The effect of egg versus seston quality on hatching success, naupliar metabolism and survival of Calanus finmarchicus in mesocosms dominated by Phaeocystis and diatoms
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Koski M, Yebra L, Dutz J, Jonasdottir SH, Vidoudez C, Jakobsen HH, Pohnert G, Nejstgaard JC
mesocosm, Phaeocystis, Calanus, Copepod, Skeletonema, 11 m3, Bergen, Espegrend, Norway
We studied the effect of a developing Skeletonemamarinoi/Phaeocystis spp. bloom on Calanus finmarchicushatching success, early naupliar survival andmetabolism. Our focus was (1) on the development ofreproductive rates during a bloom initiation, peak anddecline in relation to the production of potentially toxicalgal metabolites and (2) on the proportional importance offemale nutrition versus naupliar food environment for theproduction of viable nauplii. Despite polyunsaturatedaldehyde (PUA) production by both S. marinoi and Phaeocystissp., we did not observe any harmful effects onhatching success or naupliar survival and condition in anystages of the short-term (1 week) algal bloom. Hatchingsuccess appeared to be controlled by egg lipid composition,while the beneficial effect of a high food concentration wasreflected in naupliar RNA:DNA ratio, protein content andtotal production of viable nauplii. The egg lipids reflectedseston lipids, indicating that the egg fatty acid compositionwas not modified by the females. Our results suggest thatunselective feeding and/or retention of specific lipids caninduce qualitative food limitation, although recruitmentduring the S. marinoi/Phaeocystis sp. bloom was high.
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