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Relationship between the carbon isotope composition of soil CO 2 and dissolved carbonate species in groundwater
Author(s) -
Rightmire Craig T.,
Hanshaw Bruce B.
Publication year - 1973
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr009i004p00958
Subject(s) - carbonate , groundwater recharge , aquifer , environmental chemistry , groundwater , organic matter , dissolved organic carbon , environmental science , δ13c , saturation (graph theory) , hydrology (agriculture) , soil science , geology , chemistry , stable isotope ratio , geotechnical engineering , organic chemistry , combinatorics , physics , mathematics , quantum mechanics
To understand the carbonate geochemistry of an aquifer system, it is helpful to determine the sources of carbon in the dissolved carbonate species. Samples of ground litter, soil organic matter, soil CO 2 , and groundwater were collected in the area of recharge to the principal artesian aquifer of central Florida and were analyzed for 13 C content. Analytical results yield consistent 13 C/ 12 C values for soil organic matter, δ 13 C PDB = 23 ±1‰. The 13 C/ 12 C ratio of the litter samples ranges from δ 13 C PDB of −18.2 to −29.5‰ and indicates the presence of both Calvin and Hatch‐Slack cycle plants. The 13 C/ 12 C of the soil CO 2 ranges from −14.7 to −21.3‰, which is consistent with the trend observed in the litter. The relationship between 13 C/ 12 C of the dissolved carbonate and the percent calcite saturation indicates that the δ 13 C PDB of the source CO 2 is within the range of −25 ± 5‰, as is expected for a humid, subtropical environment.