Solar ultraviolet-B radiation at Zackenberg: The impact on higher plants and soil microbial communities

This chapter discusses the impact of depletion of the ozone layer and the consequent increase in solar ultraviolet-B (UV-B) radiation on the living conditions of arctic plants and soil microbial communities. To evaluate the way UV-B fluxes affect the heath ecosystem at Zackenberg and other high-arctic regions, experiments with various set-ups have been performed.

The range of significant responses seen in the UV-B exclusion experiments at Zackenberg clearly indicates that ambient UV-B is a plant stress factor in this area. This seems in contrast to the reported robustness toward supplemental UV-B for plants in sub-arctic Abisko and high-arctic Svalbard. However, the results from UV-B exclusion studies in the Antarctic region have demonstrated effects on plants, similar to the results from Zackenberg.

There are differences in the chosen response variables, and the contrasting responses may be because of the climatic differences among the areas. The extreme living conditions in the high-arctic Zackenberg and Antarctic region may to a larger degree amplify the effects of stress factors, thereby leading to significant UV-B impacts.

Although the responses from Zackenberg provide new insight and supplement earlier work, more work dedicated to link variables across scales is needed to take full advantage of the earlier findings. Thus, by making parallel UV-B supplementation and UV-B exclusion field experiments, it is possible to exclude the methodological differences and validate the ecosystem responses..