181. 题目: Parallel adsorption of low concentrated ciprofloxacin by a CoFe-LDH modified sludge biochar
期刊: Journal of Environmental Chemical Engineering
作者: Dayang Zheng, Min Wu, Eryang Zheng, Yayi Wang, Cang Feng, Jiali Zou, Maoling Juan, Xinxing Bai, Teng Wang, Yuxiang Shi
摘要: The sludge biochar loaded with layered double hydroxides (CoFe-LDH@SBC) was used as a composite adsorbent for removing low concentrated ciprofloxacin (CIP) effectively in water environment. The sludge biochar (SBC) and CoFe-LDH@SBC were synthesized by pyrolysis and self-assembly; and the characterization of SBC and the composite material were analyzed through a series of analytical methods including scanning electron microscopy-Energy Dispersive Spectrometer, X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller, and Zeta potential. Due to various chemisorptions, CoFe-LDH@SBC showed superior adsorption performance for CIP with 14mg/g, which was 2.8 times of that for SBC. Moreover, Artificial Neural Network (ANN) model was employed to predict the adsorption capacity and removal rate of CIP using experimental data obtained. Furthermore, according to density functional theory (DFT), parallel adsorption was proved to be dominant in the adsorption process, which indicated that the adsorption was a favorable and exothermic chemisorptions process.
182. 题目: Bacterial dynamics for gaseous emission and humification during bio-augmented composting of kitchen waste with lime addition for acidity regulation
期刊: Science of The Total Environment
作者: Chuanren Qi, Rongrong Yin, Jingwen Cheng, Zhicheng Xu, Jie Chen, Xingzu Gao, Guoxue Li, Long Nghiem, Wenhai Luo
摘要: This study investigated the impacts of lime addition and further microbial inoculum on gaseous emission and humification during kitchen waste composting. High-throughput sequencing was integrated with Linear Discriminant Analysis Effect Size (LEfSe) and Functional Annotation of Prokaryotic Taxa (FAPROTAX) to decipher bacterial dynamics in response to different additives. Results showed that lime addition enriched bacteria, such as Taibaiella and Sphingobacterium as biomarkers, to strengthen organic biodegradation toward humification. Furthermore, lime addition facilitated the proliferation of thermophilic bacteria (e.g. Bacillus and Symbiobacterium) for aerobic chemoheterotrophy, leading to enhanced organic decomposition to trigger notable gaseous emission. Such emission profile was further exacerbated by microbial inoculum to lime-regulated condition given the rapid enrichment of bacteria (e.g. Caldicoprobacter and Pusillimonas as biomarkers) for fermentation and denitrification. In addition, microbial inoculum slightly hindered humus formation by narrowing the relative abundance of bacteria for humification. Results from this study show that microbial inoculum to feedstock should be carefully regulated to accelerate composting and avoid excessive gaseous emission.
183. 题目: Untangling microbial diversity and functional properties of Jeevamrutha
期刊: Journal of Cleaner Production
作者: Duraivadivel P, Bhani Kongkham, Santosh Satya, Hariprasad P
摘要: Jeevamrutha (JA) is a complex microbial bioformulation derived from local resources (cow dung, cow urine, jaggery, pulse flour, soil, and water) used in traditional Indian organic agriculture. Farmers using JA frequently describe it as inexpensive, sustainable, and environmentally friendly, and it improves plant and soil health. Additionally, limited research studies conducted on JA support the farmers' claim. To increase JA's credibility and acceptability among users, it must be scientifically validated in-depth. It was hypothesised that the structural and functional diversity of microbes, metabolites and proteins is key to JA's success. In order to comprehend the dynamics of JA during the incubation period, physico-chemical parameters and microbial diversity were analysed until the 12-day of incubation. Dynamics of JA's pH, EC, DO, aerobic and anaerobic, and cultivable and uncultivable microbial load determined JA as a fermentative process. Phylum Firmicutes, Bacteriodetes, and Proteobacteria, and genus, Lactobacillus, Streptococcus and Clostridium, dominated the microbial composition of JA. In addition, the presence of bacteria, bacteriophages, fungi, and unclassified microorganisms in JA demonstrated the complexity of microbial diversity. The variety of JA's metabolites (lactic acid, ascorbic acid, caproic acid, succinic acid, betaine, choline, stachydrine, trehalose, etc.), proteins (chaperone proteins, heat shock proteins, elongation factor-Tu, etc.) and exopolysaccharides, that have the potential to promote microbial survival and proliferation in JA and soil. Field trials were conducted for four years under two distinct agroclimatic conditions to assess the impact of JA on soil health. At the end of the experimental period, JA along with farmyard manure/vermicompost, improved soil organic carbon content, water holding capacity, microbial load, and activity to varying degrees in both trials. This study provides in-depth information regarding the structural diversity and functional properties of JA, as well as their significance in enhancing soil health and encouraging farmers to use JA.
184. 题目: Role of terrestrial versus marine sources of humic dissolved organic matter on the behaviors of trace elements in seawater
期刊: Geochimica et Cosmochimica Acta
作者: Xiaoyu Chen, Hyeong Kyu Kwon, Dongjoo Joung, Cheolmin Baek, Tae Gyu Park, Moonho Son, Guebuem Kim
摘要: We investigated the behaviors of dissolved trace elements (Mn, Fe, Ni, Cu, Zn, and Cd) associated with humic dissolved organic matter (DOMH) of varying origins in the surface waters of two Korean coastal regions (Jinhae Bay [JH] and offshore Tongyeong [TY]). Both regions displayed intensive scavenging and settling of the particle-reactive Ce and 234Th tracers. However, in JH, where DOMH is mainly terrestrial-derived, the concentrations of trace elements (Fe, Ni, and Cu) were negatively correlated with salinity and positively correlated with DOMH. This indicates that terrestrial DOMH could form complexes with dissolved trace elements, and this complexation likely deters the adsorptive removal of trace elements by settling particles. Similar interactions between trace elements (Mn, Fe, and Cu) and DOMH were also discovered in TY, where most DOMH originated from marine biological production. Our study reveals that both terrestrial and marine DOMH would complex with dissolved trace elements, stabilizing them in the dissolved phase in coastal waters. Therefore, DOMH-trace element complexation in coastal waters could play a key role in regulating the cycling and transport of trace elements in the ocean.
185. 题目: Humic acid coupled with coal gasification slag for enhancing the remediation of Cd-contaminated soil under alternated light/dark cycle
期刊: Environmental Science and Pollution Research
作者: Yulin Xiang, Yuxiu Xiang, Xuchun Gao
摘要: In this study, the synthesis of a coal gasification slag-humic acid (SA) hybrid was purposed for the remediation of cadmium (Cd)-contaminated soil. In order to investigate the effect of SA on the Cd-contaminated soil and plant growth, a series of experiments were carried out under different illumination condition. The results showed that the SA has some the photocatalytic activity, and adding 10 wt% of SA to the soil could obviously improve the soil fertility and decrease the mobility of Cd in the soil under alternated light/dark cycle (12L/12D); the content of the residual fraction in the SA-amended soil reached 69.5%, and the Cd decreasing rates for the leaf, stem, and root of Artemisia ordosica were near 100%, 91.3%, and 75.3%, respectively. Characterizations of amendments suggested that the synergistic effect of precipitation and surface complexation played a major role in the remediation of Cd-contaminated soil. Graphical abstract
186. 题目: Novel magnetic porous biochar derived from degreasing cotton as a multifunctional adsorbent for simultaneous efficient capturing and monitoring of multiple antibiotic residues
期刊: Journal of Environmental Chemical Engineering
作者: Xu Xu, Jiaxin Gao, Di Cao, Xueyan Liu, Muyao Ma, Lei Zhang
摘要: The construction of a novel multifunctional adsorbent for simultaneous sensitive detection and capture of multiple antibiotic residues in the environment and food samples remains challenging. In this paper, the novel magnetic porous biochar (MPBC) derived from low-cost degreasing cotton was well-constructed and prepared via a simple solvent-free and one-step carbonization which has a large surface area, 3D porous structure, and good magnetism. The acquired MPBC was first used as multifunctional adsorbents for synchronous sorptive removal, sensitive detection, molecular sieve selection, and magnetic separation, exhibiting excellent adsorption capacity (102.2mgg-1) for multiple antibiotics (quinolones and sulfonamides) residue. Meanwhile, the MPBC could exclude the relatively large matrix compounds, thus eliminating matrix effects. What's more, this method has a higher detection sensitivity, a lower detection limit (0.043-0.067μgL-1), and higher enrichment factors (111
187. 题目: The effect of organic matter fractions on micropollutant ozonation in wastewater effluents
期刊: Water Research
