Grant: Discovery Grants Program - Individual

Research in my lab concerns the origin, maintenance and consequences of biological diversity. The earth is currently undergoing a crisis of extinction and declining numbers of species at the global scale. Changes in communities at local scales are often equally dramatic but more variable and context dependent. The effects of environmental changes are mediated by the complex web of interactions that link species to one another. We are interested in the forces that shape these interactions, and how these forces depend on the type of habitat. Diversity is most often represented as the number of species found in a given area; however we can also consider diversity in terms of the range of species traits like size or feeding type, or the evolutionary relationships among the species that live together. We are performing studies to determine how different kinds of diversity change the way that communities of organisms perform functions such as processing energy or cycling materials. Our research is centered on aquatic organisms living in lakes or the ocean. Aquatic ecosystems are interesting in that the plants at the base of the food web are quite different from those found on land. Algae are often microscopic and reproduce more quickly than land plants such as trees. This difference in life form has major consequences for their chemistry that affects whole food webs. We are studying the effects of differences in the chemistry of algal cells and their environment on the number of species that may coexist. We are also interested in how the diversity of these micro-organisms affects the sensitivity of communities to changes in the environment like acid rain or warmer temperatures. We are using long-term sampling of lakes and marine plankton to ask whether more diverse communities are more or less responsive to environmental changes. The results will help us to understand the importance of diversity of organisms to their collective functioning as ecosystems.