Sublethal exposure to copper supresses the ability to acclimate to hypoxia in a model fish species

Publication date: Available online 6 October 2019Source: Aquatic ToxicologyAuthor(s): Jennifer A. Fitzgerald, Mauricio G. Urbina, Nicholas J. Rogers, Nic R. Bury, Ioanna Katsiadaki, Rod W. Wilson, Eduarda M. SantosAbstractHypoxia is one of the major threats to biodiversity in aquatic systems. The association of hypoxia with nutrient-rich effluent input into aquatic systems results in scenarios where hypoxic waters could be contaminated with a wide range of chemicals, including metals. Despite this, little is known about the ability of fish to respond to hypoxia when exposures occur in the presence of environmental toxicants. We address this knowledge gap by investigating the effects of exposures to different levels of oxygen in the presence or absence of copper using the three-spined sticklebacks (Gasterosteus aculeatus) model. Fish were exposed to different air saturations (AS; 100 %, 75 % and 50 %) in combination with copper (20 μg/L) over a 4 day period. The critical oxygen level (Pcrit), an indicator of acute hypoxia tolerance, was 54.64 ± 2.51 % AS under control conditions, and 36.21 ± 2.14 % when fish were chronically exposed to hypoxia (50 % AS) for 4 days, revealing the ability of fish to acclimate to low oxygen conditions. Importantly, the additional exposure to copper (20 µg/L) prevented this improvement in Pcrit, impairing hypoxia acclimation. In addition, an increase in ventilation rate was observed for combined copper and hypoxia exposure, compare...
Source: Aquatic Toxicology - Category: Toxicology Source Type: research