HR: 13:45h
AN: NB23A-02    [Abstracts]
TI: Evaluation of Arctopsyche grandis (Hydropsychidae) as a Biological Monitoring Tool in Rocky Mountain Streams
AU: * Johnston, W D
EM: wallyj55@lamar.colostate.edu
AF: Colorado State University, 1274 Campus Delivery, Fort Collins, CO 80523 United States
AB: Trace metal loading has been shown to cause marked disturbance in benthic invertebrate communities of Rocky Mountain streams. Metal concentrations in invertebrate tissues are commonly measured in biological monitoring studies as an indicator of metals contamination in the stream. Comparisons of metal body burdens across sampling sites and occasions carry the assumption that burdens reflect metal bioavailability in the field. Laboratory experiments were conducted with indigenous, larval, net-spinning caddisflies (Arctopsyche grandis) to evaluate this important assumption. Caddisfly larvae were exposed to a range of zinc (50 to 1000 ppb) and copper (10 to 360 ppb) concentrations for 96 hours. Water hardness (50, 100 ppm) and dissolved organic carbon (3, 6 ppm) concentrations were systematically varied in order to estimate differences in metal burdens due to changes in aqueous chemistry. Whole individual larvae were analyzed for trace metal concentrations. Results suggest that larval A. grandis are capable of regulating internal zinc concentrations. Surprisingly, maximum zinc burdens were observed where hardness and DOC were highest. Conversely, copper accumulation was reduced by 30 percent where DOC (3 ppm) was added to the exposure medium. Results will be discussed with respect to their significance for future biomonitoring efforts.
DE: 1065 Trace elements (3670)
DE: 1615 Biogeochemical processes (4805)
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly