By Dr. Stacy Jupiter
I Love the Night Dive, I Got to Boogie
This is the fifth of several blogs documenting an 8-day, marine expedition to Fiji.
“Why are you wearing that funky yellow mask?” one of the crew of our research vessel asked.
“I’m going on a disco dive,” I replied.
He was rightfully perplexed. Little did he know that within minutes I would descend on a glowing underwater world with the trippy semblance of a dance club illuminated by black lights.
That is, in fact, exactly what we were doing. Pioneering work by Dr. Charles Mazel and others on coral fluorescence led to the use of blue lights and photographic filters both to produce stunning images and also to learn more about coral reef processes. On our team, Drs. David Kline, Tali Treibitz and Greg Mitchell, of Pacific Blue Foundation and the Scripps Institution of Oceanography at the University of California, San Diego, are developing unique camera systems to document these glowing reefscapes.
When excited by blue light, proteins in the tissues of algae, corals, anemones and even some fish, shrimp and worms glow in a full array of psychedelic colors, like a fashion show from the 1980s. Scientists are not entirely clear on the role of the fluorescent pigments. Some argue that they may act as “sunscreen”, protecting corals or the algae (called “zooxanthellae”) in their tissues from the sun’s harmful rays. However, this is still much debated. Others have suggested that the pigments may help the zooxanthellae convert light energy to food in darker environments.
Regardless of their original function, fluorescent pigments are incredibly useful to identify newly settled coral larvae on the reef, which are nearly impossible to find with the naked eye in full daylight. This fills an important gap in our understanding of the natural history of corals as we do not have any idea how many of these new recruits survive to the juvenile stage. Do reefs with high recruitment recovery more quickly from disturbance? Or do recovery rates depend more on the numbers of juvenile coral colonies that have proven that they can survive on the reef?
“This new technology unlocks part of the coral life cycle which we previously couldn’t measure,” explains David. “By quantifying relationships between the number of recruits and the number of juveniles, we can begin to make predictions about the future health of the reef.”
With their giant camera rigs and brilliant blue lights, David and Tali look like an alien submersible hovering over the seabed. In the meantime, I let out squeals of delight into my dive regulator as I illuminate first a mushroom coral followed by a chiton sitting on the shell of a giant clam and then a sleeping lizardfish while looking for animals for Keith to photograph.
I came up to the surface thoroughly overstimulated with a big, silly grin on my face.
“I love night dives,” Keith announced.
At his proclamation, I started humming to myself modified lyrics to Alicia Bridges 1978 hit I Love the Nightlife: “I love the night dives. I got to boogie . . . on the disco ’round, oh yea!”
[NOTE: The photographs for this blog were not manipulated or color corrected in any way]