9318529 Hobbie The research, a part of the ARCSS LAII Study, will take place in arctic Alaska in the headwaters of the Kuparuk River. There are four parts: (1) the measurements of flux of carbon as CO2 and organic matter from groundwater/land to streams and lakes and eventually, in the case of CO2, to the atmosphere (calibrations to be carried out with the help of the Chapin project); (2) the measurement of the concentration of nutrients (PO4, NO3, NH4) and dissolved and particulate organic matter in the Kukparuk River in order to calculate flux to the ocean; (3) the enhancement of a General Ecosystem Model (GEM) to include anaerobic conditions and phosphorus cycling in order to understand and predict the interactions of variations in vegetation, soil, and carbon cycling on CO2 and methane transfer to the atmosphere; and (4) the enhancement of a Terrestrial Ecosystem Model (TEM) to include permafrost in the soil moisture calculations in order to make spatially explicit regional estimates of CO2 exchange between vegetation/soil and the atmosphere. ***
