MEPS 247:297-302 (2003)  -  doi:10.3354/meps247297

Dose and dose-rate dependency in the mortality response of Calanus finmarchicus embryos exposed to ultraviolet radiation

Howard I. Browman1,3,*, Jean-François St-Pierre1, Penelope Kuhn1,2

1Department of Fisheries and Oceans Canada, Maurice Lamontagne Institute, PO Box 1000, 850 Route de la Mer, Mont-Joli, Québec G5H 3Z4, Canada
2CONFORTE (CONsulting FOR The Environment), 94 Joyce Court, Lake Echo, Nova Scotia B3E 1A8, Canada
3Present address: Institute of Marine Research, Austevoll Aquaculture Research Station, 5392 Storebø, Norway

ABSTRACT: In previous work, we reported that embryos of Calanus finmarchicus exposed to artificial ultraviolet-B (UV B) radiation exhibited high wavelength-dependent mortality. The strongest effects occurred under exposures to wavelengths below 312 nm and, at the shorter wavelengths (<305 nm), UV-B-induced mortality was strongly dependent on cumulative exposure (i.e. dose). In the experiments reported here, we tested (for C. finmarchicus) the principle of reciprocity‹that is, was the effect of cumulative UV dose the same regardless of the dose rate at which it was delivered? Dose rate had no discernible effect on the proportion of live C. finmarchicus nauplii recovered from eggs exposed to 3 different UV doses: reciprocity held. The doses and dose rates administered were ecologically relevant. However, the issue of UV dose versus dose-rate effects on marine organisms requires further investigation‹at a broad range of dose and dose rates and for different exposure durations, preferably under natural sunlight.

KEY WORDS: Calanus finmarchicus · Reciprocity · UV · Dose · Dose rate

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