Influence of seasonal variation in temperature, salinity and food availability on module size and colony growth of the estuarine bryozoan Conopeum seurati
A. O'Dea et B. Okamura, Influence of seasonal variation in temperature, salinity and food availability on module size and colony growth of the estuarine bryozoan Conopeum seurati, MARINE BIOL, 135(4), 1999, pp. 581-588
Zooid size and colony growth of the estuarine bryozoan Coilopeum seurati (C
anu) (order: Cheilostomatida; suborder: Malacostegina) were examined over 1
5 ma at Avonmouth Dock, Avon, England. Data were analysed in conjunction wi
th synchronous measurements of temperature, salinity and food availability.
Zooid length, width and area were strongly temperature-dependent, while bo
th food availability and colony growth rate had no significant effect on zo
oid length, width or area. Salinity and the interaction of temperature and-
salinity significantly influenced zooid length and area, suggesting that ch
anges in zooid size may result from oxygen limitation in warm waters. The v
alidity of a number of other mechanisms proposed to account for temperature
-related changes in zooid size is discussed. The results support the use of
zooid size as an indicator of both long-term trends and seasonal variation
s in temperature in Recent and fossil assemblages as long as data sets are
large and the effects of other factors on zooid size: are considered. Colon
y growth rate was found to be significantly influenced by both the amount o
f food available to the colonies and the combined effect of temperature and
food availability, suggesting that growth rate increases as food increases
, but that the former may be limited at low temperatures when metabolic rat
es are low.