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

Fitzgerald J.A.; Urbina M.G.; Rogers N.J.; Bury N.R.; Katsiadaki I.; Wilson R.W.; Santos E.M.

Abstract

Hypoxia 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 mu g/L) over a 4 day period. The critical oxygen level (P-crit), 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 mu g/L) prevented this improvement in Perin impairing hypoxia acclimation. In addition, an increase in ventilation rate was observed for combined copper and hypoxia exposure, compared to the single stressors or the controls. Interestingly, in the groups exposed to copper, a large increase in variation in the measured P-crit was observed between individuals, both under normoxic and hypoxic conditions. This variation, if observed in wild populations, may lead to selection for a tolerant phenotype and alterations in the gene pool of the populations, with consequences for their sustainability. Our findings provide strong evidence that copper reduces the capacity of fish to respond to hypoxia by preventing acclimation and will inform predictions of the consequences of global increases of hypoxia in water systems affected by other pollutants worldwide.

Más información

Título según WOS: Sublethal exposure to copper supresses the ability to acclimate to hypoxia in a model fish species
Título según SCOPUS: Sublethal exposure to copper supresses the ability to acclimate to hypoxia in a model fish species
Título de la Revista: AQUATIC TOXICOLOGY
Volumen: 217
Editorial: Elsevier
Fecha de publicación: 2019
Idioma: English
DOI:

10.1016/j.aquatox.2019.105325

Notas: ISI, SCOPUS