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所有论文

161. 题目: Low‐molecular‐weight reduced sulfur substances: A major component of nonvolatile dissolved organic sulfur in the Pacific Ocean
文章编号: N24063009
期刊: Limnology and Oceanography Letters
作者: Pierre Fourrier, Gabriel Dulaquais
更新时间: 2024-06-30
摘要: The low‐molecular‐weight (LMW) reduced sulfur substances (RSS) composition of dissolved organic matter (DOM) was examined along the GEOTRACES US‐GP15 section in the Pacific Ocean. We demonstrate that LMW RSS constitutes a significant fraction of nonvolatile dissolved organic sulfur (DOS). While thiols such as glutathione were below our detection limit (300 pM), RSS containing two carbon (C) sulfur (S) bonds were present at concentrations in the hundreds of nM range. RSS accumulation was observed in subtropical waters. The most likely source of these RSS is microbial alteration of sulfurized DOM with production of secondary thioamidated metabolites. RSS are initially produced by cyanobacteria to mitigate copper and oxidative stress induced by UV‐B irradiance. A preferential remineralization of RSS over dissolved organic carbon (DOC) in the upper 350 m suggests a partial lability of LMW DOS. Deeper, homogeneous concentrations and C : S ratio indicate increasing stability of this LMW DOS.

162. 题目: Preparation of biochar from anaerobic digested sludge for enhancement of sludge dewatering
文章编号: N24063008
期刊: Chemosphere
作者: Zhuo Li, Kai Chen, Shixin Zhai, Lisha Yang, Tong Yu, Huibin Yuan, Bizhen Zeng, Lan Yang, Feilan Qi, Hongtao Zhu
更新时间: 2024-06-30
摘要: Effective dewatering is vital for both sludge treatment and resource recovery. This study focuses on converting post-anaerobic digested sludge into biochar to enhance sludge dewatering. The sludge-derived biochar is further modified with polyacrylamide (PAM-ADBC) and applied with sulfuric acid-modified montmorillonite (HMTS) for better performance. Significant advancements in dewatering were noted, even at reduced HMTS (0.1 g/g DS) and PAM-ADBC (25 g/kg DS) dosages. These improvements resulted in a remarkable 41.96% enhancement in capillary suction time (17.2 s) and a notable 20.26% reduction in moisture content (66.33%), respectively, all while maintaining a stable pH level. HMTS, with leached cations, improved dewatering by decomposing the extracellular polymeric substance structure through electro-neutralization to release the internal bound water within sludge flocs. Simultaneously, PAM-ADBC coagulated decomposed sludge particles into larger flocs to form a skeletal structure with itself to discharge internal water in compression dewatering. This study introduces a resource recovery method for anaerobically digested sludge and highlights its potential for sustainable utilization.

163. 题目: The redistribution process of As(Ⅲ) and Fe(Ⅱ) caused by As/Fe ratio, organic matter, and co-existing ions: Co-precipitation and co-oxidation
文章编号: N24063007
期刊: Ecotoxicology and Environmental Safety
作者: Xin Liu, Jiankang Wang, Yongxian He, Junfeng Li, Qingyuan Tian, Hong Xu
更新时间: 2024-06-30
摘要: The contamination of arsenic (As) in aqueous environments has drawn widespread attention, and iron compounds may largely alter the migration ability of As. However, the stability of As(III) in Fe-As system with the intervention of organic matter (OM) remains unclear. Herein, we had explored the co-precipitation and co-oxidation processes of As-Fe system by using batch experiments combined with Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) in this research. The precipitation quantity of As(III) increased (28.85–92.41 %) when the As/Fe ratio decreased, and increased (24.20–64.20 %) with pH increased. The main active substance for oxidizing As(III) was HO, which was produced in the As-Fe system. FTIR and XPS revealed that As(III) was first oxidized in neutral, and then absorbed and enteredthe interior of Fe(OH) colloids. But under alkaline conditions, As(III) was adsorbed by Fe (Oxyhydr) oxides firstly, and then oxidized. The intervention of OM would inhibit the redistribution process of As(III) in aqueous environments. Functional groups and unsaturation of the carbon chain were the dominant factors that affected the precipitation and oxidation processes of As(III), respectively. Co-existing ions (especially PO) also signally affected the precipitation quantity of As(Ⅲ) in the system and, when coexisting with OM, could exacerbate this process. The influence of co-existing ions on the redistributive process of As(III) in the As-Fe system with/without OM were as follows: PO > SO > mixed ions > SiO. Moreover, high concentration of OM and PO might lead to morphological alterations of As, acting as a threat to aqueous environments. In summary, the present findings were to further understand and appreciate the changes of As toxicity in the aqueous environments. Particularly, the coexistence of OM and As can potentially increase the risk to drinking water safety.

