Organic carbon and nitrogen stable isotopes in the intertidal sediments from the Yangtze Estuary, China

Liu, M.; Hou, Lijun; Xu, Shiyuan; Dong-ni, OU; Yang, Yongqiang; Jian, Yu; Wang, Q.

doi:10.1016/j.marpolbul.2006.06.008

Cited by 93 publications

(31 citation statements)

References 48 publications

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“…Dynamic cycling of nitrogen is subject to kinetic isotope fraction effects especially during the biogenic transformation and recycling of dissolved and particulate nitrogen compounds (Cifuentes et al, 1988(Cifuentes et al, , 1996Wu et al, 2003). Liu et al (2006) reported that heavier d…”

Section: Dh-mentioning

confidence: 99%

“…Peters et al, 1978;Thornton and McManus, 1994;Gordon and Goni, 2003;Wu et al, 2007;Zhang et al, 2007;Ramaswamy et al, 2008). The use of these tracers relies on the existence of gross differences among natural abundances of stable carbon isotopes, stable nitrogen isotopes and C/N elemental ratios in organic matter from terrigenous and anthropogenic inputs and marine and freshwater in situ inputs (Liu et al, 2006). In general, terrestrial organic matter has depleted d…”

Section: Introductionmentioning

confidence: 99%

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Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures

Gao

Yang

Wang

2012

Marine Pollution Bulletin

176

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Section: Dh-mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures

Gao

Yang

Wang

2012

Marine Pollution Bulletin

176

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“…Over the last two decades, TOC/TN, δ 13 C and δ 15 N are efficiently used to estimate the relative contributions of terrestrial-and marine-derived organic matter in estuaries (Andrews et al 1998;Liu et al 2006;Hu et al 2006). The C/N ratios of terrestrial organic matter is 5-7, while for marine-derived organic matter it is >12 (Meyers 1997).…”

Section: Discussionmentioning

confidence: 99%

“…A significant portion of organic matter sinks through the water column and ultimately gets stored in sediments (Hu et al 2006) by the interaction of a series of physical, chemical and biological processes (Liu et al 2006). The characterisation of source, fate and transformation of sedimentary organic matter is important for the understanding of carbon biogeochemistry and the extent of anthropogenic impacts on these systems.…”

Section: Introductionmentioning

confidence: 99%

“…Stable isotopic ratios provide complementary information to OC/TN ratios and are used to identify the organic matter sources in estuarine systems (Andrews et al 1998;Goni and Thomas 2000;Goni et al 2003;Wu et al 2003;Liu et al 2006;Rumolo et al 2011;Gao et al 2012;Gireeshkumar et al 2013). The interpretation of bulk elemental proxies is complicated by the fact that bulk materials represent mixtures of carbon from several sources, and thus they reflect the integration of different sources.…”

Section: Introductionmentioning

confidence: 99%

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Distribution and sources of aliphatic hydrocarbons and fatty acids in surface sediments of a tropical estuary south west coast of India (Cochin estuary)

Gireeshkumar

Deepulal

Chandramohanakumar

2015

Environ Monit Assess

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Surface sediments samples from the Cochin estuary were measured for elemental, stable isotopic and molecular biomarkers (aliphatic hydrocarbons and fatty acids) to study the sources and distribution of sedimentary organic matter. Concentrations of total organic carbon (TOC), total nitrogen (TN) and stable isotopic ratios of carbon (δ(13)C) ranged from 0.62 to 2.74 %, 0.09 to 0.25 % and -27.5 to 21.7 ‰, respectively. Sedimentary n-alkanes ranged from 6.03 to 43.23 μg g(-1) with an average of 16.79 μg g(-1), while total fatty acids varied from 22.55 to 440.69 μg g(-1). The TOC/TN ratios and δ(13)C suggest a mixture of marine- and terrestrial-derived organic matter in the surface sediments with increasing contributions from marine-derived organic matter towards the seaward side. Long-chain n-alkanes derived from higher plants predominated the inner part of the estuary, while short-chain n-alkanes derived from planktonic sources predominated the bar mouth region. The even carbon preference of the C12-C22 n-alkanes may refer to the direct biogenic contribution from bacteria, fungi and yeast species and to the potential direct petroleum inputs. The presence of odd mid-chain n-alkanes in the sediments indicates the organic matter inputs from submerged and floating macrophytes (water hyacinth). Various molecular indices such as carbon preference index, terrestrial to aquatic ratio, average chain length and the ratios of mid-chain n-alkanes support the aforementioned inferences. The high contribution of odd and branched chain fatty acids along with very low contribution of polyunsaturated fatty acids, suggest the effective utilisation of algae-derived organic matter by bacteria and the effective recycling of labile organic matter in whole settling and deposition processes. The distributional variability of n-alkanes and fatty acids reveals the preferential utilisation of marine-derived organic matter and the selective preservation of terrestrial-derived organic matter in surface sediments of the Cochin estuary.

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Isotopic composition and speciation of sedimentary nitrogen and carbon in the Okinawa Trough over the past 30 ka

et al. 2015

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Total organic carbon to total nitrogen ratios (C/N) and their isotopic compositions (δ 13 C TOC and δ 15 N TN ) are oft-applied proxies to discern terrigenous from marine-sourced organics and to unravel ancient environmental information. In high depositional Asian marginal seas, the inclusion of N-bearing minerals in the bulk sediment dilutes or masks signals sought after in δ 15 N and δ 13 C analyses, thus leading to incorrect and even contradictory interpretations. We used KOH-KOBr to separate operationally defined total organic matter into oxidizable (labile) and residual fractions for content and isotope measurements. In a sediment core in the Okinawa Trough, significant amounts of carbon and nitrogen existed in the residual phase, in which the C/N ratio was~9, resembling most documented sedimentary bulk C/N ratios in the China marginal seas. The residual carbon, which was included in operationally defined total organic carbon (TOC), displayed a δ 13 C range (À22.7 to À18.9‰, mean À20.7‰) similar to the oft-used marine end-member. After removing the interference from the residual fraction, we found that the temporal pattern of δ 13 C LOC (LOC denotes labile organic carbon) was more variable. The residual nitrogen content was associated with illite, suggesting a terrestrial origin. Additionally, δ 15 N in the residual fraction likely reflected the climatic controls (e.g., precipitation) on lithogenic source materials. Further studies are required to explore the controlling factors for carbon and nitrogen isotopic speciation and to retrieve the information locked in the residual fraction.

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Organic carbon and nitrogen stable isotopes in the intertidal sediments from the Yangtze Estuary, China

Cited by 93 publications

References 48 publications

Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures

Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures

Distribution and sources of aliphatic hydrocarbons and fatty acids in surface sediments of a tropical estuary south west coast of India (Cochin estuary)

Isotopic composition and speciation of sedimentary nitrogen and carbon in the Okinawa Trough over the past 30 ka

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