Microscopic Organisms Found on Cayman Beaches
By Edwin L. Aguirre
New species of microscopic marine worms that inhabit the sands of the Cayman Islands was recently discovered by an international team of researchers led by biology Assoc. Prof. Rick Hochberg.
The worms, known as gastrotrichs, are highly complex and diverse animals less than a millimeter in size. Hochberg and his team made the find this summer at the Central Caribbean Marine Institute’s Little Cayman Research Center.
“Despite the tropical location and beauty of the Cayman Islands, there are no biodiversity studies of the islands’ marine meiofauna, which are microscopic invertebrates that live between sand grains,” says Hochberg. “Our research therefore is the first study of Little Cayman Island and, in fact, the only study of its kind from all three Cayman Islands. This could spawn numerous additional studies that will shed more light on the islands’ unique biodiversity.”
The team collected more than 20 species of gastrotrichs from samples taken from the shoreline to a depth of 120 feet.
“Most of these species are likely to be new to science,” he says. “About 800 species of gastrotrichs are currently known, but there could be as many as 10,000.”
The team’s work is funded by a three-year $598,976 grant from the National Science Foundation.
Nature’s Beach Clean-Up Crew
Scientists are not exactly sure what role gastrotrichs play in the marine ecosystem. What they do know, however, is that gastrotrichs are an important part of the seafloor food chain — they feed on small organisms like bacteria, protozoans or diatoms and are, in turn, consumed themselves by larger invertebrates.
“Gastrotrichs may also help break down organic matter from algae or dead animals that wash up and accumulate on beaches. In this way, they help keep beaches and the sands between coral heads clean,” says Hochberg.
The team focused on the Cayman Islands since they are surrounded by several trench systems more than a mile deep.
“In theory, this geographic setting should limit the dispersal of tiny animals that can only migrate through the sediments, that is, those that have no planktonic stages, such as larvae, that could be carried between islands by ocean currents.”
Research into these tiny creatures is critical as rising sea temperatures caused by global warming could lead to many species becoming extinct before they could be discovered and studied.
Joining Hochberg in the study are Hochberg’s Ph.D. student, Sarah Atherton, as well as Alexander Kieneke of the Senckenberg Research Institute and Birgen Rothe of Bielefeld University, both from Germany.
“Every new and known species we encounter will be sequenced for the gene called cytochrome oxidase I, which will help to verify the identity of the species and provide some knowledge on its evolutionary relationships to similar species,” says Hochberg.
He estimates it may take them several months, or even years, to completely analyze the data from any single collection trip.
“But that doesn’t keep us from making new collections,” he says. “At present, my team — consisting of eight to 10 international researchers divided into various working groups — is scheduled to make collections in south Florida four to six miles offshore, as well as on the islands of Curacao or Bonaire, Barbados and Tobago in 2011 and an island off Belize in 2012. We are also trying to organize a Brazilian meiofauna workshop that will teach local scientists and international students the importance of meiofauna and how to collect and identify them.”