HR: 0800h
AN: B11A-0050    [Abstracts]
TI: Effect of Urbanization on River CO₂ Emissons
AU: * Zeng, F
EM: fwzeng@rice.edu
AF: Department of Earth Science, Rice University, 6100 Main St., Houston, TX 77005, United States
AU: Masiello, C A
EM: masiello@rice.edu
AF: Department of Earth Science, Rice University, 6100 Main St., Houston, TX 77005, United States
AB: CO₂ supersaturation in rivers has been reported for a number of different systems: tropical (e.g. Amazon¹), subtropical (e.g. Xijiang River in China²) and temperate (e.g. Hudson³), indicating rivers^' role as a source of atmospheric CO₂ in regional net carbon budgets. In situ respiration of organic carbon is responsible for the high CO₂ concentrations in rivers¹. Because this organic carbon primarily originates on land¹, land use practices may alter sources and character of this organic carbon significantly, potentially impacting river CO₂ emissions. Urbanization is an important, expanding global land use. We are researching the effect of urbanization on river CO₂ emissions. In this study, partial pressure of dissolved CO₂ (pCO₂) and radiocarbon (¹⁴C) contents of riverine dissolved inorganic carbon (DIC) are directly measured in time series in Buffalo Bayou and Brays Bayou, two of the main rivers draining Houston, Texas, a developed humid subtropical city. The watersheds of both bayous are entirely unbanized. We will report seasonal trends of pCO₂ and ¹⁴C of riverine DIC to estimate sources and turnover times of dissolved CO₂. For comparison, we are also measuring pCO₂ and DIC ¹⁴C in Spring Creek, Texas, a nearby river which has a mixed forest/agriculture watershed, as a non-urbanized counterpart to Buffalo and Brays Bayous. References: 1. E. Mayorga et al., Nature 436, 538 (2005). 2. G. Yao et al., Sci. Tot. Environ. 376, 255 (2007). 3. P.A. Raymond, N.F. Caraco, and J.J. Cole, Estuaries 20, 381 (1997).
DE: 4227 Diurnal, seasonal, and annual cycles (0438)
DE: 4806 Carbon cycling (0428)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting