Effect of Ammonium Nitrate on the Development and Survival of Marsh frog (Pelophylax sp.), (Amphibian: Anura)

Amphibians are sensitive to nitrogen-based fertilizers such as ammonium nitrate, which are used in agriculture and enter aquatic ecosystems through runoff. However, data on the responses of Marsh frog (Pelophylax sp.) in north and northeast of Iran to this chemical pollution are lacking. In this study, to evaluate the toxicity of ammonium nitrate on the embryonic period (Gosner≤۲۵) and early larval period (Gosner ۲۶-۳۱), we investigated the survival rate, hatching time and hatching rate. For this purpose, ۷۸۰ eggs of Marsh frog with a density of ۲۰ and a water volume of ۱۵۰۰ ml per container, in three replicationsat concentrations of ۰ (control), ۱۰, ۲۰, ۳۰, ۵۰, ۷۰, ۹۰, ۱۲۰, ۱۵۰, ۱۸۰, ۲۲۰, ۲۲۰, ۲۶۰, ۳۰۰ mg/l, with an average temperature of ۱۴.۵۰ °C, conducted for ۵۶ days. The larvae hatched in the control treatment and concentrations of ۱۰, ۲۰ and ۳۰ on day of ۶±۰.۰۰, in concentrations of ۵۰, ۷۰, ۹۰ and ۱۲۰ on days of ۷±۰.۰۰, ۹.۶۶±۴.۶۱, ۱۲.۶۶±۴.۰۴ and ۱۳.۶۶±۱.۱۵, respectively. The hatching rate in concentrations above ۱۲۰ was ۰%, but in the control treatment and concentrations of ۱۰, ۲۰ and ۳۰ were ۱۰۰%, in concentrations of ۵۰ was ۹۵%±۸.۶۶, in concentrations of ۷۰ was ۹۶.۶۶%±۵.۷۷, in concentrations ۹۰ was ۸۸.۳۳%±۱۰.۴۰ and in concentrations of ۱۲۰ was ۴۳.۳۳%±۲۸.۸۶. The survival rate ۴۸h after hatching period (hatching period ۱۶days) in the control treatment and concentrations of ۱۰ to ۳۰, ۵۰ and ۷۰ to ۱۲۰ recorded ۱۰۰%, ۱۶.۶۶%±۳.۳۳ and ۰%, respectively. Survival rates at ۵۶ days in the control treatment and concentrations of ۱۰, ۲۰, ۳۰ recorded ۱۰۰%, ۹۵%±۸.۶۶, ۹۵%±۸.۶۶ and ۹۳.۳۳%±۷.۶۳, respectively. The results of this experiment showed that concentrations above ۳۰ mg/l of ammonium nitrate greatly affected the survival of Marsh frog larvae and may play an important role in the global amphibians decline

کلیدواژه ها:

Global amphibians decline ، Nitrogen pollution ، Embryonic period ، Larval period