A Ctenophore Feeds

A transparent ctenophore in dark water.

The comb jelly (ctenophore) Thalassocalyce inconstans is found in shallow to deep water in the Atlantic Ocean, Mediterranean Sea, and sometimes in warmer Pacific Ocean waters off the coast of California -- although this one was photographed in the Sargasso Sea by Census of Marine Zooplankton researchers.

T. inconstans has a very different feeding behavior than other ctenophores. Most ctenophores use muscles to suck in large volumes of water to capture prey. But T. inconstans has little muscle; instead, it waits until a euphausiid (small crustacean) or copepod accidentally swims inside its bell, where it sticks to the mucus-covered inner surface. Then the ctenophore closes its bell shut very fast -- in less than half of a second!

See more photos of cool zooplankton collected by the researchers in this zooplankton biodiversity slideshow.

Reference: Swift, HF, Hamner, WM, Robison, BH, Madin, LP. 2009. Feeding behavior of the ctenophore Thalassocalyce inconstans: revision of anatomy of the order Thalassocalycida. Marine Biology 156, 1049-1056. (PDF)