Effects of UV-B radiation on ingestion, fecundity, population dynamics and antioxidant enzyme activities of Schmackeria inopinus (Copepoda Calanoida)

Abstract

Effects of enhanced ultraviolet B (UV-B, 280–320 nm) on copepods have gained particular attention in recent years. In this study, we investigated the effects of UV-B radiation on ingestion, fecundity, population dynamics and antioxidant enzyme activities of copepod Schmackeria inopinus exposed to varying doses of UV-B irradiance. Artificial UV-B radiation resulted in an increased mortality of nauplii, copepodites and adults with increasing UV-B doses. Nauplii and copepodites were more sensitive to UV-B radiation than adults, and adult males had a higher UV-B radiation susceptivity in comparison with adult females. Both ingestion rates and proportion of gravid females decreased with the increase of UV-B doses; and at the same time, we also observed that adult females had higher ingestion rates as compared with adult males. In comparison with the control, the abundance of the treatment significantly decreased. Antioxidant enzyme (GPx and GR) activities attained a significant increase at lower UV-B radiation doses when compared to the control, but declined at higher UV-B doses. These results suggested that enhanced UV-B radiation might change the species composition of copepods. Our study also showed that antioxidant enzymes might protect S. inopinus against UV-induced oxidative damage.