Neutrosophic over set can deal with the uncertainties related to the information of any decision making problem in real life scenaries, where fuzzy set may fail to handle those uncertainties ...properly. The study on presented in this “Neutrosophic Over topologized domination graphs” and also classification in different frame are discussed.The idea of NOver T op-dom set, NOver T op-minimum dom set, NOver T op-minimal dom set and NOver T op-dom number are introduced and necessary examples are established. In any neutrosophic over decision-making problem, the decision maker use the comparision of neutrosophic over number to choose alternative solutions.
Human land use has led to significant changes in the character of dissolved organic matter (DOM) in lotic ecosystems. These changes are expected to have important environmental and ecological ...consequences. However, high spatiotemporal variability has been reported in previous studies, and the underlying mechanisms remain inadequately understood. This study assessed variation in the properties of stream water DOM within watersheds across a gradient of agricultural land use with grazing pasture lands as the dominant agricultural type in the southeastern United States. We collected water samples under baseflow conditions five times over eight months from a regional group of first- to fourth-order streams. Samples were analyzed for dissolved organic carbon (DOC) concentration, DOM quality based on absorbance and fluorescence properties, as well as DOM biodegradability. We found that air temperature and antecedent hydrological conditions (indicated by antecedent precipitation index and stream water sodium concentrations) positively influenced stream water DOC concentration, DOM fluorescence index, and the proportion of soil-derived, microbial humic fluorescence. This observation suggests that elevated production and release of microbial DOM in soils facilitated by high temperature, in conjunction with strong soil-stream hydrological connectivity, were important drivers for changes in the concentration and composition of stream water DOM. By comparison, watersheds with a high percentage of agricultural land use showed higher DOC concentration, larger proportion of soil-derived, humic-like DOM compounds, and higher DOC biodegradability. These observations reflect preferential mobilization of humic DOM compounds from shallow organic matter-rich soils in agricultural watersheds, likely due to enhanced soil erosion, organic matter oxidation and relatively shallow soil-to-stream flow paths.
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•We assessed DOM in streams across a gradient of agricultural land use.•Temperature and antecedent precipitation increase DOC and soil microbial DOM.•Agricultural land increases DOC, humic DOM and DOM biodegradability.•Land use alters DOM export through erosion, oxidation and shallow flow path.
•Seasonality and cross shelf distribution of DOM and its optical properties were examined in the Celtic Sea.•Strong cross shelf gradients in humic DOM components with significant negative ...correlations with salinity and DOC.•Variability in labile DOM protein components linked to biological productivity.
The Celtic Sea is a productive temperate sea located on the Northwest European Shelf. It is an important pathway for the delivery of land-derived material to the North Atlantic Ocean, including dissolved organic matter (DOM). The aim of this study was to determine the seasonal and spatial variability in the magnitude, source and composition of DOM at three sites representing on shelf, central shelf and shelf edge regions in the Celtic Sea, using observations collected during the UK Shelf Sea Biogeochemistry (SSB) research programme (November 2014 – August 2015). The concentration of dissolved organic carbon (DOC) alongside DOM absorbance and fluorescence indices were measured and fluorescence Excitation and Emission Matrices (EEMs) combined with Parallel Factor Analysis (PARAFAC) were used to assess DOM composition and lability. The PARAFAC model identified four unique fluorescent components for autumn (November 2014), winter (March 2015), spring (April 2015) and summer (July 2015) consisting of two humic-like components attributed to terrestrial (C1) and marine sources (C2), and two protein components identified as tyrosine-like (C3) and tryptophan-like (C4) attributed to in situ production. DOC varied seasonally and there were strong cross shelf trends. The protein components (C3 and C4) exhibited large seasonal and within season variability particularly during productive periods. In contrast, there were persistent cross shelf gradients in the CDOM absorption coefficient at 305 nm (a305), the UV specific absorbance at 280 nm (SUVA280), the humification index (HIX), and the humic-like fluorescent components (C1 and C2), which were higher in the on shelf region and decreased towards the shelf edge. The humic-like components and the slope ratio (SR) were significantly correlated with salinity throughout all seasons, indicating a strong influence of terrestrially-derived organic matter in the Celtic Sea, with potentially up to 35% of DOC in the central shelf during winter originating from terrestrial inputs. Results from this study illustrate the importance of monitoring DOM quantitatively and qualitatively for a better understanding of the supply, production, cycling and export of this dynamic organic carbon pool in shelf seas.
