Susceptibility to ultraviolet radiation in Calanus finmarchicus and Lepeophtheirus salmonis and the adaptive value of external filtering (Crustacea: Copepoda)
Copepods were exposed to UVB with a spectral irradiance maximum at 313 nm and additional visible light. In the holopelagic Calanus finmarchicus, with a carotenoid concentration of 0.85 μg mg−1, the LD 50 dose was 29 kJ m−2 whereas in the parasitic copepod Lepeophtheirus salmonis the LD 50 was 84 kJ...
| Published in: | Journal of Plankton Research |
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| Main Authors: | , |
| Format: | Text |
| Language: | English |
| Published: |
Oxford University Press
2002
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| Subjects: | |
| Online Access: | http://plankt.oxfordjournals.org/cgi/content/short/24/7/661 https://doi.org/10.1093/plankt/24.7.661 |
| Summary: | Copepods were exposed to UVB with a spectral irradiance maximum at 313 nm and additional visible light. In the holopelagic Calanus finmarchicus, with a carotenoid concentration of 0.85 μg mg−1, the LD 50 dose was 29 kJ m−2 whereas in the parasitic copepod Lepeophtheirus salmonis the LD 50 was 84 kJ m−2. The ability to photorepair was demonstrated for both species. The survival data were Weibull distributed, and this result is discussed relative to a mechanistic ‘Weibull model’. Attenuation of UVB (306 nm) was measured in the inner Oslo fjord (K d = 3.9 m−1). The adaptive significance of behavioural avoidance is assessed in model simulations; the results of the survival experiments are used in connection with the Morowitz formula. Two cases were compared; when Calanus was assumed incapable of active external filtering the specimens would be safe if the depth of the mixed layer was deeper than 7 m in the inner Oslo fjord, however, with the ability of behavioural avoidance, Calanus would be protected if they avoided the upper 1 m. The adaptive value associated with behavioural avoidance of toxic radiation, and the implications relative to vertical migration are discussed. |
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