164. 题目: Viral infection of coccolithophore host induces shifts in particulate organic matter stoichiometry
文章编号: N24063006
期刊: Limnology and Oceanography
作者: Tamar Dikstein, Gilad Antler, André Pellerin, Shlomit Sharoni, Miguel J Frada
更新时间: 2024-06-30
摘要: Blooms of the coccolithophore Gephyrocapsa huxleyi (formerly Emiliania huxleyi) are routinely infected by a specific lytic virus (EhV) that kills host cells and drives bloom termination. However, the impact of EhV on nutrient retention and stoichiometric ratios of particulate organic matter remains unknown, limiting our current understanding of the biogeochemical significance of the G. huxleyi–EhV interaction. To tackle this knowledge gap, we surveyed both nitrate, phosphate, and alkalinity consumption by the cells, as well as the elemental composition (C : N : P) of particulate organic matter during infections in culture. We found that within 24 h of infection, alkalinity concentration in the solution stabilized, and nutrient uptake declined to low levels. In parallel, the molar ratio of carbon to nitrogen in particulate organic matter increased by 10–17% and the nitrogen to phosphorus ratio declined by 5–12% relative to the noninfected algal cultures. These variations likely resulted from intracellular lipid accumulation as part of viral infection as well as the differential retention of phosphorus‐rich macromolecular pools in decaying cells, respectively. After infection, as most host cells lysed, we detected a progressive enrichment in phosphorus and nitrogen relative to carbon in the remaining particulate organic matter, which could be attributed to the accumulation of colonizing heterotrophic bacteria with a distinct elemental composition. This study indicate that marine viruses influence the elemental stoichiometry and fate of phytoplankton‐born organic materials in the oceans.

165. 题目: Effective Co2+ removal from aqueous solution and industrial wastewater using ZIF-7 and MnFe2O4-modified walnut shell biochar composite
文章编号: N24063005
期刊: Separation and Purification Technology
作者: Lei Yao, Chao Hong, Yangxu Qi, Lie Wu
更新时间: 2024-06-30
摘要: In this study, we developed a novel magnetic composite of walnut shell biochar (WSB) and modified it with ZIF-7 for the purpose of removing Co ions. We conducted a comprehensive evaluation of its performance in Co removal, considering various factors such as contact time, temperature, adsorbent dose, pH, and initial Co concentration. Utilizing response surface methodology-central composite design (RSM-CCD), we examined the interactions between these variables. The specific surface area and magnetic saturation value of the WSB/MnFeO/ZIF-7 composite were determined as 170.560 m.g and 23.469 emu.g, respectively. ANOVA analysis indicated that our model effectively captures the interactions between variables, with a high R value of 0.9982, explaining 99.82 % of the experimental data. Optimal conditions for maximum Co adsorption efficiency (99.05 %) were identified as follows: a contact time of 44.82 min, pH of 6.04, adsorbent dose of 0.947 mg.L, temperature of 25.55 °C, and Co concentration of 11.13 mg.g. Kinetic studies revealed that the Pseudo 2nd order kinetic model provided the best fit to the experimental data. The negative entropy parameter indicated a decrease in disorderliness during the adsorption process, while the exothermic nature of adsorption was confirmed by enthalpy values of −92.751 and −40.511 kJ.mol for WSB/MnFeO/ZIF-7 and WSB, respectively. Furthermore, the Langmuir isotherm model demonstrated excellent fitting to the isotherm results, suggesting the dominance of homogeneous surfaces in adsorption. The maximum adsorption capacities for Co using WSB/MnFeO/ZIF-7 and WSB were determined to be 29.26 and 22.39 mg.g, respectively. The WSB/MnFeO/ZIF-7 magnetic composite demonstrates promising potential for efficiently removing Co from both natural water sources and industrial wastewater, highlighting its versatility and effectiveness in environmental remediation applications.

166. 题目: Mn-Fe bimetallic oxide catalytic oxidation combined with ultrafiltration for treating secondary effluent: EfOM molecular transformation and membrane fouling control mechanism
文章编号: N24063004
期刊: Chemical Engineering Journal
作者: Peijie Li, Daliang Xu, Xiaoxiang Cheng, Junwen Ding, Jinlong Wang, Heng Liang
更新时间: 2024-06-30
摘要: Despite extensive application and research of membrane technology in secondary effluent treatment, fouling induced by effluent organic matter (EfOM) remains a challenge. Herein, a pretreatment strategy involving Mn-Fe bimetallic oxide-activated peroxymonosulfate (MnFeO/PMS) was used before ultrafiltration to decompose EfOM and tackle membrane fouling. Results showed that membrane fouling was effectively alleviated, with reductions in reversible and irreversible fouling resistances of 88.3 % and 58.9 %, respectively. Theoretical analyses illustrated a more pronounced adsorption energy and decomposition tendency of PMS on the MnFeO surface. The generated OH and SO played a key role in the degradation of EfOM. The parallel factor analysis along with self-organizing maps revealed the preferential oxidative degradation of humic acids and fulvic acids over tryptophan-like substances, which contributed to the reversible fouling mitigation. In addition, MnFeO/PMS transformed high and middle molecular weight organics into low molecular weight compounds. The primary molecular reactions involved in the degradation of EfOM included oxygen addition, dealkylation and deamination, which changed the properties of EfOM and contributed to the mitigation of membrane fouling. Morphology analysis further indicated that the fouling layer on the membrane surface was inhibited when filtering the MnFeO/PMS-pretreated sample. This study offers revelations for integrating oxidation with ultrafiltration in secondary effluent treatment to alleviate EfOM-induced membrane fouling.

