Reconstruction of sediment flux from the Changjiang (Yangtze River) to the sea since the 1860s

Wang, Houjie; Yang, Zuosheng; Wang, Yan; Saito, Yoshiki; Liu, Paul

doi:10.1016/j.jhydrol.2007.11.005

Cited by 198 publications

(90 citation statements)

References 47 publications

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“…detected among the 20 samples in this study ( Relatively low levels of PBDEs were found in the present study, which may be mainly attributed to the ''dilution effect'' of terrestrial and marine matters. Yangtze River discharges about 0.5 Gt year -1 of terrestrial matters into the ECS [24], and the coastal eutrophication due to increased human activities result in an increase in primary production and burial of marine organic matters in the marine sediments [25]. The specific hydrodynamic conditions of the ECS also result in a very high sedimentation rate in the Yangtze Delta Region and in the inner shelf of the ECS [26].…”

Section: Total Organic Carbon Analysismentioning

confidence: 99%

Distribution of polybrominated diphenyl ethers in the surface sediment of the East China Sea

Lan

et al. 2014

Chin. Sci. Bull.

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The concentrations of polybrominated diphenyl ethers (PBDEs) were determined in the surface sediments of 20 locations in the East China Sea (ECS). The P PBDEs (sum of 13 PBDE congeners, without brominated diphenyl ether 209 (BDE209) ranged from 2.6 to 49 pg g -1 (dry weight) with an average of 21 pg g -1 , which fell at the low end of the global range. The spatial distribution presented an offshore decreasing trend towards the outer shelf and along the coastline, suggesting a direct influence of the inputs by the Yangtze River. The P PBDE concentrations were influenced by the total organic carbon of the sediment, as demonstrated by their similar spatial distributions. The P C 27 ? C 29 ? C 31 n-alkanes concentrations and sand % reported in the literature for sediments in the ECS presented similar spatial distributions as P PBDEs, which suggests that a considerable part of P PBDEs may come from the Yangtze River and that grain size plays an important role in PBDE accumulation. The three dominant congeners were BDE28 (19.8 %), BDE47 (26.4 %), and BDE99 (16.8 %). The present study compared the congener patterns of the sedimentary PBDEs with those of commercial products. The results indicated the possible use of penta-BDE in the Yangtze River Basin in a wide range or the fractionation and transformation of PBDE congeners during their long-range transport.

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Section: Total Organic Carbon Analysismentioning

confidence: 99%

Distribution of polybrominated diphenyl ethers in the surface sediment of the East China Sea

Lan

et al. 2014

Chin. Sci. Bull.

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“…This reduction in sediment flux dramatically affects deltas (Ouillon, 1998;Syvitski and Saito, 2007). For example, sediment discharge decreased from 480 to approximately 150 × 10 6 t yr −1 over a 20-year period in the Yangtze River (Changjiang) (Yang et al, 2006;Wang et al, 2008) and from 1080 to 150 × 10 6 t yr −1 over a 40-year period in the Yellow River (Huanghe) (Wang et al, 2007). Large rivers and their deltas in Southeast Asia have also been impacted by other human activities such as groundwater pumping, irrigation, dredging and deforestation (Tran et al, 2004;.…”

Section: Introductionmentioning

confidence: 99%

Impact of the Hoa Binh dam (Vietnam) on water and sediment budgets in the Red River basin and delta

Vinh¹,

Ouillon

Thạnh³

et al. 2014

Hydrol. Earth Syst. Sci.

108

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Abstract. The Hoa Binh dam (HBD), located on a tributary of the Red River in Vietnam, has a capacity of 9.45 × 10 9 m 3 and was commissioned in December 1988. Although it is important for flood prevention, electricity production and irrigation in northern Vietnam, the Hoa Binh dam has also highly influenced the suspended sediment distribution in the lower Red River basin, in the delta and in the coastal zone. Its impact was analysed from a 50-year data set of water discharge and suspended sediment concentration , and the distribution of water and sediment across the nine mouths of the delta was simulated using the MIKE11 numerical model before and after the dam settlement. Although water discharge at the delta inlet decreased by only 9 %, the yearly suspended sediment flux dropped, on average, by 61 % at Son Tay near Hanoi (from 119 to 46 × 10 6 t yr −1 ). Along the coast, reduced sedimentation rates are coincident with the lower sediment delivery observed since the impoundment of the Hoa Binh dam. Water regulation has led to decreased water discharge in the wet season (−14 % in the Red River at Son Tay) and increased water discharge in the dry season (+12 % at the same station). The ratios of water and suspended sediment flows, as compared to the total flows in the nine mouths, increased in the northern and southern estuaries and decreased in the central, main Ba Lat mouth. The increasing volume of dredged sediments in the Haiphong harbour is evidence of the silting up of the northern estuary of Cam-Bach Dang. The effect of tidal pumping on enhanced flow occurring in the dry season and resulting from changed water regulation is discussed as a possible cause of the enhanced siltation of the estuary after Hoa Binh dam impoundment.

