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81. 题目: Influence of sedimentary organic matter sources on the distribution characteristics and preservation status of organic carbon, nitrogen, phosphorus, and biogenic silica in the Daya Bay, northern South China Sea
文章编号: N21040601
期刊: Science of The Total Environment
作者: Solomon Felix Dan, Shengyong Li, Bin Yang, Dongyang Cui, Zhiming Ning, Haifang Huang, Jiaodi Zhou, Jian Yang
更新时间: 2021-04-06
摘要: Surface sediment samples were collected from Daya Bay in October 2018, and analyzed for total organic carbon (OC), total nitrogen (TN) and their stable isotopes (δ13C and δ15N), total phosphorus (TP), biogenic silica (BSi), sediment textures and specific surface area (SSA). The primary objective was to evaluate the influence of mariculture/aquaculture on the distribution characteristics of organic matter (OM), and preservation status of OC, TN, TP, and BSi in sediments. The average δ13C and δ15N values, and OC/TN ratios were –21.27‰, 6.74‰, and 8.90, respectively. Monte Carlo simulation results revealed that mariculture/aquaculture biodeposits accounted for > 40% of the buried OM at sites where the breading rafts and cages are located, whereas marine OM increased gradually to the open sea. Terrestrial OM was generally low accounting for 17% by average. The contents and distribution characteristics of biogenic elements were more influenced by mariculture/aquaculture and primary productivity than sediment textures. Lower OC/SSA (0.3–1.2 mg OC/m2), TN/SSA (~0.05–0.18 mg TN/m2), and TP/SSA (0.02–0.04 mg TP/m2) loadings indicated that increased sequestration of labile OM in a coastal bay could contribute to significant degradation of recalcitrant OM in sediments with significant loss of P relative to OC. Nitrogen contamination in surface sediments was due to increased injection of aquaculture biodeposits, and may pose a detrimental effect on the ecological sustainability of the bay. Higher BSi/SSA loadings (0.9–1.7 mg BSi/m2) revealed that BSi was more preserved, and that BSi-based proxy could be used for paleo-productivity studies. However, such preservation may induce adverse dissolved silicate limitation in a bay perturbed by eutrophication. Fine-grained sediments (clay and silt) accounted for > 77% of the sediment texture types with higher SSA, and while controlling the contents of biogenic elements under given depositional conditions were not the main determining factors of OC, TN, TP, and BSi preservation.

82. 题目: pH is the dominant factor controlling the levels of phytate-like and DNA-like phosphorus in 0.5 M NaHCO3-extracts of soils: Evaluation with phosphatase-addition approach
文章编号: N21040507
期刊: Geoderma
作者: Takashi Kunito, Shingo Haraguchi, Kiyoko Hanada, Kazuki Fujita, Hitoshi Moro, Kazunari Nagaoka, Shigeto Otsuka
更新时间: 2021-04-05
摘要: To elucidate the factor(s) controlling the concentrations of readily available organic phosphorus (Po) in soils, we assessed the phosphatase-hydrolyzable Po pools in 0.5 M NaHCO3-extracts of arable and forest soils and evaluated their association with soil properties in several soil types collected in Japan. Concentrations of phosphatase-hydrolyzable Po (simple monoester P, phytate like-P, and DNA-like P) in 0.5 M NaHCO3-extracts were determined using three phosphatases with different substrate specificities. Monoester P (i.e., simple monoester P and phytate like-P) was dominant in the phosphatase-hydrolyzable Po of 0.5 M NaHCO3-extracts in all soils. In monoester P, the concentration of phytate-like P was greater than that of simple monoester P in all soil types except Fluvisols. Both phytate-like P and DNA-like P in 0.5 M NaHCO3-extracts significantly increased with decreasing soil pH, suggesting that soil pH would play a crucial role in determining the availability of Po in soils.

