Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

‘Farming’ bacteria to boost growth in the oceans

24.10.2016

Marine symbiotic bacteria may help to ‘fertilize’ animal growth in the oceans. Scientists have discovered that chemosynthetic bacteria in marine animals can fix nitrogen as well as carbon. This is the first such symbiont known to be capable of nitrogen fixation.

Chemosynthetic symbionts are bacteria living inside or on the surface of animals, supplying their host with food that would otherwise be unavailable. It has long been known that these bacteria fix carbon and convert it into organic forms.


Divers collected samples of lucinid clams and nematode worms in the coastal waters of the island Elba in Italy, for example, and subsequently investigated their symbiotic tenants.

Ulisse Cardini

Microbiologist Jillian Petersen and colleagues from the University of Vienna and the Max Planck Institute for Marine Microbiology now reveal that the same is possible for nitrogen. Chemosynthetic bacteria transform inert nitrogen gas into bioavailable forms. As nitrogen is often the limiting nutrient in the ocean, these bacteria could be fertilizing growth in marine ecosystems.

The ability to fix nitrogen has now been discovered in chemosynthetic symbionts of marine lucinid clams and nematode worms. The symbiotic clams and worms investigated in this study are found in coastal marine waters worldwide. In some regions, the clams are even considered a delicacy.

‘Chemosynthetic’ means the bacteria have the special ability to do primary production in the complete absence of sunlight, using only the energy stored in chemical bonds. This symbiotic primary production is effective enough to provide a food source for both the bacteria and their animal hosts.

Using state-of-the-art DNA sequencing technologies, Petersen and her colleagues discovered all of the genes necessary for nitrogen fixation in the symbionts of these worms and clams. No marine chemosynthetic symbiont was previously known to be capable of nitrogen fixation. “Our finding is especially surprising because these bacteria are probably able to take up nitrogen from their surroundings, and also to recycle nitrogen waste compounds from their hosts”, says Petersen.

“It seems like they wouldn’t need to fix the stuff.” The team therefore also used transcriptomic and proteomic analyses on the clams, and indeed detected expression of the genes for nitrogen fixation. “That indicates that these symbionts are actively fixing nitrogen inside their hosts”, Petersen continues. The nitrogen isotope composition of the clams showed typical signatures for biologically fixed nitrogen, further suggesting active nitrogen fixation by the symbionts.

Assistant Professor Jillian Petersen, who researches these symbioses at the University of Vienna, and previously at the Max Planck Institute for Marine Microbiology in Germany, led the team of researchers that made this discovery. The team in Vienna joined forces with institutes around the world including the Max Planck Institute, the University of Montpellier in France, the University of Calgary in Canada, and the Hydra Institute in Italy.

‘’Most of our field work was done at the HYDRA Institute on Elba’’ according to Dr. Ulisse Cardini, a postdoctoral researcher in Petersen’s team and an experienced diver who collected many of the samples by scuba diving. ‘‘In addition, our colleagues Dr. Nicolas Higgs from the Plymouth University Marine Institute and Dr. John Taylor at the Natural History Museum in London generously shared their sample collections with us, so we were able to search for these nitrogen fixation genes in marine clam species from around the world – and we found them! The ability to fix nitrogen is probably widespread in these animal-associated bacteria’’, says Cardini.

‘’Nitrogen fixation by chemosynthetic symbionts was overlooked for a long time’’, says Petersen. ‘’Since their discovery in the deep sea in the late 1970s, we have spent almost four decades researching the symbionts’ role in providing a source of carbon such as sugars for their hosts.’’ However, even marine clams cannot live from sugar alone. This new research raises the possibility that these symbionts may provide the unexpected benefit of a natural source of nitrogen to augment their host’s diet. They could even be fertilizing the surrounding habitat by releasing available nitrogen to the surrounding water. ‘‘Our future research aims to answer this question: Do these marine symbiotic bacteria help to ‘fertilize’ the oceans, too?’’

BACKGROUND INFORMATION

Nitrogen is essential to all living things. It is needed to manufacture vital cell components such as proteins and DNA. Nitrogen is plentiful on Earth, mostly in the form of N2 gas. However, nitrogen in this form is not accessible to most organisms. Thus, plants, animals and microbes can die from a lack of nitrogen while literally being surrounded by it.

Biological nitrogen fixation is the process that changes inert N2 to a biologically useful form. This process is essential for sustaining primary production, replenishing nutrients, and enabling the very persistence of diverse ecosystems on land and at sea. Biological nitrogen fixation is only carried out by a specialized group of microorganisms called ‘diazotrophs’. By transforming N2 gas into usable forms such as ammonia, diazotrophs are the main agent making sure that nitrogen is available to other organisms. They can thus be likened to micron-scale factories that synthesize the nitrogen fertilizer that keeps our ecosystems running.

On land, as farmers are acutely aware, nitrogen often limits the growth of food crops. One widespread solution to this problem is to add chemical fertilizers, thus, every year, we pour millions of tons of fertilizers onto agricultural lands. An alternative solution, which has been practiced for thousands of years, is to rotate food crops with leguminous plants. Legumes come with built-in biological fertilizers: symbiotic nitrogen-fixing bacteria that form nodules in the plant roots, fixing nitrogen and providing their plant host and the surrounding soil with this essential nutrient. New research now shows that some marine animals have evolved a similar symbiotic solution to their nitrogen limitation problems. And it might similarly serve as a fertilizer for the surrounding plants.

Publication in Nature Microbiology:
Chemosynthetic symbionts of marine invertebrate animals are capable of nitrogen fixation: Jillian M. Petersen, Anna Kemper, Harald Gruber-Vodicka, Ulisse Cardini, Matthijs van der Geest, Manuel Kleiner, Silvia Bulgheresi, Marc Mussmann, Craig Herbold, Brandon K.B. Seah, Chakkiath Paul Antony, Dan Liu, Alexandra Belitz, Miriam Weber in Nature Microbiology (2016)
DOI: 10.1038/NMICROBIOL.2016.195

Scientific contact
Ass. Prof. Dr. Jillian Petersen
Department of Microbiology and Ecosystem Science
University of Vienna
1090 Vienna, Althanstraße 14 (UZA I)
M +43-676-454 60 61
petersen@microbial-ecology.net

Press contact
Dr. Fanni Aspetsberger
Dr. Manfred Schlösser
Phone: +49 421 2028 704
E-Mail: presse@mpi-bremen.de

Weitere Informationen:

http://www.mpi-bremen.de

Dr. Fanni Aspetsberger | Max-Planck-Institut für marine Mikrobiologie

More articles from Life Sciences:

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

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...

Im Focus: Visual intelligence is not the same as IQ

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...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

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....

Im Focus: Researchers Develop Data Bus for Quantum Computer

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,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>