Acute Effects of Ammoniac Nitrogen on Marine Copepod Acartia pacifica When Exposed to Different Temperature Conditions

Abstract

Acute toxicity of ammoniac nitrogen on marine copepod Acartia pacifica when exposed to different temperatures of 10℃~25℃were performed under controlled lab conditions. The changing tendency of mortality was evaluated and the 48h LC50 was determined according to the observation. Results showed that the 48h LC50 in different temperature gradients were for Pacific spindle daphnia 48 h - LC50 is 65.889 mg/L for 25 ℃, 134.214 mg/L for 20 ℃, 71.247 mg/L for 15 ℃ and 27.318 mg/L for 10 ℃, respectively. Temperature seemed to exert impacts on the stress induced by ammoniac nitrogen, and the peak of 48h LC₅₀ appeared in between 15 ℃ and 20 ℃. The toxicity of ammonia showed a tendency to decrease with the increase of temperature before the peak while the was significantly enhanced with temperature increasing thereafter.