Uptake of Sulfate from Ambient Water by Freshwater Animals
2020
Griffith, Michael B. | Lazorchak, James M. | Haring, Herman
To better understand how the sulfate (SO₄²⁻) anion may contribute to the adverse effects associated with elevated ionic strength or salinity in freshwaters, we measured the uptake and efflux of SO₄²⁻ in four freshwater species: the fathead minnow (Pimephales promelas, Teleostei: Cyprinidae), paper pondshell (Utterbackia imbecillis, Bivalvia: Unionidae), red swamp crayfish (Procambarus clarkii, Crustacea: Cambaridae), and two-lined mayfly (Hexagenia bilineata, Insecta: Ephemeridae). Using δ(³⁴S/³²S) stable isotope ratios and the concentrations of S and SO₄²⁻, we measured the SO₄²⁻ influx rate (Jᵢₙ), net flux (Jₙₑₜ), and efflux rate (Jₒᵤₜ) during a 24 h exposure period. For all four species, the means of Jᵢₙ for SO₄²⁻ were positive, and Jᵢₙ was significantly greater than 0 at both target SO₄²⁻ concentrations in the fish and mollusk and at the lower SO₄²⁻ concentration in the crayfish. The means of Jₒᵤₜ and Jₙₑₜ were much more variable than those for Jᵢₙ, but several species by target SO₄²⁻ concentration combinations for Jₒᵤₜ and Jₙₑₜ, were negative, which suggests the net excretion of SO₄²⁻ by the animals. The results of our experiments suggest a greater regulation of SO₄²⁻ in freshwater animals than has been previously reported.
显示更多 [+] 显示较少 [-]