Berkeley Lab research also provides new clues about the roles of subsurface microbes in globally important cycles
One of the most detailed genomic studies of any ecosystem to date has revealed an underground world of stunning microbial diversity, and added dozens of new branches to the tree of life.
All the known major bacterial groups are represented by wedges in this circular 'tree of life.' The bigger wedges are more diverse groups. Green wedges are groups that have not been genomically sampled at the Rifle site --everything else has. Black wedges are previously identified bacteria groups that have also been found at Rifle. Purple wedges are groups discovered at Rifle and announced last year. Red wedges are new groups discovered in this study. Colored dots represent important metabolic processes the new groups help mediate.
Credit: Banfield Group
The bacterial bonanza comes from scientists who reconstructed the genomes of more than 2,500 microbes from sediment and groundwater samples collected at an aquifer in Colorado. The effort was led by researchers from the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley. DNA sequencing was performed at the Joint Genome Institute, a DOE Office of Science User Facility.
As reported online October 24 in the journal Nature Communications, the scientists netted genomes from 80 percent of all known bacterial phyla, a remarkable degree of biological diversity at one location. They also discovered 47 new phylum-level bacterial groups, naming many of them after influential microbiologists and other scientists. And they learned new insights about how microbial communities work together to drive processes that are critical to the planet's climate and life everywhere, such as the carbon and nitrogen cycles.
These findings shed light on one of Earth's most important and least understood realms of life. The subterranean world hosts up to one-fifth of all biomass, but it remains a mystery.
"We didn't expect to find this incredible microbial diversity. But then again, we know little about the roles of subsurface microbes in biogeochemical processes, and more broadly, we don't really know what's down there," says Jill Banfield, a Senior Faculty Scientist in Berkeley Lab's Climate & Ecosystem Sciences Division and a UC Berkeley professor in the departments of Earth and Planetary Science, and Environmental Science, Policy, and Management.
UC Berkeley's Karthik Anantharaman, the first author of the paper, adds, "To better understand what subsurface microbes are up to, our approach is to access their entire genomes. This enabled us to discover a greater interdependency among microbes than we've seen before."
The research is part of a Berkeley Lab-led project called Sustainable Systems Scientific Focus Area 2.0, which is developing a predictive understanding of terrestrial environments from the genome to the watershed scale. The project's field research takes place at a research site near the town of Rifle, Colorado, where for the past several years scientists have conducted experiments designed to stimulate populations of subterranean microbes that are naturally present in very low numbers.
The scientists sent soil and water samples from these experiments to the Joint Genome Institute for terabase-scale metagenomic sequencing. This high-throughput method isolates and purifies DNA from environmental samples, and then sequences one trillion base pairs of DNA at a time. Next, the scientists used bioinformatics tools developed in Banfield's lab to analyze the data.
Their approach has redrawn the tree of life. Between the 47 new bacterial groups reported in this work, and 35 new groups published last year (also found at the Rifle site), Banfield's team has doubled the number of known bacterial groups.
With discovery comes naming rights. The scientists named many of the new bacteria groups after Berkeley Lab and UC Berkeley researchers. For example, there's Candidatus Andersenbacteria, after phylochip inventor Gary Andersen, and there's Candidatus Doudnabacteria, after CRISPR genome-editing pioneer Jennifer Doudna. "Berkeley now dominates the tree of life as it does the periodic table," Banfield says, in a nod to the sixteen elements discovered at Berkeley Lab and UC Berkeley.
Another big outcome is a deeper understanding of the roles subsurface microbes play in globally important carbon, hydrogen, nitrogen, and sulfur cycles. This information will help to better represent these cycles in predictive models such as climate simulations.
The scientists conducted metabolic analyses of 36 percent of the organisms detected in the aquifer system. They focused on a phenomenon called metabolic handoff, which essentially means one microbe's waste is another microbe's food. It's known from lab studies that handoffs are needed in certain reactions, but these interconnected networks are widespread and vastly more complex in the real world.
To understand why it's important to represent metabolic handoffs as accurately as possible in models, consider nitrate, a groundwater contaminant from fertilizers. Subsurface microbes are the primary driver in reducing nitrate to harmless nitrogen gas. There are four steps in this denitrification process, and the third step creates nitrous oxide--one of the most potent greenhouse gases. The process breaks down if microbes that carry out the fourth step are inactive when a pulse of nitrate enters the system.
"If microbes aren't there to accept the nitrous oxide handoff, then the greenhouse gas escapes into the atmosphere," says Anantharaman.
The scientists found the carbon, hydrogen, nitrogen, and sulfur cycles are all driven by metabolic handoffs that require an unexpectedly high degree of interdependence among microbes. The vast majority of microorganisms can't fully reduce a compound on their own. It takes a team. There are also backup microbes ready to perform a handoff if first-string microbes are unavailable.
"The combination of high microbial diversity and interconnections through metabolic handoffs likely results in high ecosystem resilience," says Banfield.
Other co-authors of the paper include Berkeley Lab's Eoin Brodie, Susan Hubbard, Ulas Karaoz, and Kenneth Williams; and UC Berkeley's Chris Brown, Cindy Castelle, Laura Hug, Alexander Probst, Itai Sharon, Andrea Singh, and Brian Thomas. The research is supported by the Department of Energy's Office of Science.
Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit http://www.
DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
Dan Krotz | EurekAlert!
Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care
Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses