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Organic and black carbon 13 C and 14 C through the Santa Monica Basin sediment oxic‐anoxic transition
Author(s) -
Masiello C. A.,
Druffel E. R. M.
Publication year - 2003
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 - 10.1029/2002gl015050
Subject(s) - anoxic waters , total organic carbon , sedimentary rock , geology , oceanography , abyssal plain , abyssal zone , sediment , bottom water , environmental chemistry , geochemistry , paleontology , chemistry
Black carbon (BC) is a significant percentage of sedimentary organic carbon (SOC) at abyssal ocean sites, but its presence in shelf sediments is not well studied. Approximately 1600AD, Santa Monica Basin bottom waters shifted from oxic to very low oxygen (dysoxic) deposition conditions. Under oxic deposition conditions BC was 11 ± 4% of SOC, whereas after the overlying water became dysoxic (and sediments became anoxic), BC was 5.2 ± 1.2% of SOC. This shift may reflect the preferential remineralization of non‐black SOC under oxic conditions. There is an offset between BC and SOC 14 C ages which changes with oxidation conditions, suggesting that BC storage is related to oxygen exposure and confirming a previously published report of the vulnerability of BC to sedimentary oxidation [ Middelburg , 1999]. Terrestrial carbon is 17 ± 5% of total SOC in this core's anoxic region, and 31 ± 11% of this terrestrial carbon is BC.