Dissolved organic matter from elevated-CO2detritus and its impact on the orientation of crayfish (Orconectes virilis) to a fish food source

Abstract

AbstractCrayfish must locate food resources in a chemically complex environment in which chemicals from various sources interact and mix. We tested the hypothesis that an additional chemical food source of leachate from detritus (dissolved organic matter [DOM]) would affect crayfish orientation behavior toward a fish stimulus. In addition, we predicted that the effect of DOM would differ depending on whether the detritus was produced under ambient (AMB) or elevated (ELEV) CO2 because of changes in foliar chemistry that accompany elevated CO2 levels. DOM was collected from leaf litter derived from quaking aspen (Populus tremuloides) foliage that was produced at either AMB or ELEV CO2 and was presented at 2 concentrations (3 mg/L, 6 mg/L). Stimulus treatments were: 1) CON (control; fish odor only), 2) AMB-low (fish + AMB DOM at 3 mg/L), 3) AMB-high (fish + AMB DOM at 6 mg/L), 4) ELEV-low (fish + ELEV DOM at 3 mg/L), and 5) ELEV-high (fish + ELEV DOM at 6 mg/L). Crayfish (Orconectes virilis) were observed in...