This lectureship honors Francis Clark's life-long commitment to the greater understanding of soil, plant, and microbial interactions and of nutrient cycling in terrestrial ecosystems. This year, we have the honor to have as our speaker, Professor Peter Groffman, who is an internationally recognized environmental microbiologist, and works at City University of New York Advanced Science Research Center and Brooklyn College, Dept. of Earth and Environmental Sciences. Dr. Groffman has research interests in ecosystem, soil, landscape and microbial ecology. Recent research efforts include studies of nitrogen dynamics in urban watersheds, lawns, riparian zones and forests, winter climate change effects on nutrient cycling in forests, calcium/nitrogen/carbon interactions in forests, and exotic earthworm invasion on soil nitrogen and carbon cycling.