Photochemical reactivity of ancient marine dissolved organic carbon

TitlePhotochemical reactivity of ancient marine dissolved organic carbon
Publication TypeJournal Article
Year of Publication2012
AuthorsBeaupré, SR, Druffel, ERM
JournalGeophysical Research Letters
Volume39
PaginationL18602-L18602
ISSN0094-8276
Abstract

Marine dissolved organic carbon (DOC) is the largest reservoir of reduced carbon in seawater and persists up to 4,000-6,000 conventional radiocarbon (C-14) years on average. Photochemical degradation has been suggested as a geochemical sink for these long-lived molecules, yet there have been no studies relating photochemical lability to the C-14-ages of surface DOC. We observed apparent second order (2 degrees) kinetics with respect to DOC and a strong trend from Delta C-14-enriched to depleted values during exhaustive photomineralization of surface marine DOC with high energy UV light. Geochemically, these results suggest that surface DOC is an isotopically-heterogeneous mixture of molecules for which photochemical lability and C-14 ages are correlated. Photochemical mineralization may therefore be an important control on the persistence of C-14-depleted DOC in the ocean. Citation: Beaupre, S. R., and E. R. M. Druffel (2012), Photochemical reactivity of ancient marine dissolved organic carbon, Geophys. Res. Lett., 39, L18602, doi:10.1029/2012GL052974.

DOI10.1029/2012GL052974