83. 题目: The renaissance of Odum's outwelling hypothesis in 'Blue Carbon' science
文章编号: N21040506
期刊: Estuarine, Coastal and Shelf Science
作者: Isaac R. Santos, David J. Burdige, Tim C. Jennerjahn, Steven Bouillon, Alex Cabral, Oscar Serrano, Thomas Wernberg, Karen Filbee-Dexter, Julia Guimond, Joseph J. Tamborski
更新时间: 2021-04-05
摘要: The term 'Blue Carbon' was coined about a decade ago to highlight the important carbon sequestration capacity of coastal vegetated ecosystems. The term has paved the way for the development of programs and policies that preserve and restore these threatened coastal ecosystems for climate change mitigation. Blue carbon research has focused on quantifying carbon stocks and burial rates in sediments or accumulating as biomass. This focus on habitat-bound carbon led us to losing sight of the mobile blue carbon fraction. Oceans, the largest active reservoir of carbon, have become somewhat of a blind spot. Multiple recent investigations have revealed high outwelling (i.e., = lateral fluxes or horizontal exports) of dissolved inorganic (DIC) and organic (DOC) carbon as well as particulate organic carbon (POC) from blue carbon habitats. In this paper, we conceptualize outwelling in mangrove, saltmarsh, seagrass and macroalgae ecosystems, diagnose key challenges preventing robust quantification, and hopefully pave the way for future work integrating mobile carbon in the blue carbon framework. Outwelling in mangroves and saltmarshes is usually dominated by DIC (mostly as bicarbonate), while POC seems to be the major carbon species exported from seagrass meadows and macroalgae forests. Carbon outwelling science is still in its infancy, and estimates remain limited spatially and temporally. Nevertheless, the existing datasets imply that carbon outwelling followed by ocean storage is relevant and may exceed local sediment burial as a long-term (>centuries) blue carbon sequestration mechanism. If this proves correct as more data emerge, ignoring carbon outwelling may underestimate the perceived sequestration capacity of blue carbon ecosystems.

84. 题目: Distribution, speciation and composition of humic substances in a macro-tidal temperate estuary
文章编号: N21040505
期刊: Estuarine, Coastal and Shelf Science
作者: Ricardo Riso, Manon Mastin, Arthur Aschehoug, Romain Davy, Jeremy Devesa, Agathe Laës-Huon, Matthieu Waeles, Gabriel Dulaquais
更新时间: 2021-04-05
摘要: In aquatic environments, the term humic substances (HS) encompasses terrestrial and autochthonous refractory organic matter. HS are one of the main fractions of natural organic matter and are important chelators of trace elements. In environmental studies, the determination of HS is often restricted to the dissolved fraction, and the content of HS in the suspended particles remains unknown. In this work, we present the composition and dynamics of HS along the mixing gradient of a macrotidal estuary in both the dissolved and particulate fraction. After the isolation of particulate HS using a solid-liquid alkali extraction method, HS were characterized by size exclusion chromatography (SEC) and electrochemical methods. The method, validated using a certified reference material, demonstrated a low detection limit (μg-C L−1), a good repeatability (7.7%) an excellent reproducibility (1.3%) and was poorly prone to contamination (filter blank < 1 μg-C). Analyses of environmental samples showed a particulate fraction contributing significantly to the total humic pool in the estuary (3–20%) and representing up to 35% of electroactive HS. Phase transfers from the dissolved to the particulate fraction were observed and the electroactive HS were strongly affected in the maximum turbidity zone. Multi-detection SEC analyses showed differences in the molecular composition between the dissolved and particulate fractions. Particulate HS were more nitrogen-rich and electroactive than dissolved HS. The non-conservative changes in the composition of HS along the land-sea continuum evidence the existence of abiotic and biotic processes that altered HS during their transit from river to marine waters.

85. 题目: Carbon footprint and predicting the impact of climate change on carbon sequestration ecosystem services of organic rice farming and conventional rice farming: A case study in Phichit province, Thailand
文章编号: N21040504
期刊: Journal of Environmental Management
作者: Noppol Arunrat, Sukanya Sereenonchai, Can Wang
更新时间: 2021-04-05
摘要: Organic rice farming is a sustainable rice cultivation system that eliminates chemical inputs and has the potential to reduce environmental impacts. This study aims to: 1) evaluate and compare the carbon footprint intensity and the value of carbon sequestration ecosystem services (VCSES) between organic rice farming (OF) and conventional rice farming (CF) and 2) estimate the impact of climate change on soil organic carbon (SOC), rice yield, and VCSES of two farming types in Phichit province, Thailand. The results showed that the carbon footprint intensity in OF and CF were significantly different with −0.13 and 0.82 kg CO2eq kg−1 rice yield, respectively. The differences in SOC stocks (ΔSOCS) were more significant in OF with the increase of 1107.6 kg C ha−1 year−1 (4061.2 kg CO2eq ha−1 year−1), while the ΔSOCS value in CF was 625 kg C ha−1 year−1 (2291.7 kg CO2eq ha−1 year−1). The VCSES in OF (541,196 US$ ha−1 year−1) was nearly two times higher than in CF (305,388 US$ ha−1 year−1). Under future climate change, rice yields of both farming types are expected to increase under Representative Concentration Pathway (RCP) 2.6, RCP4.5, and RCP6.0, and it will decline under RCP8.5. The SOC and VCSES values are predicted to increase, except under RCP8.5. The dramatic declines can be found from the near future (2020–2039) to the very far future (2080–2099) period. Our finding indicates that even though climate change will have negative effects on SOC and VCSES, the OF will have less impact compared with CF.

