SEA PANSIES By Dr. Joe Richardson
I love it when someone sends me a picture of an animal they saw at the
beach, and asks, “What is this?” One of the most frequent I get asked about
is the Sea Pansy. For some reason, it is one of my favorite Tybee beach
animals, maybe because it is one of the weirdest. I especially get excited
when we find a live one during our beach ecology trips because I get to talk
about it!
A Sea Pansy is a purple round disc with a stalk extending from its bottom side.
There is a slight indention in the round, cushion-like disc where the stalk is
connected. The stalk can range in size from a short little nub to a longer stalk
an inch or two long. A Sea Pansy is a great example of a “colonial” animal. A
colony-type animal is a single organism, but it is composed of many smaller
individuals, all of which are connected to each other. In the case of a Sea
Pansy, the disc and stalk is one individual, but it buds off numerous small
anemone-like individuals (polyps) that extend upward from the top surface
of the disc. Usually, when you find a Sea Pansy washed up on the beach,
the small polyps are withdrawn down inside the disc so all you see are
numerous tiny white patches on top. But if you will put it in some seawater
and wait a little while, the polyps might extend out where you can see them,
and the surface of the disc will look fuzzy because of all the tiny tentacles
that the polyps have.
26 TYBEE BEACHCOMBER | MAY 2018
Sea Pansies are classified as a type of soft coral. Like other corals, a Sea
Pansy is a colony of many tiny, connected polyps. In the case of hard, stony,
reef-building corals, the polyps produce hard, solid limestone cups around
each polyp. But with soft corals, only small scattered fragments (spicules)
of limestone are produced around the polyps, so the colony is softer and
flexible. And if you want to get really technical, Sea Pansies are further
classified as Octocorals because each polyp has 8 tentacles.
When you find a Sea Pansy on Tybee’s beach, it has probably washed in
from offshore where it was living in the sandy bottom. Offshore, a Sea Pansy
sits with its disc on top of the sand, and its stalk digs down in the sand and
serves as an anchor to hold it in place. With the disc sitting on top of the
sand, the polyps extend upward into the seawater, and the tentacles catch
small, plankton-size food. And since all the polyps are connected to each
other down inside the disc, when one polyp catches some food, it can share
it with all the others. That’s one of the benefits of being a colonial animal!
Dr. Joe Richardson is a retired marine science professor with 35+ years of
research and teaching experience along GA and the southeastern coast and
Bahamas. Besides research, he conducts Tybee Beach Ecology Trips year
round (www.TybeeBeachEcology.com) and frequently posts pictures of what
they are finding on his Tybee Beach Ecology Trips Facebook page.
Beach Walks
with Dr. Joe
/(www.TybeeBeachEcology.com)