scholarly journals Remotely observed variations of reservoir low concentration chromophoric dissolved organic matter and its response to upstream hydrological and meteorological conditions using sentinel-2 imagery and gradient boosting regression tree

2020 ◽  
Author(s):  
Zeliang Zhang ◽  
Weining Zhu ◽  
Jiang Chen ◽  
Qian Cheng
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Environmental Factors ◽  
Dissolved Organic Matter ◽  
Regression Tree ◽  
Chromophoric Dissolved Organic Matter ◽  
Gradient Boosting ◽  
Spatiotemporal Information ◽  
Sentinel 2A ◽  
Sentinel 2

Abstract Freshwater lakes are facing increasingly serious water quality problems. Remote sensing techniques are effective tools for monitoring spatiotemporal information of chromophoric dissolved organic matter (CDOM), a biochemical indicator for water quality. In this study, the Gradient Boosting Regressing Tree (GBRT) model and Sentinel-2A/B image were combined to estimate low CDOM concentrations (0.003 m−1 < aCDOM(440) <1.787 m−1) in Xin'anjiang Reservoir, an important drinking water resource in Zhejiang Province, China, providing the CDOM distributions and dynamics with high spatial (10 m) and temporal (5 days) resolutions. The possible environmental factors that may affect CDOM spatiotemporal patterns and dynamics were analyzed using Sentinel-2 image-observed data in 2018. Results showed that CDOM in the reservoir exhibited a clear increased gradient from its transition and lacustrine zones to the riverine zones, indicating that the rivers carried a substantial load of organic matter to the lake. The precipitation may increase CDOM concentrations but it has a delay effect, while it may also shortly decrease CDOM concentrations due to the rainwater dilution. We also found that the correlations between CDOM and water temperature, air pressure, and wind speed were very low, indicating that these factors may not have significant impacts on CDOM variations in the reservoir. This study demonstrated that the GBRT model and Sentinel-2 imagery have the potential to accurately monitor CDOM spatiotemporal variations in reservoirs with low CDOM concentrations, which advancing our understanding on the relations between the dissolved organic matter and its coupling environmental factors in river-reservoir systems.

scholarly journals Influence of environmental factors on spectral characteristic of chromophoric dissolved organic matter (CDOM) in Inner Mongolia Plateau, China

2015 ◽  
Vol 12 (6) ◽  
pp. 5895-5929 ◽  
Author(s):  
Z. D. Wen ◽  
K. S. Song ◽  
Y. Zhao ◽  
J. Du ◽  
J. H. Ma
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Environmental Factors ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Light Absorption ◽  
Vascular Plant ◽  
Spectral Characteristics ◽  
Chromophoric Dissolved Organic Matter ◽  
River Waters

Abstract. Spectral characteristics of chromophoric dissolved organic matter (CDOM) were examined in conjunction with environmental factors in the waters of 22 rivers and 26 terminal waters in Hulun Buir plateau, northeast China. Dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorous (TP) were significantly higher in terminal waters than rivers waters (p < 0.01). Principal component analysis (PCA) indicated that non-water light absorption and anthropogenic nutrient disturbances might be the causes of the diversity of water quality parameters in Hulun Buir plateau. CDOM absorption in river waters was significantly lower than terminal waters (p < 0.01). Analysis of ratio of absorption at 250–365 nm (E250 : 365), specific UV absorbance (SUVA254), and spectral slope ratio (Sr) indicated that CDOM in river waters had higher aromaticity, molecular weight, and vascular plant contribution than in terminal waters. Furthermore, results showed that DOC concentration, CDOM light absorption, and the proportion of autochthonous sources of CDOM in plateau waters were all higher than in other freshwater rivers reported in the literature. The strong evapoconcentration, intense ultraviolet irradiance and landscape features of Hulun Buir plateau may be responsible for the above phenomenon. Redundancy analysis (RDA) indicated that the environmental variables TSM, TN, and EC had a strong correlation with light absorption characteristics, followed by TDS and chlorophyll a. In most sampling locations, CDOM was the dominant non-water light-absorbing substance. Light absorption by non-algal particles often exceeded that by phytoplankton in the plateau waters. Study of these optical-physicochemical correlations is helpful in the evaluation of the potential influence of water quality factors on non-water light absorption in cold plateau water environments. And the study on organic carbon in plateau lakes had a vital contribution to global carbon balance estimation.

