Diet-dependent UVAR and UVBR resistance in the high shore harpacticoid copepod Tigriopus brevicornis

Abstract

This study tested the hypotheses (1) that the upper shore rock pool harpacticoid copepod Tigriopus brevicornis is protected against ultra-violet radiation (UVR) by the orange pigment astaxanthin, and (2) that astaxanthin levels would be greater in summer than winter. Wild orange copepods lost their pigment and became white if fed on yeast in the dark; their colour was restored when they were fed microalgae. White T. brevicornis were significantly more susceptible to UVR than wild or restored orange T. brevicornis. At similar intensities of radiation, copepods showed duration of survival in the order UVAR > UVBR. Astaxanthin protected T. brevicornis against UVAR and UVBR, with the degree of effectiveness of protection being in the order UVAR > UVBR. There was no significant increase in astaxanthin levels during summer in T. brevicornis collected from 3 different shores. It is suggested that UVAR protection by astaxanthin largely follows from its effectiveness as an antioxidant, and that there are adequate plant resources available to maintain astaxanthin levels in T. brevicornis throughout the year.KEY WORDS: Astaxanthin · Ultra-violet radiation · Tigriopus · AntioxidantResale or republication not permitted without written consent of the publisher

Astaxanthin in the calanoid copepod Calanus helgolandicus: dynamics of esterification and vertical distribution in the German Bight, North Sea

“…Because of its strong antioxidant ability, astaxanthin is believed to protect zooplankton from photo-oxidative damage caused by high-energy irradiance (Hairston 1978). This view is supported by experimental studies showing the higher survival of intensely pigmented compared to transparent individuals exposed to ultraviolet (UV) or blue light (Hairston 1978, Ringelberg et al 1984, Davenport et al 2004). Furthermore, zooplankton have been shown to respond differentially to UV exposure, with lesspigmented species descending farther from the light source than more intensely pigmented ones (Rhode et al 2001).…”

“…Comparison of astaxanthin concentrations in C. helgolandicus (0.05 to 0.22 µg mg -1 DW) with those of conspicuously coloured copepods in ponds and rock pools (~2 to 10 µg mg -1 DW; Hairston 1978, Hessen & Sørensen 1990, Davenport et al 2004, indicates that the range of astaxanthin concentrations in C. hel- golandicus is unlikely to produce predation-relevant differences in visual conspicuousness, given the generally turbid conditions of the North Sea. The results of the 2 × 2 factorial experiment showed that astaxanthin production is a dynamic and rapid process.…”

Dietary Carotenoids Regulate Astaxanthin Content of Copepods and Modulate Their Susceptibility to UV Light and Copper Toxicity

“…A. atopus had a carotenoid composition similar to other copepods [23,41,42,43,44]. Copepods increased their carotenoid content up to five-fold depending on the availability of carotenoids in the diet which shows that copepods are able to profit from carotenoid enriched diets [23,44].…”

Physiological and morphological colour change in Antarctic krill, Euphausia superba: a field study in the Lazarev Sea

“…With diameters reaching 450 μm on the dorsal parts of the abdomen and thorax, krill chromatophores are large, compared with those of other crustaceans (Noël and Chassard-Bouchard, 2004) and when in CI 5, they cover large portions of light-exposed areas with a screen of astaxanthin granules (see Figs 5 and 11). Astaxanthin proved to be efficient in protecting copepod crustaceans from the harmful effects of UVR (Hairston, 1976;Hairston, 1978;Davenport et al, 2004). The highly transparent nature of krill probably necessitates additional protection of deep-lying critical structures, such as the ventral double strand of the nervous system, by 'profound' chromatophores.…”