86. 题目: Effects of Co-Applications of Biochar and Solid Digestate on Enzyme Activities and Heavy Metals Bioavailability in Cd-Polluted Greenhouse Soil
文章编号: N21040503
期刊: Water, Air, & Soil Pollution
作者: Shuaixing Xue, Fengfen Chen, Yuying Wang, Zhijiang Shao, Congguang Zhang, Ling Qiu, Yi Ran, Li He
更新时间: 2021-04-05
摘要: To deal with the problems of increasing the heavy metal (HM) bioavailability and declining the soil biological properties resulting from a direct application of solid digestate (SD). A low-temperature fruit biochar and pig-SD (BSD-0, BSD-1, BSD-2, BSD-4, BSD-8) co-application experiment was performed to evaluate enzyme activities and HM bioavailability in Cd-polluted greenhouse soil. The advantage of BSD co-applications compared to SD application was maintained the stable of pH and electrical conductivity (EC) in soil and was more effective to improve soil organic matter (OM). BSD-8 treatment significantly promoted the uptake of available nitrogen, available phosphorus, and available potassium by plants. The immobilization effect of BSD co-applications on Cu, Zn, and Cd was better than SD application. BSD-8 treatment has the best immobilization effect on Cd and the contents of bioavailable Cd was 0.167 mg kg−1. The optimal enzyme activities of invertase, urease, and alkaline phosphatase were shown in BSD-8 treatment, which were 0.027 mg glucose g−1 soil h−1, 88.654 mg NH3-N g−1 soil h−1, and 15.766 μmol PNP g−1 soil h−1, respectively. The activities of enzymes also were influenced by soil physicochemical properties and HM bioavailability. BSD-8 treatment was suggested as an appropriate mixing proportion to alleviate soil acidification and salinization, decreasing HM bioavailability and stimulating enzyme activities in Cd-polluted soil.

87. 题目: Separation and characterization of refractory colored dissolved effluent organic matter in a full-scale industrial park wastewater treatment plant
文章编号: N21040502
期刊: Environmental Science and Pollution Research
作者: Ashraful Islam, Guangxi Sun, Wei Shang, Xingcan Zheng, Pengfeng Li, Min Yang, Yu Zhang
更新时间: 2021-04-05
摘要: Colored dissolved organic matter (DOM) is a significant indicator of refractory DOM in wastewaters, and fluorescent DOM is an essential part indicating colorants. However, little is known about the composition and contribution of colored DOM to wastewater. This study provided some insights on the persistent yellowish color in biological effluent through use of a multi-characterization approach, and evaluated the effect of two advanced treatments (O3 and granular active carbon (GAC)) in a full-scale wastewater treatment plant. The multi-characterization technique incorporated resin fractionation, excitation-emission matrix spectroscopy (EEM) combined with fluorescence regional integration (FRI), size-exclusion chromatography (SEC), and X-ray photoelectron spectroscopy (XPS) analysis. The fractionation results showed that hydrophobic acid (HPOA) and hydrophilic (HPI) substances are abundant in colorants, and HPI-type colorants are comparatively resistant or unable to be removed through GAC and O3 individually. FRI-based EEMs showed that F3 (fulvic acid–like organics) and F5 (humic acid–like organics) mainly account for the yellowish color, and their combined fractions of total colorants are 50%, 31%, and 48% in biological, biological + O3, and biological + GAC effluents, respectively. SEC for measurement of the apparent molecular weight revealed that these colorants may have molecular weights in the range 2–5 kDa. The XPS analysis indicated that these colorants possess ether or hydroxyl and nitro (C-O/C-N) chromophoric groups with conjugated aromatic structures. For C-O/C-N, O3 showed good removal efficiency overall. GAC showed exceptionally high efficiency for HPOA but very low efficacy toward HPI-type colorants in terms of C-O/C-N chromophoric functional group removal.

