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361. 题目: Effect of fenton-like reactions on the hydrolysis efficiency of lignocellulose during rice straw composting based on genomics and metabolomics sequencing
文章编号: N23021902
期刊: Journal of Cleaner Production
作者: Di Wu, Hao Ren, Yue Zhao, Zimin Wei, Jie Li, Caihong Song
更新时间: 2023-02-19
摘要:

The purposes of this study were to explore the effect of Fenton-like reactions on the hydrolysis efficiency of lignocellulose and the formation mechanism of humic substance (HS) during rice straw composting based on genomics and metabolomics sequencing. The inoculation of Aspergillus fumigatus and adding Fe (II) into compost were used to establish Fenton-like reactions. Fenton-like reactions have been successfully established in vitro and in the composting process. In addition, Fenton-like reactions increased HS and humic acid concentration by 96.38% and 255.80%, respectively, further promoting the humification process. The key differential lignocellulose-degrading products in the Fenton-like reactions, especially for maltose, glucose, xylose, galactose, phenols, butyrophenone, vanillin, syringe acid, vanillic acid hydroxycinnamic acid and benzoic acid, were identified. Additionally, network analysis was divided into four modular microbes in the fungal network. The functional fungal modules' functions and their related influencing factors showed essential roles in the hydrolysis efficiency of lignocellulose and HS formation during composting. This research provides new insight into the hydrolysis efficiency of lignocellulose and then promotes the formation of HS in the Fenton-like reactions during agricultural waste composting.

362. 题目: Introducing the soil mineral carbon pump
文章编号: N23021901
期刊: Nature Reviews Earth & Environment
作者: Ke-Qing Xiao, Yao Zhao, Chao Liang, Mingyu Zhao, Oliver W Moore, Alba Otero-Fariña, Yong-Guan Zhu, Karen Johnson, Caroline L Peacock
更新时间: 2023-02-19
摘要: Microorganisms and minerals both contribute to organic carbon preservation and accumulation in soil. The soil microbial carbon pump describes the microbial processes, but a separate soil mineral carbon pump needs to be acknowledged and investigated.

363. 题目: Increased soil carbon storage through plant diversity strengthens with time and extends into the subsoil
文章编号: N23021811
期刊: Global Change Biology
作者: Markus Lange, Nico Eisenhauer, Hongmei Chen, Gerd Gleixner
更新时间: 2023-02-18
摘要: Soils are important for ecosystem functioning and service provisioning. Soil communities and their functions, in turn, are strongly promoted by plant diversity, and such positive effects strengthen with time. However, plant diversity effects on soil organic matter have mostly been investigated in the topsoil, and there are only very few long-term studies. Thus, it remains unclear if plant diversity effects strengthen with time and to which depth these effects extend. Here, we repeatedly sampled soil to one-meter depth in a long-term grassland biodiversity experiment. We investigated how plant diversity impacted soil organic carbon and nitrogen concentrations and stocks and their stable isotopes ¹³C and ¹⁵N, as well as how these effects changed after five, ten, and 14 years. We found that higher plant diversity increased carbon and nitrogen storage in the topsoil since the establishment of the experiment. Stable isotopes revealed that this increase was associated with new plant-derived inputs, resulting in less processed and less decomposed soil organic matter. In subsoils, mainly the presence of specific plant functional groups drove organic matter dynamics. For example, the presence of deep-rooting tall herbs decreased carbon concentrations, most probably through stimulating soil organic matter decomposition. Moreover, plant diversity effects on soil organic matter became stronger in topsoil over time and reached subsoil layers, while the effects of specific plant functional groups in subsoil progressively diminished over time. Our results indicate that after changing the soil system the pathways of organic matter transfer to the subsoil need time to establish. In our grassland system, organic matter storage in subsoils was driven by the redistribution of already stored soil organic matter from the topsoil to deeper soil layers, e.g., via bioturbation or dissolved organic matter. Therefore, managing plant diversity may thus have significant implications for subsoil carbon storage and other critical ecosystem services.

