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17341. 题目: Adsorption characteristics of tetracycline onto particulate polyethylene in dilute aqueous solutions
文章编号: N21052308
期刊: Environmental Pollution
作者: Thanh Binh Nguyen, Thi-Bao-Chau Ho, Chin Pao Huang, Chiu-Wen Chen, Shu-Ling Hsieh, Wen-Pei Tsai, Cheng-Di Dong
更新时间: 2021-05-23
摘要: The presence of ultrafine plastics particles and its potential to concentrate and transport organic contaminants in aquatic environments have become a major concern in recent years. Specifically, the uptake of hazardous chemicals by plastics particles may affect the distribution and bioavailability of the chemicals. In this study, the adsorption of tetracycline (TC), an antibiotic frequently found in aquatic environments, on high-density polyethylene (PE) particles with the average size of 45 μm, was investigated. The PE particles were characterized for surface acidity for the first time. Results showed that pH controls the surface charge of PE particles. TC adsorption onto PE particles was rapid as expected following the pseudo-second-order rate law (r2 > 0.99). Polar forces in addition to specific chemical interactions, such as hydrogen bonding and hydrophophilicity controlled TC adsorption onto PE particles. Parameters, including pH, dissolved organic matter, ionic strength, major cations and anions affected TC adsorption onto PE micro-particles. Results indicated that PE particles can function as a carrier of antibiotics in the aquatic environment, which potentially imposes ecosystem and human health risks.

17342. 题目: Deep roots of Carex aquatilis have greater ammonium uptake capacity than shallow roots in peatlands following permafrost thaw
文章编号: N21052307
期刊: Plant and Soil
作者: Lucas J. Albano, Merritt R. Turetsky, Michelle C. Mack, Evan S. Kane
更新时间: 2021-05-23
摘要: Aims Climate warming in northern ecosystems is triggering widespread permafrost thaw, during which deep soil nutrients, such as nitrogen, could become available for biological uptake. Permafrost thaw shift frozen organic matter to a saturated state, which could impede nutrient uptake. We assessed whether soil nitrogen can be accessed by the deep roots of vascular plants in thermokarst bogs, potentially allowing for increases in primary productivity. Methods We conducted an ammonium uptake experiment on Carex aquatilis Wahlenb. roots excavated from thermokarst bogs in interior Alaska. Ammonium uptake capacity was compared between deep and shallow roots. We also quantified differences in root ammonium uptake capacity and plant size characteristics (plant aboveground and belowground biomass, maximum shoot height, and maximum root length) between the actively-thawing margin and the centre of each thermokarst bog as a proxy for time-following-thaw. Results Deep roots had greater ammonium uptake capacity than shallow roots, while rooting depth, but not belowground biomass, was positively correlated with aboveground biomass. Although there were no differences in aboveground biomass between the margin and centre, our findings suggest that plants can benefit from investing in the acquisition of resources near the vertical thaw front. Conclusions Our results suggest that deep roots of C. aquatilis can contribute to plant nitrogen uptake and are therefore able to tolerate anoxic conditions in saturated thermokarst bogs. This work furthers our understanding of how subarctic and wetland plants respond to warming and how enhanced plant biomass production might help offset ecosystem carbon release with future permafrost thaw.

