Jonasdottir SH, Dutz J, Koski M, Yebra L, Jakobsen HH, Vidoudez C, Pohnert G, Nejstgaard JC
mesocosm, Calanus, Espegrend, 11 m3, Bergen, Norway, PUA, Skeletonema
Egg and faecal pellet production and egghatching success of the calanoid copepod Calanus finmarchicuswere monitored over a period of 14 days (14–28April, 2008) while fed water from 4 differently treatedmesocosms and ambient water. Two of the mesocosmsused were inoculated with the polyunsaturated aldehyde(PUA)-producing diatom Skeletonema marinoi, while 2received only nutrient additions with or without silica. Themesocosms developed blooms of S. marinoi, mixed diatomsor the haptophyte Phaeocystis pouchetii, respectively.Faecal pellet production of C. finmarchicus increased withincreasing food availability. Egg production increased withtime in all mesocosms to a maximum single femaleproduction of 232 eggs female-1 day-1 (average of 90eggs female-1 day-1) and followed the development ofciliates and P. pouchetii, but was not affected by theobserved high (up to 15 nmol L-1) PUA productionpotential of the phytoplankton. The hatching success of theeggs produced on the mesocosm diets was high (78–96%)and was not affected by either aldehydes in the maternaldiet or exposure to the dissolved aldehydes in the water