| Summary: | The calanoid copepod Calanus finmarchicus (Gunnerus) dominates the biomass and is considered a key species in the North Atlantic pelagic ecosystem. The species is found close to oil production fields along the Norwegian coast and may thus be exposed to discharges from petroleum-related activities. A negative effect on development and survival of the species may have major impact on the ecosystem structure and function. This has made C. finmarchicus a target species in large interdisciplinary studies and environmental monitoring. The early life stages represent a particular critical phase among the life stages in copepods and a combination of unfavourable temperatures and environmental contaminants may cause adverse effects on the development of the species. To determine to what extent the development of the early life stages of C. finmarchicus is affected by temperature, eggs and nauplii were subjected to 4 different temperatures (5.0, 7.5, 10.0 and 12.5 °C) in a series of laboratory experiment. Eggs were the starting point for each treatment. Measurements of oxygen consumption, dry weight and carbon-nitrogen analysis were done at each development stage including third-stage nauplii. Times of development were monitored. Longer development times were found with decreasing temperatures. Oxygen consumption increased with increasing temperature and increased with increasing stage of development. Considerable impacts of temperature on both carbon and nitrogen contents were found within all development stages. Repetitive lower contents were observed in nauplii treated at 12.5 °C compared to animals reared at lower temperatures. Significantly higher C and N values were found for the third naupliar stage, compared to earlier developmental stages for all treatment temperatures (except for animals developed at 5 °C).
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