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21. 题目: Humic Acid Modified Selective Nanofiltration Membrane for Efficient Separation of PFASs and Mineral Salts
文章编号: N22052102
期刊: ACS ES&T Water
作者: Tianlin Wang, Hongyi Han, Zhichao Wu, Ruobin Dai, Zhiwei Wang
更新时间: 2022-05-21
摘要: Reclaiming water that contains moderate mineral ions with a fairly low concentration of emerging micropollutants (EMPs) is beneficial for drinking water supply, groundwater replenishment, and agricultural irrigation. However, how to achieve the separation of EMPs and mineral salts, in an efficient and environmental-friendly way, remains a technical challenge. Herein, we developed a humic acid (HA) modified selective nanofiltration (NF) membrane for the efficient separation of persistent perfluoroalkyl substances (PFASs, as model EMPs) and mineral salts. The hydrophobic HA regulated the reaction kinetic of polyamide (PA) formation and consequently produced a looser and thinner PA structure. The NF-HA membrane possessed a high water permeance of 19.1 L m–2 h–1 bar–1 and enabled the selective removal of PFASs (>90% for six compounds) with a fairly low rejection of Ca2+ and Mg2+ (<10%). The passage of mineral salts for the NF-HA membrane was ascribed to weakened size exclusion and electrostatic repulsion effect, while the maintained rejection of PFASs was due to the increased electrostatic repulsion and reduced hydrophobic–hydrophilic interaction. Our study offers a green and effective approach to achieve efficient separation of EMPs and mineral salts for the production of healthy reclaimed water.

22. 题目: Spatiotemporal characteristics of enzymatic hotspots in subtropical forests: In situ evidence from 2D zymography images
文章编号: N22052101
期刊: CATENA
作者: Tingting Cao, Xiangshi Kong, Weihua He, Yunru Chen, You Fang, Qiang Li, Qi Chen, Yunchao Luo, Xingjun Tian
更新时间: 2022-05-21
摘要: Soil enzymes play a central role in organic matter decomposition and nutrient cycling in forest ecosystems. However, the spatiotemporal characteristics of in situ enzyme activities in heterogeneous soil and their drivers are still poorly understood. We applied soil zymography in the field to visualize the seasonal dynamics of enzyme activity along soil profiles (28 cm depth) in Quercus variabilis (oak) and Pinus massoniana (pine) pure and mixed forests in southern China. Temporally, the enzymatic hotspot areas were largest in summer (21.9% ± 7.1%), smallest in autumn (6.1% ± 4.9%), and medium-sized in spring (13.4% ± 5.9%) and winter (12.5% ± 7.7%) in all forest soils. The seasonal characteristics were attributed to changes in soil temperature and moisture. Spatially, the enzymatic hotspot areas were the largest at 0–10 cm (6.7% ± 3.8%), followed by 10–20 cm (5.1% ± 3.9%) and 20–28 cm (2.6% ± 2.3%) in all forest soils. In addition, the enzymatic hotspot areas of mixed forest (6.5–33.3%) were larger than those of pure oak (1.3–28.5%) and pine (0.2–22.8%) forests. This positive effect of mixed forest on enzymatic hotspot areas was mainly attributed to the higher microbial biomass and total soil faunal abundance than those in pure forests, especially under dry and cold climate conditions. These results suggest that the negative effects of drought and cold on enzymatic hotspot areas could be mitigated in the mixed forest. This study provided the first in situ evidence of the seasonal dynamics of enzymatic hotspots in forest soil profiles, which are of paramount importance for understanding nutrient cycling and ecosystem functioning.

23. 题目: Amplitude and frequency of wetting and drying cycles drive N2 and N2O emissions from a subtropical pasture
文章编号: N22052009
期刊: Biology and Fertility of Soils
作者: Johannes Friedl, Evi Deltedesco, Katharina M Keiblinger, Markus Gorfer, Daniele De Rosa, Clemens Scheer, Peter R Grace, David W Rowlings
更新时间: 2022-05-20
摘要: This study investigated the effects of irrigation frequency on N 2 and N 2 O emissions from an intensively managed pasture in the subtropics. Irrigation volumes were estimated to replace evapotranspiration and were applied either once (low frequency) or split into four applications (high frequency). To test for legacy effects, a large rainfall event was simulated at the end of the experiment. Over 15 days, 7.9 ± 2.7 kg N 2 + N 2 O-N ha −1 was emitted on average regardless of irrigation frequency, with N 2 O accounting for 25% of overall N 2 + N 2 O. Repeated, small amounts of irrigation produced an equal amount of N 2 + N 2 O losses as a single, large irrigation event. The increase in N 2 O emissions after the large rainfall event was smaller in the high-frequency treatment, shifting the N 2 O/(N 2 O + N 2 ) ratio towards N 2 , indicating a treatment legacy effect. Cumulative losses of N 2 O and N 2 did not differ between treatments, but higher CO 2 emissions were observed in the high-frequency treatment. Our results suggest that the increase in microbial activity and related O 2 consumption in response to small and repeated wetting events can offset the effects of increased soil gas diffusivity on denitrification, explaining the lack of treatment effect on cumulative N 2 O and N 2 emissions and the abundance of N cycling marker genes. The observed legacy effect may be linked to increased mineralisation and subsequent increased dissolved organic carbon availability, suggesting that increased irrigation frequency can reduce the environmental impact (N 2 O), but not overall magnitude of N 2 O and N 2 emissions from intensively managed pastures.

24. 题目: Effects of operating conditions on disinfection by-product formation, calculated toxicity, and changes in organic matter structures during seawater chlorination
文章编号: N22052008
期刊: Water Research
作者: Jiajian Liu, Li Ling, Qing Hu, Chao Wang, Chii Shang
更新时间: 2022-05-20
摘要: This study systematically quantified the impacts of different operation conditions, e.g., pH, chlorine dosages, contact times, and temperatures towards the disinfection by-product (DBP) formation, integrated toxicity, and structural changes in seawater natural organic matter during seawater chlorination. Higher concentrations of total DBPs were found under longer contact times, higher chlorine dosages, higher temperatures, and lower pH. The concentration of tribromomethane, the most abundant DBP, was found lowest at pH 10. Monobromoacetic acid, dibromoacetonitrile, and dibromoacetaldehyde were the three main contributors to integrated cyto- and geno-toxicity, stressing the need to monitor DBPs based on their contributions to integrated toxicity, regardless they are regulated or nonregulated. The concentrations of total organic chlorine remained stable under different conditions, while those of total organic bromine increased with increasing contact times, chlorine dosages, and temperatures, but with decreasing pH, indicating the changes of toxicity in chlorinated seawater compared to drinking water or groundwater. Changes of ultraviolet absorbance at 254 nm and fluorescence excitation emission matrix values are useful indicators for monitoring the concentrations of high molecular weight adsorbable organic bromine and total organic halogen under all operating conditions.

25. 题目: Molecular Level Insights into HO• and Cl2•−-Mediated Transformation of Dissolved Organic Matter in Landfill Leachate Concentrates during the Fenton Process
文章编号: N22052007
期刊: Chemical Engineering Journal
作者: Quanfa Zhong, Zhong Zhang, Qinglong Fu, Jin Yu, Xiaoting Liao, Jianshu Zhao, Di He
更新时间: 2022-05-20
摘要: Cl2•− can be the dominant radical species when high salinity wastewater is treated by advanced oxidation processes (AOPs). In this study, the steady-state concentrations of HO•, Cl• and Cl2•− were determined during the Fenton treatment of two landfill leachate concentrates with significantly different Cl− concentrations (XPNF: 1406 mg/L; SNNF: 8036 mg/L). Based on the steady-state concentrations of the radical species and measured second-order rate constants with dissolved organic matters (DOM), HO• accounted for 76.2% of DOM transformation in XPNF, while Cl2•− accounted for 96.5% in SNNF. The DOM transformation dominated by HO• or Cl2•− was then thoroughly compared to investigate the reactivities of HO• and Cl2•− with DOM at molecular level using high-resolution mass spectrometry. The results showed that formulas with low oxidation degree (O/C < 0.5) were preferentially removed by HO• and HO• was more reactive towards compounds with high saturation degree (H/C > 1.5) compared with Cl2•−. In contrast, Cl2•− was more reactive to the compounds with lower saturation level (H/C < 1.5) and the reaction of Cl2•− with DOM was less dependent on DOM oxidation degree. In addition, HO• preferentially reacted with the CHON compounds with low N content, while Cl2•− was more reactive to CHON compounds with higher N content compared with HO•. To our knowledge, this is the first study to distinguish the difference in the reactivity of HO• and Cl2•− towards DOM at molecular level.

