Absorption properties of chromophoric dissolved organic matter (CDOM) in the East China Sea and the waters off eastern Taiwan

Zhou, Fengxia; Gao, Xuelu; Song, Jinming; Chen, Chen‐Tung Arthur; Yuan, Huamao; Xing, Qianguo

doi:10.1016/j.csr.2018.03.005

Cited by 14 publications

(14 citation statements)

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“…Furthermore, the relative increase of a CDOM (355) values (150-180%) was much larger than that of DOC (60-70%), indicating that autochthonous sources contribute more to the CDOM pool than to transparent DOM pool (see section Bottom Hypoxia and AOU for detailed information). The values of S 275−295 are comparable with those observed in the Chinese coastal seas (Yang et al, 2016;Zhou et al, 2018). The average of SUVA 254 closely matches the average value derived from oceanic water (1.70 L mgC −1 m −1 ) and falls below those derived from fluvial environments (Massicotte et al, 2017).…”

Section: In Situ Productionsupporting

confidence: 72%

“…The [DOC] in March is comparable with that in the Yellow Sea in spring (215 ± 106 µmol L −1 ), and the results in August are higher than that in the Yellow Sea in autumn (267 ± 117 µmol L −1 , Liu et al, 2015). The a CDOM (355) values fall within the range in the Yellow Sea and East China (0.023-2.170 m −1 , Guo et al, 2007;Zhou et al, 2018) with the values in August at the higher end of this range. The temporal and spatial variations of a CDOM (355) values, i.e., a faster increase in the surface layer than in the bottom layer from March to August, were in line with those of DOC.…”

Section: In Situ Productionmentioning

confidence: 58%

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Origin and Dynamics of Dissolved Organic Matter in a Mariculture Area Suffering From Summertime Hypoxia and Acidification

et al. 2018

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Based on six cruises from March to September in 2016, we investigated monthly distributions of dissolved organic matter (DOM) and ancillary water chemistry parameters in a mariculture area in the Northern Yellow Sea, where summertime hypoxia and seawater acidification were observed. The most severe oxygen depletion (hypoxia covered approximately one-third of the aquaculture area) and the largest pH decrease (8.07 ± 0.05 in surface layer vs. 7.66 ± 0.07 in bottom layer) were revealed in August. Concentration of dissolved organic carbon (DOC) and the absorption properties of chromophoric DOM (CDOM) were used to characterize DOM. Results showed that DOM mainly originated from marine in situ processes. In March, a DOM pool with the lowest DOC concentration of 211 ± 23 µmol L −1 and nearly uniform optical characteristics were presented in the well-mixed water column. In August, however, DOC increased to 361 ± 29 µmol L −1 in the surface layer and 342 ± 25 µmol L −1 in the bottom layer. Two non-linear relationships between the absorption coefficient at 355 nm [a CDOM (355)] and the absorption spectral slope over 275-295 nm (S 275−295) were revealed. According to modeling results, the non-linear relationships were mostly caused by the conservative mixing of a refractory CDOM pool with a freshly produced CDOM pool. Apparent oxygen utilization in August was positively related to DOC, but not to a CDOM (355) and S 275−295 , presumably due to multiple sources of CDOM in bottom waters. Both a CDOM (355) and S 275−295 respond largely to decreasing pH; however, they would be less affected by ocean acidification since this process leads to a limited pH decline.

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Section: In Situ Productionsupporting

confidence: 72%

Section: In Situ Productionmentioning

confidence: 58%

Origin and Dynamics of Dissolved Organic Matter in a Mariculture Area Suffering From Summertime Hypoxia and Acidification

et al. 2018

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“…The average DOM concentration of each lake region revealed the order of northwestern lake region > northern lake region > southwestern lake region > northeastern lake region > southern lake region. The abundance of CDOM is usually represented by the absorption coefficient at a representative wavelength (e.g., 350, 280, or 254 nm) [46][47][48]. The a 280 values of the whole lake ranged from 6.63 to 29.87 m −1 , with a mean value of 12.03 ± 4.87 m −1 , and showed an increasing trend from southeast to northwest (Figure 2b).…”