88. 题目: Optimization of biochar production based on environmental risk and remediation performance: Take kitchen waste for example
文章编号: N21040501
期刊: Journal of Hazardous Materials
作者: Congbin Xu, Xiao Tan, Jiwei Zhao, Jinman Cao, Meng Ren, Yong Xiao, Aijun Lin
更新时间: 2021-04-05
摘要: Two major obstacles that need to be addressed for environmental application of biochar include its environmental risk and remediation performance for target pollutants. In this study, kitchen waste was taken as an example to optimize the pyrolysis temperature for biochar production based on its heavy metal risk and Cd(II) remediation performance. The results showed that the pH and ash content of kitchen waste biochar (KWB) increased; however, the yield, H/C, and N/C decreased with increasing pyrolysis temperature. Total content of heavy metals in KWB got enriched after pyrolysis, while heavy metals’ risk was reduced from moderate to low due to the transformation of directly toxic heavy metal fractions into potentially and/or non-toxic fractions. The equilibrium adsorption capacities of biochar for Cd(II) ranked as follows: 49.0mg/g (600 °C), 46.5mg/g (500 °C), 23.6mg/g (400 °C), 18.2mg/g (300 °C). KWB pyrolyzed at 500 °C was found to be the most suitable for green, efficient, and economic remediation of Cd(Ⅱ) contaminated water. SEM-EDS and XPS characterization results indicated that KWB removed Cd(II) via precipitation, complexation with carboxyl/hydroxyl, ion exchange with metal cations, and coordination with π-electrons. This study puts forward a new perspective for optimizing biochar production for environmental application.

89. 题目: Efficacy of green waste-derived biochar for lead removal from aqueous systems: Characterization, equilibrium, kinetic and application
文章编号: N21040408
期刊: Journal of Environmental Management
作者: Mahmoud M. Hammo, Tamer Akar, Fatih Sayin, Sema Celik, Sibel Tunali Akar
更新时间: 2021-04-04
摘要: The removal of toxic metals from the aquatic ecosystem is one of the most pressing environmental and public health concerns today. A strong potential has recently emerged for the removal of such metals using biochar sorbents. Biosorption technology could make a significant difference in the future. It is a viable and cost-effective alternative to the remediation of toxic pollutants utilizing various biomaterials. In the current study, batch and fixed−bed studies were performed to evaluate the performance of Capsicum annuum L. seeds biochar (CASB) as an alternative material in removing toxic Pb(II) from aqueous solutions. Removal characteristics were investigated by considering the equilibrium and kinetic aspects. Biosorption equilibrium was established within 40 min. The optimum dosage of CASB for Pb(II) removal was determined as 2.0 g L−1. Biosorption data were well predicted by a non−linear Langmuir isotherm model. Monolayer biosorption occurred for CASB with a maximum capacity of 36.43 mg g−1. Biosorption kinetics fitted well with a pseudo−first−order kinetic model. The external mass transfer may control Pb(II) transport mechanism. Dynamic flow mode biosorption and regeneration potential of CASB were also examined. The application of CASB exhibited a 100% removal yield in real apple juice samples spiked with low concentrations of Pb(II). Exhausted points for the CASB packed columns were recorded as 195 and 320 min for simulated wastewater (SW) and synthetic Pb(II) solution, respectively. FTIR, BET, SEM−EDX analysis, and zeta potential measurements were used for the characterization of biochar and assessment of the metal ion−biosorbent interaction mechanism. Finally, our study provides a practical approach for the uptake of Pb(II) ions from contaminated solutions.

90. 题目: Black carbon emissions from flaring in Russia in the period 2012-2017
文章编号: N21040407
期刊: Atmospheric Environment
作者: Kristin Böttcher, Ville-Veikko Paunu, Kaarle Kupiainen, Mikhail Zhizhin, Alexey Matveev, Mikko Savolahti, Zbigniew Klimont, Sampsa Väätäinen, Heikki Lamberg, Niko Karvosenoja
更新时间: 2021-04-04
摘要: Gas flaring in the oil and gas industry has been identified as an important source of anthropogenic black carbon (BC) affecting the climate, particularly in the Arctic. Our study provides, for the first time, spatially-explicit estimates of BC emissions from flaring in Russia utilising state-of-the-art methodology for determining the emission factors. We utilised satellite time series of the flared gas volume from Visible Infrared Imaging Radiometer Suite (VIIRS) for the period 2012 to 2017, supplemented with information on the gas and oil field type. BC emissions at flaring locations were calculated based on field type-specific emission factors, taking into account different gas compositions in each field type. We estimate that the average annual BC emissions from flaring in Russia were 68.3 Gg/year, with the largest proportion stemming from oil fields (82%). We observed a decrease in the yearly emissions during the period 2012 to 2017 with regional differences in the trend. Our results highlight the importance of detailed information on gas composition and the stage of oil and gas separation of the flared gas to reduce uncertainties in the BC emission estimates.

