HR: 11:30h
AN: NB42F-05    [Abstracts]
TI: Seasonal nutrient dynamics in three stream types in SE Alaska
AU: * Edwards, R T
EM: rtedwards@fs.fed.us
AF: Forestry Sciences Laboratory, PNW Research Station, USDA Forest Service, 2770 Sherwood Lane, Suite 2A, Juneau, AK 99801 United States
AU: Norberg, E
EM: enorberg@fs.fed.us
AF: Forestry Sciences Laboratory, PNW Research Station, USDA Forest Service, 2770 Sherwood Lane, Suite 2A, Juneau, AK 99801 United States
AU: Fellman, J
EM: jfellman@fs.fed.us
AF: Forestry Sciences Laboratory, PNW Research Station, USDA Forest Service, 2770 Sherwood Lane, Suite 2A, Juneau, AK 99801 United States
AB: The Tongass National Forest encompasses over 5,000 salmon streams draining a wide variety of lithologies, microclimates and landforms. To predict management outcomes and responses to climate change, managers need an understanding of how ecosystem processes in streams vary over large spatial scales and with major controlling landscape variables. We measured forms of N, P and DOM in three common stream types: glacial, brownwater and clearwater near Juneau, AK. Glacial and clearwater streams showed strong seasonal trends in nitrate and total nitrogen related to snow melt and summer uptake, whereas brownwater streams were variable but not highly seasonal. Total nitrogen concentrations were dominated by inorganic forms in clearwater streams, organic forms in brownwater streams and varied seasonally between organic and inorganic forms in glacial streams. DOC concentrations were low in clearwater and glacial streams and varied little seasonally. Brownwater stream DOC values were high, variable and varied with discharge, with an increasing trend during summer. The Tongass NF recently classified SE Alaska forest lands into ecological subsections based on large-scale geophysical factors such as lithology and surficial geology. Partitioning Tongass streams using this approach may lead to better management predictions by more accurately incorporating natural variation in baseline stream dynamics.
DE: 1806 Chemistry of fresh water
DE: 1845 Limnology
DE: 1860 Runoff and streamflow
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly