Land-derived organic matter in surface sediments from the Gulf of Mexico

Hedges, John I.; Parker, Patrick L.

doi:10.1016/0016-7037(76)90044-2

Cited by 526 publications

(198 citation statements)

References 12 publications

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“…lignin parameters for two pairs of sediment samples from the Washington slope core (Table I) yielded precisions similar to those previously reported for this general method (Hedges and Parker, 1976;Hedges and Mann, 19795).…”

Section: Analysessupporting

confidence: 82%

“…Lignin oxidation products of all Gulf of Mexico sediments were determined as described by Hedges and Parker (1976). Identities of the reported compounds were confirmed by analysis of the phenolic mixture from sample 87-4 with a C.E.C.…”

Section: Analysesmentioning

confidence: 99%

“…Lignin oxidation products of samples from the Washington slope sediment core were determined by a modified version of the method described by Hedges and Parker (1976). The major difference was that the oxidation product mixtures were analyzed (also as trimethylsilyl derivatives) on high resolution fused silica gas chromatographic columns coated with methylsilicone (OV-101) liquid phase.…”

Section: Analysesmentioning

confidence: 99%

“…1. The mixture of ether.extractable acidic reaction products includes eight phenols which are obtained only from lignin and, therefore, are useful as indicators of vascular plant remains (Hedges and Parker, 1976;Hedges and Mann, 1979a, b). These eight phenols constitute an unmistakable chemical signature (Fig.…”

Section: Lignin Oxidation Productsmentioning

confidence: 99%

“…Comparisons of the lignin and stable carbon isotope compositions of recent marine sediments from the Gulf of Mexico and Washington State continental shelf and slope indicate for these regions that lignin is a major component of the terrigenous fraction and that lignin oxidation products are reliable indicators of the concentrations of land-derived organic matter in general (Hedges and Parker, 1976;Hedges and Mann, 1979b). Recent evidence for the chemical stability of lignins in marine and lacustrine sediments (Hedges and Mann, 1979b;Hedges et al, submitted) suggest that lignin oxidation products should also be useful for addressing the previously discussed question of the forms and origin of 13C-depleted organic matter in glacial-age sediments from the Gulf of Mexico and Washington regions.…”

Section: Introductionmentioning

confidence: 99%

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A comparison of lignin and stable carbon isotope compositions in quaternary marine sediments

Hedges

Geen

1982

Marine Chemistry

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Heges, J.I. and van Geen, A., 1982. A comparison of lignin and stable carbon isotope compositions in quaternary marine sediments. Mar. Chem., 11: 43--53.Organic matter in four Quaternary sediment cores from the Gulf of Mexico and one core from the Washington State coast have been analyzed for lignin and stable carbon isotope compositions. Holocene sequences of all five cores contain organic matter with high relative abundances of IS c (~13C------19.0 to --22.50/o0 versus PDB) and low lignin concentrations, both of which are consistent with a marine origin. Distinctly lower 13C concentrations (813 C----24.0 to --25.50/oo ) occur in underlying glacial-age sequences from four of the five cores, including the core from the Washington coast where such trends are previously unreported. Although the carbon isotopic compositions of these Pleistocene sediments are typical of predominantly land-derived organic matter, they contain only about 5% of the lignin found in modern sediments of similar 813C from adjacent continental shelves. The lignin-poor organic matter in the glacial-age deposits appears to be either marine-derived or terrigenous material that likely was depleted in vascular plant debris at the time of deposition.

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Section: Analysessupporting

confidence: 82%

Section: Analysesmentioning

confidence: 99%

Section: Analysesmentioning

confidence: 99%

Section: Lignin Oxidation Productsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A comparison of lignin and stable carbon isotope compositions in quaternary marine sediments

Hedges

Geen

1982

Marine Chemistry

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Distribution and sources of organic matter in surface sediments of the eastern continental margin of India

et al. 2013

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[1] The sources and distribution of organic matter (OM) in surface sediments of the eastern continental margin of India, including the region influenced by river discharge, were investigated using content, molar C:N ratios and stable isotopes of carbon and nitrogen. Despite relatively high water column integrated chlorophyll-a concentrations were found in the continental shelf than the slope; however, the lower sediment organic carbon (SOC) was found in the former than the latter region suggesting that in situ production did not play significant role on preservation of SOC in the coastal Bay of Bengal. The broad range of δ 13 C of SOC (À23.2 to À16.7‰) suggests that OM is a broad mixture of terrestrial and marine OM. Relative contributions from terrestrial C 3 and C 4 plants and marine sources are quantified as 34%, 23%, and 43%, respectively, indicating that dominant source of allochthonous OM (~57%) in the coastal Bay of Bengal. Relatively higher contribution of OM from C 4 plants was found in the sediments at off river Krishna indicating that this region received detritus of agricultural crops such as jowar, bajra, and sugar cane, which are dominant in its drainage basin, during SW monsoon. This study revealed that relatively high OM preserved in the slope than shelf region along the coastal Bay of Bengal and the composition of OM is primarily controlled by the type of agricultural crops and vegetation in the drainage basin of the river.

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Salt wedge dynamics lead to enhanced sediment trapping within side embayments in high‐energy estuaries

et al. 2017

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Off‐river coves and embayments provide accommodation space for sediment accumulation, particularly for sandy estuaries where high energy in the main channel prevents significant long‐term storage of fine‐grained material. Seasonal sediment inputs to Hamburg Cove in the Connecticut River estuary (USA) were monitored to understand the timing and mechanisms for sediment storage there. Unlike in freshwater tidal coves, sediment was primarily trapped here during periods of low discharge, when the salinity intrusion extended upriver to the cove entrance. During periods of low discharge and high sediment accumulation, deposited sediment displayed geochemical signatures consistent with a marine source. Numerical simulations reveal that low discharge conditions provide several important characteristics that maximize sediment trapping. First, these conditions allow the estuarine turbidity maximum (ETM) to be located in the vicinity of the cove entrance, which increases sediment concentrations during flood tide. Second, the saltier water in the main channel can enter the cove as a density current, enhancing near‐bed velocities and resuspending sediment, providing an efficient delivery mechanism. Finally, higher salinity water accumulates in the deep basin of the cove, creating a stratified region that becomes decoupled from ebb currents, promoting retention of sediment in the cove. This process of estuarine‐enhanced sediment accumulation in off‐river coves will likely extend upriver during future sea level rise.

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Land-derived organic matter in surface sediments from the Gulf of Mexico

Cited by 526 publications

References 12 publications

A comparison of lignin and stable carbon isotope compositions in quaternary marine sediments

A comparison of lignin and stable carbon isotope compositions in quaternary marine sediments

Distribution and sources of organic matter in surface sediments of the eastern continental margin of India

Salt wedge dynamics lead to enhanced sediment trapping within side embayments in high‐energy estuaries

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