364. 题目: Chemodiversity of soil organic matters determines biodegradation of polychlorinated biphenyls by a graphene oxide-assisted bacterial agent
文章编号: N23021810
期刊: Journal of Hazardous Materials
作者: Ran Li, Ying Teng, Yi Sun, Yongfeng Xu, Zuopeng Wang, Xia Wang, Wenbo Hu, Wenjie Ren, Ling Zhao, Yongming Luo
更新时间: 2023-02-18
摘要:

A promising strategy for degrading persistent organic pollutants (POPs) in soil is amendment with nanomaterial-assisted functional bacteria. However, the influence of soil organic matter chemodiversity on the performance of nanomaterial-assisted bacterial agents remains unclear. Herein, different types of soil (Mollisol soil, MS; Ultisol soil, US; and Inceptisol soil, IS) were inoculated with a graphene oxide (GO)-assisted bacterial agent (Bradyrhizobium diazoefficiens USDA 110, B. diazoefficiens USDA 110) to investigate the association between soil organic matter chemodiversity and stimulation of polychlorinated biphenyl (PCB) degradation. Results indicated that the high-aromatic solid organic matter (SOM) inhibited PCB bioavailability, and lignin-dominant dissolved organic matter (DOM) with high biotransformation potential was a favored substrate for all PCB degraders, which led to no stimulation of PCB degradation in MS. Differently, high-aliphatic SOM in US and IS promoted PCB bioavailability. The high/low biotransformation potential of multiple DOM components (e.g., lignin, condensed hydrocarbon, unsaturated hydrocarbon, etc.) in US/IS further resulted to the enhanced PCB degradation by B. diazoefficiens USDA 110 (up to 30.34%) /all PCB degraders (up to 17.65%), respectively. Overall, the category and biotransformation potential of DOM components and the aromaticity of SOM collaboratively determine the stimulation of GO-assisted bacterial agent on PCB degradation.

365. 题目: Non-metal activated peroxydisulfate by straw biochar for tetracycline hydrochloride oxidative degradation: catalytic activity and mechanism.
文章编号: N23021809
期刊: Environmental Science and Pollution Research
作者: Chen Chen, Hao Sun, Shengyu Zhang, Xiaosi Su
更新时间: 2023-02-18
摘要: In this study, stalk biochar (BC) was prepared by a high-temperature pyrolysis process and used as a non-metallic catalyst to activate peroxydisulfate (PDS) to degrade tetracycline hydrochloride (TCH). Various characterization results showed that BC had a hollow tubular structure, irregular folds, and important active sites such as oxygen-containing functional groups. Under the optimal reaction conditions, the degradation rate of TCH reached 98.1% within 120 min. In addition, the degradation performance was satisfactory and similar under acidic and near neutral pH, and higher temperature promoted the degradation of TCH. The SO4·-, ·OH, and 1O2 generated by PDS activation were reactive oxygen species (ROS), which degraded TCH through free radical/non-radical synergistic pathways. Quenching experiments proved that the generated SO4·- and ·OH might be the dominant reactive oxygen species (ROS) during the oxidative reaction. The research results will provide a theoretical basis for the application of PDS activated by non-metallic catalysts in the remediation of tetracycline antibiotics pollution.

366. 题目: Differential trends in iron concentrations of boreal streams linked to catchment characteristics
文章编号: N23021808
期刊: Global Biogeochemical Cycles
作者: M Škerlep, S Nehzati, R A Sponseller, P Persson, H Laudon, E S Kritzberg
更新时间: 2023-02-18
摘要: Increasing iron (Fe) concentrations have been reported for freshwaters across northern Europe over the last decades. This increase, together with elevated concentrations of dissolved organic carbon (DOC), leads to browning of freshwaters, which affects aquatic organisms, ecosystem functioning, biogeochemical cycles, and brings challenges to drinking water production. Yet, how such increasing trends in stream Fe concentrations reflect the contribution of different catchment sources remains poorly resolved. Here, we explored how catchment characteristics, i.e., mires and coniferous soils, regulate spatial and temporal patterns of Fe in a boreal stream network. For this, we determined Fe speciation in riparian soils and a mire, and studied temporal Fe dynamics in soil-water and stream-water over a span of 18 years. Positive Fe trends were found in solution of the riparian soil, while no long-term trend was observed in the mire. These differences were reflected in stream-water, where three headwater streams dominated by coniferous cover also displayed positive Fe trends, whereas the mire dominated stream showed no trend. Surprisingly, the majority of higher order streams showed declining Fe trends, despite long-term increases in DOC. In addition, we found that an extreme drought event led to a prolonged release of Fe and DOC from the riparian soils, that could have long-term effects on stream Fe concentrations. Our results show that riparian forest soils can be major contributors to ongoing increases in freshwater Fe concentrations and that drought can further promote release of Fe from organic soils.

