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Description:
Colonies of Aetea sica consist
of creeping stolons from which individuals of the colony arise. Color in
this species is generally white to creamy yellow. Individuals of a
colony, called zooids, typically measure no more than 0.1 inch in height, with
the lower portion of each individual marked with fine striations. The top
portion of each zooid, where the mouth and tentacles are located, is somewhat expanded when compared to the lower portion in a ratio of
approximately 3:1. When
actively feeding, zooids extend their tentacles, which are arranged in a
funnel shape,
to filter
phytoplankton from the water column. Habitats:
Aetea sica is most commonly found on seagrasses, marine drift algae such as Sargassum, on attached algae and
on other bryozoans such as Amathia, Zoobotryon, and Bugula
species.
Similar
Species:
Aetea sica could be mistaken for A. truncata, because the growth
pattern of both species is quite similar. They can be distinguished
because A. trucata lacks the fine striations on the basal portion of
zooids observed in A. sica.
Range:
Aetea sica is highly cosmopolitan,
with wide distribution except in the polar regions. In the Western
Atlantic, it commonly occurs from Cape Hatteras south through Florida, the Gulf
of Mexico, and the Caribbean to Brazil. Within the IRL, A. sica has been
collected from seagrass beds and from the red algae Solieria tenera.
Coastally, it has been collected at Ft. Pierce Breakwater, Walton
Rocks and Seminole Shores on drift algae (Sargassum), attached algae, and bushy
bryozoans (Amathia, Zoobotryon, Bugula, etc.). A. sica
is most common in the IRL in September and October, but has been collected
from February through October.
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Photograph of an Aetea sica colony on a seagrass blade from the Indian River Lagoon. Photo
courtesy K. Hill, Smithsonian
Marine Station.
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Image from an electron microscope showing individuals of Aetea
sica budding from a stolon. Photo by J. Winston, courtesy of
American Museum of Natural History. Used
with permission. |
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Bryozoans are ecologically important in the Indian
River Lagoon due to their feeding method. As suspension feeders,
they act as living filters in the marine environment. For example, a bryozoan
colony that covers a 3 square foot area of seagrass could
potentially filter and recirculate an average of 48,000 gallons of seawater per
day.
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