Long-term research on biosphere atmosphere interactions

Selected findings from the Long Term Ecological Research (LTER) program are described in the field of biosphere-atmosphere interactions. The Palmer, Antarctic, site contributes evidence to the debate on the ecological effects of increased ultraviolet-B radiation; the ecological response to a warming trend over the past half-century has been clearly documented there. The North Temperate Lakes site in Wisconsin was the principal LTER site for an international study to document a 100-year trend of change in freeze and thaw dates of boreal lakes. A multidisciplinary approach to soil warming studies benefited from observations over decades and demonstrated the importance of initial conditions. The LTER Network permits investigation of atmosphere-ecosystem interactions over a long period encompassing storm events and quasi-periodic climate variability. LTER studies show that ecosystem dynamics often cannot be decoupled from atmospheric processes. Atmospheric processes are an integral component of the ecosystem and vice versa. Finally, we provide an example of how regionalization studies, often grounded in atmospheric data, add a spatial context to LTER sites and identify controls on ecological processes across broader environmental gradients.