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221. 题目: Inoculating indoleacetic acid bacteria promotes the enrichment of halotolerant bacteria during secondary fermentation of composting
文章编号: N22090603
期刊: Journal of Environmental Management
作者: Yanlin Li, Mingdian Zhou, Chunxing Li, Xiaofang Pan, Nan Lv, Zhilong Ye, Gefu Zhu, Quanbao Zhao, Guanjing Cai
更新时间: 2022-09-06
摘要:

The secondary fermentation stage is critical for stabilizing composting products and producing various secondary metabolites. However, the low metabolic rate of mesophilic bacteria is regarded as the rate-limiting stage in composting process. In present study, two indoleacetic acid (IAA)-producing bacteria (Bacillus safensis 33C and Corynebacterium stationis subsp. safensis 29B) were inoculated to strengthen the secondary fermentation stage to improve the plant-growth promoting potential of composting products. The results showed that the addition of IAA-producing bacteria promoted the assimilation of soluble salt, the condensation and aromatization of humus, and the accumulation of dissolved organic nitrogen (DON) and dissolved organic carbon (DOC). The bioaugmentation strategy also enabled faster microbial community succession during the medium-late phase of secondary fermentation. However, the colonization of Bacillus and Corynebacterium could not explain the disproportionate increase of IAA yield, which reached up to 5.6 times compared to the control group. Deeper analysis combined with physicochemical properties and microbial community structure suggested that IAA-producing bacteria might induce the increase of salinity, which enriched halotolerant bacteria capable of producing IAA, such as Halomonas, Brachybacterium and Flavobacterium. In addition, the results also proved that it was necessary to shorten secondary fermentation time to avoid IAA degradation without affecting composting maturity. In summary, enhancing secondary fermentation of composting via adding proper IAA-producing bacteria is an efficient strategy for upgrading the quality of organic fertilizer.

222. 题目: An increase of fine-root biomass in nutrient-poor soils increases soil organic matter but not soil cation exchange capacity
文章编号: N22090602
期刊: Plant and Soil
作者: Ryota Hayashi, Nagamitsu Maie, Rota Wagai, Yasuhiro Hirano, Yosuke Matsuda, Naoki Makita, Takeo Mizoguchi, Ryusei Wada, Toko Tanikawa
更新时间: 2022-09-06
摘要:

Purpose

Fine roots are an important source of soil organic matter (SOM); however, it is unclear whether the cation exchange capacity (CEC) of leaf-derived and root-derived organic matter is comparable. We previously found that in surface soils of Cryptomeria japonica stands with low acid buffering capacity (ABC), fine-root biomass and total carbon (TC) content were higher than in high-ABC soils, but the CEC of the two soil types was almost the same. This result was unexpected, because TC is generally related to CEC. This study aimed to clarify why CEC was not enhanced in the low-ABC soils.

Methods

Surface soils at eleven C. japonica stands with contrasting ABCs were separated into different density fractions: light (LF, containing unstabilized SOM), middle (MF, containing stabilized SOM), and heavy (HF, mainly minerals). The C composition of LF, MF, and tree organs was investigated by solid-state 13C NMR analysis.

Results

The carboxyl C content of MF, which had a significant positive correlation with CEC, did not differ significantly between the low- and high-ABC soils, even though the alkyl/O-alkyl ratio suggested more SOM decomposition in the low-ABC soils. This ratio had a significant negative correlation with soil pH (H2O) in both LF and MF and a positive correlation with fine-root biomass in MF. Furthermore, aromatic C was preferentially decomposed in the low-ABC soils.

Conclusion

In the low-ABC soils, the increase of root litter input did not increase the carboxyl group content in MF, and thus did not increase its CEC, owing to increased SOM degradation.

223. 题目: Sustainable Food Waste Management: Synthesizing Engineered Biochar for CO2 Capture
文章编号: N22090601
期刊: ACS Sustainable Chemistry & Engineering
作者: Xiangzhou Yuan, Junyao Wang, Shuai Deng, Pavani Dulanja Dissanayake, Shujun Wang, Siming You, Alex C K Yip, Shuangjun Li, Yoonah Jeong, Daniel C W Tsang, Yong Sik Ok
更新时间: 2022-09-06
摘要: Humanity needs innovative ways to combat the environmental burden caused by food waste, which is one of the critical global issues. We proposed food waste-derived engineered biochar (FWDEB) for CO2 capture from a life cycle perspective. FWDEB samples were prepared by carbonization and chemical activation for CO2 adsorption. FW400-KOH600(2), carbonized at 400 °C and then activated at 600 °C with a KOH/biochar mass ratio of 2, presented the best CO2 adsorption capacities of 4.06 mmol g–1 at 0 °C (1 bar) and 2.54 mmol g–1 at 25 °C (1 bar) among all prepared samples. The CO2 uptake at 25 °C (1 bar) was affected by both micropore volume and surface area limited by narrow micropores less than 8 Å. Basic O- and N-functional groups were generated during the KOH activation, which are beneficial for enhancing the FWDEB-based CO2 adsorption. Moreover, a life cycle assessment was implemented to quantify the potential environmental impacts of FW400-KOH600(2), indicating that negative net global warming potential could be achieved using the FWDEB-based CO2 capture approach. Owing to the environmental benefits, we highlighted its potential as a promising technical route to mitigate climate change and achieve a waste-to-resource strategy.

224. 题目: Changes in quantity and quality of dissolved organic carbon in purple soil: Roles of land use and soil depth
文章编号: N22090506
期刊: Land Degradation & Development
作者: Ke Liang, Yunfei Bi, Binghui He, Mengdie Feng, Peidong Xi, Tianyang Li
更新时间: 2022-09-05
摘要: Dissolved organic carbon (DOC) is the substrates of microbial activities and regulates the biogeochemical cycle of carbon. Plentiful croplands are converted to secondary forest and economic plantation following the implementations of “Grain-for-Green” Projects in China, remarkably altering the quantity and quality of topsoil dissolved organic carbon (DOC). However, the extent and magnitude of these land use changes affecting the soil DOC traits remain largely unclear. This study aimed to elucidate the effects of different land uses and soil depths on topsoil DOC quantity and quality. Soil samples were collected from secondary forest (SF), orchard plantation (OP), and cropland (CL) at the 0-5, 5-10, 10-15 and 15-20 cm soil depths, respectively, in a representative purple soil hillslope, southwest China. Soil DOC concentration and related UV-visible absorbance characteristics were determined to denote respectively the quantity and quality of DOC. Results showed that DOC concentration was 44% lower in the OP than in the SF and CL. Higher ratios of UV absorbance value at 254, 260, and 400 nm to DOC concentration (i.e. SUAV254, SUVA260 and C:C ratio), electronic conductivity (EC), cation exchange capacity (CEC), soil organic carbon (SOC) and total nitrogen (TN) concentration were found in the OP rather than in the SF and CL. The SUAV254, SUVA260, SOC, and TN concentration were the highest at 0-5 cm soil depth. DOC concentration showed negative relationships with most UV absorbance values, SUAV254, SUVA260, C:C ratio. Soil EC, CEC, and pH were closely correlated with the DOC concentration and its UV-visible variables. Our results indicated that DOC was relatively richer in aromatic and humic substances in the OP, providing valuable information for sustainable ecological restoration and land use management.

225. 题目: Excellent Adsorptive-Photocatalytic Performance of Zinc Oxide and Biomass Derived O, N-Contained Biochar Nanocomposites for Dyes and Antibiotic Removal
文章编号: N22090505
期刊: Chemical Engineering Journal
作者: Shunli Yu, Juan Zhou, Yanmei Ren, Zhiwang Yang, Ming Zhong, Xiaoqiang Feng, Bitao Su, Ziqiang Lei
更新时间: 2022-09-05
摘要:

Designing and constructing low cost, environmental, and efficient photocatalysts is essential to remove the organic pollutants in wastewater. In this work, two series of nanocomposites containing zinc oxide and N, O-contained biochar (ZnO/NOC) were smartly fabricated by using biomass peanut shell as carbon source and template, zinc nitrate as Zn source, and ethanol as solvent. Calcination temperature and mass ratio of biomass to ZnO were optimized to be 700 oC and 0.3. As expected, the optimal ZnO/NOC nanocomposite shows an excellent adsorptive and UV/Vis-photocatalytic performance in the removal of diverse pollutants. Particularly, the photocatalytic activities of ZnO/NOC are 3.5 and 20.5 times higher than pure ZnO for methylene blue degradation (10 mg/L) under ultraviolet and visible lights, respectively. Also, the removal efficiencies of ZnO/NOC for antibiotic (30 mg/L) under the same conditions are 5.4 and 7.7 times higher than pure ZnO. The excellent performance is mainly ascribed to large surface area, ample and proper size pore, fast charges transfer, large density and long lifetime of photogenerated charges, and strong interactions between ZnO and N, O-contained biochar, and so on. And Vis-photocatalytic mechanism was proposed.

226. 题目: Those who can don't want to, and those who want to can't: An eco-evolutionary mechanism of soil carbon persistence
文章编号: N22090504
期刊: Soil Biology and Biochemistry
作者: Mark T L Bonner, Oskar Franklin, Shun Hasegawa, Torgny Näsholm
更新时间: 2022-09-05
摘要:

Reliable manipulation of soil organic matter (SOM) – a necessity for optimal land management – is constrained by our limited mechanistic understanding of SOM formation. Here we propose a novel mechanistic element that may contribute to SOM dynamics, supplementing existing frameworks, based on evolutionary-ecological rather than chemical or physical limitations to decomposition. We argue that decomposition of some substrates may be constrained by spatial competition from opportunists. We describe and test a mathematical model based on our framework, providing a proof-of-concept that substrate can, in principle, be spared decomposition and accumulate even when it is physically and chemically accessible. Our framework can help explain a variety of SOM dynamics, including priming and the suppression of decomposition by nitrogen addition, as well as the typical composition of SOM. An augmented mechanistic framework for understanding SOM dynamics can help guide targeted empirical study, which in turn can contribute to more optimised land management.

227. 题目: Nitrogen isotope evidence for changing Arctic Ocean ventilation regimes during the Cenozoic
文章编号: N22090503
期刊: Geophysical Research Letters
作者: Jochen Knies
更新时间: 2022-09-05
摘要: In this work, I report on the coupling of dinitrogen (N2) fixation and denitrification in oxygen-deficient waters of the Arctic Ocean during the Paleogene. This coupling fertilized marine phytoplankton growth and favored organic carbon burial. Reduced vertical mixing due to salinity stratification in a tectonically closed oceanic basin created conditions favorable for N2-fixation by phytoplankton harboring diazotrophic bacterial symbionts. A positive shift of 5‰ in the δ15N record indicates a change in the main source of biologically available nitrogen due to rapidly changing nutrient availability. I interpret this shift as a switch to Atlantic-sourced nitrate as the main nitrogen source owing to the opening of the Arctic-Atlantic gateway to the northern North Atlantic. While the timing of the opening is still disputed among the available Arctic records, I use evidence from the northern North Atlantic to argue that the Arctic Ocean has been fully ventilated since the early Neogene.

228. 题目: Spectral characteristic of the waters with different sizes of particles: impact of water quality and land-use type
文章编号: N22090502
期刊: Environmental Science and Pollution Research
作者: Zelan Lv, Peng Wang, Caixia Yan, Minghua Nie, Xiaoying Xiong, Mingjun Ding
更新时间: 2022-09-05
摘要:

Natural colloids (NCs) are heterogeneous mixtures of particles in the aquatic environments that are strongly influenced by land use and water quality between terrestrial and aquatic environments. However, the relevant study paid little attention to the difference among the waters with different sizes of particles (e.g., suspended particulate matter (SPM), NCs, and the truly soluble substances). In this study, the spectral properties of these different waters were investigated from different land-use types in the Yuan River basin, China. Results of the UV–visible absorption spectral showed that with the particle size increased, the aromaticity, chromophoric dissolved organic matter, and humification degree of organic matter increased, while the condensation degree decreased. Data analysis from the fluorescence indices indicated that the source and the autochthonous feature of the truly soluble substances differed from that of NCs and SPM, whereas the protein-like component was mainly combined with the relatively larger size of particles (i.e., SPM and NCs), especially the downstream. Although the spectral characteristics of the water samples were strongly influenced by the water quality (> 45%), the land-use type might be the real potential impactor. Furthermore, the influence of land-use type on the spectral properties differed between the large and small scale of the buffer strips and between the mainstream and the tributaries. And this effect was more significant on the fluorescence properties in the mainstream and the spectral properties for NCs than for SPM. The study helps to understand the biogeochemical effects of the waters with different particle sizes.

229. 题目: Removal and toxic forecast of microplastics treated by electrocoagulation: Influence of dissolved organic matter
文章编号: N22090501
期刊: Chemosphere
作者: Mengqiao Luo, Zhaoyang Wang, Shuai Fang, Bo Song, Pengwei Cao, Hao Liu, Yixuan Yang
更新时间: 2022-09-05
摘要:

In recent years, the break of COVID-19 makes the large use of disposable products, which causes the removal of microplastics become an imperative problem. Electrocoagulation is one of the effective removal technologies, but there is hardly research concentrating on the effect of substrate in the actual water on the microplastics removal with electrocoagulation. As an important role of water bodies, dissolved organic matter (DOM) has a vital and inevitable effect on the efficiency of electrocoagulation. In this study, the effect of DOM in tailwater on microplastics during electrocoagulation is elucidated by comparing the electrocoagulation treatment results between simulated wastewater and tailwater, using parallel factor analysis (PARAFAC), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrometer (FTIR) and zeta potential analyzer. Three kinds of microplastic particles (i.e. polypropylene, polyethylene, and polymethyl methacrylate) were added into each of the two kinds of wastewaters to form six electrocoagulation systems. Results show that DOM in tailwater promotes the production of flocs and free radicals during electrocoagulation process. Fe2+ and Fe3+ are adsorbed on the surface of DOM molecules and combined with •OH form flocs. Although DOM accelerates the production of free radicals and thus promotes the aging of microplastics, flocs with DOM as crystal nucleus can prevent toxic substances and small-sized microplastics from leaching into water again. Therefore, electrocoagulation is preferred to removal microplastics in water with high concentration of DOM. This study provides a significant reference for microplastics removal by electrocoagulation in actual water, and promote the practical application of electrocoagulation for microplastics removal in water treatment.