367. 题目: Role of environmental factors on concentrations and ratios of subsoil C–N–P in subtropical paddy fields
文章编号: N23021807
期刊: Journal of Soils and Sediments
作者: Yuting Dai, Ping Zhou, Xiaobin Guo, Pei Luo, Xiangbi Chen, Jinshui Wu
更新时间: 2023-02-18
摘要:

Purpose

Environmental controls of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) in the subsoil are important for understanding nutrient cycles; however, these are poorly understood in subtropical paddy soils, especially lacking systematic regional soil profile investigations in the subsoil. The study aims to evaluate the role of environmental factors on concentrations and ratios of SOC, TN, and TP in subsoil (20–100 cm) vs. topsoil (0–20 cm).

Methods

We sampled 166 soil cores (1-m depth) from paddy fields across 10 typical counties in 4 provinces of subtropical China. Soil properties of SOC, TN, TP, pH, bulk density, and clay were determined in each soil layer. Spearman correlation analysis and random forest model were performed to correlate environmental factors with soil nutrients and to rank their relative importance throughout the soil profile.

Results

SOC was strongly coupled with TN and both decreased with soil depth. However, TP was high in topsoil and did not change in the subsoil. Thus, the soil C to N ratio (12.88–14.93) exhibited minimal variation, whereas N to P (30.93–68.99) and C to P (2.52–5.59) ratios decreased markedly with the soil depth. As compared with topsoil, subsoil revealed similar dominant negative effects of climate (temperature, precipitation) and bulk density on the concentrations and ratios of SOC, TN, and TP. The soil clay had no effect on SOC and TN, but was the dominant control on TP throughout the soil profile. The influences of straw incorporation and chemical fertilization on SOC and TN were primarily observed in topsoil.

Conclusions

There were dominant climate controls (temperature and precipitation) of soil C–N–P concentrations and ratios in the subsoil, although different soil factors control SOC and TN vs. TP. These findings highlight the importance of managing subsoil nutrients in subtropical paddy soils, since they are consistently sensitive to climate as topsoil nutrients.

368. 题目: Characterizing the effects of stormwater runoff on dissolved organic matter in an urban river (Jiujiang, Jiangxi province, China) using spectral analysis.
文章编号: N23021806
期刊: Environmental Science and Pollution Research
作者: Keting Yuan, Qiong Wan, Beibei Chai, Xiaohui Lei, Aiqing Kang, Jianghai Chen, Xiang Chen, Hongwei Shi, Lixin He, Ming Li
更新时间: 2023-02-18
摘要: The effect of stormwater runoff on dissolved organic matter (DOM) in rivers is one of the central topics in water environment research. Jiujiang is one of the first cities established in the green development demonstration zone of the Yangtze River Economic Belt (Jiangxi Province, China). Three-dimensional excitation-emission matrix fluorescence with parallel factor analysis (3DEEM-PARAFAC) and ultraviolet-visible (UV-Vis) spectroscopy were used to explore the effects of runoff on organic matter in Shili River (Jiujiang, Jiangxi Province, China). The results show that the runoff led to an increase of some critical pollutants and DOM concentrations, especially in the middle reaches of the river. The concentration and relative molecular weight of DOM in water increased as a result of runoff. Three humic-like (C1-C3) and two protein-like (C4 and C5) components of DOM were identified using the PARAFAC model. The sources of the three humic-like components (C1, C2, C3) were consistent, unlike those of the protein-like component C4. Compared with the pre-rainfall period, the content of humus compounds flowing into the river through the early rainwater runoff was lower, which caused the relative content and proportion of humic substances little change and protein-like species increasing. The DOM mainly derived from autochthonous sources, and runoff had limited effect on its characteristics. Jiujiang is a key demonstration city for Yangtze River conservation. Rainwater runoff is one of the pollution sources of urban rivers, which leads to the deterioration of water quality and influences the distribution characteristics of DOM in water bodies. The PARAFAC components could adequately represent different indicators and sources of DOM in urban rivers, providing an important reference for urban river management.

369. 题目: The characteristic difference between non-drilosphere and drilosphere-aged biochar: Revealing that earthworms accelerate the aging of biochar
文章编号: N23021805
期刊: Chemosphere
作者: Jie Wang, Jiaqiang Liu, Luo Chang, Yuting Pan, Lulu Zhai, Zhenguo Shen, Liang Shi, Yahua Chen
更新时间: 2023-02-18
摘要:

Numerous researches have been conducted on the effects of biotic and abiotic-induced aging on the physicochemical characteristics and functions of biochar; however, the impacts of earthworm-induced aging on biochar have not been reported. Hence, we conducted a microscopic experiment simulating a ‘drilosphere’ to explore the influence of earthworm activity on the natural aging of rice husk biochar (RHBC) through the difference in biochar characteristics after aging in drilosphere and non-drilosphere. The earthworm activity increases the available nitrogen (AN) and dissolved organic matter (DOM) contents of aged RHBC and changes its composition. The increase of DOM and AN content may recruit more microorganisms to colonize biochar and accelerate the biological oxidation of biochar. Furthermore, earthworm activity significantly increased the contents of oxygen (O) and O-containing functional groups in the aged RHBC and decreased the stability (aromaticity) of the aged RHBC, suggesting that the earthworm activity accelerates the natural aging of biochar. Earthworm feeding promotes physical damage to biochar. Besides, the earthworm activity decreased the pH, hydrophilicity and specific surface area (SSA) of aged RHBC but enhanced the adsorption capacity of aged RHBC for heavy metals. The higher content of O-containing functional groups on the surface of drilosphere-aged RHBC was the main reason for its higher adsorption performance. Earthworm feeding promotes physical damage to biochar. These results indicate that earthworm activity can accelerate the natural aging of biochar and alter its physicochemical characteristics and functions. This study illustrates how biochar characteristics change in earthworm-soil systems, which will help scientifically evaluate the long-term effectiveness of biochar.

370. 题目: Machine learning models for the prediction of total yield and specific surface area of biochar derived from agricultural biomass by pyrolysis
文章编号: N23021804
期刊: Environmental Technology & Innovation
作者: Abdul Hai, G Bharath, Muhamad Fazly Abdul Patah, Wan Mohd Ashri Wan Daud, Rambabu K., PauLoke Show, Fawzi Banat
更新时间: 2023-02-18
摘要:

Organic biomass pyrolysis to produce biochar is a viable approach to sustainably convert agricultural residues. The yield and SSA of biochar are contingent upon the biomass type and pyrolysis conditions, and their quantification necessitates the investment of time, energy, and resources. Therefore, in this study, data from 46 different types of biomass were extracted from the published literature and modelled based on a supervised machine learning approach with five different regression algorithms to predict the total yield and SSA of biochar. In general, the collected data were processed using a data exploration technique to remove outliers. The correlation between input variables was examined using the Pearson correlation coefficient method to eliminate highly correlated input variables, and the assorted data was further imputed for developing predictive models. The yield and SSA of biochar were predicted by feature importance analysis to reduce the computational complexity and latency of the model. Out of the 14 input variables, 9 were selected based on feature importance and redundancy, wherein pyrolysis temperature demonstrated the greatest relative importance of 33.6% in predicting targets. Compared to other models developed to predict total biochar yield and SSA, Random Forests performs better, having a maximum R² value of 85% and a minimum absolute root mean squared error (RMSE) for both biochar yield and SSA. Therefore, the developed models could help predict total biochar yield and SSA for a variety of agricultural biomasses without the need for complex and energy-intensive pyrolysis experiments.

371. 题目: Soil amended with Algal Biochar Reduces Mobility of deicing salt contaminants in the environment: An atomistic insight
文章编号: N23021803
期刊: Chemosphere
作者: Farideh Pahlavan, Hamid Ghasemi, Hessam Yazdani, Elham H Fini
更新时间: 2023-02-18
摘要:

