First global study of microbial communities at gas seeps in the deep sea shows the distribution and diversity of methane-consuming microorganisms. The specific energy source selects for unique microorganisms, which turn these ecosystems into hotspots of diversity in the deep sea.
Methane seeps are places in the ocean, where methane from deep sediment layers escapes the seabed. Specific microorganisms use the potential greenhouse gas as an energy source and thus form the basis for complex ecosystems.
Methanotrophic microorganisms of methane seep ecosystems.
Micrographs of aerobic methanotrophic bacteria (white), anaerobic methanotrophic archaea (ANME – red) and sulfate-reducing bacteria (SRB – green) visualized by fluorescence in situ hybridization. ANME and SRB perform the anaerobic oxidation of methane (AOM). AOM is a globally relevant process removing 60 million tons, the mass of ten pyramids of Giza, of the greenhouse gas methane from seafloor sediments each year. Courtesy of Katrin Knittel/Emil Ruff, MPI Bremen.
Now an international team of researchers led by the Max Planck Institute for Marine Microbiology has investigated the microbial communities of selected methane seeps from all oceans, and compared those to communities of other marine ecosystems. In the current issue of Proceedings of the National Academy of Sciences (USA), the researchers report that methane seeps contain many endemic microorganisms and therefore are hotspots of biodiversity in the deep sea.
In general, the seep communities are very different from those of other ecosystems. Only a few species of methanotrophs occur at all seeps worldwide, but these microorganisms seem to greatly influence the methane budget of the ocean.
Seafloor ecosystems have unique inhabitants
Each ecosystem in the deep sea is inhabited by certain microorganisms that can be assigned to the three domains of the tree of life: eukaryotes, archaea and bacteria. Eukaryotes have a nucleus and include all plants, fungi, animals and man. Archaea and bacteria are single cells without a nucleus.
The researchers studied the composition and relative abundance of archaea and bacteria at 77 locations of different marine ecosystems, including coastal sediments, deep-sea sediments, black smokers and methane seeps. They extracted the DNA of these organisms from the seabed samples and analyzed it using modern DNA sequencing techniques and mathematical algorithms.
Emil Ruff, scientist at the Max Planck Institute, summarizes: "Almost all of the major groups of archaea and bacteria were present at all examined sites. With increasing resolution, however, the differences between the ecosystems became clearer. At the level of individual species, which are the smallest branches of the tree of life, we found communities that are characteristic for each ecosystem and have a very specific task."
These characteristic communities were defined as the methane seep microbiome. The term microbiome is used to describe all microorganisms of a particular ecosystem and their genetic diversity. Such an ecosystem may be a methane seep, or soil or even the human intestine. The head of the research group, Prof. Dr. Antje Boetius, adds: "This study represents the first global view on microbes inhabiting methane seeps. It was enabled by a large international effort, the International Census of Marine Microbes.”
Methane seeps accommodate many specialists
Natural methane seeps (cold seeps) are found worldwide at continental margins. The gas is formed by decomposition processes in the anoxic layers deep down in the sediment, moves upwards and escapes at the seafloor. The uppermost sediment layers harbor methane oxidizers, which consume about three-quarters of the escaping methane.
This is equivalent to 60 million tons of carbon per year. At methane seeps, the primary energy source is completely different from those of the surrounding seabed. Thus, like oases in the desert methane sources attract particular organisms. These include groups with known function, such as anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB). However, the researchers also found microbial groups on the methane sources with unknown function.
Emil Ruff, first author of the study, said: "It was surprising that microorganisms from seeps that are thousands of miles away in different oceans, are so closely related. Many methane oxidizers and sulfate reducers are sensitive to oxygen. Therefore, it is a mystery how they survive the great distances between the methane seeps."
The findings of the researchers suggest that only a few worldwide populations are responsible for the bulk of the methane consumption. The vast diversity of species and the evolution of new species, however, is limited to and can only be found at certain sites. Methane seeps thus contribute greatly to the biodiversity of the deep sea.
Global dispersion and local diversification of the methane seep microbiome
Emil Ruff, Jennifer F. Biddle, Andreas Teske, Katrin Knittel, Antje Boetius, Alban Ramette PNAS 2015, DOI: 10.1073/pnas.1421865112.
Emil Ruff, Max Plank Institute for Marine Microbiology, Bremen: +49 421 2028 942; email@example.com
or from the press officer
Manfred Schlösser, Max Plank Institute for Marine Microbiology, Bremen: +49 421 2028 704 firstname.lastname@example.org
Dr. Manfred Schloesser | Max-Planck-Institut für marine Mikrobiologie
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Life Sciences
21.10.2016 | Life Sciences
21.10.2016 | Life Sciences