230. 题目: Manganese stabilization in mine tailings by MgO-loaded rice husk biochar: Performance and mechanisms
文章编号: N22090409
期刊: Chemosphere
作者: Bin Zhao, Tianyue Peng, Renjie Hou, Yao Huang, Wenjing Zong, Yuanliang Jin, David O'Connor, Shovan Kumar Sahub, Hao Zhang
更新时间: 2022-09-04
摘要:

Leachable metal in abandoned mine tailings may be toxic to vegetation, affecting effective ecological restoration. In this study, MRB was synthesized through MgCl2·6H2O wet impregnation followed by duplicate slow pyrolysis. Manganese tailings were mixed with MRB, rice husk biochar (RB), and MgO at a dosage of 0–5%, followed by 90-day incubation. Toxicity characteristic leaching procedure and sequential leaching were used to analyze the leachability and species of Mn in tailings, while a stabilization mechanism was proposed with the support of the characterization of the tailings before and after amendment. Results suggested MRB addition significantly decreased leachable Mn by 63.8%, reducing from 59.88 mg/L to 21.68 mg/L, while only a 14.39% reduction was achieved by rice husk biochar (RB). The sharp decline of leachable Mn after 90-day mixing was contributed by the transformation from labile to stable fractions. A microporous biochar matrix along with the uniform dispersion of MgO active component were both responsible for the better Mn stabilization. Only less than 10% of the variation in substrate pH was observed with the increase of MgO loading or incubation time. Linear correlation analyses indicated substrate pH's strong negative relationship with leachable Mn and moderate positive relationship with residual fraction. Characterization results revealed that MRB exhibited different stabilization mechanisms in mine tailings, where Mn was likely to be stabilized by direct interaction with active MgO or indirect alkaline precipitation to form stable MgMn2O4, Mn(CH3COO)2, and MnO(OH)2. This work validated the promoting potential of recycling agricultural biomass waste for the amendment of manganese mine tailings.

231. 题目: Contribution of sedimentary organic matter to arsenic mobilization along a potential natural reactive barrier (NRB) near a river: The Meghna river, Bangladesh
文章编号: N22090408
期刊: Chemosphere
作者: Thomas S Varner, Harshad V Kulkarni, William Nguyen, Kyungwon Kwak, M Bayani Cardenas, Peter S K Knappett, Ann S Ojeda, Natalia Malina, Mesbah Uddin Bhuiyan, Kazi M Ahmed, Saugata Datta
更新时间: 2022-09-04
摘要:

Elevated dissolved arsenic (As) concentrations in the shallow aquifers of Bangladesh are primarily caused by microbially-mediated reduction of As-bearing iron (Fe) (oxy)hydroxides in organic matter (OM) rich, reducing environments. Along the Meghna River in Bangladesh, interactions between the river and groundwater within the hyporheic zone cause fluctuating redox conditions responsible for the formation of a Fe-rich natural reactive barrier (NRB) capable of sequestering As. To understand the NRB's impact on As mobility, the geochemistry of riverbank sediment (<3 m depth) and the underlying aquifer sediment (up to 37 m depth) was analyzed. A 24-hr sediment-water extraction experiment was performed to simulate interactions of these sediments with oxic river water. The sediment and the sediment-water extracts were analyzed for inorganic and organic chemical parameters. Results revealed no differences between the elemental composition of riverbank and aquifer sediments, which contained 40 ± 12 g/kg of Fe and 7 ± 2 mg/kg of As, respectively. Yet the amounts of inorganic and organic constituents extracted were substantially different between riverbank and aquifer sediments. The water extracted 6.4 ± 16.1 mg/kg of Fe and 0.03 ± 0.02 mg/kg of As from riverbank sediments, compared to 154.0 ± 98.1 mg/kg of Fe and 0.55 ± 0.40 mg/kg of As from aquifer sediments. The riverbank and aquifer sands contained similar amounts of sedimentary organic matter (SOM) (17,705.2 ± 5157.6 mg/kg). However, the water-extractable fraction of SOM varied substantially, i.e., 67.4 ± 72.3 mg/kg in riverbank sands, and 1330.3 ± 226.6 mg/kg in aquifer sands. Detailed characterization showed that the riverbank SOM was protein-like, fresh, low molecular weight, and labile, whereas SOM in aquifer sands was humic-like, older, high molecular weight, and recalcitrant. During the dry season, oxic conditions in the riverbank may promote aerobic metabolisms, limiting As mobility within the NRB.

