Coupling between physical processes and biogeochemistry of suspended particles over the inner shelf mud in the East China Sea

Liu, James T.; Lee, Jay; Yang, Rick J.; Du, Xiaoqin; Li, Anchun; Lin, Yu‐Shih; Su, Chih-Chieh; Tao, Shuqin

doi:10.1016/j.margeo.2021.106657

Cited by 7 publications

(11 citation statements)

References 112 publications

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“…Inevitably, the Changjiang River source materials carried by the CDW will have a significant impact on the physical, chemical, and biological processes in the marine environment of the ECS. Previous studies have focused mainly on the impact of the Changjiang River source material brought by the downcoast ZFCC in winter on the inner shelf of the ECS (Deng et al., 2017; J. T. Liu et al., 2018; Q. Liu et al., 2018; Liu et al., 2021 and reference therein), often ignoring the role of typhoons in summer. Statistics show that, an average of 2 typhoons affected the Changjiang River Estuary each year since 1961, and their intensities (mainly reflected in the magnitude of wind speed) have shown an upward trend, especially since the 1990s (Figure S4 in Supporting Information ).…”

Section: Discussionmentioning

confidence: 99%

Downcoast Redistribution of Changjiang Diluted Water Due To Typhoon Chan‐Hom (2015)

Lin

Cong

et al. 2023

JGR Oceans

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Typhoons are known to substantially influence the coastal circulation and the associated biogeochemical processes. The transport of Changjiang diluted water (CDW), an important source to the coastal current in the East China Sea (ECS), varies markedly under the influence of typhoons. This study quantitively details the downcoast transport of CDW driven by Typhoon Chan‐Hom in the summer of 2015. Salinity measurements 3 days after the typhoon's passage showed the presence of a large volume of low‐salinity water, up to 70‐km wide and 20‐m thick along the Zhejiang‐Fujian coastal area with an estimated freshwater volume of 3.7 × 1010 m3. A three‐endmember mixing model shows that the CDW's contribution to the study area's surface waters (<10 m) immediately after the typhoon was as high as 40% (average 32%), much greater than the contribution under normal summer conditions of 8% (average 3%). The vast spreading of CDW along the Zhejiang‐Fujian coast created a strong stratification in the upper water column that limited the diffusion of CDW in the study area. The calculated and observed results suggest that these abnormal low‐salinity water could stay in the study area for 13–21 days. Additional nutrients in the CDW elevated the Chlorophyll‐a concentration in the upper water column (mean 3.74 mg m−3) and produced large amount of particulate organic carbon.

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Section: Discussionmentioning

confidence: 99%

Downcoast Redistribution of Changjiang Diluted Water Due To Typhoon Chan‐Hom (2015)

Lin

Cong

et al. 2023

JGR Oceans

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“…RiOMars systems (river-dominated ocean margins; McKee et al, 2004) receive a variety of terrestrial and marine substances delivered by rivers or coastal currents (Mittelstaedt, 1991;Lacan and Jeandel, 2005;Jeandel, 2016;Liu et al, 2021). The diversity of particles in these systems includes bio-aggregates or flocs on the Amazon shelf (Gibbs, 1977;Nittrouer and DeMaster, 1996;Berhane et al, 1997), terrestrially-derived organic carbon from the Mississippi River (Bianchi et al, 2007), and lithogenic particles delivered from the Changjiang (Yangtze) River (Jiang et al, 2015;Liu et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

The contrast in suspended particle dynamics at surface and near bottom on the river-dominated northern South China Sea shelf in summer: implication on physics and biogeochemistry coupling

Lee¹,

Liu²,

Lin³

et al. 2023

Front. Mar. Sci.