167. 题目: Acetate anions intercalated Fe/Mg-layered double hydroxides modified biochar for efficient adsorption of anionic and cationic heavy metal ions from polluted water
文章编号: N24063003
期刊: Chemosphere
作者: Yingchao Li, Shujia Wang, Xiao Fang Ouyang, Zhi Dang, Hua Yin
更新时间: 2024-06-30
摘要: The simultaneous removal of anionic and cationic heavy metals presents a challenge for adsorbents. In this study, acetate (Ac-) was utilized as the intercalating anion for layered double hydroxide (LDH) to prepare a novel biochar composite adsorbent (Ac-LB) designed for the adsorption of Pb(II), Cu(II), and As(V). By utilizing Ac- as the intercalating anion, the interlayer space of the LDH was enlarged from 0.803 nm to 0.869 nm, exposing more adsorption sites for the LDH and enhancing the affinity for heavy metals. The results of the adsorption experiments showed that the adsorption effect of Ac-LB on heavy metals was significantly improved compared to the original FeMg-LDH modified biochar composites (LB), and the maximum adsorption capacity of Pb(II), Cu(II), and As(V) were 402.70, 68.50, and 21.68 mg/g, respectively. Wastewater simulation tests further confirmed the promising application of Ac-LB for heavy metal adsorption. The analysis of the adsorption mechanism revealed that surface complexation, electrostatic adsorption, and chemical deposition were the main mechanisms of action between heavy metals (Pb(II) and Cu(II)) and Ac-LB. Additionally, Cu(II) ions underwent a homogeneous substitution reaction with Ac-LB. The adsorption process of As(V) by Ac-LB mainly relied on complexation and ion-exchange reactions. Lastly, the modification of the LDH structure by Ac as an intercalating anion, thereby increasing the affinity for heavy metals, was further illustrated using density-functional theory (DFT) calculations.

168. 题目: Conservation tillage enhances the sequestration and iron-mediated stabilization of aggregate-associated organic carbon in Mollisols
文章编号: N24063002
期刊: Catena
作者: Zixuan Han, Xueping Wu, Aizhen Liang, Shengping Li, Huizhou Gao, Xiaojun Song, Xiaotong Liu, Angyuan Jia, Aurore Degré
更新时间: 2024-06-30
摘要: Conservation tillage practices, which involve minimal or no soil disturbance and crop residue retention, are known to help preserve soil organic carbon (SOC). However, the mechanisms underlying the minerals-mediated chemical and physical stabilization of SOC remain unclear. Here, a long-term field experiment was initiated in 2012 to investigate the effects of tillage managements on the contents and chemical composition of SOC density fractions, iron oxides transformation and aggregate stability in Mollisols. We utilized three treatments: conventional tillage (CT) without crop residue, reduced tillage (RT) and no tillage (NT) with straw mulching. Compared to CT, RT and NT significantly increased SOC content by 13.6 % and 17.9 % in the 0–20 cm soil layer due to an increase in the aromatic compound contents. Furthermore, NT and RT increased the mean weight diameter by 17.7 % and 10.7 %, respectively, indicating increased aggregate stability compared to CT. Additionally, the contents of amorphous iron oxides (Feo) and complex iron oxides (Fep) increased under NT and RT by 10.6–14.4 % and 12.7–41.1 %, respectively, in bulk soil and silt + clay fractions within macroaggregates (>0.25 mm). The contents of Feo and Fep were strongly positively correlated with aggregate stability ( < 0.001, r = 0.64), and promote the physical protection of SOC. Both NT and RT enhanced the aromatic-C content and aromatic-C/aliphatic-C ratio by 13.6 %–24.6 % and 16.5 %–38.9 % in macroaggregates compared with CT. Moreover, the aromatic-C/aliphatic-C ratio increased with increasing Feo plus Fep contents ( < 0.001, r = 0.73), which led to an increased in the recalcitrant-C proportion, and this shift was benefit for the accumulation of mineral-associated OC. These results indicate that long-term conservation tillage can augment the accessibility of Fe for binding C, possibly by forming organo-Fe complexes, which subsequently improve soil aggregation, and thus promoted the chemical stability and long-term sequestration of SOC in Mollisols of Northeast China.