17343. 题目: Chromophoric dissolved organic matter (CDOM) in a subtropical estuary (Galveston Bay, USA) and the impact of Hurricane Harvey
文章编号: N21052306
期刊: Environmental Science and Pollution Research
作者: Gerardo Gold-Bouchot, Samuel Polis, Lauren Elizabeth Castañon, Mayra Padilla Flores, Alyssa Nicole Alsante, Daniel Conrad Ogilvie Thornton
更新时间: 2021-05-23
摘要: The landfall of Hurricane Harvey in August 2017 provided the opportunity to study the impact of extreme freshwater discharge on chromophoric dissolved organic matter (CDOM) properties in a subtropical estuary (Galveston Bay, Texas). Both fluorescence spectroscopy (excitation-emission matrices) and a three-component parallel factor analysis (PARAFAC) model identified changes in CDOM properties. Comparing to Coble’s peaks, component 1 was similar to peak C, component 2 to peak M, and component 3 to peak B. Results clearly show three periods with distinct CDOM properties: a dry season, a wet season, and Hurricane Harvey. The dry season was characterized by higher values of the spectral slope and fluorescence and biological indices. The wet season was characterized by high values of PARAFAC components 1 and 2 (humic-like) and the absorption coefficient at 350 nm. Some CDOM components were highly correlated with salinity, indicating conservative mixing. Component 3 (protein-like) had a low correlation to salinity, suggesting degradation or production processes in the bay. Silicates and NO3- + NO2- had negative relationships with salinity and a positive one with PARAFAC components 1 and 2. PARAFAC component 3 was correlated with dissolved oxygen and chlorophyll a, suggesting a relationship between CDOM fluorescent components and phytoplankton activity. High values of the humification index were observed immediately after Hurricane Harvey, indicating increased input of terrestrial organic matter into the bay. Hurricane Harvey increased CDOM levels and humification, and the variability and changes seem to be mostly due to freshwater discharge from the San Jacinto River and not the Trinity River. The influx of freshwater was sufficient to eliminate the salinity gradient in Galveston Bay and significantly change CDOM properties. Galveston Bay recovered quickly from the hurricane and associated flux of freshwater, returning to pre-hurricane CDOM characteristics in less than 2 months.

17344. 题目: Optimization of lactate production from co-fermentation of swine manure with apple waste and dynamics of microbial communities
文章编号: N21052305
期刊: Bioresource Technology
作者: Tianjing Lian, Wanqin Zhang, Qitao Cao, Shunli Wang, Fubin Yin, Yongxin Chen, Tanlong Zhou, Hongmin Dong
更新时间: 2021-05-23
摘要: Co-anaerobic fermentation (co-AF) of swine manure (SM) and apple waste (AW) has been proved to be beneficial for lactic acid (LA) production. In order to further improve the LA production, three important parameters, namely AW in feedstock, temperature, volatile solids (VS) of feedstock, were evaluated using Box-Behnken design and response surface methodology. The quadratic regression model was developed and interactive effects was found between the three parameters. Results showed that the maximum concentration, 31.18 g LA/L (with LA yield of 0.62 g/g VS), was obtained under optimum conditions of 60.4% AW in feedstock, 34.7 ℃, and 5.0% VS. At the optimum conditions, the solubilization of organic matter was enhanced compared with mono-fermentation of SM. Microbial community structure of the reactor diverged greatly with fermentation time. Clostridium and Lactobacillus were dominant bacteria in the fermentation process, resulting in a remarkably LA accumulation.

17345. 题目: The impacts of calcium oxide nanoparticles on the anaerobic granule formation: CO2 sequestration and dosing
文章编号: N21052304
期刊: Environmental Science and Pollution Research
作者: Anwar Ahmad
更新时间: 2021-05-23
摘要: Lab experiments were conducted to investigate the effects of calcium oxide nanoparticles (CaO NPs) dosing on granule formation, granule development, and carbon oxide sequestration. The results showed that dosing CaO NPs adversely affected granulation due to the formation of precipitates and hydrolyzates with poor settleability. However, the optimal dosage of CaO NPs 4.5 g/l could benefit granule formation and stability by improving the embedded extracellular polymeric substances (EPS) and physical adhesion aggregation leads for CO2 sequestration. The network of granules like Methanosarcina and in pore size 0.55 mm obtained in the reactor was 6.25 mm in average diameter, had a wet density 46 cm2, sludge volume index 0.935 ml/g, and CO2 sequestration 96.7% at 4.5 g/l CaO NP. The proposed study can provide a good prediction for the growth of granules stable texture in regular, dense, rigid, upper part smooth with below surface rough and granule yield showed CH4 production 4.6 m3/d and CO2 sequestration 4.75 l/gVS granules (w/v) granules. This study is a useful tool for studying the growth of granule growth characteristics and the mechanism of anaerobic granules for CO2 sequestration from wastewater.

