SCIENCE LAB SCHEMES : UNDERSEA ROMANCE

In 2017, two evolutionary biologists snorkeling off Panama's coast made a dazzling discovery.

Night was falling over the shallow waters of Bocas del Toro, and James Morin, an emeritus professor at Cornell University in New York State, flicked on his underwater flashlight to catch a glimpse of the seabed.

Seemingly in answer, hundreds of tiny blue lights sparked to life, rippling out in waves.

'' We were both kind of swearing into our snorkels in amazement,'' said Todd Oakley, a professor at the University of California, Santa Barbara.

In a paper published in Proceedings of the Royal Society B, the scientists detailed the courtship rituals of a new species of '' sea firefly '' - a tiny crustacean that stages a spectacular underwater display of sneezing up glowing mucus.

But these aren't simple flashes. Like the synchronous group displays of lightning bugs on land, the sea fireflies light show is a carefully choreographed dance in harmony with the rhythms of the night sky.

'' It's a firework display under water - the best fourth of July you've ever seen,'' said Nicholai Hensley, a postdoctoral fellow at Cornell who led the new study.

The creatures behind the eerie Panamanian light show are called ostracods. Dr. Hensley compares the itty-bitty crustaceans to sesame seeds with eyeballs. 

Under a microscope, you can make out an ostracod's shrimp-like body encased in a see-through shell.

An organ called the ''upper lip'' makes many ostracods bioluminescent, storing two chemicals that when combined, create a bright blue burst. '' It's literally like a handlebar moustache of glowing light right above their mouth,'' Dr. Hensley said.

Ostracods use their luminous mucus for many purposes : In addition to its usefulness in courtship displays, it induces predators to spit them back up [ apparently the mucous tastes really bad]

Dr. Morin said that the light display of the sea fireflies was '' on steroids '' the night he and Dr. Oakley observed them.

The team studied this mysterious population of sea fireflies and persuaded it to give encores of the light show in captivity. Now, the researchers believe they've pieced together the individual steps of the courtship dance

The romance begins at nautical twilight - an in-between time when the sun has set, the moon has yet to rise and the sea fireflies' only competition for luminosity is the starlight.

Each male motors up from the grass beds and then descends in a corkscrewing plunge  - sneezing up between four and eight globs of light as it goes. The result is stunning, like a string of Christmas lights or a strand of glowing pearls.

Dr. Hensley said he couldn't help but marvel at how this incredible dance had been playing out, unobserved, yet so close to civilization. [ Elizabeth Anne Brown ].