作者: K van Gijn, Y Zhao, A Balasubramaniam, H.A. de Wilt, L Carlucci, A.A.M. Langenhoff, H.H.M. Rijnaarts
摘要: Organic matter (OM) is the most important factor influencing the effectivity and efficiency of micropollutant (MP) ozonation in wastewater effluents. The importance of the quantity of OM is known, because of this, total organic carbon (TOC) is generally used to determine the required ozone dose for any water sample. Still, the effect of OM type on MP ozonation is not well understood. In this study, effluents from five wastewater treatment plants were collected and the organic matter in these effluents was fractionated using membranes (F1-4) and resin (HI, HOA, HON and HOB). Fractions were diluted to the same TOC concentration, spiked with MPs and ozonated at three ozone doses. Our results show that all five effluents had comparable OM compositions and similar MP removal, confirming the suitability of OM quantity (TOC) to compare the ozone requirements for wastewater effluents. From the 19 analysed MPs, three groups were identified that showed similar removal behaviour. The strongest differences between the groups were observed around MP ozone reactivities of 102, 104 and 106 M−1 s−1. This indicates the presence of three OM groups in the samples that interfere with the removal of different MPs. MP removal in the resin fraction HON were higher for MPs with high and medium ozone reactivity, indicating a low interference of OM in this fraction with MP ozonation. OM in the resin fractions HOA and HI showed higher interference with MP ozonation. Therefore, removing the HOA and HI fractions prior to ozonation would result in a lower required ozone dose and a more efficient removal of the MPs. MP removal correlated with the OM characteristics A300, SR and fluorescence component comp 2. These characteristics can be used as inline tools to predict the required ozone dose in water treatment plants.
188. 题目: Evaluating indices of soil organic carbon stability. A case study for forest restoration projects near Beijing, China
期刊: Ecological Indicators
作者: Zeyu Zhang, Tonggang Zha, Yang Yu, Xiaoxia Zhang, Pete Smith, Jesús Rodrigo-Comino
摘要: Afforestation of degraded lands close to mega-urban areas such as Beijing may help to restore some of the original soil carbon stocks and hold the potential for ameliorating the rate of increase in atmospheric CO2. However, the determinants of the stability of different soil carbon pools and the utility of indices of stability remain poorly characterized near these highly anthropogenic areas. In the current study, we compared metrics of soil organic carbon (SOC) stability taking into account different soil types and plantation forest combinations (Quartisamment soil-poplar plantation–QP, Eutrochrepts soil-Chinese pine plantation–ECP, Haplustepts soils-East-Liaoning oak plantation–HEO), in an experimental sub-humid area close to a mega-urban area (Beijing, China). We evaluated the following relative stability indices sequence: respired carbon from incubations (RI) for several incubation days to respire 5% of initial SOC (D), aggregate stability index (ASI), the ratio of SOC to total nitrogen (C: N), water-soluble carbon (WSC), particulate organic carbon (POC) and microbial biomass carbon (MBC). We examined the indices by three repeated measurements on soil samples from four soil layers (0–40 cm) in three soil-forest types in a forest area close to the peri-urban area of Beijing. Our results showed that there are inconsistencies among the six SOC stability indexes. The contribution rates of different indexes to the SOC in three plantations were different, for QP the highest contributor is WSC (54.73%), and for ECP and HEO the highest contributor is RI, contribution rates are 34.85% and 36.382%, respectively. Respired carbon from incubations registered the largest contribution rate to SOC (69.79%), and the correlation between RI and soil physical and chemical properties was the highest. We conclude that a combination of indices and knowledge of soil and vegetation types are needed for assessing SOC stability in restoration and reforestation projects close to mega-urban areas.
