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Climate change is predicted to have significant impacts on aquatic ecosystems. When combined with other stressors such as environmental contaminants, increasing temperatures will have serious consequences to the physiology and behavior of aquatic organisms. Pharmaceuticals such as antidepressants from wastewater treatment plants have been shown to modify the behavior of non-target aquatic species. We tested over 2000 snails (Physa gyrina) from a creek in Pennsylvania, USA for their righting behavior when exposed to different combinations of temperature (12°, 20°, and 25 °C) and antidepressant (venlafaxine and fluoxetine) concentration for one week or 48 hours. Snails exposed for one week righted significantly faster in warmer temperatures and in almost all concentrations of both antidepressants compared to controls. Snails exposed for 48 hours showed similar responses to warmer temperature as they did when exposed for one week, but only at the highest antidepressant concentrations did they right significantly faster than the controls. Exposure to venlafaxine at low concentration (1.56 µg/L) for 48 hours resulted in significant inhibition of righting, indicative of a non-monotonic dose response. We discuss the possible consequences of increased water temperature combined with antidepressant contamination on snail behavior as well as the possible physiological mechanisms of action explaining non-monotonic dose responses. [ABSTRACT FROM AUTHOR]

Climate change can exacerbate the effects of environmental pollutants on aquatic organisms. Pollutants such as human antidepressants released from wastewater treatment plants have been shown to impact life-history traits of amphibians. We exposed tadpoles of the wood frog Lithobates sylvaticus to two temperatures (20 °C and 25 °C) and two antidepressants (fluoxetine and venlafaxine), and measured timing of metamorphosis, mass at metamorphosis, and two behaviors (startle response and percent motionless). Antidepressants significantly shortened time to metamorphosis at 20 °C, but not at 25 °C. At 25 °C, tadpoles metamorphosed significantly faster than those at 20 °C independent of antidepressant exposure. Venlafaxine reduced body mass at 25 °C, but not at 20 °C. Temperature and antidepressant exposure affected the percent of tadpoles showing a startle response. Tadpoles at 20 °C displayed significantly more responses than at 25 °C. Exposure to fluoxetine also increased the percent of tadpoles showing a startle response. Venlafaxine reduced the percent of motionless tadpoles at 25 °C but not at 20 °C. While our results showed that antidepressants can affect the timing of metamorphosis in tadpoles, warmer temperatures overrode these effects and caused a reduction in an important reaction behavior (startle response). Future studies should address how warmer global temperatures may exacerbate or negate the effects of environmental pollutants. [ABSTRACT FROM AUTHOR]