Potentially Misidentified Species:
A. palmata may easily be mistaken for
silt-covered marine algae. However, the presence of the lophophore helps
differentiate bryozoans from algae.
II. HABITAT AND
A. palmata is a highly cosmopolitan species,
occurring in the western Atlantic from Massachusetts south to the Gulf of
Mexico, the Caribbean and Brazil.
A. palmata is likely to occur throughout the Indian
River Lagoon; however, it is considered to be most common around the Sebastian
Inlet area (Winston 1982).
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Individuals measure 0.79 mm X 0.13 mm on average,
with the lophophore measuring 0.205 mm in diameter (Winston 1982).
A. palmata is locally abundant at Sebastian
Inlet, where it can be collected between January and April. It has also been
collected as late in the year as September from the Walton Rocks area (Winston
1982). In the IRL, it is considered a fouling organism (Winston 1995).
The embryology of A. palmata is unknown.
IV. PHYSICAL TOLERANCES
Due to its cosmopolitan distribution, A. palmata is considered
Winston's (1982, 1995) studies have shown that A.
palmata is collected in areas where salinity is typically above 30 ‰.
V. COMMUNITY ECOLOGY
A. palmata, like all bryozoans, is a
suspension feeder. Each individual zooid in a colony has 10 ciliated tentacles
that are extended to filter phytoplankton less than 0.045 mm in size (about
1/1800 of an inch) from the water column. Bullivant (1967; 1968) showed that the
average individual zooid in a colony can clear 8.8 ml of water per day.
Typical habitat for A. palmata, especially
around the Sebastian Inlet area is on the rocks of breakwaters (Winston 1982).
VI. SPECIAL STATUS
Benefit in IRL:
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, Winston (1995) reported
that bryozoan colonies located in 1 square meter of seagrass bed could
potentially filter and recirculate
an average of 48,000 gallons of seawater per day.
Report by: K. Hill,
Smithsonian Marine Station
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Page last updated: July 25, 2001