Date of Award


Degree Type


Degree Name

Master of Science




Dr. Hugh Henry

Second Advisor

Dr. Irena Creed

Third Advisor

Dr. Norm Hüner


Global warming and increased atmospheric nitrogen deposition are expected to alter the carbon balances of ecosystems over the next century. My study measured net ecosystem CO2 exchange (NEE) in response to warming and nitrogen addition in a temperate old field using open system canopy chambers. Additionally, I assessed the indirect effects of warming and nitrogen addition on NEE caused by changes in aboveground productivity. In both 2009 and 2010, the study system was a net source of carbon, with the highest CO2 efflux during mid-summer. Warming and nitrogen addition did not affect NEE patterns in both years, notwithstanding a significant nitrogen effect on aboveground biomass in 2010. These findings suggest that the NEE of the study site was dominated by ecosystem respiration, which correlated strongly with soil temperature.



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