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Abstract Rivers and streams play an important role within the global carbon cycle, in part through emissions of carbon dioxide (CO2) to the atmosphere. However, the sources of this CO2and their spatiotemporal variability are difficult to constrain. Recent work has highlighted the role of carbonate buffering reactions that may serve as a source of CO2in high alkalinity systems. In this study, we seek to develop a quantitative framework for the role of carbonate buffering in the fluxes and spatiotemporal patterns of CO2and the stable and radio‐ isotope composition of dissolved inorganic carbon (DIC). We incorporate DIC speciation calculations of carbon isotopologues into a stream network CO2model and perform a series of simulations, ranging from the degassing of a groundwater seep to a hydrologically‐coupled 5th‐order stream network. We find that carbonate buffering reactions contribute >60% of emissions in high‐alkalinity, moderate groundwater‐CO2environments. However, atmosphere equilibration timescales of CO2are minimally affected, which contradicts hypotheses that carbonate buffering maintains high CO2across Strahler orders in high alkalinity systems. In contrast, alkalinity dramatically increases isotope equilibration timescales, which acts to decouple CO2and DIC variations from the isotopic composition even under low alkalinity. This significantly complicates a common method for carbon source identification. Based on similar impacts on atmospheric equilibration for stable and radio‐ carbon isotopologues, we develop a quantitative method for partitioning groundwater and stream corridor carbon sources in carbonate‐dominated watersheds. Together, these results provide a framework to guide fieldwork and interpretations of stream network CO2patterns across variable alkalinities.
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A PAIRED δ 44/40 CA AND Δ 47 INVESTIGATION OF EARLY MISSISSIPPIAN PLATFORM CARBONATES. DID DIAGENESIS DRIVE THE KINDERHOOKIAN-OSAGEAN BOUNDARY EXCURSION?
- Award ID(s):
- 2221962
- PAR ID:
- 10518271
- Publisher / Repository:
- Geological Society of America
- Date Published:
- Journal Name:
- Geological Society of America Abstracts with Programs
- Format(s):
- Medium: X
- Location:
- Pittsburgh
- Sponsoring Org:
- National Science Foundation
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