With technology similar to that used by physicians to perform magnetic resonance imaging (MRI) scans, researchers from six institutionsincluding the National Institute of Standards and Technology (NIST)working at the Hollings Marine Laboratory (HML) in Charleston, S.C., are studying the metabolic activity of a pathogen shown to cause coral bleaching, a serious threat to undersea reef ecosystems worldwide.
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 temperatureseither through natural seasonal changes or climate change trendsmay 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 reefsand the ecosystems they supporthave 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 c
|Contact: Michael E. Newman|
National Institute of Standards and Technology (NIST)