The importance of terrestrial organic carbon inputs on Kara Sea shelves as revealed by n - alkanes , OC and d 13 C values
نویسنده
چکیده
Organic carbon (OC) and n-alkanes were investigated in the suspended matter (SM) and sur®cial sediments of the Arctic Ob and Yenisei Rivers and the adjacent Kara Sea. Organic nitrogen and dC values were determined as additional parameters in the sediments. OC and n-alkane concentrations were highly variable in space. This variability was interpreted as the result of a complex sedimentation pattern involving the discharges of these two rivers and the seasonal occurrence of a shore-ice front along the coast. Using the constant ratio of high molecular weight odd n-alkanes to OC in both rivers, we estimated that more than 70% of the OC preserved in shelf sediments is terrestrially-derived. This result was substantiated by the overall dominance of land-derived n-alkanes. A second approach using dC values and assuming binary dilution of riverine and marine OC led to comparable estimates. # 2000 Elsevier Science Ltd. All rights reserved.
منابع مشابه
Molecular and isotopic characterization of organic matter in recent and sub-recent sediments from the Dead Sea$
Near-surface sediments from two sections in the Nahal Zeelim delta of the Dead Sea (Israel) with low total organic carbon contents of 0.4±0.8% were studied by molecular and isotopic organic geochemical techniques to determine the origin of the extractable lipid components. The molecular investigation showed most of the material in this extremely hypersaline environment to be of terrestrial orig...
متن کاملSources and transport of terrestrial organic matter in Vancouver Island fjords and the Vancouver–Washington Margin: A multiproxy approach using dCorg, lignin phenols, and the ether lipid BIT index
The Branched and Isoprenoid Tetraether (BIT) index (a ratio of marine and terrestrial glycerol dialkyl glycerol tetraether [GDGT] membrane lipids) was recently introduced as a proxy for the fraction of fluvially derived organic carbon (OC) buried in marine sediments. We investigate the source and distribution of terrestrial OC in marine sediments in a large spatial data set that encompasses the...
متن کاملRapid analysis of C in plant-wax n-alkanes for reconstruction of terrestrial vegetation signals from aquatic sediments
[1] Long-chain, odd-carbon-numbered C25 to C35 n-alkanes are characteristic components of epicuticular waxes produced by terrestrial higher plants. They are delivered to aquatic systems via eolian and fluvial transport and are preserved in underlying sediments. The isotopic compositions of these products can serve as records of past vegetation. We have developed a rapid method for stable carbon...
متن کاملAmounts, isotopic character, and ages of organic and inorganic carbon exported from rivers to ocean margins: 1. Estimates of terrestrial losses and inputs to the Middle Atlantic Bight
[1] Rivers transport carbon (C) from terrestrial ecosystems to the coastal ocean, providing significant heterotrophic support within both rivers and receiving coastal waters. The amounts and ages of these terrestrial-river-coastal ocean C fluxes, however, are still poorly constrained. To address this uncertainty, a study of eight rivers discharging to the Middle Atlantic Bight (MAB) was underta...
متن کاملCarbon inputs from riparian vegetation limit oxidation of physically-bound organic carbon via biochemical and thermodynamic processes
1 In light of increasing terrestrial carbon (C) transport across aquatic boundaries, the 2 mechanisms governing organic carbon (OC) oxidation along terrestrial-aquatic interfaces are 3 crucial to future climate predictions. Here, we investigate the biochemistry, metabolic pathways, 4 and thermodynamics corresponding to OC oxidation in the Columbia River corridor using ultra5 high resolution C c...
متن کامل