scholarly journals Sea cucumbers reduce chromophoric dissolved organic matter in aquaculture tanks

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4344 ◽  
Author(s):  
Seyed Mohammad Sadeghi-Nassaj ◽  
Teresa S. Catalá ◽  
Pedro A. Álvarez ◽  
Isabel Reche
Keyword(s):  
Water Quality ◽  
Molecular Weight ◽  
Time Series ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Chromophoric Dissolved Organic Matter ◽  
Low Molecular Weight ◽  
Optical Parameters ◽  
Absorption Coefficients ◽  
Sea Cucumbers

Background Mono-specific aquaculture effluents contain high concentrations of nutrients and organic matter, which affect negatively the water quality of the recipient ecosystems. A fundamental feature of water quality is its transparency. The fraction of dissolved organic matter that absorbs light is named chromophoric dissolved organic matter (CDOM). A sustainable alternative to mono-specific aquaculture is the multitrophic aquaculture that includes species trophically complementary named “extractive” species that uptake the waste byproducts. Sea cucumbers are recognized as efficient extractive species due to the consumption of particulate organic matter (POM). However, the effects of sea cucumbers on CDOM are still unknown. Methods During more than one year, we monitored CDOM in two big-volume tanks with different trophic structure. One of the tanks (−holothurian) only contained around 810 individuals of Anemonia sulcata, whereas the other tank (+holothurian) also included 90 individuals of Holothuria tubulosa and Holothuria forskali. We routinely analyzed CDOM absorption spectra and determined quantitative (absorption coefficients at 325 nm) and qualitative (spectral slopes) optical parameters in the inlet waters, within the tanks, and in their corresponding effluents. To confirm the time-series results, we also performed three experiments. Each experiment consisted of two treatments: +holothurians (+H) and –holothurians (−H). We set up three +H tanks with 80 individuals of A. sulcata and 10 individuals of H. tubulosa in each tank and four –H tanks that contained only 80 individuals of A. sulcata. Results In the time-series, absorption coefficients at 325 nm (a325) and spectral slopes from 275 to 295 nm (S275−295) were significantly lower in the effluent of the +holothurian tank (average: 0.33 m−1 and 16 µm−1, respectively) than in the effluent of the −holothurian tank (average: 0.69 m−1 and 34 µm−1, respectively), the former being similar to those found in the inlet waters (average: 0.32 m−1 and 22 µm−1, respectively). This reduction in the absorption of the dissolved organic matter appears to be mediated by the POM consumption by holothurians. The experiments confirmed the results observed in the time-series. The a325 and S275−295 values were significantly lower in the treatment with holothurians than in the treatment without holothurians indicating a reduction in the concentration of chromophoric organic compounds, particularly of low molecular weight. Discussion Consequently, sea cucumbers appear to improve water transparency in aquaculture tanks. The underlying mechanism of this improvement might be related to the POM consumption by holothurians, which reduces the concentration of CDOM derived from POM disaggregation or to the direct assimilation of dissolved compounds of low molecular weight as chromophoric amino acids.

Hydraulic connectivity and evaporation control the water quality and sources of chromophoric dissolved organic matter in Lake Bosten in arid northwest China

Chemosphere ◽  
2017 ◽  
Vol 188 ◽  
pp. 608-617 ◽  
Author(s):  
Lei Zhou ◽  
Yongqiang Zhou ◽  
Yang Hu ◽  
Jian Cai ◽  
Chengrong Bai ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Northwest China ◽  
Chromophoric Dissolved Organic Matter ◽  
Arid Northwest China

scholarly journals Influence of environmental factors on spectral characteristics of chromophoric dissolved organic matter (CDOM) in Inner Mongolia Plateau, China

2016 ◽  
Vol 20 (2) ◽  
pp. 787-801 ◽  
Author(s):  
Z. D. Wen ◽  
K. S. Song ◽  
Y. Zhao ◽  
J. Du ◽  
J. H. Ma
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Environmental Factors ◽  
Light Absorption ◽  
Spectral Characteristics ◽  
Chromophoric Dissolved Organic Matter ◽  
Quality Factors ◽  
River Waters ◽  
Terminal Lakes ◽  
Doc Concentration

