DURHAM, N.H., Aug. 13 (UPI) -- U.S. scientists have found that blue-green algae actually give orange coral its color.
University of New Hampshire scientists examined Caribbean great star coral and found that cyanobacteria -- commonly known as blue-green algae -- help convert nitrogen in seawater to feed the coral. Existing seawater nitrogen is in a form which the coral cannot use, the bacteria converts it into ammonia.
Coral colonies often look like large rocks and usually glow in the blue color of the water. This typical of a second type of algae, known as zooxanthellae, that are found co-existing with coral formations.
The orange color given off by coral during the day comes from pigments that fluoresce, researchers said. The cyanobacteria absorb light in the color blue and then reflect it in the orange hue.