Soil-based filter media in green infrastructure buffers only a minor portion of deicing salt in surface water, allowing most of that to infiltrate into groundwater, thus negatively impacting drinking water and the aquatic ecosystem. The capacity of the filter medium to adsorb and fixate sodium (Na⁺) and chloride (Cl⁻) ions has been shown to improve by biochar amendment. The extent of improvement, however, depends on the type and density of functional groups on the biochar surface. Here, we use density functional theory (DFT) and molecular dynamics (MD) simulations to show the merits of biochar grafted by nitrogenous functional groups to adsorb Cl⁻. Our group has shown that such functional groups are abundant in biochar made from protein-rich algae feedstock. DFT is used to model algal biochar surface and its possible interactions with Cl⁻ through two possible mechanisms: direct adsorption and cation (Na⁺)-bridging. Our DFT calculations reveal strong adsorption of Cl⁻ to the biochar surface through hydrogen bonding and electrostatic attractions between the ions and active sites on biochar. MD results indicate the efficacy of algal biochar in delaying chloride diffusion. This study demonstrates the potential of amending soils with algal biochar as a dual-targeting strategy to sequestrate carbon and prevent deicing salt contaminants from leaching into water bodies.

372. 题目: Reconciling the paradox of soil organic carbon erosion by water
文章编号: N23021802
期刊: Biogeosciences
作者: Kristof Van Oost, Johan Six
更新时间: 2023-02-18
摘要: The acceleration of erosion, transport, and burial of soil organic carbon (OC) by water in response to agricultural expansion represents a significant perturbation of the terrestrial C cycle. Recent model advances now enable improved representation of the relationships between sedimentary processes and OC cycling, and this has led to substantially revised assessments of changes in land OC as a result of land cover and climate change. However, surprisingly a consensus on both the direction and magnitude of the erosion-induced land–atmosphere OC exchange is still lacking. Here, we show that the apparent soil OC erosion paradox, i.e., whether agricultural erosion results in an OC sink or source, can be reconciled when comprehensively considering the range of temporal and spatial scales at which erosional effects on the C cycle operate. We developed a framework that describes erosion-induced OC sink and source terms across scales. We conclude that erosion induces a source for atmospheric CO₂ when considering only small temporal and spatial scales, while both sinks and sources appear when multi-scaled approaches are used. We emphasize the need for erosion control for the benefits it brings for the delivery of ecosystem services, but cross-scale approaches are essential to accurately represent erosion effects on the global C cycle.

373. 题目: Variation in soil organic carbon over time in no-till versus minimum tillage dryland wheat-fallow
文章编号: N23021801
期刊: Soil and Tillage Research
作者: Stewart B Wuest, William F Schillinger, Stephen Machado
更新时间: 2023-02-18
摘要:

Interest in soil organic carbon (SOC) levels is focused on both soil quality and sequestering carbon from the atmosphere. Farmers have developed minimum tillage systems and no-till systems. This study carefully measured SOC at three sites where long-term, randomized, replicated studies compared minimum tillage and no-till rotations in the low-precipitation inland Pacific Northwest, USA. To overcome seasonal, annual, and rotational effects, a soil sample was taken from each plot monthly for three years. The top 250 kg m^-2 dry soil mass (representing the 0- to 20-cm depth) from each core was analyzed for SOC. Averages of monthly samples revealed the tilled treatment had 7.21 g kg^-1 of SOC compared to 7.04 for the no-till treatment (p < 0.004). Examining variation month-to-month, 93% of sample variation was due to sample date, and 7% due to blocks (replications) within sites. Of 77 individual site-by-date samples, only six produced significant t-tests (p < 0.05) but SOC differences were 46–31 in favor of tillage and those 46 had larger differences. Power calculations estimated 34–100 samples would be required to detect a relative difference of 5% given the data’s standard deviation. Soil water and soil temperature to 30 cm was measured at the time of sampling, and while no-till more often had greater water, temperature differences were inconsistent. We conclude that no-till did not result in more soil carbon in these systems and judicious tillage is an option for sustainable production.

