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Triple oxygen isotope composition of tropospheric carbon dioxide as a tracer of terrestrial gross carbon fluxes
Author(s) -
Hoag K. J.,
Still C. J.,
Fung I. Y.,
Boering K. A.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl021011
Subject(s) - biosphere , tracer , troposphere , carbon cycle , atmospheric sciences , atmosphere (unit) , environmental science , carbon dioxide , carbon fibers , isotopes of carbon , climatology , environmental chemistry , chemistry , geology , total organic carbon , meteorology , materials science , physics , ecology , organic chemistry , ecosystem , composite number , nuclear physics , composite material , biology , astronomy
Stratospheric photochemistry leads to anomalous oxygen isotope enrichments in CO 2 (for which Δ 17 O = δ 17 O − 0.516 × δ 18 O ≠ 0). This isotope anomaly is not lost until air returns to the troposphere and CO 2 undergoes isotope exchange with water primarily in the terrestrial biosphere and oceans. A two‐box model is used to investigate the contribution of stratospheric production and contemporary surface carbon fluxes to tropospheric Δ 17 O CO2 . The predicted magnitude of ∼0.15‰ is large enough that measurement of a globally averaged tropospheric Δ 17 O CO2 should provide a new constraint for gross carbon exchanges between the biosphere and atmosphere in terrestrial carbon cycle models. Importantly, Δ 17 O CO2 should be complementary to the primary isotopic tracer of gross carbon exchanges, δ 18 O CO2 , but is not dependent on numerous hydrologic variables. Furthermore, with improved measurement precision, Δ 17 O CO2 could serve as a direct tracer of gross carbon exchanges and their variations.