Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Knocking on wood in the deep sea: Sunken logs form diverse and dynamic habitats

26.01.2017

The deep sea is a vast and seemingly uninhabitable place, except for some small oases of life. Sunken wood logs, so-called wood falls, can form such oases and provide for rich life for limited periods. A new study by researchers from the MPI Bremen takes a close look at the deep-sea organisms inhabiting wood falls and how they affect their surroundings. They show that sunken logs are highly dynamic ecosystems and play an important role for the diversity and distribution of bacteria and animals alike.

Food is scarce in the deep sea. Thus, morsels of organic matter sinking to the sea floor can form an important food source for many organisms and lead to the establishment of locally highly productive and diverse communities. Such large food falls can be kelp, wood or whale carcasses, for example. While they might only affect small areas of the sea floor, they occur quite frequently and supply large amounts of carbon at a particular time and place.


Freshly deployed log in the Norwegian Sea.

MARUM – Center for Marine Environmental Sciences, University of Bremen


Sampling of highly degraded logs with ROV QUEST.

MARUM – Center for Marine Environmental Sciences, University of Bremen

Make your own food fall

As large organic food falls occur sporadically and locally, they are hard to study. Thus, a team of scientists from the Max Planck Institute for Marine Microbiology in Bremen and the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Bremerhaven sank self-made food falls into the deep sea to enable them to study the organisms attracted by those morsels in great detail.

“We prepared a number of wood logs, standardised in size and age, took them to the sea and deployed them at cold seep sites in the Eastern Mediterranean and in the Norwegian Sea”, explains Petra Pop Ristova, first author of the study.

Over a period of three years the logs were repeatedly sampled for their bacterial and larger faunal inhabitants. Subsequently they were retrieved from the sea floor for more detailed analyses in the framework of a joint research project between the Max Planck Society (MPG) and the French National Center for Scientific Research (CNRS) called DIWOOD.

Constant change

“We found that sunken logs are highly dynamic ecosystems”, Pop Ristova says. They are quickly colonised by a diverse community of organisms, starting with wood boring bivalves, which are essential for chewing the wood to small pieces. The wood community is not static but changes continuously. “For example, in the Eastern Mediterranean, different species of wood-boring bivalves succeeded each other, while the number of sipunculids, the so-called peanut worms, continuously increased.” At the same time, the bacterial community changed, with sulphate-reducers and sulphide-oxidisers increasing in proportion.

Moreover, the scientists found that organisms nibbling at logs are not the same all over the ocean. “No other study has yet analysed standardised samples from different ocean regions to compare the succession of deep sea life”, says Pop Ristova. “Logs harboured different inhabitants depending on whether we deployed them in the cold Norwegian Sea or in the warm Mediterranean. Whether that is mainly due to the geographic setting or differing temperature, we can not yet resolve.”

Chips off the old log

The influence of wood falls is not restricted to the logs itself but expands to the surrounding sea floor. For example, sulphide production in the vicinity of the fall increases, accompanied by growing numbers of sulphate-reducers, the scientists report. However, this influence is restricted to a rather small area, extending only a few meters from the log. “This is clearly different from other large organic food falls such as whale carcasses”, says Antje Boetius, senior author of the study and group leader of the HGF-MPG Research Group for Deep Sea Ecology and Technology. “The impact of whale falls was shown to extend far beyond the carcass and last for several decades. Wood cellulose is much harder to degrade than lipids and proteins from a carcass and is carried out only by a few specialised organisms. Also, large mobile predators such as sharks and hagfish are not into wood – and even the wood boring bivalves totally depend on bacteria helping them to use wood as energy source.”

From stone to stone, from log to log

Nevertheless, the log falls do have a far-reaching impact: they serve as stepping stones for seep biota. Seeps and vents on the deep sea floor can lie hundreds of kilometres apart – a long way for bacteria and larvae of seep inhabitants to travel. “On wood falls, conditions favourable for these organisms develop at a certain stage. Thus, they can serve as a stop-over during dispersal”, says Pop Ristova.

Hubs of productivity and biodiversity

When large amounts of food become temporarily available in an otherwise food-deprived surrounding, prolific ecosystems develop that attract a highly adapted and opportunistic fauna. They promote the development of an ecosystem with one the highest species richness known from deep-sea habitats. While log falls might be harder to chew than large carcasses, they nevertheless play an important role for the surrounding ecosystem as hubs of biodiversity and as stepping stones for seep biota.

Original publication
Petra Pop Ristova, Christina Bienhold, Frank Wenzhöfer, Pamela E. Rossel and Antje Boetius: Temporal and spatial variations of bacterial and faunal communities associated with deep-sea wood falls. PLOS ONE.
DOI: 10.1371/journal.pone.0169906


Please direct your queries to

Dr. Petra Pop Ristova
Phone: +49 421 218 65966
E-Mail: pristova(at)marum.de

Prof. Dr. Antje Boetius
Phone: +49 421 2028 860
E-Mail: aboetius(at)mpi-bremen.de

or the press office

Dr. Fanni Aspetsberger
Dr. Manfred Schlösser
Phone: +49 421 2028 947
E-Mail: presse(at)mpi-bremen.de

Weitere Informationen:

http://www.mpi-bremen.de
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0169906 (Original publication in PLOS ONE

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

Further reports about: Max-Planck-Institut Mikrobiologie bivalves carcasses deep sea organic food sea floor

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 Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Epoxy compound gets a graphene bump

14.11.2018 | Materials Sciences

Microgel powder fights infection and helps wounds heal

14.11.2018 | Health and Medicine

How algae and carbon fibers could sustainably reduce the athmospheric carbon dioxide concentration

14.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>