Spectroscopic indices trace spatiotemporal variability of dissolved organic matter in a river system with Karst characteristic

Ni, Maofei; Jiang, Shaohua; Li, Siyue

doi:10.1016/j.jhydrol.2020.125570

Cited by 30 publications

(10 citation statements)

References 79 publications

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“…After treatment by the PCW system, it was observed that the seventh-day surface water sample exhibited visibly lower BIX and FI than the first-day samples, as shown in Figure S6, which demonstrated that the removal mechanism for different HCAPs addition of water samples was also related to microbial activity. 70 Hence, three primary factors were mainly responsible for the sharp decrease in NH 4 + -N, NO 3 − -N, and TN of surface water in the PCW. First, N was taken up by rice plants and accumulated in the shoots of rice plants.…”

Section: ■ Results and Discussionmentioning

confidence: 94%

“…Similarly, the FI for the first surface water samples was greater than 1.9 in Figure S6, indicating strong microbial activity in the first water samples. After treatment by the PCW system, it was observed that the seventh-day surface water sample exhibited visibly lower BIX and FI than the first-day samples, as shown in Figure S6, which demonstrated that the removal mechanism for different HCAPs addition of water samples was also related to microbial activity …”

Section: Results and Discussionmentioning

confidence: 99%

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Efficient Disposal of the Aqueous Products of Wet Organic Waste Hydrothermal Carbonization by Paddy Constructed Wetlands

Wang

Miao

et al. 2022

ACS EST Eng.

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The hydrothermal carbonization (HTC) technology has recently been broadly applied. However, disposal of the accompanying high-strength HTC aqueous products (HCAPs) largely determines the promotion and application of the HTC technology. The direct discharge of HCAPs might deteriorate the water environment, and previous studies have reported that HCAPs were insecurely removed via anaerobic fermentation or microalgae production. In this work, wet organic waste HCAPs were characterized and identified, and their removal efficiency in a paddy constructed wetland (PCW) was determined. The HCAPs were found to be rich in nutrients and mainly composed of humic acid (77.8−84.7%) or lignin (44.8−68.2%). With increasing HTC temperature, the relative humic acid content in HCAPs decreased by 4.4−6.4%, as determined by the three-dimensional fluorescence excitation−emission matrix (3D-EEM) analysis. HCAPs also underwent decomposition and polymerization due to the change in MW w and AI mod as determined by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) analysis. The PCW removal efficiency of NH 4 + -N and chemical oxygen demand (COD) reached 99.2 and 93.2% in the HCAP treatments, respectively, which were much higher than the values obtained for traditional disposal applications. On the basis of the higher soil NH 4 + -N content (1.6-to 6.0-fold), larger grain total nitrogen (TN) content (5.1−18.6%), and lower fluorescence intensity (5.7−88.2%), three primary processes (i.e., uptake by rice plants, microbial degradation, and soil immobilization) were proposed as PCW removal mechanisms. This study provides novel utilization prospects for the resource utilization of HCAPs in PCW systems.

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Section: ■ Results and Discussionmentioning

confidence: 94%

Section: Results and Discussionmentioning

confidence: 99%

Efficient Disposal of the Aqueous Products of Wet Organic Waste Hydrothermal Carbonization by Paddy Constructed Wetlands

Wang

Miao

et al. 2022

ACS EST Eng.

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“…Our data support this concept, as the primary predictors of DOM characteristics (land use and stream order) explained less of the variation in DOM during the driest months of the year. Dry periods are characterized by long water residence time, shortened longitudinal transport per unit time, less lateral hydrological connectivity with terrestrial and anthropogenic DOM sources, and a greater contribution of groundwater sources. ,, Our results support the conclusion that these physical drivers have important implications for DOM quality, providing further support for the general principle that DOM quality can be significantly altered by in-stream processes. First, during the driest months of August and September, only 12.4–14.5% of variation in DOM was explained, and it was exclusively attributed to land use.…”

Section: Discussionmentioning

confidence: 91%

Land Use Overrides Stream Order and Season in Driving Dissolved Organic Matter Dynamics Throughout the Year in a River Network

Coble

Wymore

Potter

et al. 2022

Environ. Sci. Technol.

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Anthropogenic land use has increased nutrient concentrations and altered dissolved organic matter (DOM) character and its bioavailability. Despite widespread recognition that DOM character and its reactivity can vary temporally, the relative influence of land use and stream order on DOM characteristics is poorly understood across seasons and the entire flow regime. We examined DOM character and 28-day bioavailable dissolved organic carbon (BDOC) across a river network to determine the relative roles of land use and stream order in driving variability in DOM character and bioavailability throughout the year. DOM in 1st-order streams was distinct from higher stream orders with lower DOC concentrations, less aromatic (specific ultraviolet absorbance at 254 nm (SUVA 254 )), more autochthonous (fluorescence index), and more recently produced (β/α) DOM. Across all months, variability in DOM character was primarily explained by land use, rather than stream order or season. Land use and stream order explained the most DOM variation in transitional and winter months and the least during dry months. BDOC was greater in watersheds with less aromatic (SUVA 254 ) and more recent allochthonous DOM (β/α) and more development and impervious surface. With continued development, the bioavailability of DOM in the smallest and most impacted watersheds is expected to increase.

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“…Three-dimensional fluorescence spectroscopy combined with parallel factor analysis can decipher the fluorescence information of AOM and better probe the composition and differences of AOM (Li et al, 2020). Phytoplankton discovered downstream of karst rivers produce a large amount of organic matter with the increase in the fluorescence index (Ni et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Compositional variations in algal organic matter during distinct growth phases in karst water

Tian

Zhang

Wang

et al. 2023

Front. Environ. Sci.

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Inland surface water plays an important role in global carbon cycling, which responds to transformation between dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC). Studies have shown that algae in karst lakes and reservoirs can convert DIC to organic matter (OM) and form stable carbon sinks via photosynthesis. However, the pathways of conversion of inorganic carbon to organic carbon during algal growth remain unclear and need further investigation. In this study, spectroscopic techniques were applied to investigate the variations in algal organic matter (AOM) composition in the growth metabolism of Chlorella vulgaris and Scenedesmus obliquus under simulated karst water condition. The results showed that algal extracellular organic matter (EOM) contained high DIC concentration during the adaptation phase, which formed the carbon source for algal photosynthesis. In addition, DOC in algae increased after entering the stationary phase, while more OM was released into water. As algal growth proceeded, the amino groups in EOM were consumed to produce more aromatic protein-like material, while more lipid material was produced in intracellular organic matter (IOM). The spectral characterization results could intuitively determine AOM dynamics in different growth stages of algae, which can be used for establishing effective approaches for detecting organic carbon variations and responding to regional carbon cycling in karst water.

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Spectroscopic indices trace spatiotemporal variability of dissolved organic matter in a river system with Karst characteristic

Cited by 30 publications

References 79 publications

Efficient Disposal of the Aqueous Products of Wet Organic Waste Hydrothermal Carbonization by Paddy Constructed Wetlands

Efficient Disposal of the Aqueous Products of Wet Organic Waste Hydrothermal Carbonization by Paddy Constructed Wetlands

Land Use Overrides Stream Order and Season in Driving Dissolved Organic Matter Dynamics Throughout the Year in a River Network

Compositional variations in algal organic matter during distinct growth phases in karst water

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