Synergistic survival-related effects of larval exposure to an aquatic pollutant and food stress get stronger during and especially after metamorphosis and shape fitness of terrestrial adults

To improve the ecological risk assessment of aquatic pollutants it is needed to study their effects not only in the aquatic larval stage, but also in the terrestrial adult stage of the many animals with a complex life cycle. This remains understudied, especially with regard to interactive effects between aquatic pollutants and natural abiotic stressors. We studied effects of exposure to the pesticide DNP (2,4-Dinitrophenol) and how these were modulated by limited food availability in the aquatic larvae, and the possible delayed effects in the terrestrial adults of the damselfly Lestes viridis. Our results revealed that DNP and low food each had large negative effects on the life history, behaviour and to a lesser extent on the physiology of not only the larvae, but also the adults. Food limitation magnified the negative effects of DNP as seen by a strong decline in larval survival, metamorphosis success and adult lifespan. Notably, the synergism between the aquatic pollutant and food limitation for survival-related traits was stronger in the non-exposed adults than in the exposed larvae, likely because metamorphosis is stressful itself. Our results highlight that identifying effects of aquatic pollutants and synergisms with natural abiotic stressors, not only in the aquatic larval but also in the terrestrial adult stage, is crucial to fully assess the ecological impact of aquatic pollutants and to reveal the impact on the receiving terrestrial ecosystem through a changed aquatic-terrestrial subsidy.

Physiological Responses of the Goldfish (Carassius auratus) During Subacute Exposure to Organic Pollutants

The aquatic environment is constantly exposed to chemical pollutants from agriculture and the urban environment. In this study, the effects of Bisphenol A, Naphthalene, and Butachlor on metabolic and antioxidant enzymes of goldfish were investigated during subacute exposure. The samples (n = 144, 100.97 ± 31.47 g) were distributed randomly in 12 glass aquaria (70 L) with a stocking density of 12 fish for each. Each aquarium was exposed to one of each pollutant (Bisphenol A with 500 μg/L, Butachlor with 0.28 μL/L and Naphthalene with 200 μg/L) separately, while the control group remained without contaminants for the entire 5 weeks of the experiment. The result showed that the activity of AST (Aspartate transaminase), ALT (Alanine transaminase), ALP (alkaline phosphatases), and POD (Guaiacol Peroxidase) significantly altered in contaminants treatments. The POD level, an antioxidant enzyme, showed a significant increase, especially on the 14th day of exposure to Bisphenol A (p < 0.05). In conclusion, these enzymes, as a biomarker, can be useful in environmental biomonitoring of aquatic ecosystems.