189. 题目: Contrasting the physical and chemical characteristics of dissolved organic matter between glacier and glacial runoff from a mountain glacier on the Tibetan Plateau
期刊: Science of The Total Environment
作者: Lixiang Zhai, Yanqing An, Lin Feng, Xiang Qin, Jianzhong Xu
摘要: Accelerated melting of mountain glaciers due to global warming has a significant impact on downstream biogeochemical evolution because a large amount of labile dissolved organic matter (DOM) is released. However, the DOM evolution processes from glacier to downstream are not well understood. To investigate these processes, samples from the glacial surface and terminating runoff of a mountain glacier on the Tibetan Plateau were collected simultaneously throughout the melting season. The samples were analyzed to determine the dissolved organic carbon (DOC) contents and chemical compositions by means of a combination of fluorescence excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results indicate that the DOC concentrations were higher in the snow samples than in the glacial runoff samples, although a significantly higher concentration of inorganic ions was found in the glacial runoff samples, suggesting the dominant source of DOM in the glacial runoff was the glacier. The EEM-PARAFAC revealed four fluorescent components in both the snow and glacial runoff samples. However, significantly different ratios between the four components of these two categories of samples suggested chemical, physical and/or biological evolution of DOM during transport. Molecular chemical composition analyses by FT-ICR MS revealed that the DOM composition varied dramatically between the glacier and the glacial runoff. More than 50 % of the molecules were transformed from aliphatic and peptide-like compounds in the snow samples into highly unsaturated and phenolic-like compounds in the glacial runoff samples. The potential chemical transformation of DOM was likely related to biological and/or photolytic evolution during transport. Our results suggest that chemical evolution of glacial DOM could occur during the downstream transport, which is expected to be useful for further research exploring the fate of DOM and carbon cycling from the cryospheric environment and evaluating the biogeochemical effects.
190. 题目: The co-application of biochar with bioremediation for the removal of petroleum hydrocarbons from contaminated soil
期刊: Science of The Total Environment
作者: Charles Chinyere Dike, Ibrahim Gbolahan Hakeem, Alka Rani, Aravind Surapaneni, Leadin Khudur, Kalpit Shah, Andrew S Ball
摘要: Soil pollution from petroleum hydrocarbon is a global environmental problem that could contribute to the non-actualisation of the United Nations Sustainable Development Goals. Several techniques have been used to remediate petroleum hydrocarbon-contaminated soils; however, there are technical and economical limitations to existing methods. As such, the development of new approaches and the improvement of existing techniques are imperative. Biochar, a low-cost carbonaceous product of thermal decomposition of waste biomass has gained relevance in soil remediation. Biochar has been applied to remediate hydrocarbon-contaminated soils with positive and negative results reported. Consequently, attempts have been made to improve the performance of biochar in the hydrocarbon-based remediation process through the co-application of biochar with other bioremediation techniques as well as modifying biochar properties before use. Despite the progress made in this domain, there is a lack of a detailed single review consolidating the critical findings, new developments, and challenges in biochar-based remediation of petroleum hydrocarbon-contaminated soil. This work assessed the potential of biochar co-application with other well-known bioremediation techniques such as bioaugmentation, phytoremediation, and biostimulation. Additionally, the benefits of modification in enhancing biochar suitability for bioremediation were examined. It was concluded that biochar co-application generally resulted in higher hydrocarbon removal than sole biochar treatment, with up to a 4-fold higher removal observed in some cases. However, most of the biochar co-applied treatments did not result in hydrocarbon removal that was greater than the additive effects of individual treatment. Overall, compared to their complementary treatments, biochar co-application with bioaugmentation was more beneficial in hydrocarbon removal than biochar co-application with either phytoremediation or biostimulation. Future studies should integrate the ecotoxicological and cost implications of biochar co-application for a viable remediation process. Lastly, improving the synergistic interactions of co-treatment on hydrocarbon removal is critical to capturing the full potential of biochar-based remediation.
191. 题目: Highly efficient activation of peroxymonosulfate by Co, S co-doped bamboo biochar for sulfamethoxazole degradation: Insights into the role of S
期刊: Journal of Environmental Chemical Engineering
作者: Xiaoyi Huang, Zhendong Yu, Yanbiao Shi, Qingsong Liu, Shengqiong Fang
摘要: Recently, highly efficient activation of peroxymonosulfate (PMS) by S-doped cobalt-based catalysts are receiving increased attention. The effect of S is worth exploring since it has a great influence on PMS activation performance. In this work, dimethyl sulfoxide was adopted as an S source and loaded on bamboo biochar (BB) with Co to form CoS/BBC, which served as an efficient catalyst for PMS activation to degrade sulfamethoxazole (SMX). The experiment results showed that CoS/BBC exhibits an excellent catalytic activity and the SMX (20mg/L) can be completely degraded under the attack of species of ·OH, SO4-·, 1O2 and electron transfer. The SMX degradation conformed to pseudo first-order kinetics with rate constant reaching 0.442min−1 in 10min under the optimal conditions (a catalyst dose of 0.02g/L, a PMS dose of 0.3g/L and an initial pH = 7.0). The electrochemical experiments and density functional theory (DFT) calculation revealed that the introduction of S can accelerate electron transfer and promote the decomposition of PMS while facilitating Co(III)/Co(II) redox cycling. Furthermore, liquid chromatograph-mass spectrometer (LC-MS) and ecological structure activity relationships (ECOSAR) proved that the degradation process of SMX in CoS/BBC/PMS system has low ecotoxicity and is harmless to the environment. This work provides a new strategy for enhancing electron transfer by S-doped metal materials and the synthesis of efficient catalysts for SMX removal.