26. 题目: Efficient removal of organic compounds in eutrophic water via a synergy of cyanobacterial extracellular polymeric substances and permanganate
文章编号: N22052006
期刊: Environmental Science and Pollution Research
作者: Jing Li, Xin Hu, Juan Wang, Youru Yao, Yong Zhang, Lixiao Ni, Shiyin Li
更新时间: 2022-05-20
摘要: This study provides a new thinking for the efficient utilization of permanganate (Mn (VII)) in eutrophic water treatment. Eutrophic water contained a large amount of extracellular polymeric substances (EPS) with reduction and chelation; this study used phenol as typical organic matter and cyanobacteria EPS as a representative EPS to explore the mechanism by which EPS influences the oxidation of phenol by Mn(VII) at pH 5.0–9.0. The results showed that under the condition of pH 5.0–7.0, adding 0.2–10 mg/L EPS to the Mn(VII) system could effectively improve the oxidation efficiency of Mn(VII) for phenol. EPS promoted the continuous formation and stability of in situ EPS-MnO2 colloids and significantly enhanced the oxidation of Mn(VII). EPS also combined with phenol and increased the electron cloud density to promote the oxidation of phenol by Mn(VII).

27. 题目: A stream‐to‐sea experiment reveals inhibitory effects of freshwater residency on organic‐matter decomposition in the sea
文章编号: N22052005
期刊: Limnology and Oceanography Letters
作者: André Frainer, Scott D Tiegs
更新时间: 2022-05-20
摘要: One billion tons of carbon are annually transported to the global ocean, and the fate of this carbon hinges not only on marine processing rates, but also on freshwater processing during downstream transport. Using a cotton-strip assay, we assessed the decomposition of organic matter in marine and freshwater sites and simulated its downstream transport from freshwater to the sea by translocating cotton strips approximately half-way through the freshwater incubation period. We observed faster decomposition in the sea relative to the stream and interestingly, an inhibitory effect of stream incubation on subsequent decomposition in the sea. Total nitrogen content and ∂15N in the cotton strips were both greater in the strips incubated entirely in the sea, suggesting greater microbial activity in the marine habitat. Our results lend needed insights into global carbon cycling, the factors that govern organic-carbon processing, and highlight the importance of connections that exist among some of Earth's major ecosystems.

28. 题目: Synergistic effects of humic acid and phosphate fertilizer facilitate root proliferation and phosphorus uptake in low-fertility soil
文章编号: N22052004
期刊: Plant and Soil
作者: Jianyuan Jing, Shuiqin Zhang, Liang Yuan, Yanting Li, Yingqiang Zhang, Bingqiang Zhao
更新时间: 2022-05-20
摘要: Background and aims Humic acid-enhanced phosphate fertilizer (HAP) is an efficient, widely used fertilizer in China produced by incorporating trace amounts of humic acid (HA) into conventional phosphate fertilizer (CP). However, the mechanism of its increased efficiency has remained unclear, limiting its optimization. Methods Maize (Zea mays L. cv ZD 958) was cultivated in root boxes to evaluate the effects of localized HAP, CP, or HA on biomass production, phosphorus (P) uptake, distribution of roots and available P in soil, and activity of C-acquiring and P-acquiring enzymes. Meanwhile, the effects of HAP, CP, and HA in fertosphere were isolated through their uniform application in confined growth tubes and quantifying root traits. Results HAP significantly increased available P content and soil area with high P content, and elevated the ratio of soil C- and P-acquiring enzyme activity. Total maize biomass and root distribution area treated with localized HAP were 12.9% and 29.7% higher than that with local CP application, and root biomass was positively correlated with soil available P. Uniform HAP supply significantly increased the maize biomass and P uptake compared to CP uniform treatments, and the biomass and P uptake were highly correlated with root length. HA alone had no impact on above indices. Conclusions The presence of HA in HAP increased the area and strength of P supply, and P in HAP guaranteed the adequate nutrient supply for maize enabling HA to stimulate growth. Thus, efficacy of HAP was resulted from the synergistic effects of HA and P fertilizer.

29. 题目: A Binary Oxide-Biochar Composite for Adsorption of Arsenic from Aqueous Solutions: Combined Microwave Pyrolysis and Electrochemical Modification
文章编号: N22052003
期刊: Chemical Engineering Journal
作者: Khaled Zoroufchi Benis, Amin Sokhansanj, Julia Norberto, Kerry N McPhedran, Jafar Soltan
更新时间: 2022-05-20
摘要: Biochar composites are promising and cost-effective materials that can be applied in wastewater treatment. In the current study, a novel biochar composite impregnated with Zn and Al oxides (AlZnBC) was synthesized utilizing a non-conventional microwave pyrolysis combined with an electrochemical modification. The temperature distribution inside the sample was modeled using COMSOL Multiphysics (USA) to identify the level of temperature non-uniformity, and a pathway was proposed for the deposition of Al(OH)3 on the composite surface. A temperature gradient of 399 to 741 °C from the reactor surface to the center of the sample was found after 9 min of microwave irradiation. Maximum arsenite and arsenate adsorption capacities of 10,728 and 11,786 µg/g were attained by AlZnBC which were markedly higher than Zn oxide impregnated biochar capacities (ZnBC) of 6,030 µg/g and 7,783 µg/g, respectively. Studying the effect of co-existing ions selenite (SeO32−), selenate (SeO42−), phosphate (PO43−), nitrate (NO3−), and chloride (Cl−) on the biochar arsenic adsorption capacities indicated an interfering effect of the SeO32− and PO43− ions with inner-sphere complexation proposed as the main adsorption mechanism. X-ray absorption near edge structure spectroscopy (XANES) demonstrated that about 24% of the added arsenite was oxidized to arsenate, while no reduction was detected in arsenate adsorption experiments. Overall, both the ZnBC and AlZnBC exhibit promising potential for use in treating arsenic contaminated waters.

30. 题目: Treatment of Pb(II) pollution in livestock wastewater by MgFe2O4 modified manure-biochar derived from livestock itself: Special role of endogenous dissolved organic matter and P species
文章编号: N22052002
期刊: Chemical Engineering Journal
作者: Zhenhua Sun, Xuejiang Wang, Siqing Xia, Jianfu Zhao
更新时间: 2022-05-20
摘要: In this work, swine manure biochar (SC) and its MgFe2O4 modified product (MFSC) were fabricated by hydrothermal method to remove Pb(II) pollution from livestock wastewater. The physicochemical properties of materials were analyzed by BET, XRD, SEM and VSM. The MFSC showed abundant pore structure, high MgFe2O4 dispersion and superior magnetization, which improved its application prospect and the capacity of pollutant removal. The results of adsorption experiments showed that MFSC has much higher Pb(II) adsorption efficiency (242.723 mg/g) than SC (42.158 mg/g), and chemical adsorption was the main removal pathway of Pb(II). The modification of MgFe2O4 changed the character of endogenous dissolved organic matter (EDOM) of MFSCs, producing more polysaccharides that could be complexed with Pb(II), further influencing the adsorption process. In addition, the addition of MgFe2O4 stimulated the activity of P for Pb(II) removal via converting organic P into inorganic P, as well increasing the percentage of Fe/Al mineral adsorbed P. The chemical precipitation of hydroxylpyromorphite (Pb5(PO4)3OH) was identified as the major pathway for Pb(II) adsorption. In conclusion, MFSC has the potential to be a novel composite for the treatment of heavy metals in livestock wastewater, and this study could be of great significance to achieve the sustainable development of the livestock industry.

