Biotic Response in Lotic Environments to Wide Range of Nutrient Levels, with an Emphasis on Diatoms

HR: 16:00h
AN: NB14E-03 INVITED [Abstracts]
TI: Biotic Response in Lotic Environments to Wide Range of Nutrient Levels, with an Emphasis on Diatoms
AU: * LaLiberte, G D
EM: Gina.LaLiberte@dnr.state.wi.us
AF: Wisconsin Department of Natural Resources, 1350 Femrite Drive, Monona, WI 53716 United States
AU: Garrison, P J
EM:
AF: Wisconsin Department of Natural Resources, 1350 Femrite Drive, Monona, WI 53716 United States
AU: Robertson, D M
EM:
AF: Wisconsin Water Science Center, U.S. Geological Survey, 8505 Research Way, Middleton, WI 53562 United States
AU: Wang, L
EM:
AF: Institute for Fisheries Research, Michigan Department of Natural Resources, 212 Museums Annex Building, 1109 N University Avenue , Ann Arbor, MI 48109 United States
AU: Graczyk, D J
EM:
AF: Wisconsin Water Science Center, U.S. Geological Survey, 8505 Research Way, Middleton, WI 53562 United States
AB: The Wisconsin Department of Natural Resources has proposed agricultural performance standards, TMDLs, and phosphorus criteria enforcement as tools to reduce eutrophication in Wisconsin's rivers. Watershed-level to ecoregional differences in nutrient effects may affect the response of water quality to nutrient reduction. Objectives of this project included determining the relationships between watershed and regional characteristics and nutrient concentrations on stream biological integrity, refining phosphorus criteria for Wisconsin, and developing a nutrient index of biological integrity. Samples were taken from 241 wadeable streams from which habitat and fish data had been collected within 5 years. Periphyton and macroinvertebrate samples were sampled once. Diatom data were used to develop a Diatom Nutrient Index based on autecological data and a Diatom Siltation Index based on the sum of epipelic taxa in counts. Relationships between nutrient concentrations and diatom community structure were examined using percentile rankings for total phosphorus (TP) and total nitrogen (TN). Best water quality as indicated by diatoms occurred in sites with either TP or TN at the 50^th percentile or below (TP ≤ 0.07 mg L^-1; TN ≤ 1.7 mg L^-1). These nutrient levels appeared to be a threshold above which headwater stream diatom community structure was relatively stable.
DE: 1871 Surface water quality
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly