The warty comb jelly, Mnemiopsis ledyi, is a voracious carnivore, competing with fish for small crustaceans and zooplankton in the European seas. (Credit: Lars Johan Hansson)
In the waters surrounding Woods Hole, Massachusetts, the warty comb jelly, Mnemiopsis ledyi, lives out its days, bumping against eel grass and collecting small crustaceans with its sticky tentacles. The delicate creature, which resembles a small jellyfish without the stinger, is just another member of the food web here on the Western Atlantic coast.
Across the ocean is a different story. Accidentally introduced to the Black Sea in the early 1980s, the warty comb jelly spread rapidly through the Caspian Sea in the 1990s and has most recently invaded the Baltic Sea. In Europe, M. ledyi is considered a voracious predator, easily snatching dinner from local fish. Countries surrounding the Baltic Sea are now concerned what’s going to happen to their waters.
“Their impact seems to be increasing and that’s been tied to warming water temperatures, giving them an ecological advantage,” says Sean Colin, assistant professor of biology at Roger Williams University. He and John Costello, professor of biology at Providence College, are at the Marine Biological Laboratory (MBL) this summer to determine who and how much M. ledyi eats.
Comb jellies are unique in how they process food. Eight rows of brush-like cilia beat against the water, creating a current that brings prey closer to the mouth. Using high-speed video, the team is observing their feeding behavior, predator and prey interactions, as well as the hydrodynamics of how they swim. “This will help us to understand on which types of ecosystems they might have a large impact or small impact and under which conditions they are going to be able to thrive,” Colin says.
Comb jellies aren’t all bad news. Also at the MBL this summer is Anthony Moss, an associate professor of biology at Auburn University, who is studying the ability of M. ledyi to quickly repair itself – a few minutes to a few hours depending on the injury – without scarring. The jellies have exceptional regenerative powers, capable of repairing up to 50 percent of their bodies. He hopes to apply his observations to wound healing across all organisms.
To see videos of the comb jelly eat its prey, visit the MBL Website.