By Susan Milius
A lot of reef creatures could be in the red.
A widespread capacity for fish, corals, worms and other animals to fluoresce red has been largely overlooked, contend Nico Michiels of the University of Tübingen in Germany and colleagues in a new study.
Seawater quickly absorbs the red wavelengths of daylight filtering through, so that at depths below 10 meters the red portion of sunlight disappears and the blues and greens dominate. The majority of fish tested so far from this zone have vision tuned to blues and greens.