169. 题目: Molecular-level insights into dissolved organic matter and its variations of the full-scale processes in a typical petrochemical wastewater treatment plant
文章编号: N24063001
期刊: Water Research
作者: Min Li, Zhouyang Li, Liya Fu, Liyan Deng, Changyong Wu
更新时间: 2024-06-30
摘要: Petrochemical wastewater (PCWW) treatment poses challenges due to its unique and complex dissolved organic matter (DOM) composition, originating from various industrial processes. Despite the addition of advanced treatment units in PCWW treatment plants to meet discharge standards, the mechanisms of molecular-level sights into DOM reactivity of the upgraded full-scale processes including multiple biological treatments and advanced treatment remain unclear. Herein, we employ water quality indexes, spectra, molecular weight (MW) distribution, and Fourier transform ion cyclotron resonance mass spectrometry to systematically characterize DOM in a typical PCWW treatment plant including influent, micro-oxygen hydrolysis acidification (MOHA), anaerobic/oxic (AO), and micro-flocculation sand filtration–catalytic ozonation (MFSF–CO). Influent DOM is dominated by tryptophan-like and soluble microbial products with MW fractions 〈 1 kDa and 〉 100 kDa, and CHO with lignin and aliphatic/protein structures. MOHA effectively degrades macromolecular CHO (10.86 %) and CHON (5.24 %) compounds via deamination and nitrogen reduction, while AO removes CHOS compounds with MW < 10 kDa by desulfurization, revealing distinct DOM conversion mechanisms. MFSF–CO transforms unsaturated components to less aromatic and more saturated DOM through oxygen addition reactions and shows high CHOS and CHONS reactivity via desulfurization and deamination reactions, respectively. Moreover, the correlation among multiple parameters suggests UV combined with AI as a simple monitoring indicator of DOM to access the chemical composition. The study provides molecular-level insights into DOM for the contribution to the improvement and optimization of the upgraded processes in PCWW.

170. 题目: A complete review on the oxygen-containing functional groups of biochar: Formation mechanisms, detection methods, engineering, and applications
文章编号: N24062906
期刊: Science of the Total Environment
作者: Jiefeng Chen, Junhui Zhou, Wei Zheng, Songqi Leng, Zejian Ai, Weijin Zhang, Zequn Yang, Jianping Yang, Zhengyong Xu, Jianbing Cao, Mingguang Zhang, Lijian Leng, Hailong Li
更新时间: 2024-06-29
摘要: Biochar is a porous carbon material generated by the thermal treatment of biomass under anaerobic or anoxic conditions with wealthy Oxygen-containing functional groups (OCFGs). To date, OCFGs of biochar have been extensively studied for their significant utility in pollutant removal, catalysis, capacitive applications, etc. This review adopted a whole system philosophy and systematically summarizes up-to-date knowledge of formation, detection methods, engineering, and application for OCFGs. The formation mechanisms and detection methods of OCFGs, as well as the relationships between OCFGs and pyrolysis conditions (such as feedstocks, temperature, atmosphere, and heating rate), were discussed in detail. The review also summarized strategies and mechanisms for the oxidation of biochar to afford OCFGs, with the performances and mechanisms of OCFGs in the various application fields (environmental remediation, catalytic biorefinery, and electrode material) being highlighted. In the end, the future research direction of biochar OCFGs was put forward.

171. 题目: Calcium regulates the interactions between dissolved organic matter and planktonic bacteria in Erhai Lake, Yunnan Province, China
文章编号: N24062905
期刊: Water Research
作者: Fan Xia, Zaihua Liu, Yunling Zhang, Qiang Li, Min Zhao, Haibo He, Qian Bao, Bo Chen, Qiufang He, Chaowei Lai, Xuejun He, Zhen Ma, Yongqiang Zhou
更新时间: 2024-06-29
摘要: In recent years, the global carbon cycle has garnered significant research attention. However, details of the intricate relationship between planktonic bacteria, hydrochemistry, and dissolved organic matter (DOM) in inland waters remain unclear, especially their effects on lake carbon sequestration. In this study, we analyzed 16S rRNA, chromophoric dissolved organic matter (CDOM), and inorganic nutrients in Erhai Lake, Yunnan Province, China. The results revealed that allochthonous DOM (C3) significantly regulated the microbial community, and that autochthonous DOM, generated via microbial mineralization (C2), was not preferred as a food source by lake bacteria, and neither was allochthonous DOM after microbial mineralization (C4). Specifically, the correlation between the fluorescence index and functional genes (FAPRPTAX) showed that the degree of utilization of DOM was a critical factor in regulating planktonic bacteria associated with the carbon cycle. Further examination of the correlation between environmental factors and planktonic bacteria revealed that Ca had a regulatory influence on the community structure of planktonic bacteria, particularly those linked to the carbon cycle. Consequently, the utilization strategy of DOM by planktonic bacteria was also determined by elevated Ca levels. This in turn influenced the development of specific recalcitrant autochthonous DOM within the high Ca environment of Erhai Lake. These findings are significant for the exploration of the stability of DOM within karst aquatic ecosystems, offering a new perspective for the investigation of terrestrial carbon sinks.

