CAREER: Using an Urban-to-Rural Gradient as a Proxy for Global Change Effects on Selected Biosphere-Atmosphere Trace Gas Exchanges

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The overarching objective is to investigate responses of biogenic volatile organic compound (BVOC) emissions to variations in climate parameters, such as temperature and humidity. BVOC emissions, particularly isoprene, exert an important direct influence on atmospheric chemistry and an indirect one on climate. Increased BVOC emissions in a warmer climate can exacerbate regional ozone pollution and reinforce global warming. However, future BVOC emissions are uncertain due to a lack of understanding of plant BVOC production and emissions' acclimatization to climate change. The specific objectives are to: determine urban-rural response gradients due to growth environment, such as T, [CO2], and [O3]; relate trace gas exchange to physical and biophysical drivers, including seasonality; and provide adequate flux data to improve isoprene response and feedback modeling on larger scales.Along four sites from central Houston to Sam Houston National Forest, biometeorological data, and [CO2] and [O3] will be recorded year-round. In addition, auxiliary data on microclimates and soil parameters will be collected. Local trees to be studied include five oak species, sweetgum, and loblolly pine. Expected temperature and CO2 gradients along the study sites are of order 1 K and 20 ppm, respectively. Controlled laboratory, branch-level experiments performed by undergraduate students will complement the field data. Research will be conducted by undergraduate and graduate students. Undergraduate students will assist with field, and perform their own laboratory measurements and analyses. The high school program will involve teachers and students in research through jump starting related GLOBE program activities at the same schools we deploy the expanded weather stations measuring the climate and air quality gradient. Teachers and students can work with these data directly, generate their own earth science data, and interact with researchers during field measurements and workshops.