91. 题目: Study on the Hg0 removal characteristics and synergistic mechanism of iron-based modified biochar doped with multiple metals
文章编号: N21040406
期刊: Bioresource Technology
作者: Li Jia, Yue Yu, Ze-peng Li, Shu-ning Qin, Jin-rong Guo, Yong-qiang Zhang, Jian-cheng Wang, Jian-chun Zhang, Bao-guo Fan, Yan Jin
更新时间: 2021-04-04
摘要: An iron-based composite adsorbent with biochar as the support was prepared by coprecipitation and the sol–gel method. Both single-iron-based modified biochar without doping with other metals and iron-based modified biochar doped with multiple metals (Ce, Cu, Co, Mn) were synthesised. The adsorption kinetics were analysed, and temperature-programmed desorption measurements were performed to reveal the inherent difference in mechanism between the oxidation and adsorption of Hg0 by the modified biochar and to elucidate the key mechanism of Hg0 removal. The results show that the removal of Hg0 by the modified biochar mainly includes adsorption and oxidation processes. The adsorption process is divided into two stages, external and internal mass transfer, both of which occur via multilayer adsorption. HgO and Hg-OM are the main forms of Hg0 present on the modified biochar surface. Doped metal oxides can play a synergistic role in enhancing the mercury removal performance of the modified biochar.

92. 题目: Root-induced fungal growth triggers macroaggregation in forest subsoils
文章编号: N21040405
期刊: Soil Biology and Biochemistry
作者: Vera L. Baumert, Stefan J. Forstner, Jeroen H.T. Zethof, Cordula Vogel, Julian Heitkötter, Stefanie Schulz, Ingrid Kögel-Knabner, Carsten W. Mueller
更新时间: 2021-04-04
摘要: Subsoils are characterized by low concentrations of organic carbon (OC); however, they contain more than half of the global soil OC because of their large volume. This discrepancy suggests that subsoils might further sequester carbon (C), thus acting as potential sinks for atmospheric C. Plant roots and associated rhizodeposits are a major OC input source to subsoils. However, whether and how increased OC inputs via plant roots to subsoils affect soil C sequestration mechanisms remains unclear. Here we set up a pot experiment with European Beech (Fagus sylvatica L.) seedlings to investigate the effect of tree roots and associated rhizosphere development on soil aggregation and C allocation in topsoil vs. subsoil material collected from three forest sites of different parent materials. Over a 5-month growth period, the seedlings developed a dense root system transforming the whole soil volume into root-affected (i.e., rhizosphere) soil. We found that roots and the associated rhizosphere development increased the amount of macroaggregates in the two finest-textured subsoils. The most C-poor and fine-textured subsoil had a 15% increase in bulk OC concentration, indicating a potential for C sequestration in subsoils by enhanced macroaggregation. Across subsoils, rooting strongly enhanced microbial abundance and was especially correlated with fungal abundance and a shift in the fungal-to-bacterial- ratio. The strong fungal growth was likely the cause for the enhanced macroaggregation in these subsoils. In topsoils, however, rooting treatment decreased macroaggregate abundance, potentially through the disruption of preexisting aggregates, as indicated by the concomitant increase in microaggregates. Our study supports the growing awareness that OC dynamics may be governed by different mechanisms in top- and subsoils, respectively. It demonstrates that the enhanced addition of OM via plant roots to subsoils boosts fungal growth and thereby increases macroaggregate formation, potentially facilitating C sequestration by occlusion.

93. 题目: Increasing Carbon-to-Phosphorus Ratio (C:P) from Seston as a Prime Indicator for the Initiation of Lake Reoligotrophication
文章编号: N21040404
期刊: Environmental Science & Technology
作者: Beat Müller, Thomas Steinsberger, Arno Stöckli, Alfred Wüest
更新时间: 2021-04-04
摘要: Decline in total phosphorus (TP) during lake reoligotrophication does not apparently immediately influence carbon assimilation or deep-water oxygen levels. Traditional monitoring and interpretation do not typically consider the amount of organic carbon exported from the productive zone into the hypolimnion as a measure of net ecosystem production. This research investigated the carbon-to-phosphorus ratios of suspended particles in the epilimnion, (C:P)epi, as indicators of changing productivity. We report sestonic C:P ratios, phytoplankton biomass, and hypolimnetic oxygen depletion rates in Lake Hallwil, a lake whose recovery from eutrophic conditions has been documented in 35 years of historic water-monitoring data. This study also interpreted long-term (C:P)epi ratios from reoligotrophication occurring in four other lakes. Lake Hallwil exhibited three distinct phases. (i) The (C:P)epi ratio remained low when TP concentrations did not limit production. (ii) (C:P)epi increased steadily when phytoplankton began optimizing the declining P and biomass remained stable. (iii) Below a critical TP threshold of ∼15 to ∼20 mg P m–3, (C:P)epi remained high and the biomass eventually declined. This analysis showed that the (C:P)epi ratio indicates the reduction of productivity prior to classic indicators such as deep-water oxygen depletion. The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.est.0c08526. Loads of bioavailable phosphorus to Lake Hallwil; tubing system for the integrated sampling of the lake water column; characteristics of Planktothrix rubescens; box plots of epilimnetic C:P ratios at monthly resolution; estimation of the TPmix threshold concentration below which NEP decreases in proportion to decreasing TPmix; evidence of decreasing production from hypolimnetic oxygen consumption; concentration of O2 in the hypolimnion of Lake Hallwil; annual loads of bioavailable P to Lake Hallwil; comparison of analytical methods for measuring (C:P)epi ratios in seston from the epilimnion of Lake Hallwil from 1985 to 2019; volume-weighted average concentrations of total P, dissolved inorganic P, and particulate P in the epilimnion of Lake Hallwil over the past 40 years; Secchi depth measurements for Lake Hallwil; box plots of (C:P)epi in Lake Hallwil; areal hypolimnetic mineralization rate and seasonal (C:P)epi ratios; threshold concentrations of TPmix calculated for Lakes Geneva, Lucerne, Pfäffikon, and Türlersee; and morphological and hydrological characteristics of Lake Hallwil and the lakes presented in Section 4.4 (PDF) This article has not yet been cited by other publications.