Abstract. Spectral characteristics of chromophoric dissolved organic matter (CDOM) were examined in conjunction with environmental factors in the waters of rivers and terminal lakes within the Hulun Buir plateau, northeast China. Dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorous (TP) were significantly higher in terminal lakes than rivers waters (p  <  0.01). Principal component analysis (PCA) indicated that non-water light absorption and anthropogenic nutrient disturbances were the likely causes of the diversity of water quality parameters. CDOM absorption in river waters was significantly lower than terminal lakes. Analysis of the ratio of absorption at 250 to 365 nm (E250 : 365), specific ultraviolet (UV) absorbance (SUVA254), and the spectral slope ratio (Sr) indicated that CDOM in river waters had higher aromaticity, molecular weight, and vascular plant contribution than in terminal lakes. Furthermore, results showed that DOC concentration, CDOM light absorption, and the proportion of autochthonous sources of CDOM in plateau waters were all higher than in other freshwater rivers reported in the literature. The strong evapoconcentration, intense ultraviolet irradiance, and landscape features of the Hulun Buir plateau may be responsible for the above phenomenon. Redundancy analysis (RDA) indicated that the environmental variables total suspended matter (TSM), TN, and electrical conductivity (EC) had a strong correlation with light absorption characteristics, followed by total dissolved solid (TDS) and chlorophyll a. In most sampling locations, CDOM was the dominant non-water light-absorbing substance. Light absorption by non-algal particles often exceeded that by phytoplankton in the plateau waters. Study of these optical–physicochemical correlations is helpful in the evaluation of the potential influence of water quality factors on non-water light absorption in cold plateau water environments. The construction of a correlation between DOC concentration and water quality factors may help contribute to regional estimates of carbon sources and fate for catchment carbon budget assessments.

Characterizing chromophoric dissolved organic matter in Guanting Reservoir Beijing using excitation-emission matrix fluorescence and parallel factor analysis

2020 ◽  
Author(s):  
Yijuan Bai ◽  
Aizhong Ding ◽  
Shurong Zhang
Keyword(s):  
Water Quality ◽  
Factor Analysis ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Parallel Factor Analysis ◽  
Chromophoric Dissolved Organic Matter ◽  
Drinking Water Source ◽  
Guanting Reservoir ◽  
Excitation Emission Matrix ◽  
Parallel Factor

&lt;p&gt;Chromophoric dissolved organic matter (CDOM) is an important optically active substance that might be used as an indicator of water quality. The study of CDOM characteristic and source identification in reservoirs is of great importance in decision- making for water quality protection.&lt;br&gt;Granting reservoir Beijing was selected as the case study, which was the drinking water source for Beijing, while it was ceased to supply water in 1997 because of water pollution. The water samples were collected from 37 sites in the reservoir. Three dimensional excitation-emission matrix (3DEEM) spectra combined with &amp;#160;parallel factor analysis (PARAFAC) was applied to investigate the fluorescence characteristics and sources of chromophoric dissolved organic matter (CDOM) in Guanting Reservoir. The results showed that: (1) four kinds of chromophoric dissolved organic matter (CDOM) was identified, which were the tryptophan-like component (C1) autochthonously, the humic-like component (C2) in the ultraviolet zone, the tryptophan-like component (C3) caused by photolysis reaction and the humic-like component (C4) in the visible light zone. (2) The tryptophan-like was the dominant fraction of CDOM in Guanting Reservoir. For the four component, C1 and C3 belong to humic-like; C2 and C4 belong to protein-like. The humic-like increases with the river flowing into the reservoir. the fluorescence intensity of humic-like and protein-like both was the highest in July. (3) the humic-like C2 and C4 were significantly correlated which might indicate they originated from the same source, while the protein-like C1 and C3 didn&amp;#8217;t show the correlation that might indicate their source is different. (4)Fluorescence index(FI), biological index (BIX) and humification index (HIX) were also used to identify the source of different components. The FI ranged from 1.8 to 1.95 indicated that CDOM principally originated from microbially derived fulvic acids. The BIX ranged from 0.9 to 1.1 indicated that CDOM was strong autochthonous component and from biological or aquatic bacterial origin. The HIX ranged 1.3 to 3.5 indicated that CDOM was weak humic characteristic and important recent autochthonous component.&lt;/p&gt;