374. 题目: An evaluation of topsoil carbon storage in Chinese deserts
文章编号: N23021708
期刊: Science of the Total Environment
作者: Guoru Wei, Chunlai Zhang, Qing Li, Hongtao Wang, Rende Wang, Yajing Zhang, Yixiao Yuan
更新时间: 2023-02-17
摘要:

Deserts are important components of the terrestrial ecosystem, and significantly affect the terrestrial carbon cycle. However, their carbon storage is poorly understood. To evaluate the topsoil carbon storage in Chinese deserts, we systematically collected topsoil samples (to a depth of 10 cm) from 12 deserts in northern China and analyzed their organic carbon storage. We used partial correlation and boosted regression tree (BRT) analysis to analyze the factors influencing the spatial distribution of soil organic carbon density based on climate, vegetation, soil grain-size distribution, and element geochemistry. The total organic carbon pool of Chinese deserts was 4.83 × 10⁸ t, the mean soil organic carbon density was 1.37 ± 0.18 kg C m⁻², and the mean turnover time was 16.50 ± 2.66 yr. With the largest area, the Taklimakan Desert had the highest topsoil organic carbon storage (1.77 × 10⁸ t). The organic carbon density was high in the east and low in the west, whereas the turnover time showed the opposite trend. The soil organic carbon density was >2 kg C m⁻² in the four sandy lands in the eastern region, and was greater than the values for the eight deserts (0.72 to 1.22 kg C m⁻²). Grain-size (i.e., the silt and clay contents) had the strongest influence on the organic carbon density in Chinese deserts, followed by element geochemistry. Precipitation was the main climatic factor that affected the distribution of organic carbon density in the deserts. Based on climate and vegetation cover trends during the past 20 years, Chinese deserts have a high potential for future organic carbon sequestration.

375. 题目: Mining activities accelerate the decomposition of organic matter from aquatic ecosystems through soil microbes
文章编号: N23021707
期刊: Land Degradation & Development
作者: Liu Run, Yang Yinghui, Zhou Zeyan, Shen Jiachen, Xingjun Tian
更新时间: 2023-02-17
摘要: Mining activities have been shown to affect the rate of carbon decomposition in aquatic ecosystems by altering the traits of the organic matter (e.g., leaf litter). However, the ecological function of soil microbes that enter aquatic ecosystems in association with organic matter is not known. Here, standardized cotton strip assays were used to quantify the effects of soil microbial colonization location (mine vs. forest riverbank) and time (7 days vs. 14 days) on cellulose decomposition in aquatic ecosystems. The cotton strip assay results showed that the mine riverbank location and microbial colonization time had significant effects on the microbial community structure, microbial biomass and functional genes of cellulose decomposition. Compared with the forest riparian zone, the fungal biomass and bacterial cellulose-decomposing gene (GH48) abundance of cotton strips colonized in the mine riparian zone for 14 days were 12.5 times and 54.93 times that of the cotton strips colonized in the forest riparian zone, respectively, while the fungal cellulose-decomposing gene (cbhI) was detected only after 14 days of colonization. After 90 days of stream incubation, the decomposition rate and GH48 gene abundance of cotton strips colonized in the mine riparian zone for 14 days were significantly higher than those of cotton strips colonized in the forest riparian zone. However, the abundance of the cbhI gene in cotton strips colonized for 14 days was significantly higher than that in cotton strips colonized for 7 days. These results show that bacteria were mainly affected by the microbial colonization environment, while fungi were mainly affected by colonization time. Mining activities accelerate the decomposition of organic matter in aquatic ecosystems by increasing soil fungal biomass and bacterial cellulose decomposition genes. To reduce the carbon loss of aquatic ecosystems, it is necessary to study the potential influence of soil microbes on the decomposition of organic carbon in riparian zones.

376. 题目: Composition of organic matter‑iron‑phosphorus associations in sediments of algae- and macrophyte-dominated zones in Lake Taihu
文章编号: N23021706
期刊: Chemical Geology
作者: Jingjing Liu, Qiaoying Zhang, Meilian Chen, Jiaru Dai, Wenxin Gu, Shuailong Wen, Yingxun Du
更新时间: 2023-02-17
摘要:

