SS3.01 Landscape Control of High Latitude Lake and River Ecosystems
Date: Thursday, June 13, 2002
Time: 2:15:00 PM
Location: Carson A
 
HobbieJE, Marine Biological Laboratory, Woods Hole, USA, jhobbie@mbl.edu
Stieglitz, M, , Lamont Doherty Earth Observatory, Palisades, USA, marc@ldeo.columbia.edu
Shaman, J, , Lamont Doherty Earth Observatory, Palisades, USA, jshaman@ldeo.columbia.edu
 
LAND-WATER TRANSFER OF WATER AND NUTRIENTS ON AN ALASKAN HILLSLOPE: A MODELLING APPROACH
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A key to predicting the impact of change on stream ecology is the land-to-water transfer of nutrients. Prediction depends on modeling both the physics of water movement on a hillslope and the biological processing of nutrients. We have coupled two dynamic models for the Imnavait Creek catchment near the Arctic LTER site in Alaska: a hydrologic model that links differing vegetation communities along a toposequence via the downslope transport of subsurface water, and a dynamic plant-soil model that operates at the plot scale. The TOPMODEL-based hydrologic model is driven by hourly weather data and is used to predict soil temperature, moisture, and catchment discharge. We show that full hydrologic connectivity between the distinct vegetative communities is most pronounced during the spring snowmelt period. In summer months, depending on antecedent conditions and storm activity, connectivity is sporadic and short lived. Despite the lack of hydrologic connection, the whole hillslope always has adequate soil moisture for continual microbial cycling. Consequently, for most of the growing season flushing of nutrients from the soil only occurs in near-stream riparian zones.