Ref ID : 7038
John F. Heinbokel, D. Wayne Coats, Kelly W. Henderson, and Mary A. Tyler; Reproduction rates and secondary production of three species of the rotifer genus Synchaeta in the estuarine Potomac River. J.Plankton Research 10(4):659-674, 1988
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Rotifers are a relatively well-studied component of lacustrine systems but their role is only poorly understood in estuaries. Three species of the genus Synchaeta-S. baltica, S. triophthalma and S. cecilia-dominate the cold-water assemblage of rotifers in Chesapeake Bay. Laboratory experiments were conducted to determine the temperature dependence of egg development time (EDT) for each species; EDT varied over an approximate range of 90-9 hr as temperature (T) varied from 2 to 22 degrees C. The EDT/temperature relationships could be closely fitted by a simple polynominal equation of the form log(EDT)=a+b(log T)+c(log T)2 for each species. Natural populations of these three rotifers were sampled during a cruise in the Potomac River (7-11 March 1983). Estimates of specific reproductive rates (b) were calculated based on the previously defined EDT/temperature relationship and the observed ratio of eggs/rotifers for each species. The two most abundant species, S. triophthalma and S. cecilia, showed a clear dependence of b on the observed chlorophyll a concentrations. Maximum reproductive rates (~0.015 hr-1) were attained only at relatively high phytoplankton densities within a bloom of Heterocapsa triquetra where the chlorophyll a concentrations exceeded 10 µg l-1. Estimates of secondary production suggest that Synchaeta spp. may contribute to the trophic flow of carbon in this system with a significance at least similar to that of the planktonic copepods.