Characterization of chromophoric dissolved organic matter and relationships among PARAFAC components and water quality parameters in Heilongjiang, China

2016 ◽  
Vol 23 (10) ◽  
pp. 10058-10071 ◽  
Author(s):  
Hongyang Cui ◽  
Jianhong Shi ◽  
Linlin Qiu ◽  
Yue Zhao ◽  
Zimin Wei ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Chromophoric Dissolved Organic Matter

scholarly journals Validation of Water Quality Monitoring Algorithms for Sentinel-2 and Sentinel-3 in Mediterranean Inland Waters with In Situ Reflectance Data

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 686
Author(s):  
Xavier Sòria-Perpinyà ◽  
Eduardo Vicente ◽  
Patricia Urrego ◽  
Marcela Pereira-Sandoval ◽  
Carolina Tenjo ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Optical Sensors ◽  
Satellite Image ◽  
European Space Agency ◽  
Water Quality Monitoring ◽  
Inland Waters ◽  
Colored Dissolved Organic Matter ◽  
Sentinel 2

Freshwater quality maintenance is essential for human use and ecological functions. To ensure this objective, governments establish programs for a continuous monitoring of the inland waters state. This could be possible with Sentinel-2 (S2) and Sentinel-3 (S3), two remote sensing satellites of the European Space Agency, equipped with spectral optical sensors. To determine optimal water quality algorithms applicable to their spectral bands, 36 algorithms were tested for different key variables (chlorophyll a (Chl_a), colored dissolved organic matter (CDOM), colored dissolved organic matter (TSS), phycocyanin (PC) and Secchi disk depth (SDD)). A database of 296 water-leaving reflectance spectra were used, as well as concomitant water quality measurements of Mediterranean reservoirs and lakes of Spain. Two equal data sets were used for calibration and validation. The best algorithms were recalculated using all database and used the following band relations: SDD, R560/R700; CDOM, R665/R490; PC, R705/R665 for S2 and R620, R665, R709 and R779 for S3, using a semi-analytical algorithm; R700 for TSS < 20 mg/L and R783/R492 (S2) or R779/R510 (S3) for TSS > 20 mg/L; and for Chl_a, the maximum (R443; R492)/R560 for Chl_a < 5 mg/m3 and R700/R665 for Chl_a > 5 mg/m3. A preliminary test with a satellite image in a well-known reservoir showed results consistent with the expected ranges and spatial patterns of the variables.

scholarly journals Chromophoric Dissolved Organic Matter as a Tracer of Fecal Contamination for Bathing Water Quality Monitoring in the Northern Tyrrhenian Sea (Latium, Italy)

2020 ◽  
Vol 8 (6) ◽  
pp. 430
Author(s):  
Alice Madonia ◽  
Gabriella Caruso ◽  
Daniele Piazzolla ◽  
Simone Bonamano ◽  
Viviana Piermattei ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Fecal Contamination ◽  
Biologically Active ◽  
Chromophoric Dissolved Organic Matter ◽  
Tyrrhenian Sea ◽  
Bathing Water ◽  
Microbiological Methods ◽  
Bathing Water Quality

Dissolved organic matter present in natural aquatic environments is a heterogeneous mixture of allochthonous and autochthonous materials. In coastal areas vulnerable to sewage waste, its biologically active component, the chromophoric dissolved organic matter (CDOM), is expected to change its composition and distribution in relation to anthropogenic activities, suggesting the possible use of CDOM as a proxy of fecal contamination. This study aimed at testing such hypothesis by investigating and relating the optical properties of CDOM with Escherichia coli abundance, physiological state, and enzymatic activities in a bathing area of the Northern Tyrrhenian Sea (Latium, Italy) affected by urban wastewaters. The parallel factor analysis (PARAFAC) applied to the excitation–emission matrices (EEMs) of CDOM allowed us to distinguish three main components: C1 (λEx/λEm = 342 nm/435 nm), C2 (λEx/λEm = 281–373 nm/460 nm), and C3 (λEx/λEm = 286 nm/360 nm). C1 and C2 corresponded to humic acids of terrestrial origin, while C3 to tryptophan, whose fluorescence peak was detected close to sewage sites, strongly related to active E. coli cells. The comparison between spectral and microbiological methods is suggested as a suitable approach to monitor bathing water quality for the implementation of coastal observing system capability.

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