sulfate, which is an overlooked metabolic strategy. The microbes obtain energy by processing carbon monoxide and sulfate. 

The energy they gain from this processing is used as a form on Chemosynthesis. "The majority of life on Earth is microbial, and most microbes have never been cultivated," said Beth Orcutt, a senior research scientist at Bigelow Laboratory and one of the study’s senior authors. 

"These findings emphasize why single cell genomics are such important tools for discovering how a huge proportion of life functions." By examining Hydrothermarchaeota genomes the researchers understood that the group belongs to a group of single-celled life known as archaea. 

Deep sea holds answers to space

Archaea evolved very early on in the history of our Earth and it's likely their uncommon metabolic process did too. By better understanding these microbes, the more we can learn about the beginning of our planet. 


The researchers suggest the subsurface ocean crust is critical in understanding not only the history of our earth but potentially other planets too. The researchers found evidence that Hydrothermarchaeota has the ability to move on their own. 

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Independent movement means the microbes can travel if necessary in their harsh, nutrient-deprived environment. "Studying these unique microbes can give us insights into both the history of Earth and the potential strategies of life on other planets," said Stephanie Carr, first author on the paper and a former postdoctoral researcher with Orcutt who is now an assistant professor at Hartwick College. 

"Their survival strategies make them incredibly versatile, and they play an important, overlooked role in the subsurface environments where they live." The research has been a long time in the making. In 2011, project scientist sailed to the edge of the Juan de Fuca Ridge, off the coast of Washington. 

Deep Sea robot will return for new samples

Here two ocean plates are separating causing a new oceanic crust. The team sent down the Woods Hole Oceanographic Institution’s deep-diving robot Jason 2.6 km to the seafloor where it collected samples of the fluid that flows through the deep crust. 

Deep Sea Microbes Hold Secret to Earths Early Life
Source: BigBelow

The fluids were then studied using a variety of cutting edge genomics techniques. The research will continue when the team returns to the Juan de Fuca Ridge to collect new samples this year. 

"The microbes living ‘buried alive’ below the seafloor are really intriguing to us, since they can survive on low amounts of energy," Orcutt said. "We hope that our experiments on these weird microbes can show how they do this, so we can imagine how life might exist on other planets." Their research has been published in a recent edition of The ISME Journal.

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