Zur Ökologie vonPomatoceros triqueter (Serpulidae, Polychaeta)

Abstract

Based on previous studies (Klöckner, 1976b) dealing with field investigations on breeding season, choice of substratum, growth and mortality of the sessile filter-feeding tube wormPomatoceros triqueter in Helgoland waters (southern North Sea), data from laboratory experiments on the physiological potential of the polychaete in regard to temperature are presented. Adult worms tolerated temperatures from −3° C (24 h LT 28) to 30° C (24 h LT 50) when heated or cooled in steps of 1 C° d⁻¹; a two-week period of acclimation within 6° to 18° C did not change their tolerance. Standard oxygen consumption and regeneration of the calcareous tube were found to be dependent on temperature, body weight and food supply; acclimation periods of two weeks had no significant influence. Highly increasing metabolic rates were noted between 6° and 18° C (Q₁₀-values up to 6) and a maximum was found between 20° and 24° C (0.32 μg O₂ mg⁻¹h⁻¹ and 10.2 μg CaCO₃ mg⁻¹d⁻¹); tube regeneration followed a nonlinear regression of y=ax^−b when compared to body weight and was reduced by starving animals to less than 50% within 15 days. Filtration activity ofP. triqueter, however, was found to be highly independent of temperature from 12° to 24° C; maximum activity was 1 ml mg⁻¹ h⁻¹ (all data refer to fresh weight). For comparisons with the results of previous field investigations onP. triqueter some intraspecific correlations of the different parameters employed (tube sizes, fresh and dry weight) are presented as exponential functions of y=ax^b.