Aquatic Sciences Meeting, Albuquerque 2001

SS46 Anadromous Fish as Links Between Marine and Freshwater Ecosystems (Spatial and Temporal Connections)

Date: Friday, February 16, 2001, Time: 8:30:00 AM

Location: Sandia/Santa Ana

Edwards, R, T, USDA Forest Service, PNW Station, Juneau AK, USA, rick.edwards@acsalaska.net

O'Keefe, T, C, School of Fisheries, University of Washington, Seattle WA, USA, okeefe@u.washington.edu

INFLUENCE OF SPAWNING SOCKEYE ON NUTRIENT CHEMISTRY OF STREAMS IN SOUTHWEST ALASKA: SURFACE AND HYPORHEIC PATTERNS

Nutrient chemistry before and during spawning periods was compared within surface waters of 23 streams in the Wood River Lake system in Southwest Alaska. Two hyporheic flowpaths were also monitored within Lynx Creek. Surface SRP concentrations increased from <4 µg P/l up to 36 µg P/l during spawning in creeks with salmon, but increased to less than 11 µg P/l in creeks without. Ammonium nitrogen increased from near detection limit to >250 µg N/L in streams with fish, and remained near detection in non-salmon streams. Ammonium concentrations within hyporheic flowpaths indicate that marine-derived ammonium penetrated into the riparian hyporheic zone, but was attenuated rapidly along flow paths. Oxygen consumption within the hyporheic zone increased greatly during spawning suggesting the input of labile carbon associated with carcass decay. MDN inputs to hyporheic zones may be an important influence on subsurface biogeochemistry.

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Aquatic Sciences Meeting, Albuquerque 2001

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