A doctoral student at Baruch College is studying the luminescent proteins of Bermuda fireworms, glowing green creatures that may have caught Christopher Columbus’s eye 520 years ago.
At 10 p.m. on Oct. 11, 1492, Christopher Columbus saw a glimmer in the distance as he stood on the deck of the Santa María. The faraway flash was “so small a body that he could not affirm it to be land,” Columbus wrote, referring to himself in the third person.
He called over two of his crew members, but the light was so faint that only one man could discern it. Staring harder, Columbus wrote, he “again perceived it once or twice, appearing like the light of a wax candle moving up and down, which some thought an indication of land.”
This mysterious light has long captivated historians and scientists, with some attributing it to canoes, fires onshore or even Columbus’s imagination. In 1935, the naturalist Lionel Ruttledge Crawshay suggested that the light emanated from luminous worms in the genus Odontosyllis, commonly known as fireworms. Like clockwork, these bioluminescent creatures swim in a circular mating dance before the twice-monthly quarter
Although these slender worms are a familiar sight and popular among both locals and tourists, biologists have much to learn about them, measuring from half a millimeter to 15 millimeters long (up to six-tenths of an inch), said Struan Smith, curator of the Bermuda Natural History Museum. What researchers do know is that the glow worms live in shallow coastal areas including Southern California, Puerto Rico, Belize, Bermuda and even British Columbia — places where they probably eat sponges and corals, studies show.
The fireworms spend most of their lives on the ocean floor but swarm to the surface to mate in a glowing bimonthly dance, said Dimitri D. Deheyn, a marine biologist at the Scripps Institution of Oceanography. Females swim in luminescent two-inch circles, while the males follow them, glowing in bursts of light.
“It really is a bit of a crescendo,” Dr. Smith said, describing how a swarm of four fireworms increases to a crowd of dozens, with the females swimming in glowing green circles. Once the males reach the bull’s-eye of a circle, the females secrete bluish luminous mucus filled with eggs, which the males then fertilize.
From June to September, Dr. Smith regularly takes visitors to well-known fireworm breeding waters where they can enjoy the sunset and, soon after, see the green glow of the circling females and the pulse of the males following them. “Everyone comes away with a smile on their face,” he said.
After around 20 to 30 minutes, the fireworms extinguish their lights, probably so they won’t attract predators, said Aida Verdes Gorín, who started her doctoral research in ecology, evolutionary biology and behavior this month. The worms also glow when they are not reproducing and may use their bioluminescence to startle predators, she added.
Ms. Verdes Gorín plans to fly to San Diego, where she can collect the fireworms and then bring them back to New York and isolate their glowing proteins with the help of her advisers, both of whom are research associates at the American Museum of Natural History. (One, David Gruber, is an assistant professor of biology and environmental science at Baruch College, and the other is María Teresa Aguado, assistant professor of biology at the Universidad Autónoma de Madrid.)
After studying the worms’ luminescent proteins, Dr. Deheyn’s group learned that the fireworms use photoproteins to glow, according to their 2009 study. Unlike the well-known green fluorescent protein, or G.F.P., whose researchers won the 2008 Nobel Prize in Chemistry, photoproteins can glow independently.
“If you have the gene of a photoprotein, you can insert that gene so that it will illuminate cancer cells or illuminate cells under stress,” Dr. Deheyn said. “The G.F.P. is fantastic, but it needs to be illuminated with the blue light in order to fluoresce, whereas with the photoprotein, you don’t need a blue light — it just needs a cofactor” like calcium, he said.
While studying the worms’ bioluminescence, Ms. Verdes Gorín plans to measure properties like wavelength in the hope of contributing to the growing arsenal of glowing proteins. “Maybe it is very different and it opens another research field, who knows,” she said.
Experts will never know exactly what Columbus saw on the next-to-last day of his voyage to the Americas. Crawshay, author of the 1935 study, makes compelling arguments that he glimpsed the fireworms, Dr. Smith said. The Nina, the Pinta and the Santa María may have passed by shallow waters where the worms breed. Not all worms breed within a few days after the full moon; some wait longer.
Another possibility, Dr. Smith suggests, is that Columbus caught sight of a luminous squid. “Even after 400 years of settlement, and a great deal of scientific endeavor since the mid-1800s, we are still discovering and learning about marine life in Bermuda,” he said.