Potentially Misidentified Species:
may easily be identified as a tube-dwelling polychaete worm, or the mud tube of
an amphipod. However, upon close examination, the stolon is revealed and the
lophophore can be observed.
II. HABITAT AND
N. stipata is
distributed throughout the western Atlantic from Canada south to the Caribbean
Winston (1982) has collected N. stipata year-round
from 3 stations in the IRL: the seagrass beds around Link Port; the breakwater
at Ft. Pierce; and at Walton Rocks. Further sampling effort could potentially
increase the known range of this species in the IRL.
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Individual zooids of N. stipata are tall and
cylindrical in shape, measuring approximately 2.1 X 0.17 mm. The lophophore
measures an average of 0.616 mm in diameter (Winston 1982).
N. stipata produces several yellow eggs per
zooid. Embryos are brooded within the zooid and develop into short-lived,
IV. PHYSICAL TOLERANCES
Because it is present year-round, N. stipata is
considered to be eurythermal.
N. stipata is typically collected from waters where
salinity remains above 30‰.
V. COMMUNITY ECOLOGY
like all bryozoans, is a suspension feeder. Each individual zooid in a colony
has ciliated tentacles that are extended to filter phytoplankton less than 0.05
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 ectoprocts in the Indian River
Lagoon include seagrasses, drift algae, oyster reef, dock, pilings, breakwaters,
and man-made debris (Winston 1995). Nolella stipata has been collected on
seagrasses, shells, algae, and on other bryozoans such as Zoobotryon
species (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. Winston (1995) reported that colonies
of Zoobotryon verticillatum 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