Grant: Research Tools and Instruments

Carbon (C) and nitrogen (N) are key elements in the biosphere whose abundance has been dramatically altered by human activities. While global increases in atmospheric C are widely acknowledged, N has also increased in the environment, which has altered the balance of C and N available for primary producers and heterotrophic microbes. The balance of these two elements with other biogeochemically important nutrients, such as phosphorus and iron, also strongly affects lower trophic levels in aquatic ecosystems. For example, changes to the relative availability of C and N in the environment can alter community composition of primary producers and cascade through the food web by altering food quantity and quality for secondary consumers. While the changing relative availability of multiple chemical elements, including C and N, is increasingly well documented, understanding the ecological consequences of these changes remains an important challenge to ecosystem ecologists and biogeochemists due to the complexity of food web interactions and the context dependency of many of these effects. Studying C and N cycling requires measuring these elements in aqueous, gas, and solid forms as they flux through both aquatic and terrestrial ecosystems. The proposed elemental analyzer is central to my research program that examines C and N availability in the environment, their relationship to other elements, and their ecological importance. Funding is requested for the purchase of a C-N analyzer, which is used to measure C and N in dried organic samples including algae, microbes, plants and other organic matter from the natural environment. With this, I will examine C and N in the environment with an aim of understanding the ecological effects of nutrients on food webs of lakes and rivers in Ontario. These data are central to understanding food web dynamics of lower trophic levels, long-term monitoring of lakes, and ecosystem function of these important environments. This equipment is thus central to better and more informed management of our aquatic resources in response to human threats to ecosystem health.