Effect of Climate Change on Fluxes of Nitrogen from the Tovdal River Basin, Norway, to Adjoining Marine Areas

摘要

The mass-transport model TEOTIL was used to project nitrate (NO_3) fluxes from the Tovdal River basin, southernmost Norwa given four scenarios of climate change. Forests, uplands, ar open water currently account for 90 percent of the NO_3 flux. Climate scenarios for 2071-2100 suggest increased temperature by 2-4 deg C and precipitation by 3-11 percent.Climate experiments and long-term monitoring were used to estimate future rates of nitrogen (N) leaching. More water will run through the terrestrial catchments during the winter but less will run in the spring. The annual NC flux from the Tovdal River to the adjoining Topdalsfjord projected to remain unchanged, but with more NO_3 delivered the winter and less in the spring. Algal blooms in coastal water can be expected to occur earlier in the year. Major sources of uncertainty are in the long-term fate of N stored in soil organ matter and the impacts of forest management.