Life history responses of Daphnia similoides simultaneously exposed to microcystin-LR and ammonia and their postexposure recovery.

Aquatic organisms often suffer episodic stress from cyanobacterial bloom-derived concomitants and sometimes interactive stressors, and they may recover when stressors terminate. To assess whether exposed Daphnia can quickly recover from combined toxicity of bloom-derived stressors, Daphnia similoides were exposed to mixtures of ammonia (0 mg L(-1) , 0.37 mg L(-1) , and 0.

The interactive effects of microcystin and nitrite on life-history parameters of the cladoceran Daphnia obtusa.

Elevated nitrite and microcystin concentrations co-occur during degradation of Microcystis blooms and are toxic to aquatic organisms. We studied the relative and combined effects of these on Daphnia obtusa life-history. Nitrite and microcystin-LR treatments were: 0, 1, 3 mg L(-1) and 0, 10, 100, 300 μg L(-1), respectively.

Acute toxicity of nitrite and ammonia to Daphnia similoides of different developmental stages: using the modified Gaussian model to describe.

To gain an insight into the tolerance of Daphnia to nitrite and ammonia, a modified Gaussian model was used to describe the trends of changes in LC50s of nitrite and ammonia to Daphnia similoides at different developmental stages. LC50s of NO(2)-N and NH(3)-N increased with age before maturation and then decreased at maturation. A modified Gaussian model provided an accurate fit for the changes in LC50s of NO(2)-N and NH(3)-N, in which the parameters have definite biological meanings.