HR: 11:00h
AN: B52A-03    [Abstracts]
TI: Relating Hydrogeomorphic Attributes to Nutrient Uptake in Alluvial Streams of a Mountain Lake District
AU: * Arp, C D
EM: carp@biology.usu.edu
AF: Department of Biology and Ecology Center, Utah State University, Logan, UT 84322 United States
AU: Baker, M A
EM: mbaker@biology.usu.edu
AF: Department of Biology and Ecology Center, Utah State University, Logan, UT 84322 United States
AB: Stream form and hydrologic processes may indirectly drive nutrient uptake, however developing predictive relationships has been elusive. Problems in establishing such relationships may lie in the sets of streams analyzed, which often span diverse channel-sizes, geology, and regions, or are too geomorphically similar. We collected field data on stream geomorphology and hydrologic and nutrient transport processes using solute injections at 22 alluvial stream reaches in the Sawtooth Mountains, Idaho, USA. Many of these streams occur near lakes, which create contrasting fluvial form and functions that we hoped would produce a broad geomorphic dataset to compare to hyporheic and dead-zone transient storage and NO₃ and PO₄ spiraling metrics. Preliminary results suggest that storage zone residence time (T_sto) was best predicted by sediment D₅₀, wood abundance (CWD), and discharge (r²=0.84, p<0.01) and relative hyporheic zone size was best related to D₁₆ and channel width/depth ratio (W/D) (r²=0.48, p=0.05). Among site variation in NO₃ uptake velocity (V_f) was best explained by CWD, W/D, and T_sto (r²=0.71, p=0.05) and PO₄-V_f was best explained by bed mobility and T_sto (r²=0.96, p<0.01). If and by what mechanisms these models represent true geomorphic drivers of stream transient storage and nutrient cycling processes should be further considered and investigated.
DE: 0400 Biogeosciences
DE: 9901 NABS Student Award - Basic Research
SC: Biogeosciences [B]
MN: 2005 Joint Assembly