31. 题目: Coagulation behavior of polyaluminum-titanium chloride composite coagulant with humic acid: A mechanism analysis
文章编号: N22052001
期刊: Water Research
作者: Beibei Liu, Yue Gao, Jingwen Pan, Qiyun Feng, Qinyan Yue, Kangying Guo, Baoyu Gao
更新时间: 2022-05-20
摘要: The hydrolysate species of metal-based coagulants and the binding sites of humic acid (HA) are highly dependent on the pH conditions. Exploring the binding sites and modes between coagulant hydrolysates and HA molecules is critical to understanding the coagulation mechanism. In this paper, the binding behavior between HA molecules and the hydrolysates of a polyaluminum-titanium chloride composite coagulant (PATC) was investigated under different pH conditions by semi-quantitative FTIR and XPS. It was found that oligomeric and mesopolymeric hydrolysates were the dominant species under acid conditions, which could complex with the hydroxyl and carboxyl groups of HA by forming C-O-Al/Ti coordinate bonds. However, large amounts of H+ could compete with Al3+ and weaken the removal efficiency of HA. With the increase of pH, the hydrolysis process of the PATC and the deprotonation of HA were simultaneously underway. Under weakly acid conditions, the complexation of the aluminum hydrolysates with carboxyl groups was improved due to the gradually diminishing competition of H+ and the enhanced charge neutralization of the further polymerized hydrolysates. Consequently, the maximum UV254 removal by adding PATC was observed at pH 6. Under alkaline conditions, the sweeping effect of amorphous hydroxide dominated the HA removals, which was accompanied by the surface complexation of Al/Ti nuclear with carboxyl groups as well as the hydrogen bonds between hydroxyl and hydroxide. This study provides a new clue for the interaction mechanisms between the hydrolysates of composite coagulants and the dominant functional groups of HA at various pH conditions.

32. 题目: A Strong Anthropogenic Black Carbon Forcing Constrained by Pollution Trends over China
文章编号: N22051916
期刊: Geophysical Research Letters
作者: Yawen Liu, Minghuai Wang, Yun Qian, Aijun Ding
更新时间: 2022-05-19
摘要: Estimates of the effective radiative forcing from aerosol-radiation interaction (ERFari) of anthropogenic Black Carbon (BC) have been disputable and require better constraints. Here we find a substantial decline in atmospheric absorption of -5.79Wm-2decade-1 over eastern central China responding to recent anthropogenic BC emission reductions. By combining the observational finding with advances from Coupled Model Intercomparison Project phase6 (CMIP6), we identify an emergent constraint on the ERFari of anthropogenic BC. We show that across CMIP6 models the simulated trends correlate well with simulated annual mean shortwave atmospheric absorption by anthropogenic BC over China. Making use of this emergent relationship allows us to constrain the aerosol absorption optical depth of anthropogenic BC and further provide a constrained range of 2.4-3.0Wm-2 for its top-of-atmosphere ERFari over China, higher than existing estimates. Our work supports a strong warming effect of BC over China, and highlights the need to improve BC simulations over source regions.

33. 题目: Effect of fulvic acid concentration levels on the cleavage of piperazinyl and defluorination of ciprofloxacin photodegradation in ice
文章编号: N22051915
期刊: Environmental Pollution
作者: Zhuojuan Li, Deming Dong, Liwen Zhang, Yanchun Li, Zhiyong Guo
更新时间: 2022-05-19
摘要: Ice is an important physical and chemical sink for various pollutants in cold regions. The photodegradation of emerging fluoroquinolone (FQ) antibiotic contaminants with dissolved organic matter (DOM) in ice remains poorly understood. Here, the photodegradation of ciprofloxacin (CIP) and fulvic acid (FA) in different proportions as representative FQ and DOM in ice were investigated. Results suggested that the photodegradation rate constant of CIP in ice was 1.9 times higher than that in water. When CFA/CCIP ≤ 60, promotion was caused by FA sensitization. FA increased the formation rate of cleavage in the piperazine ring and defluorination products. When 60 < CFA/CCIP < 650, the effect of FA on CIP changed from promoting to inhibiting. When 650 ≤ CFA/CCIP ≤ 2600, inhibition was caused by both quenching effects of 143.9%–51.3% and light screening effects of 0%–48.7%. FA inhibited cleavage in the piperazine ring for CIP by the scavenging reaction intermediate of aniline radical cation in ice. When CFA/CCIP > 2600, the light screening effect was greater than the quenching effect. This work provides new insights into how DOM affects the FQ photodegradation with different concentration proportions, which is beneficial for understanding the environmental behaviors of fluorinated pharmaceuticals in cold regions.

34. 题目: Comparison of extraction methods for extracellular polymeric substances (EPS) and dynamic characterization of EPS from sessile microorganisms during pyrite bioleaching
文章编号: N22051914
期刊: Journal of Environmental Chemical Engineering
作者: Li Shen, Jinju Cheng, Junjun Wang, Linlin Cui, Yejuan Zhang, Wanqing Liao, Zhiru Liu, Hao Zhou, Xueling Wu, Jiaokun Li, Weiming Zeng
更新时间: 2022-05-19
摘要: Extracellular polymeric substances (EPS) have many beneficial functions in the bioleaching process. A mixed culture of moderate thermophilic microorganisms was used to bioleach pyrite concentrate in a stirred tank reactor at a pulp density of 6%. Three physical methods (heating, ultrasound and vibration with glass beads) and three chemical methods (NaOH, H2SO4 and formaldehyde) were assessed for the extraction of EPS from sessile microorganisms. The parameter conditions for each method were optimised to obtain the optimal settings. The EPS content of each extract varied depending on the extraction method used. Cell lysis can be minimised by optimizing the extraction conditions. Results indicated that heating method outperformed other methods with low cell lysis and yielded 355.56±116.56 ug/108 cells of protein and 16.72±1.45 ug/108 cells of polysaccharides. Thereafter, this method was applied to extract EPS from pyrite surface during the bioleaching process. During pyrite bioleaching, extracellular proteins were the major component of EPS extracted from sessile strains. Confocal laser scanning microscope and scanning electron microscope showed that pyrite grains were wrapped by many extracellular proteins. Therefore, this research can provide a reference for the extraction of EPS from moderate thermophilic bioleaching systems by analysing the potential impact of extraction methods.

35. 题目: In-Use Passenger Vessel Emission Rates of Black Carbon and Nitrogen Oxides
文章编号: N22051913
期刊: Environmental Science & Technology
作者: Rebecca A Sugrue, Chelsea V Preble, Anna G Tarplin, Thomas W Kirchstetter
更新时间: 2022-05-19
摘要: This study quantified emission factors of black carbon (BC) and nitrogen oxides (NOx) from 21 engines on in-use excursion vessels and ferries operating in California’s San Francisco Bay, including EPA uncertified and Tier 1–4 engines and across engine operating modes. On average, ∼60 fuel-based emission factors per engine were measured using a novel combination of exhaust plume capture combined with GPS location and speed data that can be more readily deployed than common portable emissions measurement systems. BC and NOx emission factors (g kg–1) were lowest and least variable during fast cruising and highest during maneuvering and docked operation. Selective catalytic reduction (SCR) reduced NOx emissions by ∼80% when functional. However, elevated NOx emissions that exceeded corresponding exhaust standards were measured on most Tier 3 and Tier 4 engines sampled, which can be attributed to inactive SCR during frequent low engine load operation. In contrast, BC emissions exceeded the PM emission standard for only one engine, and SCR systems employed as a NOx reduction technology also reduced emitted BC. Using these measured emission factors to compare commuting options, we show that the CO2-equivalent emissions per passenger-kilometer are comparable when commuting by car and ferry, but BC and NOx emissions can be several to more than ten times larger when commuting by ferry.

