Exotic kingdoms and bizarre creatures deep beneath the sea or within the bowels of the Earth have been the stuff of myths, science fiction and steampunk fantasy since before Jules Verne first set pen to paper. However, a real-life realm of strange beings lurks within undersea volcanoes and understanding that ecosystem on Earth helps in the search for past or present life on Mars.
“We’re interested in the microbes in the deep rock, and the best place to study them is at hydrothermal vents at undersea volcanoes,” said James Holden of the University of Massachusetts-Amherst in a press release. “Warm water there brings the nutrient and energy sources these microbes need….Models have predicted the ‘habitability’ of the rocky environments we’re most interested in, but we wanted to ground-truth these models and refine them.”
Conditions that are perfect for one of these microbes would instantly kill a human. Holden and his colleagues had to recreate the deep sea vent’s high-pressure, intense heat and cocktail of chemicals in a laboratory. A two liter replica of those extreme conditions was created using a bioreactor.
The microbiologists also had to bring in samples of microbes from the wild to compare to other known species. The research was focused on methanogens, species that inhale hydrogen and carbon dioxide and exhale methane. The wild specimen were collected by Alvin, the research submarine star of numerous documentaries. Alvin caught his quarry a mile beneath the surface about 200 miles off the coast of Washington and Oregon.
The ecosystems that thrive in the rock around undersea vents are proving to be complex. At one site, a species of methanogen was found to feed on the waste of other microorganisms.
“This was extremely exciting,” says Holden. “We’ve described a methanogen ecosystem that includes a symbiotic relationship between microbes.” Holden and his team published the first detailed data on methane-exhaling microbes in a recent paper in the journal of the Proceedings of the National Academy of Sciences.
The life of microorganisms that live out of sight in the soil and rocks, often remain out of mind, but there may be a world going on underground, as Tom Waits said.
“Evidence has built that there’s an incredible amount of biomass in the Earth’s subsurface, in the crust and marine sediments, perhaps as much as all the plants and animals on the surface,” said Holden.
IMAGE: Alvin extends its mechanical arm to a high-temperature black smoker at Endeavor Segment. (Credit: Bruce Strickrott/WHOI)