192. 题目: Combined effects of biochar and biogas slurry on soil nitrogen transformation rates and N2O emission in a subtropical poplar plantation
期刊: Science of The Total Environment
作者: Xiaolin Liao, Shuxia Mao, Yajuan Chen, Jinbo Zhang, Christoph Müller, Saadatullah Malghani
摘要: It has been widely accepted that biochar has a great potential of mitigating soil nitrous oxide (N2O) emission. However, the underlying mechanism about how biochar affects nitrogen transformation and the pathways of soil N2O production is under discussion. A 15N-tracer incubation experiment was conducted to investigate the short-term effects of biochar on soil N transformation rates and source partitioning of N2O emissions in soils from a poplar plantation system. A two-factor experimental design was adopted using biogas digestate slurry and biochar as soil amendments. In total, there were 12 treatments, including three rates of biochar: B0 (control), B2 (80 t ha−1), and B3 (120 t ha−1), and four rates of biogas digestate slurry: C (0 m3 ha−1), L (125 m3 ha−1), M (250 m3 ha−1), and H (375 m3 ha−1). We observed significantly lower rates of net nitrification (Nn) and mineralization (Mn) in biochar-treated soils. The 15N tracer analysis revealed a significant decrease in gross autotrophic (ONH4), heterotrophic nitrification (ONrec), and mineralization (MNorg) rates while an increase in gross immobilization (INH4 and INO3) rates in biochar amended soils. When biogas slurry was applied, biochar only significantly reduced ONH4 except in the moderate slurry treatment. Regardless of the slurry application, biochar consistently suppressed N2O emission by 58–89 %, and nitrification was the dominant pathway accounting contributing >90 % to cumulative N2O emissions. Moreover, soil cumulative N2O emissions significantly negatively correlated with soil ammonium contents and positively with MNorg, Mn, and Nn, showing that biochar decreased N2O emission via a reducing effect on nitrification rates and associated N2O emissions. Our results also highlight that application of N fertilizer greatly influence the biochar's impacts on soil N transformation rates and N2O emission, calling for further studies on their interactions to develop mitigate options and to improve N use efficiency.
193. 题目: Microphytobenthos as a source of labile organic matter for denitrifying microbes
期刊: Estuarine, Coastal and Shelf Science
作者: Jérôme Morelle, Céline Roose-Amsaleg, Anniet M Laverman
摘要: Nitrogen loads in natural waters remain elevated in populated and agricultural areas with serious impact on estuarine and coastal ecosystems. Intertidal sediments can play a significant role in attenuating the high nitrogen levels in water via microbial nitrate reduction, in general dominated by denitrification. These heterotrophic processes are heavily mediated by both the quantity and quality of organic matter available. Benthic microalgae were experimentally investigated as organic carbon source for denitrifying microbes in intertidal mudflat sediments from the Seine Estuary (France). Dry microphytobenthos (including algae and their extracellular polymeric substances) were added to sediments and nitrate reduction rates were monitored over a two-week period using anoxic controlled flow-through reactor approach. Our results show that microphytobenthos addition resulted in significantly higher nitrate reduction (67–332% increase), highly related to the added amount of microphytobenthos. Moreover, increase of the low molecular weight carbohydrates consumption (11–39%) highlight the measurable contribution of extracellular polymeric substances to the carbon consumption during nitrate reduction. The addition of microphytobenthos increased the abundance of nitrite reductase genes, especially those encoding the nirS gene (43–152% increase) while nitrous oxide reductase genes (nosZ gene) remained constant. Microphytobenthos appeared to favor complete denitrification as suggested by an increase in nirS and a decrease in clade II nosZ gene copy numbers. This study confirms experimentally the assumption that microbes use microalgae and particularly labile extracellular polymeric substances as a carbon substrate for nitrate reduction. These results reinforce the impact played by microphytobenthos in intertidal mudflats by highlighting their role on denitrifying microbes and nitrate removal from water.