172. 题目: Critical Review of Fluorescence and Absorbance Measurements as Surrogates for the Molecular Weight and Aromaticity of Dissolved Organic Matter
文章编号: N24062904
期刊: Environmental Science: Processes & Impacts
作者: Julie A Korak, Garrett McKay
更新时间: 2024-06-29
摘要: Dissolved organic matter (DOM) is ubiquitous in aquatic environments and challenging to characterize due to its heterogeneity. Optical measurements (i.e., absorbance and fluorescence spectroscopy) are popular characterization tools, because they are non-destructive, require small sample volumes, and are relatively inexpensive and more accessible compared to other techniques (e.g., high resolution mass spectrometry). To make inferences about DOM chemistry, optical surrogates have been derived from absorbance and fluorescence spectra to describe differences in spectral shape (e.g., E2:E3 ratio, spectral slope, fluorescence indices) or quantify carbon-normalized optical responses (e.g., specific absorbance (SUVA) or specific fluorescence intensity (SFI)). The most common interpretations relate these optical surrogates to DOM molecular weight or aromaticity. This critical review traces the genesis of each of these interpretations and, to the extent possible, discusses additional lines of evidence that have been developed since their inception using datasets comparing diverse DOM sources or strategic endmembers. This review draws several conclusions. More caution is needed to avoid presenting surrogates as specific to either molecular weight or aromaticity, as these physicochemical characteristics are often correlated or interdependent. Many surrogates are proposed using narrow contexts. For example, fractionation of a limited number of samples or dependence on isolates and generalizing interpretations to whole-waters warrants further study. Lastly, there is a broad opportunity to identify why endmembers with low abundance of aromatic carbon (e.g., effluent organic matter, Antarctic lakes) often do not follow systematic trends with molecular weight or aromaticity as observed in endmembers from terrestrial environments with higher plant inputs.

173. 题目: Soil C, N, and P contents and organic phosphorus mineralization in constructed wetlands with different litter input in northern China
文章编号: N24062903
期刊: Journal of Soils and Sediments
作者: Zhiying Tang, Jingxiao Chen, Yinghu Zhang
更新时间: 2024-06-29
摘要:

Purpose

Constructed wetlands have profound influences on efficient wastewater purification and treatment. However, what extent and how different kinds of constructed wetland can effectively influence the distribution of nutrients content and mineralization Specially, whether the response of the changes of soil nutrients content and mineralization to different amounts of litter input was consistent It has not been resolved.

Methods

In this study, five constructed wetland systems (i.e., the Circulating Water Treatment Pond 1 (CW), Recirculating Water Treatment Pond 2 (RCW), Reclaimed Water Treatment Pond (RW), Plant Oxidation Pond (POP), and Mixed Oxidation Pond (MOP)) in the Beijing Olympic Forest Park were studied. CW, RCW, and RW belong to the composite vertical-flow systems, while POP and MOP belong to the free surface systems. Field litter input (5 and 20 g, respectively) with five replicates applied to the constructed wetland systems were conducted. The contents of soil total carbon (TC), soil total nitrogen (TN), soil total phosphorus (TP), and phosphorus mineralization rates were quantified. Ordinary kriging interpolation was used to characterize the spatial distribution of soil TC, TN, TP and phosphorus mineralization rates.

Results

The results showed that the contents of soil TC and TN in the composite vertical-flow systems (CW, RCW, and RW) were greater than those in the free surface systems (POP and MOP), while it was contrary for the content of soil TP. Soil organic phosphorus (accounting for 45.80 ± 8.12%) and inorganic phosphorus (accounting for 51.81 ± 7.46%) were the main components of soil TP. Phosphorus mineralization rates in the composite vertical-flow systems were greater than the free surface systems. The phosphorus mineralization rates were the smallest in MOP (-2.06 mg·kg−1·d−1) and the highest in RW (0.32 mg·kg−1·d−1). Litter input decreased the contents of soil TC and TN in the composite vertical-flow systems and MOP, while increased in POP. Soil TP content after the litter input increased in CW, RCW, and MOP, while decreased in RW and POP. The litter input was beneficial for improving the phosphorus mineralization rates. The effects of 5 g litter input on the changes of the contents of soil TC, TN, TP and phosphorus mineralization rates were stronger than that of 20 g litter input.

