A bizarre group of microbes — named in honor of the Greek god of the underworld, Hades — thrives abundantly underneath the Earth's surface without any need for oxygen or light, researchers have discovered.
An international team of researchers analyzed the lifestyle of these strange microbes called the Hadesarchaea, which were initially found 2 miles deep into the Earth's surface in a gold mine in South Africa.
Microbiologists Thijs Ettema and Brett Baker, who led a team of researchers from the University of Texas and University of North Carolina at Chapel Hill in the United States, Uppsala University in Sweden and the University of Bremen in Germany found the new microbe class in various environments.
Archaea are microscopic single-celled organisms discovered about four decades ago by Carl Woese, an American biologist. There are very few scientific studies on the archaea compared to bacteria. In a previous study, researchers found that buried marine archaea can shed light on the ocean's temperature history. Marine archaea make up approximately 20 percent of the microbial life underwater.
A genome sequence of several Hadesarchaea samples revealed how the microbes survived without light and oxygen. Findings suggested that the new microbes survive on the carbon monoxide found underground by using it as energy. Moreover, the chemical pathways used in metabolizing the carbon monoxide are different compared to previously observed activities in older Archaea samples.
"The new discovery expands our knowledge of how these organisms may have adapted to the extreme conditions of the deep biosphere," says co-author Jimmy Saw from the Uppsala University.
The researchers also found the microbes in deep mud at a temperate estuary located in North Carolina and underneath Yellowstone National Park's hot springs. They continue to thrive underground in various settings. Ettema says that the new discovery will help the scientific community better understand the lifestyle and biology of the archaea that thrive underneath the Earth's surface.
The discovery was published in the journal Nature Microbiology on Feb. 15.
Photo: U.S. Geological Survey | Flickr
