Impacts of maricultural activities on characteristics of dissolved organic carbon and nutrients in a typical raft-culture area of the Yellow Sea, North China

The variable optical properties of chromophoric dissolved organic matter (CDOM) under the complicated dynamic marine environment make it difficult to establish a robust inversion algorithm for quantifying the dissolved organic carbon (DOC). To better understand the main factors affecting the relationship between the DOC and the CDOM when the Changjiang diluted water (CDW) interacts with the marine currents on the wide continental shelf, we measured the DOC concentration, the absorption, and the fluorescence spectra of the CDOM along the main axis and the northern boundary of the CDW. The sources of DOC and their impacts on the relationship between the optical properties of the DOC and CDOM are discussed. We reached the following conclusions: There are strong positive correlations between the absorptive and fluorescent properties of the DOC and the CDOM as a whole. The dilution of the terrestrial DOC carried by the CDW through mixing with saline sea water is the dominant mechanism controlling the characteristics of the optical properties of the CDOM. CDOM optical properties can be adopted to establish inversion models in retrieving DOC in Changjiang River Estuary. It is concluded that the introduction of extra DOC from different sources is the main factor causing the regional optical complexity leading to the bias of DOC estimation rather than removal mechanism. As whole, the input of polluted water from Huangpujiang River with abnormally high a(355) and Fs(355) will induce the overestimation of DOC. In the main axis of CDW, the impact from autochthonous DOC input to the correlation between DOC and CDOM can be neglected in comparison with conservative dilution procedure. The relationship between the DOC and the CDOM on the northern boundary of the CDW is more complicated, which can be attributed to the continuous input of terrestrial material from the Old Huanghe Delta by the Subei Coastal Current, the input of materials from the Yellow sea by the Yellow Sea Warm Western Coastal Current, and the input of materials from the Changjiang Basin by the CDW. The results of this study suggest that long-term observations of the regional variations in the DOM inputs from multiple sources in the interior of the CDW are essential, which is conducive to assess the degree of impact to the DOC estimation through the CDOM in the East China Sea.

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Characterizing the origins of dissolved organic carbon in coastal seawater using stable carbon isotope and light absorption characteristics

Biogeosciences ◽

10.5194/bg-18-1793-2021 ◽

2021 ◽

Vol 18 (5) ◽

pp. 1793-1801

Author(s):

Heejun Han ◽

Jeomshik Hwang ◽

Guebuem Kim

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Carbon Isotope ◽

Stable Carbon Isotope ◽

The Yellow Sea ◽

Bacterial Degradation ◽

Western Coast ◽

Stable Carbon ◽

Δ13c Values ◽

Lower Salinity

Abstract. In order to determine the origins of dissolved organic matter (DOM) occurring in the seawater of Sihwa Lake, we measured the stable carbon isotope ratios of dissolved organic carbon (DOC-δ13C) and the optical properties (absorbance and fluorescence) of DOM in two different seasons (March 2017 and September 2018). Sihwa Lake is enclosed by a dike along the western coast of South Korea, and the water is exchanged with the Yellow Sea twice a day through the sluice gates. The DOC concentrations were generally higher in lower-salinity waters in both periods, and excess of DOC was also observed in 2017 in high-salinity waters. Here, the excess DOC represents any DOC concentrations higher than those in the incoming open-ocean seawater. The excess DOC occurring in the lower-salinity waters originated mainly from marine sediments of tidal flats, based on the DOC-δ13C values (-20.7±1.2 ‰) and good correlations among the DOC, humic-like fluorescent DOM (FDOMH), and NH4+ concentrations. However, the origins of the excess DOC observed in 2017 appear to be from two different sources: one mainly from marine sources such as biological production based on the DOC-δ13C values (−19.1 ‰ to −20.5 ‰) and the other mainly from terrestrial sources by land–seawater interactions based on its depleted DOC-δ13C values (−21.5 ‰ to −27.8 ‰). This terrestrial DOM source observed in 2017 was likely associated with DOM on the reclaimed land, which experienced extended exposure to light and bacterial degradation as indicated by the higher spectral slope ratio (SR) of light absorbance and no concurrent increases in the FDOMH and NH4+ concentrations. Our study demonstrates that the combination of these biogeochemical tools can be a powerful tracer of DOM sources and characteristics in coastal environments.