17346. 题目: Roles of biochar-derived dissolved organic matter in soil amendment and environmental remediation: A critical review
文章编号: N21052303
期刊: Chemical Engineering Journal
作者: Yuqing Sun, Xinni Xiong, Mingjing He, Zibo Xu, Deyi Hou, Weihua Zhang, Yong Sik Ok, Jörg Rinklebe, Linling Wang, Daniel C.W. Tsang
更新时间: 2021-05-23
摘要: Biochar is an emerging, cost-effective, and renewable carbonaceous material with abundant functional groups and tuneable mesoporous structure, showing a promising performance in fertility improvement, nutrient retention, microbial activity enhancement, contaminant immobilization, etc. Dissolved organic matter (DOM) from biochar, which can be readily mobilized during soil application, is a key component for the soil matrix, microbial community, and the fate of contaminants. Comprehensive assessments of both positive and negative effects of biochar-derived DOM present critical environmental implications. This paper is the first of its kind to critically review the compositions and structures of biochar-derived DOM as well as its multiple roles in soil application. The effects of biochar-derived DOM on stabilization or migration/mobilization of contaminants/nutrients, as well as stimulation or inhibition of microbial activity and plant growth, depend on the nature of biochar-derived DOM, pollutant properties, soil characteristics, and environmental conditions including weather and hydrological conditions. The long-term stability of biochar-derived DOM is vital during soil application and involves various interactions such as physical disintegration, infiltration, sorption, and biotic/abiotic oxidation. Further studies of biochar-derived DOM are necessary for us to understand the fate of DOM and minimize the ecological and environmental risks (e.g., toxicity, competitive sorption, blockage effect, and solubilization) of biochar application.

17347. 题目: Soil microbial community response to permafrost degradation in palsa fields of the Hudson Bay Lowlands: Implications for greenhouse gas production in a warming climate
文章编号: N21052302
期刊: Global Biogeochemical Cycles
作者: J. Adam H. Kirkwood, Pascale Roy‐Léveillée, Nadia Mykytczuk, Maara Packalen, Jim McLaughlin, Amy Laframboise, Nathan Basiliko
更新时间: 2021-05-23
摘要: Permafrost thaw in northern peatlands alters the ground thermal conditions, moisture, and chemistry that control microbial activity responsible for the production of greenhouse gases like methane from decomposing organic matter. This paper examines interactions between microbial communities, peat chemistry, moisture content, and temperature in the context of degrading palsa fields in the vast (372,000 km2), carbon rich, and rapidly warming permafrost peatlands of the Hudson Bay Lowlands. The temperature sensitivities of microbial GHG production and consumption from palsa and fen peat was assessed, and microbial community structure was examined as a potential constraint on greenhouse gas production in relation to changes in peat chemistry associated with thermokarst encroachment and active layer deepening. High CH4 production was observed from thermokarst peat, under controlled moisture and temperature conditions, associated with increased pH. A shift in methanogen taxonomic and metabolic diversity favouring aceticlastic methanogenesis was associated with changes in peat chemistry and pH from palsa to thermokarst fen peat. In palsa peat, CH4 production rates were lowest but most sensitive to temperature variations, due to recalcitrant carbon compounds. CH4 production was highly sensitive to increased temperatures, yet was balanced by high temperature sensitivity of CH4 oxidation in oxic conditions, consistent with the low temperature sensitivity of fluxes observed in field studies from other permafrost peatlands. Building on the microbial controls in this study, future work should explore how permafrost degradation and increased hydrological connectivity to mineral substrates are changing in this globally significant permafrost peatland, and how this impacts net CH4 emissions.