232. 题目: Long-term film mulching with manure amendment increases crop yield and water productivity but decreases the soil carbon and nitrogen sequestration potential in semiarid farmland
文章编号: N22090407
期刊: Agricultural Water Management
作者: Fangfang Zhang, Ya'nan Wei, Qifei Bo, An Tang, Qilong Song, Shiqing Li, Shanchao Yue
更新时间: 2022-09-04
摘要:

Plastic film and gravel mulching in combination with fertilization are widely used to increase crop yields and water productivity (WP) in arid and semiarid areas, but soil surface mulching may stimulate soil organic carbon (SOC) mineralization; therefore, film mulching with manure amendment was proposed to improve soil fertility. However, the combined effects of these practices on yield, WP, and the stocks of SOC and total nitrogen (TN) need to be better understood. This study investigated the long-term effects of different practices on crop yields, WP, and SOC and TN stocks in the 0–20, 20–40 and 40–60 cm layers based on a 12-year spring maize (Zea mays L.) field experiment on the Loess Plateau. The treatments included no mulching + NPK (CK), gravel mulching + NPK (GM), film mulching + NPK (FM), and film mulching + NPK + cow manure (FCM). In 2019 and 2020, compared with the control, both FM and FCM significantly increased crop yields, WP, N uptake efficiency (NupE) and N fertilizer productivity (NfP). Compared with CK, the FCM treatment significantly increased the SOC and TN stocks by 44.10% and 39.51%, respectively, on average, and the minimum C input that could maintain the soil C balance on the Loess Plateau was 0.67 Mg ha−1 yr−1. Over the 12 experimental years, compared with the initial value in 2009, the trends of SOC and TN contents in the FM treatment were downward, while those in the FCM treatment increased by 41.61% and 30.27%, respectively, but yearly input of manure led to SOC equilibrium. Compared with CK, the FCM treatment significantly decreased SOC and TN sequestration potential by 33.38% and 19.59%, respectively, on average in topsoil (0–20 cm), but it had less of an effect on SOC and TN sequestration at 20–40 and 40–60 cm soil depths. The reasons for SOC reaching equilibrium in the FCM treatment were analyzed, and periodic subsoiling was proposed to break the equilibrium state to further improve the sequestration amount of SOC and TN at 0–60 cm soil depths. In conclusion, film mulching with manure amendment was recommended as a long-term strategy to improve soil productivity and soil fertility in semiarid farmland.

233. 题目: Citric acid modified biochar application at a low dosage can synchronically mitigate the nitrogenous gas pollutants emission from rice paddy soils
文章编号: N22090406
期刊: Environmental Pollution
作者: Haijun Sun, Zhenghua Yi, Paramsothy Jeyakumar, Changlei Xia, Yanfang Feng, Su Shiung Lam, Christian Sonne, Hailong Wang, Weiming Shi
更新时间: 2022-09-04
摘要:

Raw biochar with high pH possibly stimulated ammonia (NH3) volatilization in the agricultural soil. We hypothesized that the modified biochar (MBC) with low pH can synchronically decrease the NH3 and nitrous oxide (N2O) losses. We performed a two-year experiment to clarify how citric acid MBC influence the NH3 volatilization and N2O emission as well as the underlying mechanisms. Two typical paddy soils, i.e., Hydragric Anthrosol and Haplic Acrisol, receiving equal urea N with 240 kg ha−1 but varied rates of MBC with 0, 5, 10, and 20 t ha−1 (named Urea, Urea + MBC5, Urea + MBC10, and Urea + MBC20, respectively) were studied. The results showed that MBC-amended treatments effectively mitigated the NH3 volatilization from Hydragric Anthrosol and Haplic Acrisol by 29.6%–57.9% and 30.5%–62.4% in 2017, and by 16.5%–21.0% and 24.5%–35.0% in 2018, respectively, compared to Urea treatment. In addition, significantly lower N2O emissions with averaged 38.3% and 43.1% in 2017, and 51.7% and 26.7% were recorded under Hydragric Anthrosol and Haplic Acrisol, respectively, following the MBC application (P < 0.05). Increased MBC addition performed higher efficacy on mitigating NH3 volatilization, particularly in the first rice season, while this “dosage effect” was not found for N2O reduction. Lowered pH in overlying water, enhanced adsorption of NH4+-N and its nitrification rate likely contributed to the lower NH3 volatilization as result of MBC addition. The nirS and nosZ gene copies were not changed by MBC, while the nirK gene copies were decreased as result of MBC amendment by 8.3%–25.2% under Hydragric Anthrosol and by 21.8%–24.9% under Haplic Acrisol. Consequent lower ratio of nirK/(nirS +  nosZ) explained the mitigation effect of MBC on N2O emission. In conclusion, the present two-year study recommends that MBC applied at a low dosage can perform positive effect on controlling the nitrogenous gas pollutants from paddy soil.