Section: Spatial Distributions Of Dom and Cdom In Overlying Watermentioning

confidence: 99%

Characteristics of Dissolved Organic Matter and Its Role in Lake Eutrophication at the Early Stage of Algal Blooms—A Case Study of Lake Taihu, China

Wang

Chen

et al. 2020

Water

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Decaying algal blooms in eutrophic lakes can introduce organic matter into the water and change nutrient concentrations in the water column. The spatial distribution and composition characteristics, sources, and contribution to eutrophication of dissolved organic matter (DOM) in the overlying water of Lake Taihu, a typical eutrophic lake in China, were analyzed by ultraviolet–visible spectra and three-dimensional fluorescence excitation–emission matrix spectra combined with the statistical decomposition technique, parallel factor analysis. The concentration of DOM was represented by dissolved organic carbon (DOC), and DOC in overlying water of Lake Taihu was 2.86–11.83 mg/L. The colored DOM (CDOM) was characterized by an absorption coefficient at 280 nm (a280) and 350 nm (a350), which were 6.63–29.87 and 1.84–10.41 m−1, respectively. These values showed an increasing trend from southeast to northwest, and the high values were concentrated in the northwest and northern lake areas. The parallel factor analysis (PARAFAC) identified two protein-like (C1: tyrosine-like and C2: tryptophan-like) and one humic-like (C3: humic acid and fulvic acid) fluorescence components for fluorescent DOM (FDOM). The most dominant components were protein-like components (C1 + C2), whose fluorescence intensity contributed 87.55% ± 3.39% to the total fluorescence intensity (Ft) of FDOM (3.38 R.U.). The mean value of the fluorescence index (FI) and index of recent autochthonous contribution (BIX) of DOM was 1.77 and 0.92, and DOC, a280 and fluorescence intensities of FDOM components were all significantly and positively correlated with chl. a, indicating that DOM, CDOM, and FDOM were all mainly derived from algal activities and metabolites. The average humification index of the DOM was 0.66, which indicated a low humification degree. The protein-like DOM was correlated with DON and DOP, and might make great contributions to the continuous occurrence of algal blooms.

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“…Because the Yellow Sea is greatly affected by terrestrial importing, the molecular weight of CDOM contained in the seawater is larger. Therefore, the diffusion of these CDOM macromolecules in the vertical direction will make the molecular weight of CDOM show a tendency to decrease with the increasing depth [41]. The molecular weight of CDOM is reflected by the spectral absorption slope S in the absorption equation.…”

Section: Real Water Simulationmentioning

confidence: 99%

Detection of Chlorophyll a and CDOM Absorption Coefficient with a Dual-Wavelength Oceanic Lidar: Wavelength Optimization Method

et al. 2020

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To overcome the retrieval problems in complex water, dual working wavelengths are required instead of a single wavelength in oceanic lidar. The wavelength optimization method of detecting chlorophyll a and Colored Dissolved Organic Matter (CDOM) absorption coefficient with a dual-wavelength lidar is studied in this paper. The inversion methods of chlorophyll a and CDOM absorption are developed based on the water absorption characteristics, which then lead to the inversion error equations. The effects of the wavelength on the inversion errors are studied. For the case in which λ1 and λ2 are both random, the errors are relatively small when λ1 is chosen between 420 and 560 nm and λ2 is selected under 420 nm. For the case in which λ1 is fixed at 532 nm, the errors generally decrease with decreasing λ2, with minimums around 300 and 356–360 nm under different water conditions. The wavelength optimization method discussed in this paper and the penetration depth criterion will be beneficial to the design of the dual-wavelength lidar.

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Absorption properties of chromophoric dissolved organic matter (CDOM) in the East China Sea and the waters off eastern Taiwan

Cited by 14 publications

References 93 publications

Origin and Dynamics of Dissolved Organic Matter in a Mariculture Area Suffering From Summertime Hypoxia and Acidification

Origin and Dynamics of Dissolved Organic Matter in a Mariculture Area Suffering From Summertime Hypoxia and Acidification

Characteristics of Dissolved Organic Matter and Its Role in Lake Eutrophication at the Early Stage of Algal Blooms—A Case Study of Lake Taihu, China

Detection of Chlorophyll a and CDOM Absorption Coefficient with a Dual-Wavelength Oceanic Lidar: Wavelength Optimization Method

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