Open AccessConstraining Instantaneous Fluxes and Integrated Compositions of Fluvially Discharged Organic Matter
Author(s) -
Freymond Chantal V.,
Lupker Maarten,
Peterse Francien,
Haghipour Negar,
Wacker Lukas,
Filip Florin,
Giosan Liviu,
Eglinton Timothy I.
Publication year - 2018
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2018gc007539
Subject(s) - organic matter , biosphere , total organic carbon , sink (geography) , isotopes of carbon , sediment , geology , biomarker , fluvial , carbon fibers , environmental chemistry , carbon sink , carbon cycle , δ13c , oceanography , stable isotope ratio , paleontology , chemistry , ecology , ecosystem , climate change , biology , materials science , composite material , biochemistry , quantum mechanics , physics , cartography , structural basin , geography , composite number
Fluvial export of organic carbon (OC) and burial in ocean sediments comprises an important carbon sink, but fluxes remain poorly constrained, particularly for specific organic components. Here OC and lipid biomarker contents and isotopic characteristics of suspended matter determined in depth profiles across an active channel close to the terminus of the Danube River are used to constrain instantaneous OC and biomarker fluxes and integrated compositions during high to moderate discharges. During high ( moderate ) discharge, the total Danube exports 8 ( 7 ) kg/s OC, 7 ( 3 ) g/s higher plant‐derived long‐chain fatty acids (LCFA), 34 ( 21 ) g/s short‐chain fatty acids (SCFA), and 0.5 ( 0.2 ) g/s soil bacterial membrane lipids (brGDGTs). Integrated stable carbon isotopic compositions were TOC: −28.0 ( −27.6 )‰, LCFA: −33.5 ( −32.8 )‰ and Δ 14 C TOC: −129 ( −38 )‰, LCFA: −134 ( −143 )‰, respectively. Such estimates will aid in establishing quantitative links between production, export, and burial of OC from the terrestrial biosphere.