234. 题目: Reduction mechanisms of V5+ by vanadium-reducing bacteria in aqueous environments: Role of different molecular weight fractionated extracellular polymeric substances
文章编号: N22090405
期刊: Science of the Total Environment
作者: Dan Zhou, Mengmeng Liang, Yonglian Xia, Chao Li, Mingzheng Huang, Shuming Peng, Yi Huang
更新时间: 2022-09-04
摘要:

Extracellular polymeric substances (EPS) are high-molecular polymers secreted by microbes and play essential roles in metallic biogeochemical cycling. Previous studies demonstrated the reducing capacity of the functional groups on EPS for metal reduction. However, the roles of different EPS components in vanadium speciation and their responsible reducing substances for vanadium reduction are still unknown. In this study, the EPS of Bacillus sp. PFYN01 was fractionated via ultrafiltration into six components with different kDa (EPS>100, EPS100–50, EPS50–30, EPS30–10, EPS10–3, and EPS<3). Batch reduction experiments of the intact cells, EPS-free cells, the pristine and fractionated EPS with V5+ were conducted and characterized. The results demonstrated that the extracellular reduction of V5+ into V4+ by EPS was the major reduction process. Among the functional groups in EPS, C=O/C-N of amide in protein/polypeptide and CdoubleO of carboxyl in fulvic acid-like substances might act as the reductants for V5+, while CsingleO in polysaccharide molecules and PdoubleO in phosphodiester played a key role in the adsorption process. The intracellular reduction was via translocating V5+ into the cells and releasing V4+ by the intracellular reductases. The reducing capacity of the fractionated EPS followed a sequence of EPS<3 > EPS10–3 > EPS50–30 > EPS100–50 > EPS30–10 > EPS>100. The small molecules of fulvic acid-like substances and amino acids were responsible for the high reducing capacity of EPS<3. EPS>100 had the lowest reducing capacity due to its macromolecular structure decreasing the exposure of the reactive sites. In addition to reduction, those intermediate EPS components may also have supporting functions, such as connecting protein skeletons and increasing the specific surface area of EPS. Therefore, the diverse effects of the EPS components cannot be neglected in vanadium biogeochemical cycling.

235. 题目: Evaluation of the impact of varied biochars produced from M.× giganteus waste and application rate on the soil properties and physiological parameters of Spinacia oleracea L.
文章编号: N22090404
期刊: Environmental Technology & Innovation
作者: Oleksandr Kononchuk, Valentina Pidlisnyuk, Aigerim Mamirova, Volodymyr Khomenchuk, Andriy Herts, Barbora Grycová, Kateřina Klemencová, Pavel Leštinský, Pavlo Shapoval
更新时间: 2022-09-04
摘要:

The use of M. × giganteus in phytoremediation requires treatment of the contaminated biomass, which can be done by pyrolysis to produce biochar. Due to its potentially detrimental properties, the application of biochar in soil remediation must first be evaluated on a test plant to infer how the growth process was affected by the impact on soil parameters. The main goal of the current research was to investigate the effects of waste-derived Miscanthus biochars (from contaminated rhizomes (B1) and aboveground biomass (B2)) on soil properties and evaluate the impact of biochar doses and properties on Spinacia oleracea L. growth. It was revealed that incorporation of B1 at a dose of 5% and B2 at doses of 1, 3, and 5% increased soil organic carbon, pH, K (at 3 and 5%), and P2O5 (at 5% B2). Cultivation of S. oleracea reduced organic carbon, soil pH as a function of biochar dosage, and K, P2O5, NH4, and NO3 content in all treatments tested. The highest biomass yield was recorded at 3% B2. The photosynthetic parameters indicated that the doses of 3 and 5% B2 led to dissociation of light-harvesting complexes. Increasing the biochar dose did not necessarily increase yield or improve photosynthetic parameters. S. oleracea adapted to the initial stress by incorporating biochar and managed to establish a balance between nutrients, water supply, and light. It is recommended that the effects of biochar on the development of the target crop be evaluated through preliminary trials before biochar is applied at field scale.

236. 题目: Role of extracellular polymeric substances in methane production from waste activated sludge induced by conductive materials
文章编号: N22090403
期刊: Science of the Total Environment
作者: Hong-Yu Jin, Zhang-Wei He, Yong-Xiang Ren, Cong-Cong Tang, Ai-Juan Zhou, Wenzong Liu, Qian Sun, Zhihua Li, Aijie Wang
更新时间: 2022-09-04
摘要:

Conductive materials have been widely used to establish direct interspecies electron transfer (DIET) for enhancing methane production potential from anaerobic digestion of waste activated sludge (WAS). However, the roles of extracellular polymeric substances (EPSs) affected by conductive materials on anaerobic digestion have been rarely reported. This study selected four widely used conductive materials, i.e., granular active carbon (GAC), biochar (BC), zero-valent iron (ZVI), and magnetite (Mag), to reveal the roles of EPSs. Results showed that methane production potentials were increased by BC, ZVI and Mag compared to that of control, with increase ratios of 13.4 %, 22.2 % and 12.2 %, while a decrease was observed by GAC. The contents, components and characteristics of EPSs were all affected by conductive materials. The contents of EPSs were increased by ZVI and Mag, while they were decreased by BC and GAC. The ratios between proteins and polysaccharides (PN/PS) in loosely bound EPSs (LB-EPSs) were reduced in all groups, while they were similar in tightly bound EPSs (TB-EPSs) of ZVI and Mag groups. In addition, the cytochrome C and redox properties were remarkably promoted in suspension rather than in LB- and TB-EPSs. It was found that the correlation relationships between the maximal methane production potential (Pmax) and PN/PS in EPSs were positive, as well as fluorescent substances, especially tyrosine-like and tryptophan-like substances, with R2 of 0.96 and 0.98. Furthermore, the correlation relationships also existed between EPSs and microbial communities. Clostridium and Methanobacterium, potential DIET partners, presented significant positive correlation relationships (P < 0.05) with Pmax, PN/PS and fluorescent substances in EPSs. The findings may provide some new insights for mechanism investigation of anaerobic digestion induced by conductive materials.