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Levels and distribution of Dechlorane Plus in coastal sediments of the Yellow Sea, North China

Chemosphere ◽

10.1016/j.chemosphere.2011.02.011 ◽

2011 ◽

Vol 83 (7) ◽

pp. 984-990 ◽

Cited By ~ 40

Author(s):

Zhen Zhao ◽

Guangcai Zhong ◽

Axel Möller ◽

Zhiyong Xie ◽

Renate Sturm ◽

...

Keyword(s):

Yellow Sea ◽

North China ◽

Coastal Sediments ◽

The Yellow Sea ◽

Dechlorane Plus

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Major Components of Aerosols in North China: Desert Region and the Yellow Sea in the Spring and Summer of 1995 and 1996

Journal of the Atmospheric Sciences ◽

10.1175/1520-0469(2002)059<1515:mcoain>2.0.co;2 ◽

2002 ◽

Vol 59 (9) ◽

pp. 1515-1532 ◽

Cited By ~ 18

Author(s):

J. Zhang ◽

Y. Wu ◽

C. L. Liu ◽

Z. B. Shen ◽

Y. Zhang

Keyword(s):

Yellow Sea ◽

North China ◽

The Yellow Sea ◽

Desert Region

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Polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants (aBFRs) in sediments from four bays of the Yellow Sea, North China

Environmental Pollution ◽

10.1016/j.envpol.2016.02.042 ◽

2016 ◽

Vol 213 ◽

pp. 386-394 ◽

Cited By ~ 38

Author(s):

Xiaomei Zhen ◽

Jianhui Tang ◽

Zhiyong Xie ◽

Runmei Wang ◽

Guopei Huang ◽

...

Keyword(s):

Yellow Sea ◽

Polybrominated Diphenyl Ethers ◽

Flame Retardants ◽

North China ◽

Brominated Flame Retardants ◽

The Yellow Sea ◽

Diphenyl Ethers

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A paleoenvironmental reconstruction of the last 15 000 cal yr BP via Yellow Sea sediments using biomarkers and isotopic composition of organic matter

Climate of the Past Discussions ◽

10.5194/cpd-10-1527-2014 ◽

2014 ◽

Vol 10 (2) ◽

pp. 1527-1565 ◽

Cited By ~ 1

Author(s):

A. O. Badejo ◽

B.-H. Choi ◽

H.-G. Cho ◽

H.-I. Yi ◽

K.-H. Shin

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Yellow Sea ◽

Climatic Conditions ◽

Plant Distribution ◽

The Yellow Sea ◽

Paleoenvironmental Reconstruction ◽

Glacial Period ◽

The Holocene ◽

Glacial Periods

Abstract. This study is the first reconstruction of the paleoenvironment and paleovegetation during the Holocene (interglacial) and glacial periods of the Yellow Sea. We report the carbon isotopic and biomarker (n-alkane and alkenone) compositions of organic matter from Yellow Sea sediments since the glacial period. Our findings show that the variability of the East Asian Monsoon (EAM) affected the sedimentary profile of total organic carbon (TOC), the stable isotopes of bulk organic carbon (δ13Corg), the atomic ratio of carbon and nitrogen (C/N ratio), and biomarker content. The sedimentary δ13Corg profile along the core exhibited more negative δ13Corg values under cold/dry climatic conditions (Younger and Oldest Dryas). The carbon preference index (CPI), the pristane to phytane ratio (Pr/Ph) and the pristane to n-C17 ratio (Pr/n-C17) were used to determine the early stages of diagenesis along the sediment core. Two climatic conditions were distinguished (warm/humid and cold/dry) based on an n-alkane proxy, and the observed changes in δ13C of individual n-alkane (δ13CALK) between the Holocene and glacial periods were attributed to changes in plant distribution/type. Clear differences were not found in the calculated alkenone sea surface temperature (SST) between those of the Holocene and glacial periods. This anomaly during the glacial period might be attributed to the seasonal water mass distribution in the Yellow Sea or a seasonal shift in the timing of maximum alkenone production as well as the Bølling/Allerød interstadial.

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