36. 题目: Faeces traits as unifying predictors of detritivore effects on organic matter turnover
文章编号: N22051912
期刊: Geoderma
作者: Sylvain Coq, Pierre Ganault, Guillaume Le Mer, Johanne Nahmani, Yvan Capowiez, Marie-France Dignac, Cornelia Rumpel, François-Xavier Joly
更新时间: 2022-05-19
摘要: In the last decade, our understanding of plant litter decomposition and soil organic matter formation substantially improved but critical blind spots remain. Particularly, the role of detritivores, i.e. soil animals that feed on litter and soil, is poorly understood and notoriously missing from biogeochemical models. This major gap results from methodological difficulties to isolate their effect and from the astonishing diversity of detritivorous organisms with few common features, thereby hampering the identification of general patterns. In this viewpoint, we propose that the characteristics of their faeces can predict detritivore effects on soil processes related to organic matter turnover across the large detritivore diversity. Indeed, faeces are common to all detritivores, and a large part of organic matter is transformed into faeces in many ecosystems. Two recent studies presented here showed that faeces characteristics are powerful predictors of the fate and turnover of this transformed organic matter. We suggest that faeces characteristics, such as water-holding capacity, size and spatial organisation of the faecal pellets and of their constituting particles, particulate organic matter connectivity, as well as the characteristics of dissolved organic matter in faecal pellets, are promising ‘effect traits’. By focusing on similar features rather than differences, this approach has the potential to break down barriers of this highly fragmented soil animal group, in particular between earthworms that are often studied as ecosystem engineers and classical litter transformers such as millipedes, woodlice, or snails. We discuss ways of tackling the complexity of using such traits, particularly regarding the composite determinism of faeces characteristics that are driven both by the detritivore identity and the ingested organic matter. Rigorous and hypothesis-based use of faeces characteristics as effect traits, including clear identification of studied processes, could allow integrating detritivores in our current understanding of organic matter turnover.

37. 题目: Response of soil organic carbon content to crop rotation and its controls: A global synthesis
文章编号: N22051911
期刊: Agriculture, Ecosystems & Environment
作者: Xiaotong Liu, Senwen Tan, Xiaojun Song, Xueping Wu, Gang Zhao, Shengping Li, Guopeng Liang
更新时间: 2022-05-19
摘要: Determining the effect of crop rotation (CR) on soil organic carbon (SOC) and its controls is vital for improving the potential benefits of CR in agroecosystems to achieve carbon neutrality. However, there has been no comprehensive and systematic evaluation of the response of SOC content to CR and its underlying drivers on the global level. Using 513 pairwise data from 167 studies, we conducted a global-scale meta-analysis to illuminate the changes in SOC content induced by CR and to explore the roles of climatic, edaphic, and agronomic factors in driving such changes. Results revealed that CR overall enhanced SOC content by 6.6% relative to continuous crop monoculture. SOC content under CR increased more in regions with intermediate mean annual temperature (MAT, 8–15°C) and precipitation (MAP, 600–1000 mm) than in regions with other climate types. CR had greater SOC content benefits in neutral (pH = 6–8) soils with loamy texture and medium levels of initial SOC (15–20 g kg–1) and total nitrogen (1.00–1.50 g kg–1). Also, CR performed better in the soybean-based cropping systems with more rotation cycles, longer rotation length, medium nitrogen fertilization input rate (100–200 kg N ha–1 yr–1), and the applications of no-till, straw retention, and organic fertilizers. Furthermore, the variance partitioning analysis revealed that soil (31%) and climate variables (18%) accounted for the major variations in SOC content response. Moreover, the random forest model demonstrated that soil texture, climatic factors (i.e., MAT and MAP), and initial SOC content were the predominant drivers of the response of SOC content. Overall, our findings highlight that CR is a critical practice to increase SOC content in global croplands, whereas the variations in response are governed by specific climatic, edaphic, and agronomic factors. This study helps to establish and manage site-specific CR systems that could enhance SOC in agroecosystems, ultimately facilitating carbon neutrality.

38. 题目: Comparison of natural and technogenic soils developed on volcanic ash by Vis-NIR spectroscopy
文章编号: N22051910
期刊: CATENA
作者: Erika Di Iorio, Pasquale Napoletano, Luana Circelli, Valeria Memoli, Lucia Santorufo, Anna De Marco, Claudio Colombo
更新时间: 2022-05-19
摘要: Soil biological properties and carbon storage of three young Technosols deriving from volcanic soil of Campi Flegrei, Italy, were compared with two natural volcanic soils, sampled from two forest ecosystem sites (chestnut and Mediterranean maquis). The soil properties were examined with Vis-NIR spectroscopy and portable XRF, along the soil profile. The results showed that the average soil organic matter (SOM) amount in Technosols profiles were lower than in natural volcanic soils. The differences in SOM content between the two investigated natural volcanic soils probably resulted from their land-use histories and different plant cover. Indeed, the chestnut soil profile, which has a higher SOM content, was covered by an old chestnut grove, while the second soil profile, after a severe burning, showed a change in natural Oak forest vegetation towards the typical Mediterranean maquis. The microbial biomass can be predicted with Vis-NIR spectroscopy coupled with PLS Regression. Our results showed that 6-year natural incorporation of organic residue in Technosols significantly increased the C storage on the top soils due to the increase in C input with rhizodeposition. The forest soils show higher TOC content also with the depth that indicate a greater capacity of C storage in response to litter incorporation, whereas the Technosols accumulated about half the amount of TOC, compared to the chestnut grove. Indeed, after six years of natural vegetation, the Technosols showed a large potential to sequester C and to sustain biological activity. Overall, the emerging knowledge on Technosols make them highly promising for the regeneration of urban area.

