HR: 1330h
AN: B33E-06    [Abstracts]
TI: Effects of Deposited Sediment on the Growth and Behavior of Physa Snails
AU: * Kent, T R
EM: kentt63@uwosh.edu
AF: University Wisconsin Oshkosh, Department of Biology and Microbiology 800 Algoma Bld, Oshkosh, WI 54901 United States
AU: Stelzer, R S
EM: stelzer@uwosh.edu
AF: University Wisconsin Oshkosh, Department of Biology and Microbiology 800 Algoma Bld, Oshkosh, WI 54901 United States
AB: Fine sediment loading is one of the leading causes of ecological impairment to rivers and streams in the United States, yet few studies have addressed how deposited silt affects benthic invertebrates. We determined how deposited silt affects the growth and behavior of Physa integra snails from Emmons Creek, WI by exposing them to 3 levels of silt (ambient, low, high) in streamside once-through flumes and recirculating chambers. While there were no significant differences in snail growth rates among silt treatments, the behavioral differences were striking. Snails that received added silt spent less time on algal-covered tiles than those not receiving silt. Elemental analysis of periphyton revealed higher nitrogen, carbon, and phosphorus levels for the silt addition treatments, which may be providing the snails with more nutritious food, although this was not reflected in their growth rates. Per capita egestion rates were significantly higher for the high-silt treatment. These snails may have ingested more of the algae and silt but the presence of silt may have decreased assimilation, nullifying any positive effect on growth. In conclusion, silt addition did not affect Physa integra growth rates but did influence their behavior and egestion rates.
DE: 0345 Pollution--urban and regional (0305)
DE: 0614 Biological effects
DE: 1615 Biogeochemical processes (4805)
DE: 1845 Limnology
DE: 1860 Runoff and streamflow
SC: Biogeosciences [B]
MN: 2005 Joint Assembly