Sea Pansy (Renilla reniformis)

Description
The sea pansy is an anthozoan and is a collection of polyps having different forms and functions. A single, giant polyp up to two inches in diameter forms the anchoring stem (peduncle). This peduncle can be distended to better anchor the colony in the sand flats it typically inhabits. The pansy-like body bears many small, anemone-like feeding polyps. A cluster of tentacleless polyps form an outlet valve that releases water to deflate the colony. If the colony is on a sand bar at low tide, it usually deflates and becomes covered with a thin film of silty sand. Small white dots between the feeding polyps are polyps that act as pumps to expand the deflated colony. The feeding polyps secrete a sticky mucus to trap tiny organisms suspended in the water. The colony’s rigidity and purple color come from calcium carbonate spicules throughout the polyps tissues.

It is common on current-swept sand flats in protected areas, distributed from low tide to subtidal areas. Its predator is the striped sea slug, Armina tigrina.

The sea pansy is strikingly bioluminescent when disturbed. A chemiluminescent reaction generates a blue light that is transformed to a green light by Green Fluorescent Protein, an extremely important molecule for modern cell science. [Ref. Ruppert and Fox]

http://www.nature.com/nrn/journal/v2/n4/slideshow/nrn0401_274a_bx1.html
Description of how green fluorescent protein works.

http://bmbiris.bmb.uga.edu/wampler/biolum/gfp/
Discussion of green fluorescent protein in the sea pansy.

http://www-bioc.rice.edu/Bioch/Phillips/Papers/gfpbio.html
Review of the structural solution of green fluorescent protein.

http://citd.scar.utoronto.ca/EESC04/SCMEDIA/INVPHYLO/Cnidaria/Cnidaria45.html
Picture of a sea pansy

http://citd.scar.utoronto.ca/EESC04/SCMEDIA/INVPHYLO/Cnidaria/Cnidaria46.html
Picture of a sea pansy feeding polyp

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