94. 题目: Construction of fungi-microalgae symbiotic system and adsorption study of heavy metal ions
文章编号: N21040403
期刊: Separation and Purification Technology
作者: Junjun Wang Writing-Original Draft, Ran Chen, Ling Fan, Linlin Cui, Yejuan Zhang, Jinju Cheng, Xueling Wu, Weimin Zeng, Qinghua Tian, Li Shen
更新时间: 2021-04-04
摘要: Harvesting and immobilization are problem in microalgae water treatment. Here, mycelial pellets (Aspergillus fumigatus) and Synechocystis sp. PCC6803 comprised a fungi-microalgae symbiotic system (FMSS) of hypha-pellet flocculant auxiliary microalgae solidification. Optical and scanning electron microscopy (SEM) revealed that green particles were attached to fungal mycelia. A 98% adsorption and immobilization efficiency of mycelium pellets to microalgae was evident. Under the condition of 108 cells/mL logarithmic phase microalgae and no fungal culture medium, the symbiotic system had higher stability and better Cd(II) adsorption efficiency (98.89%, 37.3 mg g-1). Meanwhile, the symbiotic system prolonged the growth cycle of microalgae in the adsorption. After Cd(II) ion stimulation, the content of total extracellular polymeric substances (EPS) in the FMSS was significantly higher than that in the control group, and the change of extracellular polysaccharide was more obvious. High performance anion exchange chromatography-pulsed amperometric detection (HPAEC-PAD) showed that the monosaccharide composition of extracellular polysaccharides increased. Three dimensional excitation emission matrix (3D-EEM) spectrum analysis showed the peak intensity of protein fluorescence changed with the treatment of heavy metals. FTIR spectra showed that the functional groups (such as - OH, -CONH-) of EPS participated in the adsorption process. The findings showed that the key components of EPS, extracellular polysaccharides and extracellular proteins, played an important role in the symbiotic system to cope with the stress of heavy metal and resist the toxicity of heavy metal. The preliminary data can inform development and utilization of engineering strains and gene transformation.

95. 题目: Influence of biochar and biochar-based fertilizer on yield, quality of tea and microbial community in an acid tea orchard soil
文章编号: N21040402
期刊: Applied Soil Ecology
作者: Wenhao Yang, Changjuan Li, Shanshan Wang, Biqing Zhou, Yanling Mao, Christopher Rensing, Shihe Xing
更新时间: 2021-04-04
摘要: Biochar combined with chemical fertilizer have been proven to be effective in improving soil fertility and crop yield. However, the effects of biochar-based fertilizer on yield, quality of tea and microbial community composition in tea orchard soil are unclear. To address this, four different treatments including CK (no fertilizer), B (biochar), F (chemical fertilizer), BF (biochar-based fertilizer) were performed in a tea orchard to explore the effects of different fertilizations on tea growth and the soil bacterial and fungal community. After one growing season, the BF increased the yield, 100-sproutweight and sprout density of tea by 39.2%, 26.6% and 10.7%, respectively, compared to CK. Amino acid content of F and BF, caffeine content of B, F and BF and the water extracts in BF were increased than those of CK. Soil bacterial and fungal diversity indices (chao1 and observed species) were generally higher under B than BF and F treatment. Cluster analysis revealed that bacterial and fungal community structures under BF treatment differed from those under CK, B and F treatment. The relative abundance of 10 key bacterial genera and 13 fungal genera were increased under BF treatment, including some plant beneficial microbes such as bacterial genera Rhodanobacter, Mizugakiibacter, Pedobacter, Sphingomonas and Devosia as well as fungal genera Rhodosporidiobolus, Chloridium, Amylocorticium, Clavulina, Inocybe and Mycofalcella. These genera were significantly positive correlated to yield and quality of tea. Redundancy analysis revealed that pH, total nitrogen and available potassium were the major properties shaping soil bacterial community, and dissolved organic carbon, exchangeable Ca, pH and total nitrogen were for fungal community. These results indicated that biochar-based fertilizer altered soil microbial community and enhanced some plant growth-promoting microbes, which were associated with the improvements of yield and quality of tea plants. Thus, the combination of biochar and chemical fertilizer is feasible for the improvements of tea growth and low nutrients acidic tea orchard soil.