The biogeochemical cycles of phosphorus (P) and organic matter (OM) are significantly influenced by iron (Fe) through forming OM-Fe-P associations. The sources and compositions of organic matter in the two typical states (algae-dominated and macrophyte-dominated) of shallow lakes are different, which could modulate the formation of OM-Fe-P associations and influence the internal loadings of P in lakes. In this study, OM and P bound with Fe were extracted from the sediments of algae-dominated zone (A-zone) and macrophyte-dominated zone (M-zone) in Lake Taihu via the citrate-bicarbonate-dithionite (CBD) reduction method, and were subsequently analyzed to elucidate the differences in OM-Fe-P associations between the two zones. The results showed that OM-Fe-P associations in the sediments of M-zone had higher a molar C/Fe ratio but a lower molar P/Fe ratio. Four components identified by excitation-emission matrix fluorescence coupled with parallel factor analysis (EEM-PARAFAC) in OM-Fe-P associations in the two zones were all humic-like substances and the relative abundance of the corresponding PARAFAC components had no significant difference between the two zones. However, the total fluorescence intensity of the humic-like components was higher in M-zone than those in A-zone. This could be attributed to the higher aromaticity of OM produced from macrophyte than that from algae, as evidenced by the difference in the easily-desorbed OM between two zones. In M-zone, high aromatic compounds which are preferentially associated with Fe, could be more produced from macrophyte plants than from algae and resulted in the higher C/Fe molar ratio. The higher C/Fe molar ratio (2.1 ± 0.9) of OM-Fe-P associations in M-zone reflected that more OM originated from macrophyte could be involved in the coprecipitation with Fe (III) and OM-Fe-P associations in M-zone were probably more resistant to the microbial and chemical reduction. Our results from the real situation confirmed the mechanism related to the reduction of OM-Fe-P associations for the lower internal loading of P in M-zone than that in A-zone.

377. 题目: Selective Exclusion of Aromatic Organic Carbon During Lake Ice Formation
文章编号: N23021705
期刊: Geophysical Research Letters
作者: Yongqiang Zhou, Carolin Hiller, Sara Andersson, Elizabeth Jakobsson, Lei Zhou, Jeffery A Hawkes, Dolly N Kothawala, Lars J Tranvik
更新时间: 2023-02-17
摘要: Earth's lakes at northern latitudes are mostly ice-covered in winter. When lake water freezes, some organic matter dissolved in the water is excluded from the ice. We performed complementary field sampling and laboratory freeze-up experiments to explore how freeze-up may impact the partitioning and composition of dissolved organic matter (DOM) in boreal lakes. We found that 16.2 ± 4.7% of dissolved organic carbon (DOC) was retained in the overlying ice, 81.3 ± 5.7% of DOC was expelled to underlying unfrozen water, and 1.3 ± 0.7% was expelled as flocs. During ice formation, nitrogen (TDN, total dissolved nitrogen), ions (specific conductance), and oxidized and aromatic DOM were preferentially expelled to the underlying water column. The apparent retention factor DOC_Ice: DOC_Before decreased from clearwater to brownwater lakes, that is, with increasing allochthonous DOC lost from lake ice, indicating that DOM exclusion from the ice cover will become more prevalent as lakes experience browning.

378. 题目: Key drivers regulating arsenic enrichment in shallow groundwater of the Pearl River Delta: Comprehensive analyses of iron, competitive anions, and dissolved organic matter
文章编号: N23021704
期刊: Applied Geochemistry
作者: Hulong Yi, Jinli Cui, Jianteng Sun, Xingyu Zhou, Tiancai Ye, Shuchai Gan, Jingcheng Chen, Yuzhong Yang, Weixin Liang, Pengran Guo, Amal Abdelhaleem, Tangfu Xiao
更新时间: 2023-02-17
摘要:

Arsenic (As) contamination in groundwater is a global environmental geochemical problem that threatens over 100 million people around the world. Although groundwater As enrichment has been demonstrated to result from some major complex processes, including competitive desorption by anions and reductive release of As from iron (Fe) oxyhydroxides due to microbial respiration of dissolved organic matter (DOM), knowledge of the detailed interactions among these processes and their respective contributions is still limited. In this study, we aimed to elucidate the key variables that regulate the evolution of dissolved As in shallow groundwater from a typical As-contaminated region of the Pearl River Delta (PRD) after comprehensive statistical analysis of hydrogeochemical characteristics. The results showed that the highest concentration of As in the groundwater samples (n = 77) was 57 μg/L, with 9% of samples exceeding the drinking water standard. In comparison with other regions with geogenic As contamination in groundwater, the relatively low As concentration range is primarily controlled by the well-oxygenated environment, which also contributed to the dominance of As(V) (19.5–100.0%, median of 100.0%). Hierarchical cluster analysis (HCA) and principal component analysis (PCA) suggested that the presence of As in groundwater may be impacted by the reduction process of Fe/Mn oxyhydroxides and by competitive anions. Further analysis using structural equation modeling (SEM) indicated that the increased concentration of As(V) in the shallow groundwater was primarily induced by the competitive roles of phosphate and silicate, explaining 65.2% and 31.5% of total As(V), respectively. In contrast, the presence of As(III) was strongly explained by DOM (23.8%, 12.4%, and 5.7% from microbial humic-like, terrestrial humic-like, and protein-like components, respectively) and Fe (31.8%), followed by competitive desorption (26.3%), revealing the dominant contribution from DOM-facilitated Fe reduction to As(III) enrichment. Our study empirically demonstrated that decreasing the concentrations of phosphate and reactive organic matter can effectively alleviate As contamination in groundwater.