Three-dimensional excitation-emission matrix fluorescence spectroscopy (3D EEMs) has been extensively used for dissolved organic matter (DOM) characterization. However, the application of 3D EEMs is ...constantly limited by issues such as contradictory component identification, confusing interpretation of spectral indicators, and inability to establish biodegradability. In this study, some improvements were proposed by investigating the 3D EEMs, spectral indicators, and degradability of the standard and representative DOM. To overcome the unclear identification of DOM components, it was recommended to partition 3D EEMs into three subareas: aromatic protein (New-I), humic-like (New-II), and soluble microbial by-product-like (New-III). Significant strong positive correlations (ρ = 0.727, P < 0.001) were observed between fluorescence index (FI) and biological index (BIX), and (R = 0.809, P < 0.001) humification index (HIX) and specific ultraviolet absorbance of 254 nm (SUVA254). Except for FI (R = -0.483, P = 0.023), no other spectral indicators (P > 0.05) were found to be significantly correlated with molecular weight. As thence results, the FI and HIX were the most suitable indicators for evaluating DOM. The half-life (20 < 21 < 26 < 29 < 46 days) revealed that the degradability of individual DOM components was in the order of tyrosine > tryptophan > fulvic acid > protein > humic acid. The degradation dynamics were governed by first-order decay kinetics (R2 = 0.91–0.99). This study clarified the fluorescence properties and degradability of DOM, as well as the reliability of spectral indicators. The degradation performance of individual DOM components engaged in the carbon cycling process was revealed, paving the path for further applications of 3D EEMs in DOM research.
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•The study re-examined the utility of the 3D EEMs application in DOM research.•The 3D EEMs was re-divided into aromatic protein, humic-like and SMP-like DOM.•The FI and HIX were the most suitable indicators for evaluating DOM.•There were differences in the degradability and degradation dynamics of DOM.
There is growing concern about the rising levels of dissolved organic matter (DOM) in surface waters across the Northern hemisphere. However, only limited research has been conducted to unveil its ...precise origin. Compositional changes along terrestrial-aquatic pathways can help determine the terrestrial sources of DOM in streams. Stream water, soil water and soil horizons were sampled at four sites representing typical settings within a forested catchment in the Ore Mountains (Erzgebirge, Germany) from winter 2020 to spring 2022. The samples were analyzed using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The resulting data were successfully subjected to semi-automatic processing of the molecular composition of DOM, reaching a percentage of identified peaks up to 98 %. Principal component analysis (PCA) and cluster analyses were carried out to identify distinct differences between DOM from the potential sources and in the streams. According to the PCA, organic soil horizons, soil water, and stream water samples could be clearly distinguished. Cluster analysis revealed that soil water DOM at all depths of Peats and deeper horizons of the Peaty Gleysols contributed the most to DOM in the stream section dominated by organic soils. In areas dominated by mineral soils, stream DOM resembled the DOM from the deeper mineral horizons of Cambisols and Podzols. Overall, our results suggested that most of the DOM exported from the catchment was derived from deeper mineral soil horizons, with little contribution of DOM derived from organic soils. Therefore, DOM fingerprint analysis of in-situ soil water proved to be a promising approach for tracing back the main sources of stream water DOM.
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•Chemical signature was used to identify sources of DOM in stream water.•Solid organic matter samples were of limited use for source identification.•Peats contributed hardly to downstream DOM.•Peaty Gleysol signals still detectable downstream the source location.•Mineral soil horizons exerted the strongest overall control on stream DOM.
