influence of environmental factors on biotic responses to nutrient ...

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seasonal weather-related hydrologic events (Perkins and Jones, 1994; Figueroa-Nieves ...... able data checking and summaries. Bob Black assisted with piece-.
JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION AMERICAN WATER RESOURCES ASSOCIATION

INFLUENCE OF ENVIRONMENTAL FACTORS ON BIOTIC RESPONSES

TO NUTRIENT ENRICHMENT IN AGRICULTURAL STREAMS1

Terry R. Maret, Christopher P. Konrad, and Andrew W. Tranmer2

ABSTRACT: The influence of environmental factors on biotic responses to nutrients was examined in three diverse agricultural regions of the United States. Seventy wadeable sites were selected along an agricultural land use gradient while minimizing natural variation within each region. Nutrients, habitat, algae, macroinver­ tebrates, and macrophyte cover were sampled during a single summer low-flow period in 2006 or 2007. Continu­ ous stream stage and water temperature were collected at each site for 30 days prior to sampling. Wide ranges of concentrations were found for total nitrogen (TN) (0.07-9.61 mg ⁄ l) and total phosphorus (TP) (