Organic Carbon Geochemistry in the North-western Black Sea–Danube River System

Galimov, É. M.; Kodina, L. A.; Zhiltsova, L.I.; Tokarev, Vasily; Vlasova, L. N.; Bogacheva, Marina; Korobeinik, G S; Vaisman, T.I.

doi:10.1006/ecss.2000.0670

Cited by 11 publications

(5 citation statements)

References 10 publications

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“…The δ 13 C POC values were observed in a narrow range of −27.4 to −28.9‰, averaging at −27.9 ± 0.5‰. This is consistent with the findings that the River Danube delivers to its mouth terrestrial material with isotopically light OC (δ 13 C = −28 to −26‰) [32] and the values found in the Danube Delta area (δ 13 C = −27.5 ± 0.9‰) [33]. Downloaded by [Temple University Libraries] at 22:09 19 November 2014 Furthermore, these values were associated with relatively high C/N ratios (9.0-16.2), suggesting that, in early spring, a major fraction of POC was derived from allochthonous matter [34].…”

Section: Isotopic Resultssupporting

confidence: 91%

Spatial and temporal variability of stable isotopes and biological parameters for the Danube River in Serbia

Mitrović¹,

Obradović²,

Golobočanin

et al. 2010

Isotopes in Environmental and Health Studies

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This paper presents the results of hydrological, physicochemical, biological, and isotopic investigations of the Danube River along the stretch through Serbian territory conducted during four campaigns in September and November 2007, September 2008 and April 2009. The stable isotope values exhibited significant changes both in the Danube (-10.7 to-9.5 per thousand for delta(18)O and-73.7 to-67.1 per thousand for delta(2)H) and in its tributaries (-9.1 to-8.5 per thousand for delta(18)O and-69.4 to-59.4 per thousand for delta(2)H) depending on the time of survey, which could be partly attributed to the influences of seasonal effects. Results emphasise the dominant role of tributaries inflows from aquifers along the Danube. The very narrow range of delta(13)C(POC) (from-28.9 to-27.4 per thousand) was associated with relatively high C/N ratios (C/N>9), and together with delta(15)N(TPN) values, the date suggested that, in early spring, a major fraction of particulate organic matter was derived from allochthonous matter. An orthogonal varimax rotation of the principal components analysis identified four latent factors ('mineral related', 'biological', 'hardness', and 'soil inlets') which are responsible for the data structure covering 79% of the observed variations among the variables studied. A reliable grouping of samples with respect to the season was found.

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Section: Isotopic Resultssupporting

confidence: 91%

Spatial and temporal variability of stable isotopes and biological parameters for the Danube River in Serbia

Mitrović¹,

Obradović²,

Golobočanin

et al. 2010

Isotopes in Environmental and Health Studies

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“…The C org concentrations ranging from 0.0% to 1.1% with an average of 0.3% are observed in the surface sediments of the southeastern YS [ Cho et al , 1999]. In general, the C org concentration in the YS and ECS sediments is lower than the average value of 0.75% for the world shelf [ Berner , 1982] and those observed in other shelf sediments, such as the northwestern Black Sea shelf [ Galimov et al , 2002]. However, the methanogenesis rates depend strongly on the availability of organic matter [ Heyer et al , 1990], and a considerable part of the methane produced in sediments can be oxidized in the upper horizons of bottom sediments and the overlying water column [ Ivanov et al , 2002].…”

Section: Resultsmentioning

confidence: 99%

Distributions and fluxes of methane in the East China Sea and the Yellow Sea in spring

Zhang

Kang

et al. 2004

J. Geophys. Res.

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[1] Distributions and fluxes of methane were determined during two surveys in March-May 2001 in the Yellow Sea and the East China Sea. Methane concentrations in the surface and bottom waters range from 2.52 to 5.48 and 2.81 to 8.17 nM, respectively. The distributions of methane are influenced obviously by the Yangtze River effluent and Kuroshio water. CH 4 input via the Yangtze River is estimated to be 3.17 mol/s, of which a considerable part may be lost by air-sea exchange during estuarine mixing. Net CH 4 flux exported from the shelf to the Kuroshio is about 1.84 mol/s. Methane enrichments in bottom waters occur widely, which reveals sediment sources of CH 4 . However, the CH 4 input from the sediments of the studied region in spring is lower than other shelf regions due to low organic carbon in the sediments and high O 2 contents in the water column. The sea-to-air methane fluxes are estimated to be 1.36 ± 1.45 and 2.30 ± 2.36 mmol m À2 d À1 using Liss and Merlivat [1986] and Wanninkhof [1992] relationships, respectively, and the estimated spring emission rate of methane ranges from 9.32 Â 10 À3 to 15.7 Â 10 À3 Tg CH 4 yr À1 . However, these estimations suffer from the neglect of seasonal variability and should be taken as a low limit. Therefore more measurement campaigns should be carried out to enhance our understanding of this particular oceanic region.

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“…Only a small fraction (i.e., less than 10% for the 1 m d −1 sinking material and negligible fractions for the sedimenting material with velocity higher than 5 m d −1 ) is transported offshore or is resuspended and exported along the shelf. Spatial patterns of sediment quality and benthic communities, organic matter composition in terms of biodegradability [e.g., Cauwet et al , 1998; Wijsman et al , 1999; Saliot et al , 2002] and δ 13 C isotopic signature [e.g., Galimov et al , 2002] confirm model results giving strong evidence of the riverine origin of most material sedimenting in the area close to the Danube delta. However, it should be noted that the model may underestimate the lateral export of particles since the process of sediment transport is not taken into account.…”

Section: Resultsmentioning

confidence: 78%

Exchange processes and nitrogen cycling on the shelf and continental slope of the Black Sea basin

Grégoire¹,

Lacroix

2003

Global Biogeochemical Cycles

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A 3D coupled biogeochemical‐hydrodynamical model has been applied to the Black Sea to simulate nitrogen cycling and to estimate the exchange of biogeochemical components at the shelf break and between the continental slope and the deep sea. It was found that biological processes on the northwestern shelf are in approximate balance. Primary production is fueled by river discharge, nitrate input from the open sea at the shelf break, and in situ remineralization. The input of nitrate from the open sea is roughly equivalent to the river nitrate discharge but is half the nitrate export from the shelf toward the open sea. Also, the Black Sea shelf acts throughout the year as a nitrate source for the open sea. The amount of shelf production not remineralized in the euphotic layer is 22.2% and is exported to lower layers (20%) or offshore (2.2%). We estimate that the export of carbon from the shelf to the interior of the basin represents 2.5% of the new production of the open sea. The upper slope adjoining the northwestern shelf is the site of downwelling events responsible for the downward transport to the intermediate layer of the continental slope of biogeochemical components exported from the shelf in the upper layer. The shelf has been found to be an efficient trap for the refractory material discharged by the Danube.

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Organic Carbon Geochemistry in the North-western Black Sea–Danube River System

Cited by 11 publications

References 10 publications

Spatial and temporal variability of stable isotopes and biological parameters for the Danube River in Serbia

Spatial and temporal variability of stable isotopes and biological parameters for the Danube River in Serbia

Distributions and fluxes of methane in the East China Sea and the Yellow Sea in spring

Exchange processes and nitrogen cycling on the shelf and continental slope of the Black Sea basin

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