Coral bleaching is the whitening of living coral due to a disruption of the symbiosis (two organisms whose living together benefits both) with its zooxanthellae, tiny photosynthesizing algae. These unicellular creatures reside within the coral's tissues and provide the host organism with up to 90 percent of its energy.
It's the solar-derived chemical products of these algae that give the world's coral species a rainbow of vivid colors. Unfortunately, ecologically valuable coral colonies around the globe are being threatened by an ocean-dwelling bacterium known as Vibrio coralliilyticus. When the microbe becomes virulent, it can infiltrate coral and dislodge the zooxanthellae, causing the coral to lose its pigmentation. If symbiosis is disrupted long enough, the coral dies from starvation.
Environmental scientists have shown in laboratory experiments that the virulence of V. coralliilyticus is temperature dependent, causing bleaching at temperatures above 24 degrees Celsius (75 degrees Fahrenheit). These findings have raised concerns that increasing ocean temperatures—either through natural seasonal changes or climate change trends—may lead to increased risk of widespread coral bleaching. During the past two decades, it has been reported that nearly 30 percent of the world's coral reefs—and the ecosystems they support—have been severely degraded by bleaching.
In a recent paper in Environmental Science and Technology,* the HML research team described how it used nuclear magnetic resonance (NMR) to study metabolic changes in V. coralliilyticus resulting from temperature effects. The technique allows discovery of small-molecule metabolism-related compounds that correlate with different biological conditions. In this study, the levels of three compounds—betaine, glutamate and succinate—that help regulate energy production and osmotic pressure (a mechanism for maintaining cellular integrity) in V. coralliilyticus were determined to vary significantly between 24 degrees Celsius when the bacterium is not virulent and 27 degrees Celsius (81 degrees Fahrenheit) when it is. These metabolic changes, the HML team believes, are clues to learning why the small temperature change can turn non-virulent V. coralliilyticus into a coral bleaching menace.
Future metabolomic studies of V. coralliilyticus are planned to better understand the complete temperature-dependent mechanism involved in its pathogenicity. The researchers hope that these findings will lead to a better understanding of the symbiotic relationships that exist in healthy coral and the potential impacts on those relationships under changing ecological conditions.
Teaming on this study with three NIST researchers were scientists from the Medical University of South Carolina, Tennessee Technological University, The Richard Stockton College of New Jersey, Mt. Holyoke College and the College of Charleston. The team included self-funded visiting scientists, graduate students from HML partner agencies and visiting undergraduate students funded through the National Oceanic and Atmospheric Administration (NOAA) and National Science Foundation programs.
The HML is a unique partnership of governmental and academic agencies including NIST, NOAA's National Ocean Service, the South Carolina Department of Natural Resources, the College of Charleston and the Medical University of South Carolina.
* A.F.B. Boroujerdi, M.I. Vizcaino, A. Meyers, E.C. Pollock, S.L. Huynh, T.B. Schock, P.J. Morris and D.W. Bearden. NMR-based microbial metabolomics and the temperature-dependent coral pathogen Vibrio coralliilyticus. Environmental Science and Technology, Vol. 43, No. 20 (Oct. 15, 2009).
Michael E. Newman | Newswise Science News
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences