Encrusting Bryozoan
Membranipora tuberculata

This close-up of a portion of a Giant Kelp blade shows a colony of encrusting bryozoans, Membranopora tuberculata.

Bryozoans are made up of colonies of individuals, called zooids, which are less than one thirty-second of an inch in size.  Zooids live together in an encrusting lacework "crust", which is formed by a limestone covering secreted by the colony.  They feed on plankton and bacteria by sweeping the surrounding water with their lophophore -- an "O" or "U" shaped fold in the body surrounded by cilia-covered tentacles.

Bryozoan colonies can get very large--containing about two million zooids and stretching a foot or more across.  They are mainly preyed upon by nudibranchs and sea spiders.

Lens: 60mm macro
Film: Velvia
Location: San Clemente Island, CA
©1999 Garry McCarthy