Other Taxonomic Groupings
Colonies of A. distans
appear fragile and translucent. The stolon is thin and dichotomously branching, with zooids located in clumps at intervals. Stolons and zooids
are brown in color but have bright yellow pigmentation that makes living
colonies appear to be yellow. Zooids are somewhat shorter than in A.
alternata, and average approximately 0.4 mm in height. Zooids are
arranged in double rows at the distal ends of internodes, with each set of
zooids making a full or partial turn around the axis of the stolon. The
growing ends of stolons often have no zooids on the first 2 internodes.
HABITAT AND DISTRIBUTION
A. distans is a circumtropical species and is highly cosmopolitan in warm seas. In the
western Atlantic it is found from the Carolinas south through Florida and the
Gulf of Mexico, to the Caribbean and Brazil.
In the IRL, A. distans has
been collected year-round at Ft. Pierce Inlet, Walton Rocks, and Seminole
Shores. It has also been taken in offshore collections from the continental
shelf off Florida where it was found in association with algae (Winston 1982,
LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan
The stolon in A. distans is
fragile and thin in appearance, measuring only 0.11 - 0.12 mm in diameter
(Winston 1982). Individual zooids may grow to approximately 0.4 mm in height.
is most abundant in the winter months in Florida, especially in December. It is
not considered to be as abundant as A. alternata (Winston 1995). In the
IRL, it is considered a fouling organism (Winston 1995).
The embryology of A. alternata
A. distans is eurythermal. It is most abundant in Florida during the winter months, especially
December (Winston 1982).
was generally collected in areas where salinity exceeds 30‰ (Winston 1995).
like all bryozoans, is a suspension feeder. Each individual zooid in a colony
has ciliated tentacles that are extended to filter phytoplankton less than 0.045
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 ectoprocts in
the Indian River Lagoon include seagrasses, drift algae, oyster reef, dock,
pilings, breakwaters, and man-made debris (Winston 1995). A. distans was
most commonly observed attached to rocks in the IRL or in coastal areas. It was
also observed in association with algae in offshore collections (Winston 1982).
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,
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.
Winston JE. 1982. Marine bryozoans (Ectoprocta) of the Indian River area (Florida). Bull Amer Mus
Nat Hist 173: 99-176.
Winston JE. 1995. Ectoproct diversity of the Indian River coastal lagoon. Bull Mar Sci 57: 84-93.
Report by: K. Hill,
Smithsonian Marine Station
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Page last updated: July 25, 2001