Researchers have shown for the first time that some corals surviving bleaching events obtain more nutrients from a particular group of bacteria, which may make the coral more heat-tolerant and enhance their recovery.
This is the key finding of a new study carried out by an international research team under the supervision of Prof. Dr. Christian Wild (Marine Ecology, University of Bremen, Germany).
The study was recently published in the prestigious international journal “Environmental Microbiology”. Dr. Ulisse Cardini, who graduated last year at the University of Bremen and now works as researcher at the University of Vienna (Austria), is the first author of the study.
Coral bleaching and its linkage to ocean warming
Warm water corals are animals that grow optimally in water temperatures between ca. 23° and 30 °C. If temperatures exceed this comfort zone, then often coral bleaching occurs. In this process, corals loose most of their color as millions of microalgae that live within the corals leave their animal host.
As bleaching occurs, corals are not dead, but in a state of great weakness since they lack the algae that normally provide them with essential energy and nutrients. That is why bleaching often leads to mass mortality of corals, particularly if the heat stress is long-lasting and pronounced. Conversely, corals can re-uptake the microalgae and recover from bleaching when temperatures drop back to normal.
In recent years, ocean warming in combination with El-Nino phenomena led to a high frequency of extended coral bleaching events with ensuing mass mortality (e.g. 1998 in the Indian Ocean, 2002 in the Pacific Ocean, and 2005 in the Caribbean). At the moment, we are witnessing the worst mass coral bleaching on record affecting all world oceans.
The important role of bacteria in bleached corals
The study by Ulisse Cardini, Christian Wild, and others provided evidence supporting the hypothesis that a group of bacteria capable of nitrogen fixation may help their host corals to better survive through heat stress events. In fact, these microbes are able to provide essential nutrients that may be deficient in the coral when their symbiosis with microalgae is heat impaired.
During field and laboratory experiments at the Northern Red Sea (Aqaba, Jordan) the research team could demonstrate that nitrogen fixation increased by up to 300% in some of the corals exposed to heat stress. However, the outcome of the temperature stress was different in different corals.
In this context, the highly under-investigated interplay between the coral animals, the symbiotic algae, and the associated bacteria plays an important role and may select winners and losers in the world's coral reefs of the future.
Cardini et al. (2016) Microbial dinitrogen fixation in coral holobionts exposed to thermal stress and bleaching (in press at Environmental Microbiology).
Prof. Dr. Christian Wild
University of Bremen
Faculty Biology / Chemistry
Phone. 0421 218 63367
Dr. Ulisse Cardini
University of Vienna
Department of Microbiology and Ecosystem Science
Division of Microbial Ecology
Phone: +43 677 61633148
Eberhard Scholz | Universität Bremen
Scientists enlist engineered protein to battle the MERS virus
22.05.2017 | University of Toronto
Insight into enzyme's 3-D structure could cut biofuel costs
19.05.2017 | DOE/Los Alamos National Laboratory
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.
Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...
22.05.2017 | Event News
17.05.2017 | Event News
16.05.2017 | Event News
22.05.2017 | Materials Sciences
22.05.2017 | Life Sciences
22.05.2017 | Physics and Astronomy