194. 题目: Soil organic carbon decomposition responding to warming under nitrogen addition across Chinese vegetable soils
期刊: Ecotoxicology and Environmental Safety
作者: Xintong Xu, Qianqian Zhang, Mengxin Song, Xi Zhang, Ruiyu Bi, Liping Zhan, Yubing Dong, Zhengqin Xiong
摘要: Chemical fertilization in excess and warming disrupt the soil microbes and alter resource stoichiometry, particularly in intensive vegetable soils, while the effects of these variables on the temperature sensitivity of soil organic carbon (SOC) decomposition (Q10) and SOC stability remain elusive. Thus, we collected six long-term vegetable soils along a climatic gradient to examine the microbial mechanisms and resource stoichiometry effects on fluctuations in Q10 and SOC stability induced by warming and fertilization from vegetable soils. Our results showed that the SOC decomposition was dominated by microbes and regulated by stoichiometry. Compared to cold sites, higher Q10 of SOC decomposition was observed in warm sites, accompanied by lower enzyme activities, microbial CUE, and C:N ratio. In this context, warming reduced SOC stability as evidenced by up to 31.8% greater Q10 (1.45) at warm sites than at cold sites (1.10) owing to less richness of microbial communities and lower microbial CUE. The relatively lower pH and labile organic C value restricted the development of microbial richness, and decreased C- and N-related enzyme activities and a lower C:N ratio resulted in microbial CUE reduction. Additionally, N fertilization altered the C:N imbalance and enhanced SOC stability in vegetable soils, exhibiting an increase of Q10 values, particularly of great importance in warm sites. Collectively, our findings emphasize the importance of the microbial mechanism and resource stoichiometry in predicting variations in Q10 and fluctuations in SOC stability, and provide theoretical advice on improving management policies in the context of warming and fertilization from vegetable soils.
195. 题目: Estimation of chromophoric dissolved organic matter and its controlling factors in Beaufort Sea using mixture density network and Sentinel-3 data
期刊: Science of The Total Environment
作者: Jue Huang, Junjie Chen, Ming Wu, Lijiao Gong, Xiang Zhang
摘要: With the warming of the high-latitude regional climate, melting of permafrost, and acceleration of hydrological cycles, the Arctic Ocean (AO) has undergone a series of rapid changes in the past decades. As a dominant optical component of the AO, the variations in chromophoric dissolved organic matter (CDOM) concentration affect the physiological state marine organisms. In this study, machine learning retrieval model based on in situ data and mixture density network (MDN) was developed. Compared to other models, MDN model performed better on test data (R2 = 0.83, and root mean squared error = 0.22 m−1) and was applied to Sentinel-3 OLCI data. Afterward, the spatiotemporal distribution of CDOM during the ice-free (June–September) from 2016 to 2020 in the Beaufort Sea was obtained. CDOM concentration generally exhibited an upward trend. The maximum monthly average CDOM concentration appeared in June and gradually decreased thereafter, reaching its lowest value in September of each year. The maximum value appeared in June 2020 (0.91 m−1), and the minimum value was observed in September 2017 (0.81 m−1). The CDOM concentration nearshore was higher than that in other areas; and gradually decreased from offshore to the open sea. CDOM was highly correlated with salinity (R2 = 0.49) and discharge (R2 = 0.53), and the tight correlation between salinity and CDOM further suggested that terrestrial inputs were the main source of CDOM in the Beaufort Sea. However, sea level pressure contributed to the spatial variations in CDOM. When southerly wind prevailed and wind direction was aligned with the CDOM diffusion direction, the wind accelerated the diffusion of CDOM into the open sea. Meanwhile, seawater was diluted by the sea ice melting, resulting in decrease in CDOM concentration. Herein, this paper proposed a robust and near real-time method for CDOM monitoring and influence factor analysis, which would promote the understanding of AO CDOM budgets.