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To understand the process-response relations among physical forcing and biogeochemical properties of suspended particles (SPs) in the river-dominated northern South China Sea shelf, a 5-day shipboard observation was conducted at a fixed location on the dispersal pathway of the Zhujiang (Pearl) River plume (ZRP) in the summer of 2016. Instrumented moorings were deployed near the sampling site to record the flow and wave fields every 10 minutes. Hydrographic properties were measured hourly to identify different water masses. Water and SPs samples at the surface (3 m) and near the bottom (3 m above the bed) were taken every 3 h for the analyses of nutrients, chlorophyll-a (Chl-a), and particulate organic matter (POM including POC, PN, and δ13CPOC). Meanwhile, the grain-size composition of SPs and seafloor sediment were also analyzed. Results showed that monsoon winds drove cold upwelling and ZRP waters at the surface. Both the upwelling and ZRP regimes contained newly produced marine phytoplankton based on low POC/Chl-a ratio (PC ratio) and enriched δ13CPOC. However, SPs in the ZRP regime were smaller (<153 µm), having denser particle bulk density, and less enriched δ13CPOC, indicating different bio-communities from the upwelling regime. EOF analysis of the surface data suggested that mixing processes and the dispersal of the ZRP regime were mainly controlled by far-field storm winds, tidal modulation, and strength of mixing. On the other hand, a bottom nepheloid layer (BNL) was observed, mainly consisting of SPs<63 μm with higher bulk density than SPs at the surface. POM in the BNL was degraded and δ13CPOC-depleted according to the PC ratio and δ13CPOC. EOF analysis of the near-bottom data indicated that the dominant physical processes influencing the biogeochemical properties of SPs in the BNL were jointly the upwelling-associated lateral transport (first order) and tide-related resuspension (second order). Our study identified the contrast between the surface and near-bottom regimes with the coupling patterns among physical forcing and physiochemical properties of SPs using good constraints on particle dynamics and particle sources.

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“…From the source-to-sink (S2S) perspective, this conduit is subject to seasonal monsoons and episodic deliveries of OM from several contrasting sources (Yang et al, 2021). Suspended particles exported from these rivers are transported by monsoonregulated currents: the southbound ZMCC (Liu et al, 2021a) and the northbound South China SCSWC into the TS (Yang et al, 2021). ZMCC brings cold water mass and SCSWC brings warm water mass to the TS (Yang et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Deciphering organic matter distribution by source-specific biomarkers in the shallow Taiwan Strait from a source-to-sink perspective

et al. 2022

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Sedimentary organic matter (OM) in coastal systems is inherently diverse, often with multiple particulate sources and transport histories. The Taiwan Strait (TS) is a typical shallow conduit region, linking the East and South China Seas. Strong ocean currents, coastal upwellings, distal large rivers, and proximal small mountainous rivers all influence the distribution of OM in the TS. We investigated the covarying patterns in the distribution of gain size classes of sand, silt, and clay; terrestrial-sourced biomarkers (n-C27+29+31 alkanes, n-C26+28+30 fatty acids (FAs), and n-C28+30+32 alkanols); marine-sourced biomarkers (phytoplankton-derived alkenones, brassicasterol, dinosterol, and zooplankton-derived cholesterol) in sea floor sediment; indicator satellite-derived primary production (Chl-a); and water-mass indicator (sea surface temperature, SST). We used an empirical orthogonal/eigen function (EOF) analysis to distinguish the influence of four hypothetical sources that entered the TS through the north, south, west, and east boundaries. Results show that input sources from the south-bound ZMCC (Zhejiang-Fujian Coastal Current) and north-bound SCSWC (South China Sea Warm Current) had the dominant influence on the OM distributions buried in the TS. Input sources via river plumes on lateral boundaries and upwellings in the TS were the secondary factors that affected the sedimentary OM distribution. Within this source-to-sink system of multiple sources and transport processes, silt and clay were the major carriers of the OM signals. Terrestrial biomarkers and primary production (Chl-a) were associated with the two major current systems and river plumes along the edge of TS. Marine biomarkers were associated with upwellings in the interior of the TS. Our finding points out that the physical systems of ocean currents, river plumes, and upwelling not only determine the distributions of biomarkers in the TS but also determine the diversity of OM in the TS.

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Coupling between physical processes and biogeochemistry of suspended particles over the inner shelf mud in the East China Sea

Cited by 7 publications

References 112 publications

Downcoast Redistribution of Changjiang Diluted Water Due To Typhoon Chan‐Hom (2015)

Downcoast Redistribution of Changjiang Diluted Water Due To Typhoon Chan‐Hom (2015)

The contrast in suspended particle dynamics at surface and near bottom on the river-dominated northern South China Sea shelf in summer: implication on physics and biogeochemistry coupling

Deciphering organic matter distribution by source-specific biomarkers in the shallow Taiwan Strait from a source-to-sink perspective

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