Distribution of Humic Fluorescent Dissolved Organic Matter in Lake Shihwa: the Role of the Redox Condition

Kim, Jeonghyun; Kim, Tae-Hoon

doi:10.1007/s12237-018-00491-0

Cited by 7 publications

(11 citation statements)

References 57 publications

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“…3). The concentrations of FDOM H and FDOM M were generally higher in the upstream stations (Kim and Kim, 2018) (Fig. 3).…”

mentioning

confidence: 91%

“…CC BY 4.0 License. organic matter (Coble, 2007;Kim and Kim, 2016;Kim and Kim, 2018). The major fraction of CDOM, which is fluorescent after absorbing energy, is referred to as fluorescent DOM (FDOM) (Coble, 2007;Kim and Kim, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Rivers are known as the major source of the humic-like FDOM (FDOM H ) in coastal oceans (Stedmon and Nelson, 2015;Kim and Kim, 2016), while aerobic microbial remineralization of sinking organic matter is the major source of FDOM H in deep oceans (Jørgensen et al, 2011;Catalá et al, 2015;Kim and Kim, 2016). Recently, the anaerobic process in the bottom sediment has also been 35 suggested as an important source of FDOM H in coastal marine environment (Kim and Kim, 2018). On the other hand, Kim and Kim (2016) showed that the anaerobic production in the bottom sediments of the deep East Sea (Japan Sea) accounted for about 10% of the total production of FDOM H in the deep water column.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, Kim and Kim (2016) showed that the anaerobic production in the bottom sediments of the deep East Sea (Japan Sea) accounted for about 10% of the total production of FDOM H in the deep water column. In order to obtain such information on FDOM, an excitation-emission matrix (EEM) spectroscopy method combined with a parallel factor analysis (PARAFAC) model has been employed (Coble, 2007;Kim and Kim, 2016;Kim and Kim 2018). In addition, the absorption spectral slope ratio (S R ) 40 can be used as an indicator of molecular weight, source, and photochemistry of DOM since the absorption spectra and spectral parameters for CDOM are largely dependent on its source and photochemical processes (Helms et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…In this study, we used DOC-δ 13 C combined with FDOM and S R values to characterize different sources of DOM in Sihwa, Korea. This region is known for one of the most dynamic coastal settings in terms of salinity changes, hypoxia, metal 55 pollution, and eutrophication (Kim et al, 2009;Ra et al, 2011;Lee et al, 2014;Kim and Kim, 2014;Lee et al, 2017;Kim and Kim, 2018).…”

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confidence: 99%

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

Han¹,

Hwang²,

Kim³

2020

Preprint

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Abstract. In order to determine the origins of dissolved organic matter (DOM) occurring in coastal seawater of the Sihwa Lake, South Korea, which is semi-enclosed by a dyke, we measured the stable carbon isotopic ratio of dissolved organic carbon (DOC-δ13C) and optical properties (absorbance and fluorescence) of the DOM in two different seasons (March 2017 and September 2018). The concentrations of DOC were generally higher in lower-salinity waters in both periods, while a significant excess of DOC was observed in 2017 in the same salinity range. The main source of DOC, dependent on salinity, was found to be from marine sediments in the freshwater-seawater mixing zone rather than from terrestrial sources based on the DOC-δ13C values (−20.7±1.2 ‰) and good correlations among DOC, humic-like fluorescent DOM (FDOMH), and NH4+ concentrations. However, the excess DOC observed in 2017 seems to originate from terrestrial sources by direct land-seawater interactions rather than from in-situ biological production, considering the lower DOC-δ13C values (−27.8 ‰ to −22.6 ‰) and higher spectral slope ratio (SR) of light absorbance, without increases in FDOMH and NH4+ concentrations. This terrestrial DOM source could have been exposed to light and bacterial degradation for a long time, resulting in nonfluorescent and low-molecular-weight DOM, as this study area is surrounded by the reclaimed land. Our results suggest that the combination of these biogeochemical tools can be a powerful tracer of coastal DOM sources.

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“…3). The concentrations of FDOM H and FDOM M were generally higher in the upstream stations (Kim and Kim, 2018) (Fig. 3).…”

mentioning

confidence: 91%