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
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
25.04.2018 | Physics and Astronomy
25.04.2018 | Physics and Astronomy
25.04.2018 | Information Technology