The Effect of Gamma Radiation on Parthenogenetic Artemia (Branchiopoda, Anostraca) Cysts: Nauplius Hatching and Postnauplial Survival under Varying Salinity

Abstract

Abstract—The effect of gamma radiation doses of 2.5, 5.5, and 7.5 Gy received by Artemia cysts on hatching of nauplii and postnauplial survival of crustaceans has been studied at salinities of 0, 9, 18, 36, 54, 62, 78, and 88 g/L. Under the same salinities, the above parameters are estimated without irradiation. It has been found that the rate of nauplii hatching from cysts depends primarily on the salinity, the coefficient of determination being equal to 90%. The radiation dose does not affect nauplii hatching at any salinity, except 54 g/L, when a significant negative relationship is found between the proportion of hatched nauplii and the radiation dose. The survival of crustaceans appearing from irradiated cysts depends on the salinity. In the salinity range of 9–52 g/L, it is significantly less than in the range of 62–88 g/L (2.5 and 5.5 Gy). The crustaceans emerged from cysts which received 7.5 Gy do not survive to day 12 at the salinity of 88 g/L. The minimum post-nauplial survival of crustaceans is recorded at a salinity of 54 g/L under all irradiation doses; such salinity may be considered critical for Artemia at which the osmoregulation mechanism reconfigures. Ecological effects in Artemia populations can occur starting from a dose of 2.5 Gy. The studied radiation doses may have remote consequences for Artemia populations in hypersaline water bodies. To quantify the effect of these doses on Artemia populations correctly, it is necessary to study not only the generation of crustaceans immediately hatched from irradiated cysts but also 2–3 subsequent generations.