196. 题目: A regional assessment of permanganate oxidizable carbon for potential use as a soil health indicator in managed pine plantations
期刊: Forest Ecology and Management
作者: Fernanda C. C. Oliveira, Allan Bacon, Thomas R Fox, Eric J Jokela, Michael B Kane, Timothy A Martin, Asko Noormets, C. Wade Ross, Jason Vogel, Daniel Markewitz
摘要: Soil health assessments require the establishment of soil indicators that are easy to measure and sensitive to changes in management practices. Despite the global demand for wood products and the intensification of silvicultural practices, very few indicators are currently used to monitor changes in soil properties and processes in managed forest plantations. Labile pools of soil organic carbon (SOC) have been widely used in agriculture to detect early alterations in carbon (C) cycling processes but are largely untested in managed forests. Here, we investigate the potential use of permanganate oxidizable carbon (POXC) to monitor impacts of silvicultural practices on soil properties in loblolly pine plantations. Soil samples were collected from 77 managed forest sites and 297 experimental plots throughout the southeastern U.S. at four soil depths: 0–10, 10–20, 20–50, and 50–100 cm. Sites encompassed plantations with ages ranging from 2 to 29 yr that were distributed over five soil orders. Silvicultural practices included herbicide, fertilization at multiple rates, and thinning. Our study showed that POXC concentration decreases with soil depth, while POXC increased proportionally to SOC with depth. POXC positively correlates with SOC, total nitrogen, and mass of soil woody detritus other than live roots, and negatively correlates with soil pH across all soil depths. Impacts of silvicultural practices on POXC concentration were variable across sites. The mean relative response of POXC to silvicultural practices was negative in general but only significant (p < 0.10) in herbicide treatments; compared to control plots herbicide plots at 50–100 cm depth had on average 20% less POXC. The decade-long rotation lengths of southern pine plantations and the carbon cycling dynamics of forest soil O horizons may impact the sensitivity of POXC as an indicator in managed plantations. In contrast to this regional analysis, monitoring POXC in local assessments may be a more practical approach to investigate short-term impacts of silvicultural practices.
197. 题目: Alfalfa-grass mixtures reduce greenhouse gas emissions and net global warming potential while maintaining yield advantages over monocultures
期刊: Science of The Total Environment
作者: Muhammad Usman Ghani, Muhammad Kamran, Irshad Ahmad, Adnan Arshad, Cheng Zhang, Wanhe Zhu, Shanning Lou, Fujiang Hou
摘要: Improving forage productivity with lower greenhouse gas (GHG) emissions from limited grassland has been a hotspot of interest in global agricultural production. In this study, we analyzed the effects of grasses (tall fescue, smooth bromegrass), legume (alfalfa), and alfalfa-grass (alfalfa + smooth bromegrass and alfalfa + tall fescue) mixtures on GHG emissions, net global warming potential (Net GWP), yield-based greenhouse gas intensity (GHGI), soil chemical properties and forage productivity in cultivated grassland in northwest China during 2020–2021. Our results demonstrated that alfalfa-grass mixtures significantly improved forage productivity. The highest total dry matter yield (DMY) during 2020 and 2021 was obtained from alfalfa-tall fescue (11,311 and 13,338 kg ha−1) and alfalfa-smooth bromegrass mixtures (10,781 and 12,467 kg ha−1). The annual cumulative GHG emissions from mixtures were lower than alfalfa monoculture. Alfalfa-grass mixtures significantly reduced GHGI compared with the grass or alfalfa monocultures. Furthermore, results indicated that grass, alfalfa and alfalfa-grass mixtures differentially affected soil chemical properties. Lower soil pH and C/N ratio were recorded in alfalfa monoculture. Alfalfa and mixtures increased soil organic carbon (SOC) and soil total nitrogen (STN) contents. Importantly, alfalfa-grass mixtures are necessary for improving forage productivity and mitigating the GHG emissions in this region. In conclusion, the alfalfa-tall fescue mixture lowered net GWP and GHGI in cultivated grassland while maintaining high forage productivity. These advanced agricultural practices could contribute to the development of climate-sustainable grassland production in China.
