Sediment records of environmental changes in the south end of the Zhejiang-Fujian coastal mud area during the past 100 years

Wang, Linmiao; Li, Guangxue; Gao, Fei; Liu, Ling; Liu, Yong; Dada, Olusegun A.

doi:10.1007/s00343-014-3220-5

Cited by 10 publications

(2 citation statements)

References 25 publications

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“…In the past decades, previous studies about mud deposits in the East China Sea shelf mainly focused on sedimentary environment and climatic changes utilizing sedimentary records (e.g., Demaster et al, 1985;Guo et al, 2003;Sun et al, 2008;Liu et al, 2009;Wang et al, 2012;Zhu et al, 2012;Wang et al, 2014). Recent study of the impact of the Three Gorges Dam (TGD) on subsequent sediment dispersal in the East China Sea reveals that the modern riverine muds are replaced seawards by older sands due to erosion driven by the significant decrease of the sediment supply from the Yangtze River (Luo et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Three Gorges Dam controls sediment coarsening of the mud patch on the inner East China Sea shelf

Miao

Chu

2016

J. Ocean Univ. China

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The well-known Three Gorges Dam (TGD) within the Yangtze catchment launched its operation in 2003. The effect of the TGD operation on the sediment size on the East China Sea shelf is rarely known. High resolution (0.5 cm sampling) grain size analysis and 137 Cs and 210 Pb dating of the DH8-1 core were conducted with core collected from the distal part of a main sink for the modern Yangtze sediment entering the sea, the Min-Zhe Coastal Mud Deposits (MZCMD) on the inner East China Sea shelf. The 137 Cs dating results show that the core DH8-1 formed during 1946-2012 with a mean deposition rate of 0.65 cm yr −1 , indicating that the 0.5 cm sampling for grain size analysis in this local area could reflect environmental changes generally on a one-year time scale. The mean grain size of DH8-1 core sediment that deposited after 2003 is significantly larger than that deposited during 1988-2002. After ruling out other possible factors, we infer that the sediment coarsening of DH8-1 core after 2003 is attributed to the TGD operation which causes the erosion of the Yangtze subaqueous delta. Specifically, the TGD operation significantly intensifies the declining trend of the Yangtze sediment loads to the sea despite no decreased water discharge, which results in extensive erosion of the Yangtze subaqueous delta. The relatively coarse sediment of the subaqueous delta is eroded and resuspended by ocean dynamics and then transported by coastal current, finally depositing on the MZCMD area. In addition, the general sediment fining of core DH8-1 that deposited during 1988-2002, comparing with 1946-1987, is mainly caused by dam construction and soil and water conservation within the Yangtze catchment. Our findings are helpful for better understanding the effects of such a huge dam as the TGD on a sediment sink like the MZCMD of such a large river as the Yangtze River.

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Section: Introductionmentioning

confidence: 99%

Three Gorges Dam controls sediment coarsening of the mud patch on the inner East China Sea shelf

Miao

Chu

2016

J. Ocean Univ. China

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“…Moreover, more than 50,000 dams (including dams on farmers' fields and dams higher than 100 m) have been constructed in the Changjiang catchment since the 1950s, which has led to significant decreases of riverine sediment discharge and changes in the aquatic ecosystems (Yang et al, 2005(Yang et al, , 2011bZhang et al, 2014). Also, there has recently been an increase in the number of studies on historical reconstruction of eco-environmental evolution of the Changjiang Estuary and adjacent ECS shelf, including the history of eutrophication, phytoplankton community changes, hypoxia, Changjiang flooding and drought events, and the response to monsoons (Hu et al, 2014;Jiang et al, 2014;Li et al, 2011Li et al, , 2013Liu et al, 2015;Wang et al, 2014aWang et al, , 2014bZhao et al, 2012). However, little remains known about the relative importance of anthropogenic activities and regional climate variability on eco-environmental evolution in different areas of the Changjiang Estuary and adjacent ECS shelf.…”

Section: Introductionmentioning

confidence: 99%

Historical reconstruction of organic carbon inputs to the East China Sea inner shelf: Implications for anthropogenic activities and regional climate variability

Yao

Bianchi

et al. 2015

The Holocene

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A gravity core collected from the East China Sea (ECS) inner shelf was analyzed for elemental and stable isotopic composition, lignin-phenols, and sedimentary pigments to investigate changes of organic carbon (OC) inputs during the past two centuries. In particular, we examined the linkages between terrestrial and marine OC inputs with climate variability and anthropogenic activities. The decrease of terrestrial OC contribution (from 41% to 28%) and increasing diagenetic indices of lignin-phenols (P/(S + V): from 0.12 to 0.22; 3,5-Bd/V: from 0.03 to 0.09) after the 1970s were possibly attributed to intensified deforestation, dam construction, and channel erosion. Lignin content (Λ 8 ) ranged from 0.35 mg/100 mg OC to 6.92 mg/100 mg OC, with lower values corresponding to the worst flooding events in the Changjiang watershed and weaker East Asian Winter Monsoon (EAWM), while higher Λ 8 was more correlated to the strengthening of EAWM. This indicates that terrestrial inputs to Zhe-Min Coast are different from those in Changjiang Estuary during flooding events and strongly linked with regional climate variability. The total contents of sedimentary chloropigments (i.e. pheophorbide-a, pheophytin-a, pyropheophytin-a, sterol chlorin esters, and carotenol chlorin esters) ranged from 663.4 to 74.9 nmol g −1 OC, and decreased exponentially downwards. Sedimentary chloropigments that were used to document historical change of phytoplankton biomass were decoupled with historical changes of Changjiang riverine nutrient inputs but corresponded well to the fluctuation of regional climate variability. Higher phytoplankton biomasses usually were observed during positive phases of Pacific Decadal Oscillation (PDO) and/or warm El Niño-Southern Oscillation (ENSO) events, and lower algal biomass usually corresponded to the negative phase of PDO and/or cold ENSO events.

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Heavy Minerals in Shelf Sediments off Fujian-Zhejiang Coast of the East China Sea: Their Provenance and Geological Application

Han

Zhang

et al. 2018

J. Ocean Univ. China

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Sediment records of environmental changes in the south end of the Zhejiang-Fujian coastal mud area during the past 100 years

Cited by 10 publications

References 25 publications

Three Gorges Dam controls sediment coarsening of the mud patch on the inner East China Sea shelf

Three Gorges Dam controls sediment coarsening of the mud patch on the inner East China Sea shelf

Historical reconstruction of organic carbon inputs to the East China Sea inner shelf: Implications for anthropogenic activities and regional climate variability

Heavy Minerals in Shelf Sediments off Fujian-Zhejiang Coast of the East China Sea: Their Provenance and Geological Application

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