Kentucky State University

Training of Undergraduate and Graduate Students in Ecosystem Scale Measurements of Greenhouse Gases at Kentucky State University

Institution

Kentucky State University

Abstract

Ecosystems respond to directional changes in physical, biological, and social drivers and quantifying these changes require a unique set of instrumentation and monitoring techniques to: i) reliably predict the interaction between ecosystem and climate, ii) offer better insights and predictive power on a larger scale, and iii) be able to link mechanistic understanding of the ecosystem, atmosphere, soil linkage, drivers and processes. We measured the exchange of carbon dioxide (CO2), methane (CH4) and energy (sensible and latent heat) using the eddy covariance method over a year round grazed pasture land, vegetated with a mix of Johnson grass, fescue, white clover and wild carrot. The flux station (38˚6ˈ56.42N, 84˚53ˈ22.81 W) at the Research and Demonstration Farm, Kentucky State University, is equipped with the closed path infrared Li7200 CO2/H2O) and Li-7700 open path CH4 analyzer along with sonic anemometer (WindMaster Pro R3-50). This study presents instrumentation setup along with data processing methodology applied and a preliminary result. Diurnal flux measurements showed that the pasture ecosystem CO2 uptake and release (ecosystem respiration, Re) were strongly coupled with diurnal pattern of photosynthetic photon flux density (PPFD) and air temperature (Ta), respectively. Lowest midday CH4 concentration occurred around the noon time hours (local time) and gradually increased and reached maximum in the evening. This nocturnal peak in CH4 emission could be explained, in part by, the presence of elongated footprint around the tower resulted from absence of turbulence at night. In addition, the rate of CH4 efflux was tightly linked with soil moisture levels, with higher levels of CH4 exchange observed from moist soil. The measuring station not only was the essential infrastructure to provide a holistic understanding of the biophysical drivers of ecosystem fluxes of processes the but also served as the backbone for scaling up flux measurements to broader spatial scales.

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Training of Undergraduate and Graduate Students in Ecosystem Scale Measurements of Greenhouse Gases at Kentucky State University

Ecosystems respond to directional changes in physical, biological, and social drivers and quantifying these changes require a unique set of instrumentation and monitoring techniques to: i) reliably predict the interaction between ecosystem and climate, ii) offer better insights and predictive power on a larger scale, and iii) be able to link mechanistic understanding of the ecosystem, atmosphere, soil linkage, drivers and processes. We measured the exchange of carbon dioxide (CO2), methane (CH4) and energy (sensible and latent heat) using the eddy covariance method over a year round grazed pasture land, vegetated with a mix of Johnson grass, fescue, white clover and wild carrot. The flux station (38˚6ˈ56.42N, 84˚53ˈ22.81 W) at the Research and Demonstration Farm, Kentucky State University, is equipped with the closed path infrared Li7200 CO2/H2O) and Li-7700 open path CH4 analyzer along with sonic anemometer (WindMaster Pro R3-50). This study presents instrumentation setup along with data processing methodology applied and a preliminary result. Diurnal flux measurements showed that the pasture ecosystem CO2 uptake and release (ecosystem respiration, Re) were strongly coupled with diurnal pattern of photosynthetic photon flux density (PPFD) and air temperature (Ta), respectively. Lowest midday CH4 concentration occurred around the noon time hours (local time) and gradually increased and reached maximum in the evening. This nocturnal peak in CH4 emission could be explained, in part by, the presence of elongated footprint around the tower resulted from absence of turbulence at night. In addition, the rate of CH4 efflux was tightly linked with soil moisture levels, with higher levels of CH4 exchange observed from moist soil. The measuring station not only was the essential infrastructure to provide a holistic understanding of the biophysical drivers of ecosystem fluxes of processes the but also served as the backbone for scaling up flux measurements to broader spatial scales.