96. 题目: Real-time fouling monitoring and membrane autopsy analysis in forward osmosis for wastewater reuse
文章编号: N21040401
期刊: Water Research
作者: Sung Ju Im, Luca Fortunato, Am Jang
更新时间: 2021-04-04
摘要: Forward osmosis process in emerging technology which can applicable in wastewater reuse and desalination simultaneously. In this study, the development of fouling on the FO membrane surface was monitored in real-time. The investigation of fouling layer physical and chemical characteristics was assessed by performance evaluation and in-depth analysis of fouling layer. Non-invasive visual monitoring and in-depth autopsy, combined with the performance and image analyses provided a better understanding of fouling phenomena. The relative roughness of the fouling layer was correlated with water flux decrease while the fouling layer thickness decreased rapidly when fouling was stabilized. From 66-day operation using the primary wastewater as the feed, membrane fouling development was classified into 4 phases: virgin performance, initial deposition, stabilization and aggregation. With the growing fouling layer and with aggregation, the removal rate of organic matter was reduced from 99 to 70%. Conversely, the removal rate of inorganic matter was maintained at a level higher than 90%. The fractionation of physical and chemical extraction had the following characteristics: TPI>HPI>HPO and HPI>TPI>HPO respectively. Also, low molecular weight and building blocks like organic matter were observed with a high composition ratio of fouling layer. Through the correlation between the process performance, real-time monitoring of fouling layer formation and deep-layer fouling analysis, it was possible to identify the major membrane contaminants and propose process optimization guidelines.

97. 题目: Activation of biochar through exoenzymes prompted by earthworms for vermibiochar production: A viable resource recovery option for heavy metal contaminated soils and water
文章编号: N21040304
期刊: Chemosphere
作者: Ananthanarayanan Yuvaraj, Ramasundaram Thangaraj, Natchimuthu Karmegam, Balasubramani Ravindran, Soon Woong Chang, Mukesh Kumar Awasthi, Soundarapandian Kannan
更新时间: 2021-04-03
摘要: The industrial revolution and indiscriminate usage of a wide spectrum of agrochemicals account for the dumping of heavy metals in the environment. In-situ/ex-situ physicochemical, and bioremediation strategies with pros and cons have been adopted for recovering metal contaminated soils and water. Therefore, there is an urgent requirement for a cost-effective and environment-friendly technique to combat metal pollution. Biochar combined with earthworms and vermifiltration is a suitable emerging technique for the remediation of metal-polluted soils and water. The chemical substances (e.g., sodium hydroxide, zinc chloride, potassium hydroxide, and phosphoric acid) have been used to activate biochar, which also faces several shortcomings. Studies reveal that extracellular enzymes have been used to activate biochar which is produced by earthworms and microbes that can alter the surface of the biochar. The present review focuses on the global scenario of metal pollution and its remediation through biochar activation using earthworms. The earthworms and biochar can produce “vermibiochar” which is capable of reducing the metal ions from contaminated water and soils. The vermifiltration can be a suitable technology for metal removal from wastewater/effluent. Thus, the biochar has a trick of producing entirely new options at a time when vermifiltration and other technologies are least expected. Further attention to the biochar-assisted vermifiltration of different sources of wastewater is required to be explored for the large-scale utilization of the process.

98. 题目: Production of hydroxyl radicals following water-level drawdown in peatlands: A new induction mechanism for enhancing laccase activity in carbon cycling
文章编号: N21040303
期刊: Soil Biology and Biochemistry
作者: Yunpeng Zhao, Wu Xiang, Chunlei Huang, Yang Liu, Yu Tan
更新时间: 2021-04-03
摘要: The hydroxyl radical (•OH) is the most powerful reactive oxygen species that plays a critical role in the fate of redox-active substances. Peatlands are carbon-rich ecosystems with highly reduced substances and ubiquitous redox interfaces. However, little is known about the production of •OH during the reoxidation of peatlands under waterlogged conditions. Here, we conduct a set of reoxidation experiments using waterlogged peat soil dominated by various vegetation species and monitored •OH production. The results show that the cumulative concentrations of •OH produced within 24 h upon oxygenation of waterlogged peat samples are 307−840 mmol g-1. The main factors affecting the production of •OH include an acidic environment, abundant reduced dissolved organic matter and Fe(II). In addition, •OH production enhances laccase activity (the largest class of phenol oxidases in the soil) by 7.7% ∼ 20.4% and increases soil respiration by 3.17% ∼ 23.67% during the reoxidation of the waterlogged peat samples. In addition, the simulation experiments confirm that •OH can promote laccase activity directly by serving as an electron acceptor and indirectly by oxidizing substrates. Both mechanisms are greater than the effect of oxygen (O2) alone on laccase activity. Our results indicate a new induction mechanism for enhancing laccase activity by •OH when subjected to anoxic-oxic interface fluctuations, which is particularly important for carbon cycling in peatlands because it can break the decomposition latch and can further promote soil organic carbon mineralization.