The transport of organic contaminants in groundwater might be greatly affected by coexistence of dissolved organic matter (DOM) from different sources. In this study, the effects of endogenous and ...exogenous DOMs (referred to as DOMen and DOMex, respectively) on sorption behavior of bisphenol A (BPA) onto two reference soils were investigated by batch experiments and microscopic characterization. The results showed that BPA sorption onto soils was dominated by soil organic matter content and affected by DOM properties. The effect of DOMen on BPA sorption was also related to the inorganic components of the two soils. The decrease of organic matter content reduced the sorption capacity of fluvo-aquic soil. However, because the content of available inorganic components in black soil was high, after removing DOMen, more inorganic sites were exposed to increase the sorption capacity. In addition, DOMen could form complexes with BPA in solution, thus the removal of DOMen promoted BPA sorption onto black soil. Under the experimental conditions, contribution of DOMex to the total sorption of BPA onto both soils was not more than 30%. Results of dialysis experiments and soil sorption experiments indicated that effects of coexisting DOMex on BPA sorption was related to the affinity of DOMex to soils and complexation of BPA and DOMex. Since the affinity of DOMex to fluvo-aquic soil was relatively low, the complex of BPA and DOMex in solution was the main inhibition mechanism for BPA sorption. For black soil, higher complexation proportion of BPA with DOMex adsorbed onto soil which promoted BPA sorption onto soil. The findings are of significance for understanding the co-migration of DOM with BPA through soils.
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•Removal of endogenous DOM could expose available inorganic sorption sites on soil.•Distribution of exogenous DOM-BPA complexes determined BPA sorption to soils.•Affinity between exogenous DOM and soil was the main factor affecting BPA sorption.•Complexation of BPA to DOMex in solution inhibited sorption onto fluvo-aquic soil.•DOMex sorbed onto black soil, and promoted co-sorption of BPA.
We describe petrographic, electron microprobe, and laser ablation ICP‐MS analyses of Mg‐rich harzburgite clasts in the Dominion Range 2010 howardites, and conclude that they are xenolithic samples of ...the vestan mantle. Key chemical and petrologic characteristics of these rocks provide tests for differentiation models. Our results indicate the mantle of Vesta formed through variable degrees of partial melting, which left behind a harzburgite and possibly dunite residuum. The Mg‐rich clasts are composed of orthopyroxene and olivine, with minor clinopyroxene, FeNi metal, and distinctive pyroxene–chromite symplectites. We use mineral chemistry to demonstrate the absence of a genetic link between diogenites and the Mg‐rich harzburgites. We propose a secondary origin for the formation of symplectites: interaction of silicate and metallic melts during primordial differentiation and core formation. The occurrence of FeNi metal containing ~1.5 wt% Cr within the assemblage indicates a very reducing environment during mantle differentiation (≪IW). Our study suggests that Vesta did not experience complete melting early in its history, and instead supports the formation of a shallow magma ocean.
Effects of photochemical and microbial degradation on variations in composition and molecular-size of dissolved organic matter (DOM) from different sources (algal and soil) and the subsequent ...influence on Cu(II) binding were investigated using UV–Vis, fluorescence excitation-emission matrices coupled with parallel factor analysis, flow field-flow fractionation (FlFFF), and metal titration. The degradation processes resulted in an initial rapid decline in the bulk dissolved organic carbon and chromophoric and fluorescent DOM components, followed by a small or little decrease. Specifically, photochemical reaction decreased the aromaticity, humification and apparent molecular weights of all DOM samples, whereas a reverse trend was observed during microbial degradation. The FlFFF fractograms revealed that coagulation of both protein- and humic-like DOM induced an increase in molecular weights for algal-DOM, while the molecular weight enhancement for allochthonous soil samples was mainly attributed to the self-assembly of humic-like components. The Cu(II) binding capacity of algal-derived humic-like and fulvic-like DOM consistently increased during photo- and bio-degradation, while the soil-derived DOM exhibited a slight decline in Cu(II) binding capacity during photo-degradation but a substantial increase during microbial degradation, indicating source- and degradation-dependent metal binding heterogeneities. Pearson correlation analysis demonstrated that the Cu(II) binding potential was mostly related with aromaticity and molecular size for allochthonous soil-derived DOM, but was regulated by both DOM properties and specific degradation processes for autochthonous algal-derived DOM. This study highlighted the coupling role of inherent DOM properties and external environmental processes in regulating metal binding, and provided new insights into metal-DOM interactions and the behavior and fate of DOM-bound metals in aquatic environments.
