Department Chair
Dr. Gregory Wadsworth
Date of Award
12-2012
Access Control
Open Access
Degree Name
Biology, M.A.
Department
Biology Department
Advisor
Dr. Daniel L. Potts
Department Home page
http://biology.buffalostate.edu/
First Reader
Dr. Christopher Pennuto
Second Reader
Dr. Edward Standora
Abstract
Nitrogen (N) and phosphorus (P) affect the structure and function of grasslands by altering plant competitive interactions, shifting patterns of above- and belowground biomass allocation, and by increasing net primary production. However, the influence of N and P on net ecosystem productivity is poorly understood. In the context of a field-based factorial N- and P-addition experiment, I measured soil moisture, leaf area index and component fluxes of ecosystem CO2 exchange throughout the growing season in a restored temperate grassland near Buffalo, New York. I predicted that N-addition would enhance ecosystem CO2 uptake (GEE) while P-addition would stimulate ecosystem respiration (Re). As predicted, N-addition increased GEE and correspondingly amplified net ecosystem CO2 exchange (NEE) to increase ecosystem CO2 uptake. In contrast, P-addition did not significantly increase Re. However, N- and P-addition interacted to significantly reduce NEE in comparison with plots that received N alone. Moreover, water limitation and phenological constraints during the middle and late growing season appear to limit autotrophic responses to nutrient addition. These results suggest that influences of N- and P-addition on ecosystem processes are seasonally dynamic and that the availability of N and P in soils may interact to weaken the strength of the terrestrial carbon sink.
Recommended Citation
Socha, Lynn M., "Influence of Nitrogen and Phosphorus on Ecosystem CO2 Exchange in a Restored Temperate Grassland" (2012). Biology Theses. 4.
https://digitalcommons.buffalostate.edu/biology_theses/4