99. 题目: Excitation-emission matrix fluorescence spectra of chromophoric dissolved organic matter reflected the composition and origination of dissolved organic carbon in Lijiang River, Southwest China
文章编号: N21040302
期刊: Journal of Hydrology
作者: Qiufang He, Qiong Xiao, Jiaxing Fan, Haijuan Zhao, Min Cao, Cheng Zhang, Yongjun Jiang
更新时间: 2021-04-03
摘要: Aquatic photosynthesis transforms inorganic carbon to organic carbon (OC), which contributes to autochthonous organic carbon (AOC) in sediment and particulate organic carbon in surface karst aquatic systems. Aquatic plant and microbes are participated in autochthonous dissolved organic carbon (ADOC) formation in surface karst aquatic systems, but the composition and formation of ADOC remains little known, which leaves problem on calculation of organic carbon flux. In this study, the Lijiang River was chosen as typical surface karst river to identify the DOC composition and its origin, and to explore the environmental influencing factors. Samples were collected seasonally from the upper to lower reaches of the river to analyze hydrochemical parameters and the excitation-emission matrix (EEM) spectrum of chromophoric dissolved organic matter (CDOM). Three CDOM components were calculated by parallel factor analysis (PARAFAC) from EEM spectra, which were allochthonous soil-sourced DOC (SDOC), autochthonous aquatic plant-sourced DOC (APDOC), and microbial-sourced DOC (MDOC). Based on the DOC component concentrations, SDOC is induced by large amounts of precipitation causing soil erosion in summer. APDOC formation is encouraged by moderate water temperatures in spring and fall restricted by high water turbidity in summer. The significant positive linear correlations between APDOC and dissolved inorganic carbon (DIC) and MDOC indicate DIC fertilization effect in karst aquatic systems directly promotes APDOC formation and indirectly promotes MDOC. Our study develops a relatively simple way to calculate composition of karst aquatic DOC, which demonstrates the participation of aquatic plants and microbes in APDOC production and reiterate that autochthonous DOC should be considered when calculating the carbon sink in surface karst aquatic systems.

100. 题目: Soil microbial communities-mediated bioattenuation in simulated aquifer storage and recovery (ASR) condition: Long-term study
文章编号: N21040301
期刊: Environmental Research
作者: Hien Thi Nguyen, Youngjae Kim, Jae-Woo Choi, Seongpil Jeong, Kyungjin Cho
更新时间: 2021-04-03
摘要: This study evaluated the long-term organic removal performance and microbial community shift in simulated aquifer storage and recovery (ASR) conditions. For this purpose, anoxic soil box systems were operated at 15 °C for one year. The results showed that the assimilable organic carbon (AOC) concentration in the anoxic soil box systems was successfully decreased by 79.1%. The dissolved organic carbon (DOC) concentration increased during the initial operational periods; however, it subsequently decreased during long-term operation. Readily biodegradable organic fractions (i.e., low-molecular weight (LMW) neutrals and LMW acids) decreased along with time elapsed, whereas non-biodegradable fraction (i.e., humic substances) increased. Proteobacteria and Acidobacteriota were predominant in the anoxic box systems throughout the operational periods. Firmicutes and Bacteroidota suddenly increased during the initial operational period while Gemmatimonadota slightly increased during prolonged long-term operation. Interestingly, the microbial community structures were significantly shifted with respect to the operational periods while the effects of AOC/NO3− addition were negligible. Various bacterial species preferring low temperature or anoxic conditions were detected as predominant bacteria. Some denitrifying (i.e., Noviherbaspirillum denitrificans) and iron reducing bacteria (i.e., Geobacter spp.) appeared during the long-term operation; these bacterial communities also acted as organic degraders in the simulated ASR systems. The findings of this study suggest that the application of natural bioattenuation using indigenous soil microbial communities can be a promising option as an organic carbon management strategy in ASR systems.

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