Exploring the Coral Canyons on Boston's Doorstep

Creatures Of Light: Biofluorescence

If a coral species biofluoresces, it is generally thought that the coral is healthy. But in some cases, if a large bleaching event is occurring, corals will fluoresce extra brightly, as if giving a final warning that they are about to succumb. These signals, which are invisible to humans otherwise, are a source of much mystery to scientists. As Vincent Pieribone puts it, &ldquo;These signals are cryptic. We don&rsquo;t know to whom they&rsquo;re sending them. And it&rsquo;s a lot of work for a coral to glow. You can understand why a mobile creature like a bird would want to make itself colorful, to attract a mate. But for corals, which are sessile, and which eject their sperm and eggs into the water column, it must be serving a different function.&rdquo; One reason could be to attract fish. The waters in which most corals live are very clear and beautiful&mdash;but what makes them so clear is they&rsquo;re nutrient poor. So if they look pretty and glowing to a fish, perhaps they&rsquo;ll come and live on them. Corals need CO2, water, and nitrogen and phosphate&mdash;the last two come from fish poop. Fish also eat algae, which are constantly trying to overgrow corals. Vincent and team were happy to observe that the reef was healthy and beautiful. They were even joined by a curious turtle (you can&rsquo;t see it in this footage, but they said its shell was biofluorescent also!)

Subject Overview

Most people are somewhat aware that there are animals in the ocean that make their own light. But there are also proteins that &ldquo;glow&rdquo; when a specific (blue) wavelength of light is shone at them.This was a first attempt to combine biofluorescent imaging of coral with microbial and disease ecology data collected from the other science teams from MOTE MARINE LABORATORY AND AQUARIUM, SCRIPPS INSTITUTION OF OCEANOGRAPHY, and the WOODS HOLE OCEANOGRAPHIC INSTITUTION. As our Research Associate Mattie Rodrigue put it in one of her recent updates, &ldquo;Real coral heavy-hitters.&rdquo; They are doing incredible work. In the future, we hope to couple these data when evaluating the health of a reef.

Healthy Corals Glow