See more from this Division: Joint Sessions
See more from this Session: Soil Respiration: From Human to Geologic Time Scales
Abstract:
Carbon isotopic signatures of riverine dissolved inorganic carbon (DIC) point to different CO2 sources for the two rivers. DIC in Spring Creek is generally young and more d13C-depleted, indicating that a young carbon pool is cycling rapidly and sustaining the high CO2 concentration in Spring Creek. For Buffalo Bayou, DIC is always depleted in Δ14C and more enriched in d13C, suggesting an input of DIC from carbonate dissolution. This is also supported by a local soil survey, which shows the presence of soil carbonates in the Buffalo Bayou watershed.
There are two possible sources of soil carbonates in the Buffalo Bayou watershed: naturally precipitated pedogenic CaCO3, and CaCO3 from shells used to make roads in East Texas in the early 20th century. In the first scenario, soil carbonates are likely in steady state and thus act only to shift the isotopic signature of respired riverine CO2. In the second scenario, shells from road building are both a net source of CO2 to the atmosphere and are altering the C isotopic signature of Houston-area respiration.
See more from this Division: Joint Sessions
See more from this Session: Soil Respiration: From Human to Geologic Time Scales