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“…The Bay is affected by river runoff and tide from the East China Sea. The Yangtze (Changjiang) River with an average water runoff of 925 × 10 9 m 3 yr −1 and sediment load of 480 × 10 9 kg yr −1 supplied the dominant amount of sediment to the Hangzhou Bay Wang et al, 2008), where it is re-deposited by southward coastal currents and tides (Jilan and Kangshan, 1989;Xi et al, 2009). The climate is subtropical monsoonal with annual average temperature and rainfall of 16.3 • C and 1418 mm, respectively.…”

Section: Study Sitesmentioning

confidence: 99%

Intra- versus inter-site macroscale variation in biogeochemical properties along a paddy soil chronosequence

Mueller-Niggemann

Bannert²,

Schloter

et al. 2012

Biogeosciences

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Abstract. In order to assess the intrinsic heterogeneity of paddy soils, a set of biogeochemical soil parameters was investigated in five field replicates of seven paddy fields (50, 100, 300, 500, 700, 1000, and 2000 yr of wetland rice cultivation), one flooded paddy nursery, one tidal wetland (TW), and one freshwater site (FW) from a coastal area at Hangzhou Bay, Zhejiang Province, China. All soils evolved from a marine tidal flat substrate due to land reclamation. The biogeochemical parameters based on their properties were differentiated into (i) a group behaving conservatively (TC, TOC, TN, TS, magnetic susceptibility, soil lightness and colour parameters, δ 13 C, δ 15 N, lipids and n-alkanes) and (ii) one encompassing more labile properties or fast cycling components (N mic , C mic , nitrate, ammonium, DON and DOC). The macroscale heterogeneity in paddy soils was assessed by evaluating intra-versus inter-site spatial variability of biogeochemical properties using statistical data analysis (descriptive, explorative and non-parametric). Results show that the intrinsic heterogeneity of paddy soil organic and minerogenic components per field is smaller than between study sites. The coefficient of variation (CV) values of conservative parameters varied in a low range (10 % to 20 %), decreasing from younger towards older paddy soils. This indicates a declining variability of soil biogeochemical properties in longer used cropping sites according to progress in soil evolution. A generally higher variation of CV values (>20-40 %) observed for labile parameters implies a need for substantially higher sampling frequency when investigating these as compared to more conservative parameters. Since the representativeness of the sampling strategy could be sufficiently demonstrated, an investigation of long-term carbon accumulation/sequestration trends in topsoils of the 2000 yr paddy chronosequence under wetland rice cultivation restricted was conducted. Observations cannot be extrapolated to global scale but with coastal paddy fields developed on marine tidal flat substrates after land reclamation in the Zhejiang Province represent a small fraction (<1 %) of the total rice cropping area. The evolutionary trend showed that the biogeochemical signatures characteristic for paddy soils were fully developed in less than 300 yr since onset of wetland rice cultivation. A six-fold increase of topsoil TOC suggests a substantial gain in CO 2 sequestration potential when marine tidal wetland substrate developed to 2000 yr old paddy soil.

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Reconstruction of sediment flux from the Changjiang (Yangtze River) to the sea since the 1860s

Cited by 198 publications

References 47 publications

Distribution of polybrominated diphenyl ethers in the surface sediment of the East China Sea

Distribution of polybrominated diphenyl ethers in the surface sediment of the East China Sea

Impact of the Hoa Binh dam (Vietnam) on water and sediment budgets in the Red River basin and delta

Intra- versus inter-site macroscale variation in biogeochemical properties along a paddy soil chronosequence

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