237. 题目: A first-order approximation of floodplain soil organic carbon stocks in a river network: The South Platte River, Colorado, USA as a case study
文章编号: N22090402
期刊: Science of the Total Environment
作者: Ellen Wohl, Richard L Knox
更新时间: 2022-09-04
摘要:

The lack of watershed-scale estimates of floodplain carbon stocks limits recognition of the important role of floodplains and river corridor restoration in efforts to enhance carbon sequestration. We use the South Platte River watershed of Colorado, USA as a case study to illustrate spatial patterns of, and controls on, floodplain carbon stocks at the watershed scale. This case study illustrates the disproportionate importance of floodplains for soil carbon stocks relative to adjacent uplands and provides an example of how spatially explicit data can be used to prioritize floodplain restoration with regard to carbon sequestration. We use the hydrogeomorphic floodplain tool GFPLAIN to delineate the extent of 100-year floodplains in the South Platte River watershed. We distinguish elevation bands for the steppe, montane, subalpine, and alpine zones. We also differentiate bead (floodplain width/channel width ≥ 5) and string (floodplain width/channel width < 5) reaches within the montane and subalpine zones. Drawing on prior, field-based measurements of organic carbon stock in downed, dead wood and soil in these floodplain types, we estimate total floodplain organic carbon stock based on median values of stock in different floodplain types and the spatial extent of these floodplain types. This estimate includes organic carbon stocks in lake and reservoir sediments in the watershed. Soil constitutes the greatest reservoir of floodplain carbon. The total estimated area of floodplain is 2916 km2, which is 4.3 % of the total watershed area of the South Platte River. Our preferred estimate is 42.7 Tg C stock (likely range of 39.1–42.7 Tg). This equates to 11.1 % of a previously estimated overall carbon stock (above and belowground biomass and soil organic carbon) in the entire watershed of 384 Tg C. Floodplains are thus disproportionately important, relative to their surface area, in storing organic carbon in this semiarid watershed. Field measurements of floodplain soil organic carbon stocks from across the globe indicate that this finding is not unique to this watershed, with implications for prioritizing floodplain management and restoration as a means of enhancing carbon sequestration.

238. 题目: Microspectroscopic visualization of how biochar lifts the soil organic carbon ceiling
文章编号: N22090401
期刊: Nature Communications
作者: Zhe (Han) Weng, Lukas Van Zwieten, Ehsan Tavakkoli, Michael T Rose, Bhupinder Pal Singh, Stephen Joseph, Lynne M Macdonald, Stephen Kimber, Stephen Morris, Terry J Rose, Braulio S Archanjo, Caixian Tang, Ashley E Franks, Hui Diao, Steffen Schweizer, Mark J Tobin, Annaleise R Klein, Jitraporn Vongsvivut, Shery L Y Chang, Peter M Kopittke, Annette Cowie
更新时间: 2022-09-04
摘要:

The soil carbon (C) saturation concept suggests an upper limit to the storage of soil organic carbon (SOC). It is set by the mechanisms that protect soil organic matter from mineralization. Biochar has the capacity to protect new C, including rhizodeposits and microbial necromass. However, the decadal-scale mechanisms by which biochar influences the molecular diversity, spatial heterogeneity, and temporal changes in SOC persistence, remain unresolved. Here we show that the soil C storage ceiling of a Ferralsol under subtropical pasture was raised by a second application of Eucalyptus saligna biochar 8.2 years after the first application—the first application raised the soil C storage ceiling by 9.3 Mg new C ha−1 and the second application raised this by another 2.3 Mg new C ha−1. Linking direct visual evidence from one-, two-, and three-dimensional analyses with SOC quantification, we found high spatial heterogeneity of C functional groups that resulted in the retention of rhizodeposits and microbial necromass in microaggregates (53–250 µm) and the mineral fraction (<53 µm). Microbial C-use efficiency was concomitantly increased by lowering specific enzyme activities, contributing to the decreased mineralization of native SOC by 18%. We suggest that the SOC ceiling can be lifted using biochar in (sub)tropical grasslands globally.

