By some estimates, a third of Earth's organisms live in our planet's rocks and sediments, yet their lives are almost a complete mystery.
Hydrothermal vent field seen through the porthole of the submersible Alvin.
This week, the work of microbiologist James Holden of the University of Massachusetts-Amherst and colleagues shines a light into this dark world.
In the journal Proceedings of the National Academy of Sciences (PNAS), they report the first detailed data on methane-exhaling microbes that live deep in the cracks of hot undersea volcanoes.
"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," says Holden.
"We're interested in the microbes in the deep rock, and the best place to study them is at hydrothermal vents at undersea volcanoes. Warm water there brings the nutrient and energy sources these microbes need."
Just as biologists studied the habitats and life requirements of giraffes and penguins when they were new to science, Holden says, "for the first time we're studying these subsurface microorganisms, defining their habitat requirements and determining how they differ among species."
The result will advance scientists' comprehension of biogeochemical cycles in the deep ocean, he and co-authors believe.
"Studies such as this add greatly to our understanding of microbial processes in the still poorly-known deep biosphere," says David Garrison, program director in the National Science Foundation's Division of Ocean Sciences, which funded the research.
The project also addresses such questions as what metabolic processes may have looked like on Earth three billion years ago, and what alien microbial life might look like on other planets.
Because the study involves methanogens--microbes that inhale hydrogen and carbon dioxide to produce methane as waste--it may also shed light on natural gas formation on Earth.
One major goal was to test results of predictive computer models and to establish the first environmental hydrogen threshold for hyperthermophilic (super-heat-loving), methanogenic (methane-producing) microbes in hydrothermal vent fluids.
"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," Holden says.
In a two-liter bioreactor at UMass Amherst where the scientists could control hydrogen levels, they grew pure cultures of hyperthermophilic methanogens from their study site alongside a commercially available hyperthermophilic methanogen species.
The researchers found that growth measurements for the organisms were about the same. All grew at the same rate when given equal amounts of hydrogen and had the same minimum growth requirements.
Holden and Helene Ver Eecke at UMass Amherst used culturing techniques to look for organisms in nature and then study their growth in the lab.
Co-investigators Julie Huber at the Marine Biological Laboratory on Cape Cod provided molecular analyses of the microbes, while David Butterfield and Marvin Lilley at the University of Washington contributed geochemical fluid analyses.
Using the research submarine Alvin, they collected samples of hydrothermal fluids flowing from black smokers up to 350 degrees C (662 degrees F), and from ocean floor cracks with lower temperatures.
Samples were taken from Axial Volcano and the Endeavour Segment, both long-term observatory sites along an undersea mountain range about 200 miles off the coast of Washington and Oregon and more than a mile below the ocean's surface.
"We used specialized sampling instruments to measure both the chemical and microbial composition of hydrothermal fluids," says Butterfield.
"This was an effort to understand the biological and chemical factors that determine microbial community structure and growth rates."
A happy twist awaited the researchers as they pieced together a picture of how the methanogens live and work.
At the low-hydrogen Endeavour site, they found that a few hyperthermophilic methanogens eke out a living by feeding on the hydrogen waste produced by other hyperthermophiles.
"This was extremely exciting," says Holden. "We've described a methanogen ecosystem that includes a symbiotic relationship between microbes."
The research was also supported by the NASA Astrobiology Institute and the National Oceanic and Atmospheric Administration.Media Contacts
Cheryl Dybas | EurekAlert!
Further reports about: > Earth's magnetic field > Endeavour > Forum Life Science > Microbial Nitrogen > NSF > Science TV > Undersea > computer model > energy source > hydrothermal fluid > hydrothermal fluids > hyperthermophilic methanogens > metabolic process > microbial composition > undersea volcano > volcano
Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel
The Nagoya Protocol Creates Disadvantages for Many Countries when Applied to Microorganisms
05.12.2016 | Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
05.12.2016 | Power and Electrical Engineering
05.12.2016 | Materials Sciences
05.12.2016 | Power and Electrical Engineering