379. 题目: Biochar as smart organic catalyst to regulate bacterial dynamics during food waste composting
文章编号: N23021703
期刊: Bioresource Technology
作者: Shivpal Verma, Mukesh Kumar Awasthi, Tao Liu, Sanjeev Kumar Awasthi, Vivek Yadav, Balasubramani Ravindran, Asad Syed, Rajalakshmanan Eswaramoorthy, Zengqiang Zhang
更新时间: 2023-02-17
摘要:

The impact of wheat straw biochar (WSB) on bacterial dynamics succession during food waste (FW) composting was analyzed. Six treatments [0(T1), 2.5(T2), 5 (T3), 7.5 (T4), 10 (T5), and 15%(T6)] dry weight WSB were used with FW and saw dust for composting. At the highest thermal peak at 59 ℃ in T6, the pH varied from 4.5-7.3, and electrical conductivity among the treatments varied from 1.2-2.0 mScm¹. Firmicutes (25-97%), Proteobacteria (8-45%), and Bacteroidota (5-50%) were among the dominate phyla of the treatments. Whereas, Bacillus (5-85%), Limoslactobacillus (2-40%), and Sphingobacterium (2-32%) were highest among the identified genus in treatments but surprisingly Bacteroides was in greater abundance in the control treatments. Moreover, heatmap constructed with 35 various genera in all the treatments showed that Gammaproteobacterial genera contributed in large proportion after 42 days in T6. Additionally, a dynamic shift from Lactobacillus fermentum to higher abundance of Bacillus thermoamylovorans was reported on 42 days of FW composting. Biochar 15% amendment can improve FW composting by influencing bacterial dynamics.

380. 题目: Effects of digestate-encapsulated biochar on plant growth, soil microbiome and nitrogen leaching
文章编号: N23021702
期刊: Journal of Environmental Management
作者: Miao Yan, Hailin Tian, Shuang Song, Hugh T W Tan, Jonathan T E Lee, Jingxin Zhang, Pooja Sharma, Yong Wei Tiong, Yen Wah Tong
更新时间: 2023-02-17
摘要:

The increasing amount of food waste and the excessive use of mineral fertilizers have caused detrimental impacts on soil, water, and air quality. Though digestate derived from food waste has been reported to partially replace fertilizer, its efficiency requires further improvement. In this study, the effects of digestate-encapsulated biochar were comprehensively investigated based on growth of an ornamental plant, soil characteristics, nutrient leaching and soil microbiome. Results showed that except for biochar, the tested fertilizers and soil additives, i.e., digestate, compost, commercial fertilizer, digestate-encapsulated biochar had positive effects on plants. Especially, the digestate-encapsulated biochar had the best effectiveness as evidenced by 9–25% increase in chlorophyll content index, fresh weight, leaf area and blossom frequency. For the effects of fertilizers or soil additives on soil characteristics and nutrient retention, the digestate-encapsulated biochar leached least N-nutrients (<8%), while the compost, digestate and mineral fertilizer leached up to 25% N-nutrients. All the treatments had minimal effects on the soil properties of pH and electrical conductivity. According to the microbial analysis, the digestate-encapsulated biochar has the comparable role with compost in improving the soil immune system against pathogen infection. The metagenomics coupling with qPCR analysis suggested that digestate-encapsulated biochar boosted the nitrification process and inhibited the denitrification process. This study provides an extensive understanding into the impacts of the digestate-encapsulated biochar on an ornamental plant and offers practical implications for the choice of sustainable fertilizers or soil additives and food-waste digestate management.