Conclusion

Our study has supplemented the inconclusive results of the influences of different constructed wetlands and amounts of litter input on soil nutrient content and mineralization. The findings of this study could provide data support for better constructed wetland management, which could help the managers understand the mechanisms of improving the efficiency of wastewater treatment in constructed wetlands.

174. 题目: Phragmites australis straw and biochar additives regulate soil organic carbon fractions in a degraded coastal salt marsh
文章编号: N24062902
期刊: Ecological Engineering
作者: Guozhu Chen, Junhong Bai, Lu Yu, Wei Wang, Yaqi Wang, Jichen Qiu, Baoshan Cui
更新时间: 2024-06-29
摘要: Severely degraded coastal salt marshes with impaired ecological functions urgently need to be restored to improve blue carbon sequestration. Although plant residues and biochar have been used to restore degraded wetlands, the dose-effects of these plant additives on soil organic carbon fractions in degraded coastal wetlands are still unclear. Here, we investigated the dynamic changes in DOC components and mineral-associated organic carbon, such as calcium-bound organic carbon (Ca-OC) and iron/aluminum-bound organic carbon (Fe/Al-OC), in a degraded coastal salt marsh in a 60-day incubation experiment with low (0.1%), medium (1%), and high (3%) doses of straw (PS) and -derived biochar (PB) addition treatments. The results showed that the medium and high doses of PB additives increased humus-like substances, with the maximum proportion occurring on day 60 of the incubation. The fluorescence index (FI) and biological index (BIX) were >1.9 and 0.8, respectively, and the humification index (HIX) was < 4 in most treatment groups. The mineral-associated organic carbon (Ca-OC and Fe/Al-OC) contents were higher in the 1% PS and 3% PS treatments ( < 0.05). The PS additives increased the soil Ca-OC/SOC and Fe/Al-OC/SOC ratios, whereas the PB additives decreased them. This study demonstrated that PS and PB are potential carbon-rich additives for enhancing soil organic carbon stability and carbon sequestration in coastal wetland restoration projects, contributing to regional carbon neutrality.

175. 题目: Depositional controls and budget of organic carbon burial in fine-grained sediments of the North Sea – the Helgoland Mud Area as a test field
文章编号: N24062901
期刊: Biogeosciences
作者: Daniel Müller, Bo Liu, Walter Geibert, Moritz Holtappels, Lasse Sander, Elda Miramontes, Heidi Taubner, Susann Henkel, Kai-Uwe Hinrichs, Denise Bethke, Ingrid Dohrmann, Sabine Kasten
更新时间: 2024-06-29
摘要: . The burial of organic matter (OM) within fine-grained continental shelf sediments represents one of the major long-term sinks of carbon. We investigated the key factors controlling organic carbon burial in sediments of the Helgoland Mud Area (HMA), which represents the most significant depocentre of fine-grained and organic-rich sediments in the German Bight (SE North Sea). The examined factors include sedimentation and accumulation rates, sediment mixing rates, grain size, total organic carbon (TOC) content and aerobic remineralisation rates. Highest sedimentation rates of up to ~4.5 mm yr-1 and average TOC contents of 2 wt% were found in the southern part of the HMA which is under the influence of the Elbe river outflow. The overall highest organic carbon burial efficiencies of >65 % were also determined in this area. Four times lower sedimentation rates and lowest TOC contents were found in the shallow, eastern part of the research area, with the lowest organic carbon burial efficiencies being 30 %. High sedimentation rates are known to limit oxygen exposure time and thereby enhance OM preservation. Our data support this finding and demonstrate that sedimentation rate is the key factor determining organic carbon burial efficiency and long-term sedimentary carbon storage. The area of the HMA is characterized by varying mixtures of OM from marine and terrestrial sources. In the southern part of the HMA, close to the outflow of the Elbe river, the OM being degraded is primarily of terrigenous origin, while in the central and northern part of the HMA a mixture of marine and terrigenous OM has been shown to be remineralised. At the sites dominated by the degradation of marine organic matter, as found in the western and northwestern HMA, the organic carbon burial efficiency is lower and fluctuates around 55 %. The burial efficiency of OM is highest in sedimentary habitats characterised by high sedimentation rates and OM of terrigenous sources. Our modelled sediment mixing rates were highest in the northwestern HMA, where also the highest bottom trawling activity is reported. The comparison of sites similar in depositional characteristics but different in bottom trawling intensity suggests that in the area of intense bottom trawling in the northwestern HMA the sequestration of OM is reduced by around 30 %. Furthermore, we have determined the annual burial flux of organic carbon in the HMA that amounted to an average of 22.5 g C m-2 yr-1. Considering the strong tidal currents in the shallow HMA, the burial flux is exceptionally high and even compares with those reported for the deeper Skagerrak and Norwegian Trough (~10 to 66 g C m-2 yr-1), which are the main depocentres for fine-grained and organic-rich sediments in the North Sea. For the entire HMA the determined burial flux results in a total annual organic carbon accumulation of 0.011 Tg C yr-1. These findings highlight the importance of depocentres for fine-grained sediments as important carbon sinks: while the area of the HMA represents only 0.09 % of the North Sea it stores 0.76 % of the total annual accumulated organic carbon in this shelf sea area.

176. 题目: Inhibition of zinc ions in sulfur-driven autotrophic denitrification process: What is the behavior of extracellular polymeric substances?
文章编号: N24062820
期刊: Science of the Total Environment
作者: Wen-Jie Ma, Zi-Shang Ma, Han-Min Zhang
更新时间: 2024-06-28
摘要: Sulfur-driven autotrophic denitrification (SAD) process is a cost-effective and sustainable method for nitrogen removal from wastewater. However, a higher concentration of zinc ions (Zn(II)) flowing into wastewater treatment plants poses a potential threat to the SAD process. This study examined that a half maximal inhibitory concentration (IC) of Zn(II) was 7 mg·L in the SAD process. Additionally, the addition of 20 mg·L Zn(II) resulted in a severe accumulation of nitrite to 150.20 ± 6.00 mg·L when the initial concentration of nitrate was 500 mg·L. Moreover, the activities of nitrate reductase, nitrite reductase, dehydrogenase and electron transport system were significantly inhibited under Zn(II) stress. The addition of Zn(II) inhibited EPS secretion and worsened electrochemical properties. The result was attributed to the spontaneous binding between EPS and Zn(II), with a ΔG of −17.50 KJ·mol and a binding constant of 1.77 × 10 M, respectively. Meanwhile, the protein, fulvic acid, and humic-like substances occurred static quenching after Zn(II) addition, with -OH and -C=O groups providing binding sites. The binding sequence was fulvic acid→protein→humic acid and -OH → -C=O. Zn(II) also reduced the content of α-helix, which was unfavorable for electron transfer. Additionally, the Zn(II) loosened protein structure, resulting in a 50 % decrease in α-helix/(β-sheet+random coil). This study reveals the effect of Zn(II) on the SAD process and enhances our understanding of EPS behavior under metal ions stress.

177. 题目: Remote sensing of depth-induced variations in soil organic carbon stocks distribution within different vegetated landscapes
文章编号: N24062819
期刊: Catena
作者: Omosalewa Odebiri, Onisimo Mutanga, John Odindi, Rob Slotow, Paramu Mafongoya, Romano Lottering, Rowan Naicker, Trylee Nyasha Matongera, Mthembeni Mngadi
更新时间: 2024-06-28
摘要: The preservation and augmentation of soil organic carbon (SOC) stocks is critical to designing climate change mitigation strategies and alleviating global warming. However, due to the susceptibility of SOC stocks to environmental and topo-climatic variability and changes, it is essential to obtain a comprehensive understanding of the state of current SOC stocks both spatially and vertically. Consequently, to effectively assess SOC storage and sequestration capacity, precise evaluations at multiple soil depths are required. Hence, this study implemented an advanced Deep Neural Network (DNN) model incorporating Sentinel-1 Synthetic Aperture Radar (SAR) data, topo-climatic features, and soil physical properties to predict SOC stocks at multiple depths (0–30 cm, 30–60 cm, 60–100 cm, and 100–200 cm) across diverse land-use categories in the KwaZulu-Natal province, South Africa. There was a general decline in the accuracy of the DNN model’s prediction with increasing soil depth, with the root mean square error (RMSE) ranging from 8.34 t/h to 11.97 t/h for the four depths. These findings imply that the link between environmental covariates and SOC stocks weakens with soil depth. Additionally, distinct factors driving SOC stocks were discovered in both topsoil and deep-soil, with vegetation having the strongest effect in topsoil, and topo-climate factors and soil physical properties becoming more important as depth increases. This underscores the importance of incorporating depth-related soil properties in SOC modelling. Grasslands had the largest SOC stocks, while commercial forests have the highest SOC sequestration rates per unit area. This study offers valuable insights to policymakers and provides a basis for devising regional management strategies that can be used to effectively mitigate climate change.

