Biogeochemical Cycles along an Urban-to-Rural Gradient: Virtual Experiment for Climate Change Impact on Ecosystem

The climate has dramatically changed during most recent decade and it is likely to continue. Therefore, it is important to understand the response of ecosystems to current changes in climate in order to predict the future biogeochemical behavior of the ecosystem. Global mean surface temperature has increased by about 0.89°C since 1901, and it is projected to increase up to 8.4°C relative to 1986-2005 under a high anthropogenic carbon dioxide emission scenario. An urban-to-suburban gradient can be considered as a surrogate for exploring the impacts of changing climate in the future, by reflecting elevated atmospheric CO2 concentration, capturing increased temperature through the urban heat island effect, and incorporating disturbed water and nitrogen cycles. Studying ecological systems in urban environments, however, has been avoided until recently due to the problems in establishing disturbance histories, untangling the complexities of multiple stresses on the system, and the lack of dedicated research sites. With advances in computing power, there now exists the ability to incorporate multi-source data (such as cumulative historical records, field data, and recent remote sensing products) into process-based ecosystem models to improve state and parameter estimation for systematic and synergistic analysis. The objective of this research is to incorporate ground-based in-situ observations and remote-sensing data into a physical process-based eco-hydrological model, Regional Hydro-Ecological Simulation System (RHESSys), to quantitatively analyze the integrated response of the ecosystem processes along an urban-to-suburban gradient in the urbanized Charles River Basin, the major watershed associated with the city of Boston, MA.