title: Mimicking natural systems: Changes in behavior as a result of dynamic exposure to naproxen.
abstract: Animals living in aquatic habitats regularly encounter anthropogenic chemical pollution. Typically, the toxicity of a chemical toxicant is determined by the median lethal concentration (LC50) through a static exposure test. However, LC50values and static tests do not provide an accurate representation of exposure to pollutants within natural stream systems. In their native habitats, animals experience exposure as a fluctuating concentration due to turbulent mixing, temporal variations of contamination (seasonal inputs), and contaminant input type (point vs. non-point). Research has shown that turbulent environments produce exposures with a high degree of fluctuation in frequency, duration, and intensity. In order to more effectively evaluate the effects of pollutants, we created a dynamic exposure paradigm, utilizing both flow and substrate within a small mesocosm. A commonly used pharmaceutical, naproxen, was used as the toxicant and female crayfish (Orconectes virilis) as the target organism to investigate changes in fighting behavior as a result of dynamic exposure. Crayfish underwent either a 23h long static or a dynamic exposure to naproxen. Following exposure, the target crayfish and an unexposed size matched opponent underwent a 15min fight trial. These fight trials were recorded and later analyzed using a standard ethogram. Results indicate that exposure to sublethal concentrations of naproxen, in both static and flowing conditions, negatively impact aggressive behavior. Results also indicate that a dynamic exposure paradigm has a greater negative impact on behavior than a static exposure. Turbulence and habitat structure play important roles in shaping chemical exposure. Future research should incorporate features of dynamic chemical exposure in order to form a more comprehensive image of chemical exposure and predict the resulting sublethal effects from exposure. Possible techniques for assessment include utilizing flow-through experimental set-ups in tandem with behavioral or physiological endpoints as opposed to acute toxicity. Other possibilities of assessment could involve utilizing fine-scale chemical measurements of pollutants to determine the actual concentrations animals encounter during an exposure event.
authors: Laboratory for Sensory Ecology, Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA; University of Michigan Biological Station, 9133 Biological Road, Pellston, MI 49769, USA.
authors: Alexandra E
authors: AE
authors: Neal
authors: Laboratory for Sensory Ecology, Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA; University of Michigan Biological Station, 9133 Biological Road, Pellston, MI 49769, USA. Electronic address: pmoore@bgsu.edu.
authors: Paul A
authors: PA
authors: Moore
mesh_terms: D000374:Aggression / Q000187:drug effects; D000818:Animals; D003400:Astacoidea / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects*; D017753:Ecosystem; D004781:Environmental Exposure; D005260:Female; D009288:Naproxen / Q000633:toxicity*; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D009288:Naproxen
keywords: Behavioral impairments; Dynamic exposure; Naproxen; Sublethal effects; Turbulence