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•Effect of photo-/microbial degradation on metal binding with DOM from different origins was studied.•Different variations in abundance, composition, and size were observed for different DOMs under photo-/bio-degradation.•logKM increased during algal-DOM degradation but varied for soil-DOM depending on degradation.•Metal binding with allochthonous DOM was controlled by aromaticity and molecular size.•Metal binding with autochthonous DOM was regulated by both DOM properties and degradation processes.
Metal-DOM binding was mostly controlled by aromaticity and molecular size for the allochthonous DOM, but was regulated by both DOM property and degradation process for the autochthonous DOM.
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•Biodegradation preferentially decomposes the low molecular weight DOMs.•Aromatic and lignin fraction are accumulated in the mainstem.•Aquatic respiration of DOMs explain pCO2 levels ...in the post-wet and drought periods.•Terrestrial inputs are dominant pCO2 source in the initial-wet period.•pCO2 is positively correlated with DOM optical parameters.
The mineralization of dissolved organic matter (DOM) can partially explain riverine carbon dioxide (CO2) emissions to the atmosphere. However, little is known about how the DOM origin and composition drive CO2 partial pressures (pCO2). Here, we reveal links between aquatic pCO2, DOM optical parameters (a254, a350 and S275-295 and S350-400) and nutrients in a subtropical river in China’s Dry-hot Valley Region. Biodegradation preferentially decomposed low molecular weight (LMW) DOMs, increasing high molecular weight (HMW) DOMs along the main stem. pCO2 was positively correlated with aromatic and lignin compounds, but negatively correlated with DOM molecular weight. Aquatic respiration of DOMs largely explained the pCO2 levels in the drought period, while terrestrial inputs were a pCO2 source in the initial-wet period. Our results illustrate how both DOM concentrations and speciation can explain pCO2 distribution and sources in rivers.
•Aquatic dissolved and particulate organic matter composition varied spatially.•Physical location, land use and vegetation cover affected organic matter composition.•Organic matter composition could ...be grouped into clusters with similar traits to maximise water treatment efficiency.
Water supply companies with reservoirs in peatland areas need to know how land use and vegetation cover in their supply catchments impact the amount and composition of aquatic organic matter in raw waters. Drinking water treatment processes remove organic matter from potable supplies, but recent increases in concentration and changes in composition have made this more difficult. This study analysed the composition of aquatic organic matter from peatland catchments in the UK and Faroe Islands. Both dissolved organic matter (DOM) and particulate organic matter (POM) compositions varied spatially, but these differences were not consistent as water moved through catchments, from headwaters and peatland pools to lake and reservoir outlets. These data showed that lakes and reservoirs are acting as flocculation hotspots, processing OM, releasing carbon (C), hydrogen (H) and oxygen (O) compounds to the atmosphere, and resulting in OM with higher N content. DOM compositions could be grouped into five clusters, showing that water treatment processes can be maximised to target ‘envelopes’ or clusters of DOM compositions. Catchment factors such as land use, vegetation cover, percentage peat cover and catchment area are good indicators of OM compositions likely to be present in a reservoir, and can guide water companies to maximise efficiency of their raw water treatment processes.
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