HR: 11:15h
AN: NB42F-04    [Abstracts]
TI: Storage and Transformation of Artificial and Natural Salmon-Derived Nutrients in the Hyporheic Zone of a Southeast Alaska Stream
AU: * Marshall, M C
EM: marshall@uwyo.edu
AF: Department of Zoology and Physiology, University of Wyoming , Laramie, WY 82071 United States
AU: Edwards, R T
EM: rtedwards@fs.fed.us
AF: Pacific Northwest Research Station, USDA Forest Service, 2770 Sherwood Lane, Juneau, AK 99801 United States
AU: Hall, R O
EM: bhall@uwyo.edu
AF: Department of Zoology and Physiology, University of Wyoming , Laramie, WY 82071 United States
AU: Norberg, E C
EM: enorberg@fs.fed.us
AF: Pacific Northwest Research Station, USDA Forest Service, 2770 Sherwood Lane, Juneau, AK 99801 United States
AB: Adding nutrients in organic pellets (analogs) or salmon carcasses (SDN) is one strategy resource managers use to enhance productivity in streams where natural salmon nutrient subsidies have been reduced. We compared hyporheic storage and transformation of nutrients from carcasses to those from analogs added to surface water of two tributaries of a salmon stream in Southeast Alaska. Hyporheic sediments responded differently to the two sources with some responses detectable the following summer. Average hyporheic and phreatic SRP concentrations in the analog treatment were 2.5 and 3.5 times greater, respectively, than controls one month after the August additions. Subsurface SRP was again higher the following spring and summer in the analog treatment. Surface water SRP was higher in the analog treatment in late summer a year after the addition. Respiration in phreatic zones in analog and control reaches remained under 1.1 mg DO L sediment^-1 h^-1. However, respiration rates were elevated in phreatic zones in the carcass treatment reach (3.0 mg DO L sediment^-1 h^-1) the summer after the addition, suggesting delayed use of stored carcass carbon. These results support the hypothesis that hyporheic zones provide long-term storage and remobilization of SDN thereby enhancing stream productivity in subsequent years.
DE: 1615 Biogeochemical processes (4805)
DE: 1831 Groundwater quality
DE: 4815 Ecosystems, structure and dynamics
DE: 4845 Nutrients and nutrient cycling
DE: 9902 NABS Student Award Applied Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly