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Concentrations and radiocarbon signatures of dissolved organic matter in the Pacific Ocean
Author(s) -
Druffel Ellen R. M.,
Williams Peter M.,
Suzuki Yoshimi
Publication year - 1989
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/gl016i009p00991
Subject(s) - dissolved organic carbon , seawater , accelerator mass spectrometry , environmental chemistry , ocean gyre , radiocarbon dating , humic acid , organic matter , chemistry , carbon fibers , mass spectrometry , environmental science , oceanography , geology , ecology , chromatography , organic chemistry , biology , materials science , subtropics , paleontology , composite number , composite material , fertilizer
We present evidence suggesting that only a portion of the dissolved organic carbon (DOC) in the seawater analyzed previously by Williams and Druffel (1987) was oxidized by the UV‐radiation method. High temperature catalytic (HTC) methods (Sugimura and Suzuki, 1988) used to reoxidize the central North Pacific gyre water samples reveal that the total DOC (DOC HTC ) is about twice that of the UV‐oxidizable DOC (DOC uv ). Indications from the original study suggest that this additional DOC contains higher concentrations of radiocarbon than in the DOC uv (Williams and Druffel, 1987). This evidence implies that DOC is older and thus more refractory with respect to biological utilization, yet is more chemically reactive with respect to photooxidation, than the fraction resistant to UV (DOC res ). We report accelerator mass spectrometry (AMS) Δ 14 C measurements of humic, fulvic and hydrophilic acid fractions isolated from water collected at 180 m in the North Pacific (19°N, 158°W) using XAD macroreticular resins. Δ 14 C values of the humic material are less than those of DOC uv from a similar depth 1200 km further north (Williams and Druffel, 1987) indicating that these humic substances are part of the ‘old’ recycled DOC uv in the ocean.