Impact of solar ultraviolet radiation on hatching of a marine copepod, Calanus finmarchicus

Abstract

The calanold copepod Calanus finmarchicus 1s a key component of the zooplankton community in the estuary and Gulf of St. Lawrence, Canada. During the spring and summer months, C. firmarchicus eggs are released into the shallow (0 to 15 m) mixed surface layer, where they incubate for 1 to 3 d. Radiometric measurements in this region show that biologically significant levels of solar ultraviolet radiation (UV = 280 to 400 nm) penetrate into the mixed surface layer. Thus, C. finmarchicus eggs are potentially susceptible to UV-induced mortality. This possibility was evaluated by incubating C. finmarchicus eggs in an outdoor reservoir under natural sunlight. There were 3 spectral exposures regimes [UV-B (280-320 nm) + UV-A (320-400 nm) + PAR (400-700 nm); UV-A+PAR; PAR only]. Control groups were kept in the dark. Incubations were conducted at depths of 2 and 60 cm and the percentage of eggs that hatched was determined following 2 to 3 d exposures in 3 independent experiments. Both the UV-BtUV-A+PAR and the UV-A+PAR treatments exhibited low percent hatching compared to the PAR and dark treatments: UV radiation had a strong negative impact on C. finmarchicus eggs. Further, percent hatching in UV-B-exposed eggs was not significantly lower than that in eggs exposed to UV-A only: under natural sunlight, W -A radiation appeared to be more detrimental to C. finmarchcus embryos than W -B . UV penetration into the experimental reservoir was similar to that observed in estuarine waters of this region, but lower than the clearer waters of the Gulf of St. Lawrence. This suggests that, at current levels of exposure, UV radiation has a negative effect on C. finmarchicus eggs residing in the first few meters of the water columns in this geographic region.

Influence of Salinity Concentration on Aquatic Insect Community Structure: A Mesocosm Experiment in the Dead Sea Basin Region

“…The observed patterns in community structure could be the result of oviposition habitat selection (Eitam et al, 2002), hatching success (Rodriguez et al, 2000), larval development rate and survival (Fagan & Hurd, 1994;Blaustein et al, 1999;Ryan & Winne, 2001). Oviposition habitat selection and larval success may not only be determined by physiological costs of salinity, but also by biotic interactions (e.g.…”

Ultraviolet (280-400 nm)-induced DNA Damage in the Eggs and Larvae of Calanus finmarchicus G. (Copepoda) and Atlantic Cod (Gadus morhua) ¶

“…Our previous experiments were conducted outdoors under natural UV (8,9) and in the laboratory under simulated UV (10,11). In the outdoor experiments eggs of both species were incubated with and without the UV-A (320-400 nm) or UV-B (280-320 nm) wave bands.…”

“…In the outdoor experiments eggs of both species were incubated with and without the UV-A (320-400 nm) or UV-B (280-320 nm) wave bands. Hatching success in the eggs of C. finmarchicus was Ó 2003 American Society for Photobiology 0031-8655/01 $5.0010.00 determined after 2-3 days of exposures (9). UV-exposed eggs exhibited low percent hatching compared with those protected from UV.…”

Effects of ultraviolet radiation and visible light on the development of encapsulated molluscan embryos

“…UV-B is particularly deleterious and can negatively affect reproduction, development, and behavior in many organisms including marine invertebrates (reviewed by Haeder et al 1998, Rodriguez et al 2000, Kuffner 2001). Previous studies indicate that in some encapsulated molluscan embryos, UVR exposure can cause stunted development, deformities, and death (Biermann 1992, Rawlings 1996, Carefoot et al 1998.…”