Land use effects on nutrient cycling and loss from headwaters to Great Lakes in the Fox River Basin,
William Richardson, U.S. Geological Survey, [email protected]
Rebecca M Kreiling, U.S.G.S., [email protected]
Lynn Bartsch, USGS, [email protected]
Victoria Christensen, USGS, [email protected]
Abstract
The Fox River courses 322 km from northern and central Wisconsin, USA, into the Laurentian Great Lake Michigan at Green Bay (average discharge 117m3/s). The catchment encompasses three distinct sub-catchments. From the north, the Wolf River catchment contains little agriculture, has high water quality, is heavily forested, and overlays sandy soils; from the east, the Upper Fox catchment is dominated by relatively small farms and wetlands and has slightly degraded water quality; to the west, the Lower Fox catchment is heavily urbanized and with intense agriculture, dominated by large dairy farms including confined animal feeding operations. We report on our attempt to link land use and land management to metrics of nitrogen [N] (e.g., denitrification) and phosphorus[P] (e.g., equilibrium phosphorus concentration) cycling and local (sediment particle size, redox potential) and regional (best management practices, land use patterns) physical characteristics influencing these metrics. While loading rates are reasonably well documented, land-use patterns and in-river conditions that create biogeochemical hot spots for nitrogen and phosphorus processing and loss are less well understood. We attempt to link land-use to alterations of cycling and retention of N and P in the Fox River system over a gradient from nearly pristine and forested to heavily
1. Keyword
biogeochemistry
2. Keyword
nutrients
3. Keyword
Lake Michigan
4. Additional Keyword
denitrification
5. Additional Keyword
sediment phosphorus equilibrium