Synergism between elevated temperature and nitrate: Impact on aerobic capacity of European grayling, Thymallusthymallus in warm, eutrophic waters.

Synergism between elevated temperature and nitrate: Impact on aerobic capacity of European grayling, Thymallusthymallus in warm, eutrophic waters.
Aquat Toxicol. 2020 Jul 07;226:105563
Authors: Opinion AGR, De Boeck G, Rodgers EM
Abstract
Climate warming and nitrate pollution are pervasive aquatic stressors that endanger the persistence of fishes prevailing in anthropogenically disturbed habitats. Individually, elevated nitrate and temperature can influence fish energy homeostasis by increasing maintenance costs and impairing oxygen transport capacity. However, it remains unknown how fish respond to simultaneous exposure to elevated temperature and nitrate pollution. Hence, we examined the combined effects of nitrate and elevated temperatures on aerobic scope (AS, maximum-standard metabolic rates) and cardiorespiratory attributes (haemoglobin HB, haematocrit HCT, relative ventricle mass RVM, and somatic spleen index SSI) in a freshwater salmonid, Thymallus thymallus. A 3 × 2 factorial design was used, where fish were exposed to one of three ecologically relevant levels of nitrate (0, 50, or 200 mg NO3- l-1) and one of two temperatures (18 °C or 22 °C) for 6 weeks. Elevated temperature increased AS by 36 % and the improvement was stronger when coupled with nitrate exposure, indicating a positive synergistic interaction. HB was reduced by nitrate exposure, while HCT was independent of nitrate pollution and temperature. Stressor expo...

Source: Aquatic Toxicology - July 6, 2020 Category: Toxicology Authors: Opinion AGR, De Boeck G, Rodgers EM Tags: Aquat Toxicol Source Type: research