HR: 1330h
AN: NB33Q-10    [Abstracts]
TI: Marine Derived Nutrients (MDN) in Riverine Ecosystems: Developing Monitoring Tools for Tracking MDN in Alaska Watersheds
AU: * Rinella, D J
EM: rinella@uaa.alaska.edu
AF: Environment and Natural Resources Institute, University of Alaska Anchorage, 707 A Street, Anchorage, AK 99501 United States
AU: Wipfli, M S
EM: mark.wipfli@uaf.edu
AF: Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, 209 Irving I, Fairbanks, AK 99775 United States
AU: Walker, C
EM: coowe_walker@fishgame.state.ak.us
AF: Kachemak Bay Research Reserve, Alaska Department of Fish and Game, 95 Sterling Highway, Suite 2, Homer, AK 99603 United States
AU: Stricker, C A
EM: cstricker@usgs.gov
AF: U.S. Geological Survey, Denver Federal Center, Box 25046 Bldg 21 MS963, Denver, CO 80225 United States
AB: The objective of this study is to measure marine derived nutrient (MDN) presence and effects in stream and riparian habitats on the southern Kenai Peninsula, Alaska. Year 1 approach was to link stream chemistry, marine isotope signatures, and lipid measures along a gradient from headwaters to mouth in watersheds with and without spawning salmon (i.e., N.F. Anchor River and Happy Creek, respectively). The N.F. Anchor River received 13,000 kg of chinook (Oncorhynchus tshawytscha) and 2000 kg of coho (O. kisutch) biomass in 2004. Contrary to our hypothesis, NH4 concentrations were not related to salmon escapement, possibly due to rapid uptake in this apparently phosphorus-rich system. Dolly Varden char (Salvelinus malma), horsetail (Equisetum sp.), and macroinvertebrates collected in spawning reaches showed enriched 15N values relative to an upstream reference and Happy Valley Creek. Biota also showed a general trend toward 15N enrichment along a gradient from headwaters to mouth for both streams, suggesting that trophic complexity increased with stream size regardless of spawning salmon presence. In years 2 and 3 we will expand this study across replicate salmon and non-salmon watersheds and integrate with related studies develop a broader regional understanding of MDN effects in watersheds.
DE: 1806 Chemistry of fresh water
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly