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321. 题目: Effects of organic carbon and subsurface dams on saltwater intrusion and nitrate pollution in sandy coastal aquifers
文章编号: N24011314
期刊: Environmental Science and Pollution Research
作者: Chao Gao, Jun Kong, Jun Wang, Yuncheng Wen
更新时间: 2024-01-13
摘要:

This study explores the impact of a novel approach on the levels of SWI (saltwater intrusion) and NO3 (nitrate) contamination. Some numerical simulations were conducted utilizing a coupled model that incorporates variably saturation and density, as well as convection diffusion reaction within a sandy coastal aquifer. We verified the reliability of the model for SWI based on comparison lab experiments and for chemical reactions based on a comparison of previous in situ observations. Cutoff walls and subsurface dams cannot simultaneously control SWI and reduce NO3 contamination. A novel approach that combines subsurface dams and permeable CH2O (organic carbon) walls (PC-Wall) is proposed. Subsurface dams are utilized to prevent SWI, while PC-Walls are employed to mitigate NO3 pollution. Results demonstrate that the construction of a PC-Wall with a concentration of 1.0 mM facilitated a transition from nitrification (Ni)-dominated to denitrification (Dn)-dominated. An increase in CH2O concentration to 1.0 mM caused a significant 1942.5 % rise in mDn (the mass of NO3 removed through Dn). Increment of the distance between the PC-Wall and the ocean from 35 to 45 m could result in a 103.7 % mDn increase and reduce mN (the compound mass of NO3 remaining in the aquifer) by 11.7 %. The study offers a detailed comprehension of the intricate hydrodynamics of SWI and NO3 pollution. In addition, it provides design guidance for engineering to mitigate contamination by NO3 and controlling SWI, thus fostering the management of groundwater quality.

322. 题目: Conversion of biobased substances into biochar to enhances nutrient adsorption and retention capacity
文章编号: N24011313
期刊: Environmental Monitoring and Assessment
作者: Shaon Kumar Das
更新时间: 2024-01-13
摘要:

Reducing the environmental issues brought on by nutrients especially nitrogen pollution and loss is important. Owing to its unique composition and physico-chemical characteristics, biomass-derived biochar exhibits varying degrees of adsorption and interception for all types of soil nutrients. Thus, a novel way to improve nutrient absorption in the soil is to include biomass derived biochar into it. Various biomass-derived biochar from locally available biobased substances was synthesized through low-cost portable charring kiln. It has been quantified the influence of four biobased substances and three pyrolysis temperature on different morphomineralogical characteristics of biochar for utilizing as low-cost sorbent to manage nutrient adsorption and retention capacity. The morphomineralogical characteristics were principally manipulated by feedstocks rather than pyrolysis temperature. Higher porosity and surface area of biomass-derived biochar illustrated its soil structural modification and nutrient retention capacity along with their utilization for adsorbents. With increase in pyrolysis temperature, the adsorption capacity of biochar for NH4+-N and NO3-N was gradually weakened and gradually enhanced respectively. The adsorption process of ammonia nitrogen and nitrate nitrogen conformed to the Langmuir model and the fitted KL value was less than 1 indicating that the adsorption process was uniform monolayer adsorption and the adsorption of biochar was favorable adsorption. With increase in biochar application rate the leaching of NO3-N decreased having higher at 2.5 t ha−1 application rate followed by 5 t ha−1 and lower at 7.5 t ha−1. In packed soil column, the NH4+-N in leachate was maximum in T7 (18.6), followed by T4 (17.9), T13 (17.3) and minimum in T10 (17.2) at same application rate of manures and biochar. Finally, results also revealed that packed soil column performed better as compared with intact soil column to retain soil nutrient and hence, leaching potential of nutrient was less in packed column than intact soil column. In conclusion, biomass-derived biochar can enhance the amount of nutrient that is absorbed into the soil while decreasing the loss of nutrient from the soil in the form of ammonia and nitrate. To sum up, biomass-derived biochar can increase the adsorption amount of the nitrogen and reduce the loss of ammonia nitrogen and nitrate nitrogen in the soil, thus retaining the nitrogen.

323. 题目: Zero-valent iron addition stimulated straw-derived carbon accumulation in submerged soil
文章编号: N24011312
期刊: Soil and Tillage Research
作者: Jinli Hu, Muhammad Shaaban, Yan Wang, Shan Lin, Huabin Li, Xian Wu, Ronggui Hu
更新时间: 2024-01-13
摘要:

Soil organic carbon (SOC) is the key indicator of soil fertility, and its stabilization plays a significant role in terrestrial carbon cycling. The turnover of SOC often interacts with iron due to its active redox characteristics, especially in paddy soils. Zero-valent iron (ZVI) is highly reductive, while how its addition controls SOC turning over in soil received less attention and knowledge gap exists on soil C dynamics. Therefore, we investigated the influence of ZVI addition on soil and straw C dynamics in submerged soil over a period of 30 days in an incubation study. The results showed that ZVI addition enhanced the endogenous Fe(III) reduction, and the exogenous ZVI was oxidized mostly to Fe(II), resulting in substantial Fe(II) accumulation, with the content 33.39–164.9% higher than that in non-ZVI treatments after incubation. At the initial stage of incubation during day 0–10, ZVI addition showed a stimulated effect on OC accumulation as both the cumulative CO2 emission and dissolved organic carbon (DOC) released were reduced in ZVI-amended treatments. This could be attributed to the O2 limitation on OC mineralization caused by the lower oxidation-reduction potential (ORP) by ZVI addition. Besides, endogenous Fe(III) reduction boosted by ZVI addition could release fresh surfaces on Fe mineral for C accumulation by forming organics-Fe mineral complexes. During the latter stage of day 10–30, ZVI addition showed an inhibited effect on OC accumulation as both the cumulative CO2 emission and DOC released were increased in ZVI-amended treatments, and CH4 emission was vigorous after a 10-day lag phase. Labile OC was liberated and vulnerable to decomposition by microorganisms due to the dissolution of OC-Fe(III) oxide complexes as Fe(III) reduction was enhanced by ZVI addition. Furthermore, CH4 emission was promoted by ZVI addition through lowering soil ORP and supplying electrons for methanogenesis. ZVI addition mitigated OC decomposition during the initial stage and stimulated that during the latter stage of incubation. Overall, ZVI addition increased straw C accumulation in the form of insoluble carbon (Caccumulated), but the different responses of C dynamic between days 0–10 and 10–30 led to a statistic insignificant positive effect. However, the association between iron oxides and OC was enhanced in ZVI addition treatments due to the anaerobic corrosion of ZVI, which may increase the stability of OC, indicating a potential to accumulate more straw C in the long term.

324. 题目: The dependence in microcystin removal with powdered activated carbon on variant properties, carbon properties, and dissolved organic matter
文章编号: N24011311
期刊: Chemosphere
作者: Yuzhou Huang, John J Lenhart
更新时间: 2024-01-13
摘要:

Powdered activated carbon (PAC) is commonly used by water treatment plants to remove harmful cyanotoxins such as microcystins (MCs) produced during seasonal harmful algal blooms. MC removal by PAC depends upon the properties of the PAC, the properties of the MC variant, and the presence and properties of dissolved organic matter (DOM). To identify which of these factors has the greatest impact on the removal of MC by PAC, we evaluated the removal of four different MC variants (MC-LR, MC-LA, MC-RR and desmethylated MC-RR) by three different PAC types (wood-based, coal-blend and coal-based). The role of DOM properties was evaluated using DOM isolated from two different sources, a terrestrial source (Suwannee River Fulvic Acid, SRFA) and a microbial source (Grand Lake St Marys DOM, GLSM). The results of adsorption experiments conducted over a period of 72 h demonstrated the wood-based PAC, which had the highest surface area and mesopore volume of the PAC tested, had the highest adsorption rate and capacity for all four MC variants. Of the variants studied, neutrally charged MC-RR was adsorbed more rapidly and to a greater extent on all of the PAC types than were the other variants. Although MC-LA and MC-LR had the greatest hydrophobicity, their negative charges resulted in their being adsorbed the least. As expected, DOM inhibited microcystin adsorption to PAC. The degree of inhibition, however, did not significantly vary for the two DOM types evaluated, indicating the properties of the DOM on MC adsorption to PAC was less important than the PAC properties or MC variant properties. Overall, PAC properties were a more important factor in MC removal than were the MC properties or DOM conditions.

325. 题目: Facilitate the preparation of naturally modified and self-healing superhydrophobic/superoleophilic biochar-based foams for efficient oil-water separation
文章编号: N24011310
期刊: Journal of Hazardous Materials
作者: Kai Hu, Honghong Lyu, Haonan Duan, Zhenzhong Hu, Boxiong Shen
更新时间: 2024-01-13
摘要:

Oil spills are sudden, complex, and long-term hazardous, and the existing adsorption materials still have the disadvantages of small selective adsorption capacity, easy secondary contamination, and difficult to repair after breakage in practical applications. Herein, melamine foam (MF) coated by ball milled biochar (BMBC) and natural beeswax (Wax@BMBC@MF) was prepared by a bio-inspired functionalization method and further added with self-healing function (SH-Wax@BMBC@MF) to cope with complex environments, and applied to oil-water separation for oil adsorption. SEM and FTIR results showed that BMBC and natural beeswax nanoparticles successfully encapsulated the smooth surface of the melamine foam skeleton. The loading of natural beeswax increased the foam's ability to absorb oil and organic solvents from 0.6108-1.134 g to 0.850-1.391 g, and the oil-absorbing capacity of the foam remained at 0. 758-1.263 g after being cut by a knife and self-healing. The oil-absorbing capacity of SH-Wax@BMBC@MF remained in the range of 0.936-1.336 g under acid/alkali environment (pH =1-13). The surface functional groups of BMBC improved the surface roughness of the material and strengthen the MF skeleton to adsorb oils and organic solvents by capillary action. The generation of the di-coordinated structure by Fe3+ and catechol group contributed the restoration of SH-Wax@BMBC@MF structure and oil absorption capacity. SH-Wax@BMBC@MF has superiority of superhydrophobic, superoleophilic, self-healing after damage, and environmental friendliness, which provides a promising solution for the treatment of oil spills at sea.

326. 题目: Highly efficient Ni(II) adsorption by industrial lignin-based biochar: a pivotal role of dissolved substances within biochar
文章编号: N24011309
期刊: Environmental Science and Pollution Research
作者: Yanying He, Qianyi Deng, Liwen Cao, Cheng Luo, Wenjie Zhao, Honglin Tao, Long Chen, Yule Zhu, Jing Zhang, Xueying Mo, Baobin Mi, Fangfang Wu
更新时间: 2024-01-13
摘要:

In the context of carbon neutrality, promoting resource utilization of industrial alkali lignin addressing heavy metal pollution is crucial for China’s pollution alleviation and carbon reduction. Microwave pyrolysis produced functionalized biochar from industrial alkali lignin for Ni(II) adsorption. LB400 achieved 343.15 mg g−1 saturated adsorption capacity in 30 min. Pseudo-second-order kinetic and Temkin isotherm models accurately described the adsorption, which was endothermic and spontaneous (ΔGϴ < 0, ΔHϴ > 0). Quantitative analysis revealed that both dissolved substances and carbon skeleton from biochar contributed to adsorption, with the former predominates (93.76%), including mineral precipitation NiCO3 (Qp) and adsorption of dissolved organic matter (QDOM). Surface complexation (Qc) and ion exchange (Qi) on the carbon skeleton accounted for 6.3%. Higher biochar preparation temperature reduced Ni(II) adsorption by dissolved substances. Overall, biochar which comes from the advantageous disposal of industrial lignin effectively removes Ni(II) contamination, encouraging ecologically sound treatment of heavy metal pollution and sustainable resource utilization.

Graphical abstract

327. 题目: Polysaccharide preferred minority-dominant community assembly and exoenzyme enrichment in transparent exopolymer particles: Implication for global carbon cycle in water
文章编号: N24011308
期刊: Science of the Total Environment
作者: Xiaonan Wang, Jiahao Li, Jieyan Zheng, Lanxin Zhao, Chenghao Ruan, Daoyong Zhang, Xiangliang Pan
更新时间: 2024-01-13
摘要:

The ubiquitous transparent exopolymer particles (TEPs) are an important organic carbon pool and an ideal microhabitat for bacteria in aquatic environments. They play a crucial role in the global carbon cycle. Organic matter transformation and carbon turnover in TEPs strongly depend on the assembly of their associated bacterial communities and enzyme activity. However, the mechanisms of bacterial community assembly and their potential effects on the organic carbon cycle in TEPs are still unclear. In this study, we comparatively explored the community assembly of TEP-associated bacteria and bacterioplankton from surface freshwater using metagenomics. It was found that the bacterial community assembly in TEPs followed a minority-dominant rule and was governed by homogeneous selection. Pseudomonadota and Actinomycetota, which are responsible for polysaccharide degradation, serve as taxon-specific biomarkers among the abundant and diverse bacteria in TEPs. The network of TEP-associated bacteria displayed stronger robustness than that of bacterioplankton. Bin 76 (majorly Acinetobacter) was the overwhelmingly dominant taxa in TEPs, whereas there was no clearly dominant taxa in TEP-free water. Exoenzyme analysis showed that 64 out of 71 identified polysaccharide hydrolases were markedly linked with the dominant bin 76 in TEPs, while no such linkage was observed for bacterioplankton. Generally, Acinetobacter, which is capable of utilizing polysaccharides, is preferred to be assembled in TEPs together with high polysaccharide hydrolase activity. This may significantly accelerate the turnover of organic carbon in the giant global TEP pool. These findings are important for a deep understanding of the carbon cycle in water.

328. 题目: Photochemical demethylation of methylmercury (MeHg) in aquatic systems: A review of MeHg species, mechanisms, and influencing factors
文章编号: N24011307
期刊: Environmental Pollution
作者: Chenghao Yu, Mao Peng, Xiaonan Wang, Xiangliang Pan
更新时间: 2024-01-13
摘要:

Photodemethylation is the major pathway of methylmercury (MeHg) demethylation in surface water before uptake by the food chain, whose mechanisms and influence factors are still not completely understood. Here, we review the current knowledge on photodemethylation of MeHg and divide MeHg photolysis into three pathways: (1) direct photodemethylation, (2) free radical attack, and (3) intramolecular electron or energy transfer. In aquatic environments, dissolved organic matter is involved into all above pathways, and due to its complex compositions, properties and concentrations, DOM poses multiple functions during the PD of MeHg. DOM-MeHg complex (mainly by sulfur-containing molecules) might weaken the C–Hg bond and enhance PD through both direct and indirect pathways. In special, synergistic effects of both strong binding sites and chromophoric moieties in DOM might lead to intramolecular electron or energy transfer. Moreover, DOM might play a role of radical scavenger; while triplet state DOM, which is generated by chromophoric DOM under light, might become a source of free radicals. Apart from DOMs, transition metals, halides, NO3, NO2, and carbonates also act as radical initialaters or scavengers, and significantly pose effects on radical demethylation, which is generally mediated by hydroxyl radicals and singlet oxygen. Environmental factors such as pH, light wavelength, light intensity, dissolved oxygen, salinity, and suspended particles also affect the PD of MeHg. This study assessed previously published works on three major mechanisms, with the goal of providing general estimates for photodemethylation under various environment factors according to know effects, and highlighting the current uncertainties for future research directions.

329. 题目: Effects of biochar pyrolysis temperature on uranium immobilization in soil remediation: revealed by 16 S rDNA and metabolomic analyses
文章编号: N24011306
期刊: Journal of Hazardous Materials
作者: Huachuan Feng, Yilin Wang, Nan Li, Zishu Qian, Tao Chen, Xiaoming Chen, Qing Wang, Wenkun Zhu
更新时间: 2024-01-13
摘要:

Uranium-stressed soil caused by nuclear industry development and energy acquisition have attracted extensive attentions for a long time. This study investigated the effects of biochar application with different pyrolysis temperatures (300℃, 500℃ and 700℃) on remediation of uranium-stressed soil. The results showed that higher pyrolysis temperature (700℃) was benefit for ryegrass growing and caused a lower uranium accumulation in plants. At the same time, uranium immobilization was more effective at higher biochar pyrolysis temperature. Careful investigations indicated that activities of soil urease and sucrase were promoted, and bacterial diversity was strengthened in C700 group, which may contribute to uranium immobilization. The biochar application could activate metabolic of lipids and amino acids, organic acids and derivatives, and organic oxygen compounds. Nicotinate and nicotinamide metabolism, and Benzoxazinoid biosynthesis were unique metabolic pathways in the C700 group, which could enhance the uranium tolerance from different perspectives. Based on these results, we recommend to use biochar with 700°C pyrolysis temperature when processing remediation of uranium-stressed soil. This study will facilitate the implementation of biochar screening and provide theoretical helps for remediation of uranium-stressed soil.

Environmental Implication

Uranium mining is widely conducted, and the resulting issue of soil uranium pollution has garnered significant attention worldwide. Biochar has long been used as an additive for soil improvement and remediation. In this study, we report on the use of biochar produced at different pyrolysis temperatures for phytoremediation of uranium-contaminated soil. The combination of biochar, plant roots, and microorganisms forms a more integrated interacting system, effectively reducing the bioavailable uranium content in the rhizosphere soil, thus facilitating uranium immobilization. Furthermore, the underlying mechanisms of biochar addition in conjunction with phytoremediation have also been elucidated.

330. 题目: Influence of watershed characteristics and human activities on the occurrence of organophosphate esters related to dissolved organic matter in estuarine surface water
文章编号: N24011305
期刊: Science of the Total Environment
作者: Ziyan Ke, Jianfeng Tang, Jing Sun, Qingwei Bu, Lei Yang, Yaoyang Xu
更新时间: 2024-01-13
摘要:

Organophosphate esters (OPEs) are widespread in aquatic environments and pose potential threats to ecosystem and human health. Here, we profiled OPEs in surface water samples of heavily urbanized estuaries in eastern China and investigated the influence of watershed characteristics and human activities on the spatial distribution of OPEs related to dissolved organic matter (DOM). The total OPE concentration ranged from 22.3 to 1201 ng/L, with a mean of 162.6 ± 179.8 ng/L. Chlorinated OPEs were the predominant contaminant group, accounting for 27.4–99.6 % of the total OPE concentration. Tris(2-chloroisopropyl) phosphate, tris(1,3-dichloro-2-propyl) phosphate, and tributyl phosphate were the dominant compounds, with mean concentrations of 111.2 ± 176.0 ng/L, 22.6 ± 21.5 ng/L, and 14.8 ± 14.9 ng/L, respectively. Variable OPE levels were observed in various functional areas, with significantly higher concentrations in industrial areas than in other areas. Potential source analysis revealed that sewage treatment plant effluents and industrial activities were the primary OPE sources. The total OPE concentrations were negatively correlated to the mean slope, plan curvature, and elevation, indicating that watershed characteristics play a role in the occurrence of OPEs. Individual OPEs (triisobutyl phosphate, tris(2-butoxyethyl) phosphate, tris(2-chloroethyl) phosphate, and tricresyl phosphate) and Σalkyl-OPEs were positively correlated to the night light index or population density, suggesting a significant contribution of human activity to OPE pollution. The co-occurrence of OPEs and DOM was also observed, and the fluorescence indices of DOM were found to be possible indicators for tracing OPEs. These findings can elucidate the potential OPE dynamics in response to DOM in urbanized estuarine water environments with intensive human activities.

331. 题目: Changes in chemical fractionation of copper and zinc in soil as a function of incubation moisture content and organic matter amendments
文章编号: N24011304
期刊: Chemosphere
作者: Guo Wang, Gaoussou Cissé, Siobhan Staunton
更新时间: 2024-01-13
摘要:

Copper and zinc are essential micronutrients that are potentially toxic when present in excess in soils. Their bioavailability depends on their speciation in soil, but this may vary with environmental conditions. Aeration and hence redox conditions, and organic matter amendments are among the factors likely to cause variation on metal fractionation. We have monitored the chemical fractionation of both native and added copper and zinc in a clay loam top soil during a 5-month laboratory incubation. The effects of aeration (moist soil or flooded) and addition of two organic matter amendments, alfalfa straw or leaf compost, were studied. Metal spike was more labile than legacy metal, and was slowly redistributed over the incubation period. Organic matter caused short-lived flushes of metals, attributed to metal chelation with soluble organic matter. This effect was greater for straw than for more stable compost. There was no evidence that added organic matter increased the capacity of soil organic matter to immobilise metal. Flooding solubilized soil metal (hydr)oxides, releasing legacy Cu and Zn, but with less effect on the capacity to immobilise metal spike. Effects of flooding and organic matter addition were not additive. Both metals appear to be precipitated as sulphides under reducing conditions, and accounted for in the acid soluble phase. Monitoring the dynamics of metal distribution gives a more comprehensive understanding of underlying processes than would a single measurement, and is closer to in campo conditions than slurry microcosms.

332. 题目: Can natural undisturbed revegetation restores soil organic carbon to levels under native climax vegetation under tropical semiarid climate?
文章编号: N24011303
期刊: Land Degradation & Development
作者: Aline Roma Tomaz, Ademir de Oliveira Ferreira, Rattan Lal, Telmo Jorge Carneiro Amado, Belchior Oliveira Trigueiro da Silva, William Ramos da Silva, Felipe José Cury Fracetto, Thiago Massao Inagaki, Maria Betânia Galvão dos Santos Freire, Elves Obede dos Santos Nunes
更新时间: 2024-01-13
摘要: Land-use change has driven soil carbon stock losses in ecosystems worldwide. Implementing agricultural crops and exploiting forest resources trigger the breakdown of soil aggregates, thus exposing organic matter to microbial decomposition and enhancing carbon dioxide emissions, especially in biomes more susceptible to climate extremes as in the tropical semiarid regions. This study was based on the hypothesis that the undisturbed soil from the dry forest (Caatinga biome under natural revegetation in Brazilian semiarid) would have an improvement in the mass of macroaggregates and recover more than 50% of the soil C stock within 10 years. Thus, a field experiment was conducted to investigate soils from the Caatinga biome under native vegetation, “cowpea cropping” for over 30 years, and soil under natural revegetation for over 10 years, after conventional soil cultivation of maize and cowpea, to determine soil and soil-aggregates carbon stocks and to estimate the recovery rate of these stocks. The proportional mass of aggregates of different sizes and the total stock of particulate organic carbon (POC) were also quantified. The results showed that soil under preserved native vegetation of dry forest Caatinga biome had higher total soil C stock (50.9 Mg ha−1) than that under cowpea cropping (23.2 Mg ha−1) and natural revegetation (45.1 Mg ha−1). The proportional mass of large macroaggregates was higher in soil under native vegetation for all depths. However, soil under cowpea cropping had lower C stocks in macroaggregates, and recovered roughly 63% of the original C stocks, while revegetation recovered 78% of the stock in 10 years. Although the conventional management system for cowpea monoculture aggravated losses in soil carbon stock by more than 50% of the original C stocks, dry forest under natural revegetation recovered 79% of this stock and almost 100% of POC stock in 10 years (~12 Mg ha−1). Furthermore, soil under undisturbed Caatinga dry forest achieved C stock levels equivalent to that of the global average range for semiarid tropical environments. The high recovery rate of C stock in forest soil under natural revegetation indicates the resilience potential of organisms responsible for structural protection of aggregates and the encapsulated soil organic matter content.

333. 题目: Anthropogenic Activities Enhance Mercury Methylation in Sediments of a Multifunctional Lake: Evidence from Dissolved Organic Matter and Mercury-methylating Microorganisms
文章编号: N24011302
期刊: Journal of Hazardous Materials
作者: Juan Wang, Qing Xie, Yuping Xiang, Jinping Xue, Tao Jiang, Cheng Zhang, Jiajia Li, Yongmin Wang, Dingyong Wang
更新时间: 2024-01-13
摘要:

Multifunctional lakes are highly susceptible to anthropogenic influences, potentially introducing exogenous pollutants or nutrients into aquatic sediments. This, in turn, affects the mercury (Hg) methylation in the sediment. This study was conducted in the Changshou Lake, a representative multifunctional lake in southwestern China, with a specific focus on investigating the Hg variations, the potential of Hg methylation, and the influential factors affecting the methylation process within sediments across different functional areas. The results revealed significant variations in total mercury concentrations between the ecological culture area (area I), the ecological tourism area (area II), and the wetland protection area (area III), suggesting the possibility of exogenous Hg introduction associated with human activities. Furthermore, sediments from areas I and II displayed a greater potential for Hg methylation. This was ascribed to the enhanced diversity and relative abundance of Hg-methylating microorganisms, especially Geobacteraceae, induced by elevated levels of dissolved organic carbon in these two areas from human activities like historical cage culture. This study provides evidence that anthropogenic activities enhance the process of Hg methylation in the sediments of multifunctional lakes, highlighting the necessity of implementing comprehensive scientific water quality management practices to mitigate the negative impacts of human influences on these unique ecosystems.

Environmental Implication

Multifunctional lakes are commonly subjected to direct or indirect anthropogenic influences, potentially introducing exogenous pollutants or nutrients into aquatic sediments. Sediments serve as a hotspot for Hg methylation. Nevertheless, numerous extensive human activities probably play crucial but unclear roles in sediment MeHg formation in multifunctional lakes. Therefore, it is worth figuring out the effects of human activities on MeHg production and its primary influencing factors, which would provide new insights into the elevated MeHg production in sediment of multifunctional lake. This is certainly informative to the research community of mercury-related issues and within the scope of JHM.

334. 题目: The ability of soils to aggregate, more than the state of aggregation, promotes protected soil organic matter formation
文章编号: N24011301
期刊: Geoderma
作者: Rebecca J Even, M Francesca Cotrufo
更新时间: 2024-01-13
摘要:

Efforts to increase soil organic carbon (SOC) are pursued as a viable climate change mitigation strategy. Boosting SOC stocks requires increasing plant carbon (C) inputs and promoting their persistence in SOC. In well aerated mineral soils, water soluble inputs are expected to stabilize through chemical binding to minerals, forming mineral-associated organic carbon (MAOC) before or after microbial transformation, while structural inputs are expected to stabilize as particulate organic carbon (POC) via protection in soil aggregates. Although ample research is centered on the effects of soil aggregation, its disturbance (e.g., tillage), and microbial processing on SOC cycling, we still lack mechanistic understanding of how plant C input type (i.e., soluble versus structural) and disturbance (i.e., aggregate disruption) independently and in interaction affect POC and MAOC formation and stabilization in soils with inherently different degrees of aggregation.

To this end, using 13C enriched structural and soluble plant inputs, we traced SOC formation and stabilization in a lab incubation experiment in soils with differing levels of aggregation, and capacity to form aggregates after disturbance. Our results showed that soluble plant inputs contributed substantially to MAOC and that higher formation and persistence of MAOC occurred in the highly aggregated soil. Moreover, the highly aggregated soil retained more soluble inputs stabilized as MAOC when disturbed. Disturbance in this fine textured, organic carbon rich soil stimulated regeneration of aggregates around structural plant inputs leading to greater persistence of aggregate-occluded POC. Soluble plant inputs, specifically, as well as structural plant inputs in the highly aggregated disturbed soil, compensated for SOC lost due to disturbance alone.

Overall, this study provides mechanistic evidence suggesting that management strategies for SOC accrual should consider soil type, aggregation potential, and plant attributes to inform decisions surrounding tillage frequency and cropping regimes. Our mechanistic findings require testing. If confirmed in the field, they would suggest that no disturbance in tandem with high structural plant C inputs would benefit most SOC accrual in systems with soils that have little capacity to form organo-mineral complexes, including large aggregates. On the contrary, with sustained plant inputs, occasional disturbance in systems with soils that have a high capacity to form organo-mineral complexes can promote both POC and MAOC formation and stabilization.

335. 题目: Archaeal lipid biomarkers in near-surface sediments at a giant colony of the bivalve Calyptogena: molecular records of a massive methane release event associated with methane hydrate dissociation
文章编号: N24011213
期刊: Organic Geochemistry
作者: Susumu Sakata, Urumu Tsunogai, Masahiro Oba, Tomomi Ujiie, Manabu Tanahashi
更新时间: 2024-01-12
摘要:

To investigate the possibility that dissociation of subsurface methane hydrate (MH) in the eastern Nankai Trough, offshore of Japan, led to the formation of a giant colony of the bivalve Calyptogena (currently mostly dead), the carbon isotope ratios (δ13C) of archaeal lipids and methane were measured in near-surface core sediments at Daini-Tenryu Knoll. The irregular variation of porewater methane δ13C with depth (from −75‰ to −26‰) suggested that originally low-δ13C microbial methane was degraded in different proportions by anaerobic methane oxidation. Consistent with this inference, biomarkers of anaerobic methanotrophic archaea (ANME), namely, crocetane (2,6,11,15-tetramethylhexadecane), PMI (2,6,10,15,19-pentamethylicosane), and diethers (archaeol and hydroxyarchaeols), were detected in lipid extracts. The low diether δ13C values (−121‰ to −104‰) were characteristic of ANME, but less variable than the methane δ13C values, and the relationships between diethers and methane δ13C values deviated from regression lines derived using worldwide data from modern methane seep sites. In contrast, δ13C values of the ANME source methane predicted from those regression lines and the diether δ13C values agreed well with methane δ13C values in MH samples obtained by nearby deep drilling. This result strongly suggests that most of the diethers were produced by ANME that proliferated during a past massive methane release event associated with MH dissociation. The crocetane δ13C value, measured in a mixture with phytane and estimated from the correlation of the δ13C of the mixture with the mole fraction of crocetane, was about −127‰. More than half of the PMI δ13C values were greater than −100‰, suggesting the background presence of fossil PMI from methanogens.

336. 题目: Self-motivated photoaging of microplastics by biochar-dissolved organic matter under different pyrolysis temperatures
文章编号: N24011212
期刊: Science of the Total Environment
作者: Saisai Guo, Linan Liu, Honghong Lyu, Weitao Liu, Yuhe He, Jingchun Tang
更新时间: 2024-01-12
摘要:

Dissolved organic matter (DOM) released from biochar (BDOM) can interact with microplastics (MPs) in the environment, inevitably affecting their environmental behaviour. Information regarding the influence of BDOM on MPs during photoaging and associated variations in the MP aging mechanism remains unclear. This study evaluated the effect of BDOM on the aging of polystyrene (PS) MPs. The results showed that among three pyrolysis temperatures, low-temperature BDOM significantly enhanced the photoaging process of PS MPs, with the smallest average particle size and highest carbonyl index value after 15 days of aging under light conditions. The DOM level decreased after 5 days, increased after 5–10 days, and stabilised after 15 d. BDOM accelerates PS MPs aging, leading to more DOM released from PS, which can be transformed into 1O2 via triplet-excited state (3DOM and 3PS) to further enhance PS MPs aging, resulting in the realisation of the self-accelerated aging process of PS MPs. 1O2 plays a crucial role in the self-motivated accelerated aging process of PS MPs. These findings provide new insights into the effects of the DOM structure and composition on reactive oxygen species generation during MPs aging.

337. 题目: Cotton farmers’ intention to adopt biochar as climate change adaptation and sustainable land management strategy in Benin
文章编号: N24011211
期刊: Journal of Cleaner Production
作者: Fèmi E Hounnou, Albertine M Houessou, Faith O Kasim, Jacob A Yabi
更新时间: 2024-01-12
摘要:

Innovative agricultural practices represent the future of the world in the sustainable improvement of agricultural productivity. Sustainable farming practices have been recognized and accepted by agricultural development stakeholders, to provide a wide range of social, economic, financial, and environmental benefits. Despite this recognition, the application of these practices in the literature has focused on socio-economic and technical aspects while the psychosocial elements of the application have received limited attention. To contribute to a broad understanding of the concept, this study aims at analyzing the psychosociological motivations of cotton farmers to use biochar as a sustainable land management strategy. Adopting a survey research design, a sample of 528 farmers in Benin (West Africa) was interviewed on the pillars of the Theory of Planned Behavior (TPB) (Attitude, Subjective norms, Behavioral Control) and three other aspects (Climate change perception, Past behavior and Productivity risk perception) for an extension of TPB. The data collected were analyzed using the structural equation model of the SmartPLS 4 program. The results of this study confirmed all TPB relationships except for the construction of the “Attitude pillar where Perceived ease of use had no significant influence. Apart from the classical TPB factors, perception of climate change and past behavior in adopting new agricultural practices positively affect the application of biochar. However, possible yield decreases at the beginning of biochar use demotivate farmers to take initiatives in this direction. The study notes that the role of a good perception and knowledge of the effects of climate change and the benefits of biochar action are elements to be considered in promoting sustainable cotton farming and agricultural practices.

338. 题目: Artificial humic acid coated ferrihydrite strengthens the adsorption of phosphate and increases soil phosphate retention
文章编号: N24011210
期刊: Science of the Total Environment
作者: Shuang Gai, Bing Liu, Yibo Lan, Lin Han, Yixiong Hu, Guanghao Dongye, Kui Cheng, Zhuqing Liu, Fan Yang
更新时间: 2024-01-12
摘要:

Phosphorus (P) leaching loss from farmland soils is one of the main causes of water eutrophication. Thus, effective methods must be developed to maintain sustainability in agricultural soils. Herein, we design artificial humic acid (A-HA) coated ferrihydrite (Fh) particles for fixing phosphate in soil. The experiments in water and soil are successively conducted to explore the phosphorus adsorption mechanism and soil phosphorus retention performance of A-HA coated ferrihydrite particles (A-Fh). Compared with unmodified ferrihydrite (Fh), the phosphate adsorption capacity of A-Fh is increased by 15 %, and the phosphate adsorption speed and selectivity are also significantly improved. The ligand exchange, electrostatic attraction and hydrogen bonding are the dominant mechanisms of phosphate adsorption by A-Fh. In soil experiments, the addition of 2 % A-Fh increases the soil P retention performance from 0.15 to 0.7 mg/kg, and A-Fh are able to convert more phosphate adsorbed by itself into soil available P to improve soil fertility. Overall, this work highlights the importance of this a highly effective amendment for improving poor soils.

339. 题目: Seasonal and daily patterns in known dissolved metabolites in the northwestern Sargasso Sea
文章编号: N24011209
期刊: Limnology and Oceanography
作者: Krista Longnecker, Melissa C Kido Soule, Gretchen J Swarr, Rachel J Parsons, Shuting Liu, Winifred M Johnson, Brittany Widner, Ruth Curry, Craig A Carlson, Elizabeth B Kujawinski
更新时间: 2024-01-12
摘要: Organic carbon in seawater plays a significant role in the global carbon cycle. The concentration and composition of dissolved organic carbon reflect the activity of the biological community and chemical reactions that occur in seawater. From 2016 to 2019, we repeatedly sampled the oligotrophic northwest Sargasso Sea in the vicinity of the Bermuda Atlantic Time-series Study site (BATS) to quantitatively follow known compounds within the pool of dissolved organic matter in the upper 1000 m of the water column. Most metabolites showed surface enrichment, and 83% of the metabolites had significantly lower concentrations with increasing depth. Dissolved metabolite concentrations most notably revealed temporal variability. Fourteen metabolites displayed seasonality that was repeated in each of the 4 yr sampled. Concentrations of vitamins, including pantothenic acid (vitamin B5) and riboflavin (vitamin B2), increased annually during winter periods when mixed layer depths were deepest. During diel sampling, light-sensitive riboflavin decreased significantly during daylight hours. The temporal variability in metabolites at BATS was less than the spatial variability in metabolites from a previous sample set collected over a broad latitudinal range in the western Atlantic Ocean. The metabolites examined in this study are all components of central carbon metabolism. By examining these metabolites at finer resolution and in a time-series, we begin to provide insights into the chemical compounds that may be exchanged by microorganisms in marine systems, data which are fundamental to understanding the chemical response of marine systems to future changes in climate.

340. 题目: Unraveling the mechanisms behind sodium persulphate-induced changes in petroleum-contaminated aquifers’ biogeochemical parameters and microbial communities
文章编号: N24011208
期刊: Chemosphere
作者: Yuqi Qi, Jun Zeng, Junshi Tao, Rentao Liu, Renchuan Fu, Chao Yan, Xiao Liu, Na Liu, Yanru Hao
更新时间: 2024-01-12
摘要:

Sodium persulphate (PS) is a highly effective oxidising agent widely used in groundwater remediation and wastewater treatment. Although numerous studies have examined the impact of PS with respect to the removal efficiency of organic pollutants, the residual effects of PS exposure on the biogeochemical parameters and microbial ecosystems of contaminated aquifers are not well understood. This study investigates the effects of exposure to different concentrations of PS on the biogeochemical parameters of petroleum-contaminated aquifers using microcosm batch experiments. The results demonstrate that PS exposure increases the oxidation-reduction potential (ORP) and electrical conductivity (EC), while decreasing total organic carbon (TOC), dehydrogenase (DE), and polyphenol oxidase (PO) in the aquifer. Three-dimensional excitation-emission matrix (3D-EEM) analysis indicates PS is effective at reducing fulvic acid-like and humic acid-like substances and promoting microbial metabolic activity. In addition, PS exposure reduces the abundance of bacterial community species and the diversity index of evolutionary distance, with a more pronounced effect at high PS concentrations (31.25 mmol/L). Long-term (90 d) PS exposure results in an increase in the abundance of microorganisms with environmental resistance, organic matter degradation, and the ability to promote functional genes related to biological processes such as basal metabolism, transmission of genetic information, and cell motility of microorganisms. Structural equation modeling (SEM) further confirms that ORP and TOC are important drivers of change in the abundance of dominant phyla and functional genes. These results suggest exposure to different concentrations of PS has both direct and indirect effects on the dominant phyla and functional genes by influencing the geochemical parameters and enzymatic activity of the aquifer. This study provides a valuable reference for the application of PS in ecological engineering.

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