239. 题目: From soil to sea: sources and transport of organic carbon traced by tetraether lipids in the monsoonal Godavari River, India
文章编号: N22090310
期刊: Biogeosciences
作者: Frédérique M S A Kirkels, Huub M Zwart, Muhammed O Usman, Suning Hou, Camilo Ponton, Liviu Giosan, Timothy I Eglinton, Francien Peterse
更新时间: 2022-09-03
摘要: Monsoonal rivers play an important role in the land-to-sea transport of soil-derived organic carbon (OC). However, spatial and temporal variation in the concentration, composition, and fate of this OC in these rivers remains poorly understood. We investigate soil-to-sea transport of soil OC by the Godavari River in India using glycerol dialkyl glycerol tetraether (GDGT) lipids in soils, river suspended particulate matter (SPM), and riverbed sediments, as well as in a marine sediment core from the Bay of Bengal. The abundance and composition of GDGTs in SPM and sediments in the Godavari River differs between the dry and wet season. In the dry season, SPM and riverbed sediments from the whole basin contain more 6-methyl branched GDGTs (brGDGTs) than the soils. In the upper basin, where mobilisation and transport of soils is limited due to deficient rainfall and damming, contributions of 6-methyl brGDGTs in SPM and riverbed sediments are relatively high year-round, suggesting that they have an aquatic source. Aquatic brGDGT production coincides with elevated values of the isoprenoid GDGT-0 / crenarchaeol ratio in SPM and riverbed sediments from the upper basin, indicating low-oxygen conditions. In the wet season, brGDGT distributions in SPM from the lower basin closely resemble those in soils, mostly from the north and east tributaries, corresponding to precipitation patterns. The brGDGT composition in SPM and sediments from the delta suggests that soil OC is only effectively transported to the Bay of Bengal in the wet season, when the river plume extends beyond the river mouth. The sediment geochemistry indicates that also the mineral particles exported by the Godavari River primarily originate from the lower basin, similar to the brGDGTs, suggesting that they are transported together. However, river depth profiles in the downstream Godavari reveal no hydrodynamic sorting effect on brGDGTs in either season, indicating that brGDGTs are not closely associated with mineral particles. The similarity of brGDGT distributions in bulk and fine-grained sediments ( 63 µm) further confirms the absence of selective transport mechanisms. Nevertheless, the composition of brGDGTs in a Holocene, marine sediment core near the river mouth appears substantially different from that in the modern Godavari basin, suggesting that terrestrial-derived brGDGTs are rapidly lost upon discharge into the Bay of Bengal and/or overprinted by marine in situ production. The large change in brGDGT distributions at the river–sea transition implies that this zone is key in the transfer of soil OC, as well as that of the environmental signal carried by brGDGTs from the river basin.

240. 题目: Contribution of species and functional richness to carbon storage in eucalypt woodland restoration
文章编号: N22090309
期刊: Forest Ecology and Management
作者: Rachel J Standish, Ryan Borrett, Tim Morald, Richard J Hobbs, Suzanne M Prober
更新时间: 2022-09-03
摘要:

Biologically diverse forest and woodland restoration can mitigate climate change and biodiversity loss. Understanding the trade-off between carbon storage and biodiversity is important to maximise the value of restoration opportunities. Ecological theory suggests biological diversity contributes positively to carbon storage until the relationship plateaus (i.e., species are added with no effect on carbon storage), and yet in practice, tree monocultures are perceived to sequester more carbon than diverse plantings. Here, we measured the contribution of plant diversity to carbon storage in trees and shrubs ten years after planting for yate (Eucalyptus occidentalis) woodland restoration. We found no evidence for a trade-off between carbon storage and plant diversity. We planted yate with mixes of yate woodland species including native grasses, shrubs, and trees. Ten years after planting, grass establishment was poor, and density of trees and shrubs was patchy. There was some unassisted recruitment of woody species. Diversity was measured as observed species richness and observed functional richness, which incorporated taxonomic diversity, structural diversity, and presence/absence of nitrogen-fixing legumes. Carbon stocks measured were above and belowground tree and shrub biomass, leaf and twig litter biomass, and organic carbon (%) in the topsoil. Across all three carbon stocks diverse yate plantings sequestered as much carbon as yate monocultures. Observed species richness had a weak negative effect on tree and shrub biomass in the best linear mixed model but this effect diminished with the removal of an outlier. Tree density had a positive effect on tree and shrub biomass in models with and without the outlier. There was no effect of diversity on litter biomass and soil organic carbon. Instead, linear mixed models of these stocks showed the influence of soil properties. Litter biomass increased with soil potassium and decreased with soil pH. Soil organic carbon increased with initial soil organic carbon and soil nitrogen. There are potential additional biodiversity benefits of diverse plantings that we did not measure (e.g., soil erosion control, wildlife habitat). We call for more field experiments to explore these potential benefits and to generate the ecological knowledge needed to improve the quality of global forest and woodland restoration efforts.

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