39. 题目: Effect of varying pH and co-existing microcystin-LR on time- and concentration-dependent cadmium sorption by goethite-modified biochar derived from distillers’ grains
文章编号: N22051909
期刊: Environmental Pollution
作者: Yu Zhao, Jieming Li
更新时间: 2022-05-19
摘要: Cadimium (Cd) is one dangerous and widespread heavy metal that of great environmental concern. To cost-efficiently adsorb aqueous Cd under influence of various factors, this study succeeded in fabricating goethite-modified biochar (GBC) derived from distillers’ grains (DGs) for Cd sorption of different concentrations (10–100 mg L−1) at pH of 3, 6 and 8 with and without microcystin-LR (MC-LR). Sorption kinetics and isotherms data revealed that Cd sorption capacity of GBC and unmodified BC increased as pH elevated from 3 to 6 but stabilized when pH further elevated to 8. Pseudo-second-order and Langmuir models more accurately fitted to sorption data for both BCs, implying monolayer chemisorption of Cd onto BCs. GBC exhibited more robust sorption for each Cd concentration than unmodified BC, with the maximum sorption capacity of around 28 mg g−1 at neutral and weak alkaline pH. Notably, goethite-modification obviously increased bulk polarity, specific surface area, porosity and surface oxygenic group abundance of BC, thus strongly enhancing Cd sorption by creating more sorption sites mainly via pore-filling, electrostatic attraction, and also via complexation and cation exchange. Co-existing MC-LR of100 μg L−1 did not obviously affect Cd sorption by both BCs for most Cd levels at each pH, mostly because sorption mechanisms diverged between MC-LR and Cd to largely avoid their competition for sorption sties. Thus, goethite could modify DG-BC as promising and cost-efficient sorbent for Cd even with co-existing MC-LR, especially at neutral and weak alkaline pH that common in nature. This study was greatly implicated in modifying and applying DG-BC for Cd immobilization in MC-LR laden waters with various pH circumstances.

40. 题目: Natural Asphalt Seeps Are Potential Sources for Recalcitrant Oceanic Dissolved Organic Sulfur and Dissolved Black Carbon
文章编号: N22051908
期刊: Environmental Science & Technology
作者: Jonas Brünjes, Michael Seidel, Thorsten Dittmar, Jutta Niggemann, Florence Schubotz
更新时间: 2022-05-19
摘要: Natural oil seepages contribute about one-half of the annual petroleum input to marine systems. Yet, environmental implications and the persistence of water-soluble hydrocarbons from these seeps are vastly unknown. We investigated the release of oil-derived dissolved organic matter (DOM) from natural deep sea asphalt seeps using laboratory incubation experiments. Fresh asphalt samples collected at the Chapopote asphalt volcano in the Southern Gulf of Mexico were incubated aerobically in artificial seawater over 4 weeks. The compositional changes in the water-soluble fraction of asphalt-derived DOM were determined with ultrahigh-resolution mass spectrometry (Fourier-transform ion cyclotron resonance mass spectrometry, FT-ICR-MS) and by excitation–emission matrix spectroscopy to characterize fluorescent DOM (FDOM) applying parallel factor (PARAFAC) analysis. Highly reduced aliphatic asphalt-derived DOM was readily biodegraded, while aromatic and sulfur-enriched DOM appeared to be less bioavailable and accumulated in the aqueous phase. A quantitative molecular tracer approach revealed the abundance of highly condensed aromatic molecules of thermogenic origin. Our results indicate that natural asphalt and potentially other petroleum seepages can be sources of recalcitrant dissolved organic sulfur and dissolved black carbon to the ocean.

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