Get access
Advertisement

Thermal tolerance of juvenile freshwater mussels (Unionidae) under the added stress of copper

Authors

  • Tamara J. Pandolfo,

    Corresponding author
    1. Department of Environmental and Molecular Toxicology, North Carolina State University, Box 7633, Raleigh, North Carolina 27695, USA
    • Department of Environmental and Molecular Toxicology, North Carolina State University, Box 7633, Raleigh, North Carolina 27695, USA.
    Search for more papers by this author
  • W. Gregory Cope,

    1. Department of Environmental and Molecular Toxicology, North Carolina State University, Box 7633, Raleigh, North Carolina 27695, USA
    Search for more papers by this author
  • Consuelo Arellano

    1. Department of Statistics, North Carolina State University, Box 8203, Raleigh, North Carolina 27695, USA
    Search for more papers by this author

Abstract

Freshwater mussels fulfill an essential role in aquatic communities, but are also one of the most sensitive and rapidly declining faunal groups in North America. Rising water temperatures, caused by global climate change or industrial discharges, can further challenge impaired unionid communities, but thermal stress is almost certainly not the only stressor affecting freshwater mussels. Metals, such as copper (Cu), are a common source of toxicant exposure in aquatic environments. The toxic effects of Cu on the early life stages of freshwater mussels have been well studied, and freshwater mussels are more sensitive to Cu than most aquatic organisms. The purpose of the present study was to determine the effect of a sublethal copper concentration on the upper thermal tolerance of three species, Lampsilis siliquoidea, Potamilus alatus, and Ligumia recta, of juvenile freshwater mussels in 48- and 96-h tests. Thermal tolerance was determined over a range of experimental temperatures (20–42°C) at three acclimation temperatures (17, 22, and 27°C). Median lethal temperatures (LT50s) were calculated in the absence and presence of Cu, and at 48 h ranged from 34.6 to 44.4°C (mean 37.7°C) without Cu, and from 33.8 to 38.9°C (mean 35.8°C) with Cu. The LT50s at 96 h ranged from 32.5 to 35.6°C (mean 34.5°C) without Cu and from 33.0 to 35.4°C (mean 34.2°C) with Cu. Potamilus alatus had a significantly lower 48 h LT50 with Cu than without Cu at the 22°C acclimation temperature; there were no other significant differences in LT50s attributed to Cu. Survival trends showed limited evidence of interactive effects between copper and temperature for all three species, suggesting the combined stress of elevated temperatures and copper exposure to freshwater mussels should be further explored. Environ. Toxicol. Chem. 2010;29:691–699. © 2009 SETAC

Get access to the full text of this article

Ancillary