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Species Description:
S. floridana
colonies are encrusting, and appear in a variety of forms from unilaminar or
multilaminar, to foliacious or tubular. Zooids are rectangular in
shape and measure an average of 0.49 X 0.36 mm. Specimens from the Indian River
Lagoon are heavily calcified, somewhat granular in texture, and have a number of
large pores perforating the calcification. A heavy umbo is present suborally.
The orifice may sometimes lie at an angle to the midline of the zooid.
Avicularia are rounded at the base, with pointed mandibles, and may occur singly
or in pairs just inferior to the orifice. They orient upward on mammillate
processes at an angle of approximately 30 degrees. Polypides are pink. The
lophophore measures approximately 0.509 mm in diameter and bears an average of
17 tentacles.
Synonymy:
None.
Other Taxonomic Groupings:
Suborder: Ascophora
II. HABITAT AND
DISTRIBUTION
Regional Occurrence:
In the western Atlantic, S. floridana occurs
from Beaufort, North Carolina south to Florida, the Gulf of Mexico and the
Caribbean. Ryland (1965, in Winston 1982) reported that this species is possibly
a variety of Schizoporella errata, a species common in Europe and the
Mediterranean.
IRL Distribution:
S. floridana is
likely to be found throughout the Indian River Lagoon in association with
seagrass beds, specifically Thalassia beds.
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Rectangular zooids measure an average of 0.49 X
0.36 mm.
Abundance:
S. floridana is
one of the most abundant fouling organisms in the Indian River Lagoon.
Locomotion:
Sessile
Reproduction:
Colonies only a few millimeters in size are capable
of producing embryos. Ovicells begin to be seen only a few generations out from
the ancestrula.
Embryology:
Ovicells are hyperstomial and large, covered on the
frontal surface with pores. The ovicell itself is somewhat wider than it is
long. Embryos, when present are colored a pale orange. Recruitment occurs from
January to August, with peak settlement occurring in April and May.
IV. PHYSICAL TOLERANCES
Temperature:
S. floridana is
common throughout the warm waters of the western Atlantic and the Caribbean. It
is likely to be somewhat cold sensitive, however, as it has only been observed
from January through August.
Salinity:
S. floridana is
typically collected from waters where the salinity is below 30‰.
V. COMMUNITY ECOLOGY
Trophic Mode:
S. floridana,
like all bryozoans, is a suspension feeder. Each individual zooid in a colony
has 17 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.
Habitats:
Typical habitat for ectoprocts in the Indian River
Lagoon include seagrasses, drift algae, oyster reef, dock, pilings, breakwaters,
and man-made debris (Winston 1995). S. floridana was typically found
encrusting the seagrass Thalassia in the Indian River Lagoon. However,
colonies settling on Thalassia tend to remain small, and do not become
multiserial. Winston (1982) reported that S. floridana did not occur at
any of the coastal stations in her study. Further, she found no evidence of the
massive, coral-like colonies S. floridana is reported to form along the
Gulf coast of Florida, and at other locations.
Associated Species:
Seagrasses as well as floating macroalgae, provide
support for bryozoan colonies. In turn, bryozoans provide habitat for many
species of juvenile fishes and their invertebrate prey such as polychaete worms,
amphipods and copepods. (Winston 1995).
Bryozoans are also found in association with other
species that act as support structures: mangrove roots, oyster beds, mussels,
etc.
VI. SPECIAL STATUS
Special Status:
None.
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.
Economic Importance:
None
Report by: K. Hill,
Smithsonian Marine Station
Submit additional information, photos or comments to:
irl_webmaster@si.edu
Page last updated: July 25, 2001
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