Discovery of new species spurs biologist to expand Caribbean research

Over semester break, biology professor Ray Gerber and Scott O'Donnell '06 bushwhacked through mangrove swamps, slogged through mud-bottomed ponds and swatted mosquitoes, while gulping Gatorade to keep ahead of the steamy tropical heat.

copepod
This tiny crustacean, or copepod, lives in lagoons with up to six times the concentration of salt in the ocean. "The high salt content makes it stressful to most forms of life, so it was surprising and exciting to find it living there," says Gerber. He named the species "Cletocamptus tainoi" in honor of the Taino Indians who were the original inhabitants of the Virgin Islands.

Dr. Gerber and O'Donnell were sampling ponds ...on an island in the Caribbean. Okay, it was the stunning Virgin Islands National Park in January, but, still, it was scientific field sampling.

It all started when Gerber and his wife vacationed at the park on the island of St. John the previous year. Trained as an oceanographer, he was curious about what plankton species might live in the ponds on St. John island. When a literature search yielded no information, he contacted the park and was given a scientific sampling permit.

Gerber brought along his plankton net, as he often does. Since seventh grade, when his mother fashioned him a net from curtain fabric, he samples water wherever he finds it. In the first tow of his net through one of the salt ponds on St. John, he found a tiny crustacean that looked different than anything he had ever seen.

Though 90 percent certain it was a new species when he peeked at it under the microscope back on the mainland, it took nearly a year of combing scientific journals, contacting colleagues and consulting taxonomists to confirm the shrimp-like organism as new to science.

"It's new knowledge for science," Gerber says. "It's important to understand the biodiversity of the ponds in this region," he adds. "Very little is known about the ponds in the Caribbean islands, except for Cuba."

With funding provided by Saint Joseph's through a Faculty Professorship Award, he decided to go back this year to scientifically sample more types of ponds on the island. "No plankton studies had ever been done before on these ponds," says Gerber.

Gerber invited O'Donnell, a recent environmental studies graduate from Sanford, Maine, to come along as his field assistant. Camped in a tent-platform at the national park for a week, Gerber and O'Donnell sampled 15 sites on the island. They drove their rented Jeep over steep and winding roads - on the left side, a throwback to the former Danish owners of the island - and trekked through dense vegetation to the ponds. They lugged their equipment as they went. They tried to stay focused on the job instead of the biting insects and the sticky heat.

As Gerber sampled the freshwater, brackish or hypersaline ponds, O'Donnell checked the water chemistry: dissolved oxygen content, salinity, temperature, conductivity and pH. These factors would help them understand the copepods in the ponds.

"Scott was outstanding," says Gerber of his field assistant, who got stung when they unwittingly hiked through a wasp nesting area. An outdoorsman who used to live in Alaska, Scott is both smart and rugged, says Gerber.

When they returned to their campsite at night, the two would pick through the "pond goo." Anything unique had to be labeled, cataloged and preserved by slowly adding alcohol. On the trip down to St. John, Gerber discovered that Homeland Security considers the formaldehyde he normally uses to preserve samples a security threat. Fortunately, the 150-proof rum available on St. John made an excellent replacement.

Gerber says it's important to know what species are on St. John, because that information can illuminate a species' origin and how it got there, or why it can persist on St. John while another species has disappeared, for example. He says the biogeography of the new species is important to the National Park Service, especially as areas surrounding the park are developed. (The tiny crustaceans provide a link in the food chain between the algae and the fish and between the algae and the shorebirds.) The park staff, which helped
Gerber locate sampling sites, was very interested in his findings.

Gerber's task upon returning to Maine was to examine the new samples for the species he discovered last year. He found them in the same salt lagoon sampled last winter, but also in another salt pond on the island. "Clearly, they thrive in these very salty environments where little else can survive," he says.

Gerber will continue to comb through the rest of his samples from all the ponds. Next, he'll make detailed illustrations and write up the results for publication. He's already planning his next expedition to the nearby island of Culebra to determine if species found on St. John are more widespread.

"Who knows," he says, "I may find other new species as well."

- by Charmaine Daniels