178. 题目: Integrated remediation and detoxification of triclocarban-contaminated water using waste-derived biochar-immobilized cells by long-term column experiments
文章编号: N24062818
期刊: Environmental Pollution
作者: Khuanchanok Sonsuphab, Wittawat Toomsan, Somphong Soontharo, Nontipa Supanchaiyamat, Andrew J Hunt, Yuvarat Ngernyen, Sawinee Nasompag, Pradabduang Kiattisaksiri, Thunyalux Ratpukdi, Sumana Siripattanakul-Ratpukdi
更新时间: 2024-06-28
摘要: Triclocarban (TCC), an antibacterial agent commonly used in personal care products, is one of the top ten contaminants of emerging concern in various environmental media, including soil and contaminated water in vadose zone. This study aimed to investigate TCC-contaminated water remediation using biochar-immobilized bacterial cells. strain MC46 (MC46), an efficient TCC-degrading isolate, was chosen, whereas agro-industrial carbonized waste as biochar was directly used as a sustainable cell immobilization carrier. According to the long-term TCC removal performance results (160 d), the biochar-immobilized cells consistently exhibited high TCC removal efficiencies (84–97%), whereas the free MC46 removed TCC for 76–94%. At 100 days, the detachment of the MC46 cells from the immobilized cell column was observed. The micro-Fourier-transform infrared spectroscopy results indicated that extracellular polymeric substance (EPS) was produced, but polysaccharide and protein fractions were washed out of the column. The lipid fraction of EPS adhered to the biochar, promoting TCC sorption for long-term treatment. The shortening of MC46 cells improved the tolerance of TCC toxicity. The TCC-contaminated water was successfully detoxified by the biochar-immobilized MC46 cells. Overall, the waste-derived biochar-immobilized cell system proposed in this study for the removal of emerging contaminants, including TCC, is efficient, economical, and aligned with the sustainable development concept of value-added utilization of waste.

179. 题目: Transport of polystyrene microplastics in bare and iron oxide-coated quartz sand: Effects of ionic strength, humic acid, and co-existing graphene oxide
文章编号: N24062817
期刊: Science of the Total Environment
作者: Dan Zhou, Yanpeng Cai, Zhifeng Yang
更新时间: 2024-06-28
摘要: This research explored the effects of widely utilized nanomaterial graphene oxide (GO) and organic matter humic acid (HA) on the transport of microplastics under different ionic solution strengths in bare sand and iron oxide-coated sand. The results found transport of polystyrene microplastics (PS) did not respond to the presence of HA in sand that contains large amounts of iron oxide. Compared to bare quartz sand, ionic strength had little effect: <20 % of PS passed through Fe sand columns. There was a significant promotion of PS transport in the presence of GO, however, which can be attributed to the increased surface electronegativity of PS and steric hindrance. Moreover, GO combined with HA significantly promoted the transport of PS in the Fe sand, and transport further increased when the concentration of HA increased from 5 to 10 mg/L. Interestingly, the degree of this increase exactly corresponded to the change in the surface charge of the microplastics, demonstrating that electrostatic interaction dominated the PS transport. Further results indicated that co-existing pollutants had significant impacts on the transport of microplastics under various conditions by altering the surface characteristics of the plastic particles and the spatial steric hindrance within porous media. This research will offer insights into predicting the transport and fate of microplastics in complex environments.

180. 题目: Zooplankton fecal pellet flux drives the biological carbon pump during the winter–spring transition in a high‐Arctic system
文章编号: N24062816
期刊: Limnology and Oceanography
作者: Gérald Darnis, Maxime Geoffroy, Malin Daase, Catherine Lalande, Janne E Søreide, Eva Leu, Paul E Renaud, Jørgen Berge
更新时间: 2024-06-28
摘要: Recent research highlighted significant marine biological activity during the Arctic winter, with poorly known implications for the biological carbon pump. We used moored instruments to (1) track the development of the pelagic food web of a high‐Arctic marine ecosystem from winter to spring, and (2) assess the role of zooplankton‐mediated processes in the sinking export of particulate organic carbon (POC). Zooplankton collected by a sediment trap at 40 m depth in Kongsfjorden showed a shift in species composition in February coinciding with an inflow of Atlantic water and the return of sunlight. The Atlantic copepod Calanus finmarchicus and the Arctic Calanus glacialis became dominant in the post‐inflow assemblage of large mesozooplankton. However, large copepods were never abundant (0.3–4.6 ind m−3) in January–April in the upper 40 m. Despite the low chlorophyll fluorescence, POC export increased substantially, from 2–13 mg C m−2 d−1 in January–February to 13–35 mg C m−2 d−1 in March–April 2014. By late March, zooplankton fecal pellets contributed largely (23–100%) to this significant POC export before the phytoplankton bloom. The lack of change in copepod and euphausiid population sizes suggests that enhanced feeding activity in the surface layer supported the increasing fecal pellet export. Our results revealed the swift response of active zooplankton in winter, evidenced by increased carbon export, to improved food availability.

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