198. 题目: Soil pore structure changes induced by biochar affect microbial diversity and community structure in an Ultisol
期刊: Soil and Tillage Research
作者: Caidi Yang, Jingjing Liu, Huanchang Ying, Shenggao Lu
摘要: The chemical mechanisms by which biochar addition affected soil microorganisms have been extensively studied. However, few studies investigated the effect of physical alteration induced by biochar application on microorganisms in soils. The study focused on how the pore structure affected microbial diversity and community structure in an Ultisol amended with straw-derived biochars. The nitrogen adsorption isotherm (NAI) and mercury intrusion porosimetry (MIP) were used to measure the soil pore characteristics. The bacterial and fungal community composition and diversity were analyzed by the sequencing of V4-V5 of 16 S rRNA gene and ITS1 gene, respectively. MIP results showed that biochar increased the total porosity, total pore volume, average pore diameter and the volumes of > 75, 30–75 and 5–30 µm pores in soils. The straw feedstock and pyrolysis temperature of biochar affected the microbial diversity and community structure in soils. The soil amended with RB550 had the highest Shannon diversity of bacteria and fungi, while the soil treated with CB350 had the highest bacterial abundance. The addition of biochar mainly increased the relative abundances of bacterial genera Actinospica, Ellin6067, Streptomyces and Massilia, while decreased the abundance of Pseudomonas, Methylobacterium and Nitrosospira. However, the fungal genera had a greater variation in biochar-amended soils. The > 5 µm pores in soils had positive effects on the microbial diversity and abundance. The bacterial genera that were acidophilic and aerobic had positive correlations with the volumes of > 75, 30–75 and 5–30 µm pores, especially Ellin6067, Flavisolibacter and Haliangium. Inversely, the genera that were facultative anaerobic (Methylobacterium, Pseudomonas and Nitrosospira) and anaerobic (Christensenellaceae_R-7_group) showed a positive correlation with the volume of < 5 µm pores or no obvious regularity. Most fungal genera tended to live in the larger pores of > 5 µm and could extend into smaller pores. Therefore, the pore characteristics largely determined the microbial community structure in the biochar-amended soils.
199. 题目: Biochar addition regulates soil phosphorus fractions and improves release of available phosphorus under freezing-thawing cycles
期刊: Science of The Total Environment
作者: Long Sui, Chunyu Tang, Kui Cheng, Fan Yang
摘要: Currently, the shortage of phosphorus resources is becoming more and more serious. In general, phosphorus fertilizer is poorly utilized in soil and tends to gradually accumulate. Freezing-thawing cycles (FT) are seasonal phenomenon occurring in high latitudes and altitudes regions, which have obvious influence on the form of phosphorus in soil. This study investigates the effect of biochar on soil physicochemical properties, phosphorus form and availability under FT and thermostatic incubation (TH) condition. Compared with treatment without biochar, 4 % biochar addition increased the soil pH value, electrical conductivity, organic matter and Olsen-P of soil by a maximum of 0.76, 285.55 μS/cm, 28.60 g/kg and 139.27 mg/kg, respectively. Moreover, according to Hedley-P classification results, under FT condition, the content of labile phosphorus pool is always greater than those under TH. FT may promote the conversion of phosphorus from other fractions to labile phosphorus pools. Redundancy analysis results show that biochar addition and FT can not only directly change the soil phosphorus pool, but also alter the soil physicochemical properties and microbial community, which further affect the adsorption and mineralization of phosphorus in soil. The results of this study will be devoted to understanding the changes in soil phosphorus fractions under the effects of biochar addition and FT, providing references for agricultural production in areas where FT occur.
200. 题目: A 10-year field experiment proves the neutralization of soil pH in Chinese hickory plantation of southeastern China
期刊: Journal of Soils and Sediments
作者: Jin Jin, Xingzhao Huang, Jiasen Wu, Weiming Zhao, Weijun Fu
摘要: Purpose Stable soil pH is the key property to maintain soil biogeochemical balance, structure, and function stability of the terrestrial ecosystem. Understanding the soil pH change and its influencing factors is critical for maintaining soil quality and the sustainability of agricultural resources. Materials and methods In our study, 215 soil samples were collected using a paired comparison method from a typical hickory plantation region between 2008 and 2018 in southeastern China. The geostatistics and kriging interpolation method were used to evaluate the change in pH (CIP). The structural equation model (SEM) was combined to quantify the contribution of driving factors to CIP. Results and discussion The results suggested that the pH value of the soil had a significant neutralization effect which was manifested by increased pH value of the relatively acidic soil but decreased pH value of the relatively alkaline soil. The soil pH threshold (pHτ, the point at which the soil pH changes from positive to negative) was 5.96. The spatial distribution trend of pH between 2008 and 2018 was similar, while the local variation was different. Soil initial pH (IpH) was the most critical negative driving factor influencing CIP, while the mean annual temperature (MAT) and the mean annual precipitation (MAP) had positive effects on CIP. In addition, soil organic matter content (SOM) and bulk density were also important factors affecting CIP. Conclusions Our results indicated that long-term management could increase, decrease, or remain the soil pH value, with CIP mainly dependent on IpH, climatic factors, soil organic matter content, and bulk density. Lime, sod cultivation, and organic fertilizers are recommended to increase soil pH.