17348. 题目: Characterization of landfill leachate molecular composition using ultrahigh resolution mass spectrometry
文章编号: N21052301
期刊: Environmental Science: Water Research & Technology
作者: Katherine R. Martin, Nicole M. Robey, Shirley Ma, Leanne C. Powers, Andrew Heyes, Philippe Schmitt-Kopplin, William J. Cooper, Timothy G. Townsend, Michael Gonsior
更新时间: 2021-05-23
摘要: Landfill leachate (LL) is a complex wastewater and an important potential source of environmental contamination. LL can contain high concentrations of ammonia, metals, other inorganic species, and dissolved organic carbon; however, bulk composition of dissolved LL organic matter (LLOM) is poorly understood. A better understanding of LLOM composition will inform treatment development and improve LL pollution tracing. In this study, we addressed this need for compositional and treatment information by characterizing LL from an active bioreactor municipal solid waste (MSW) landfill as well as from a closed MSW landfill. Through non-targeted ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) we were able to assign chemical formulas to thousands of singly charged molecular ions and compare samples to natural dissolved organic matter (DOM). LLOM was differentiated by a higher presence of sulfur-, nitrogen-, and chlorine-, particularly nitrogen–sulfur-, containing formulas. The abundance of chlorine-containing molecular formulas supports the existence of a non-volatile organochlorine component in MSW LL. We performed tandem MS (MS-MS) analyses to tentatively identify the presence of the flame retardant, chlorendic acid, and likely related compounds. Additionally, we measured contaminants of emerging concern (CECs) and other chemical parameters to further characterize LLs and found evidence suggesting a significant percent of Fe may be bound in Fe–organic complexes.

17349. 题目: Synthesis, characteristics and mechanistic insight into the clays and clay minerals-biochar surface interactions for contaminants removal-A review
文章编号: N21052116
期刊: Journal of Cleaner Production
作者: Muhammad Arif, Guijian Liu, Balal Yousaf, Rafay Ahmed, Samina Irshad, Aniqa Ashraf, Muhammad Zia-ur-Rehman, Muhammad Saqib Rashid
更新时间: 2021-05-21
摘要: Biochar (BC), a low-cost, porous and carbon-rich material, exhibits excellent potential as an adsorbent in the immobilization and removal of environmental contaminants from water and soil. To enhance the surface area, functionalities and adsorption efficiency of BC, various clay and clay mineral-based physical and chemical modification methods have been adopted. Although extensive studies have been conducted to evaluate the removal efficiencies of BC-clays and clay minerals composites, insight into synthesis, characteristics, and mechanistic understanding between adsorbents and contaminants in environmental remediation has not been fully developed. Therefore, this review focuses on production methods of BC composites with different clays and clay minerals, their surface interactions, physicochemical characteristics, and specifically various adsorption mechanisms involved in the removal process of in-/organic contaminants, and explains how the sorption capacity of the BC-clay/mineral composites is altered. Environmental applications of various BC-clay/mineral composites and factors affecting the surface chemical reactions and interactions of BC-clay/mineral composites are also provided comprehensively. Moreover, this article discusses the increasing interest of BC-clay/mineral composites in enhancing the adsorption efficiency of different contaminants through various mechanisms. The combined effects of BC-clay/mineral composites for the adsorption of in-/organic contaminants both in soil and water are critically reviewed. Future challenges and prospects regarding the use of BC-clay/mineral composites in environmental remediation and achieving commercialization of this promising technology are also considered.

17350. 题目: Development of Soil Radiocarbon Profiles in a Reactive Transport Framework
文章编号: N21052115
期刊: Geochimica et Cosmochimica Acta
作者: Jennifer L. Druhan, Corey R. Lawrence
更新时间: 2021-05-21
摘要: Today, there is a greater appreciation for the importance of the physical protection of carbon (C) through interactions with mineral surfaces, isolation from microbes, and the important role of transport in shaping soil properties and controlling moisture limitations on decomposition. As our paradigm for soil organic carbon (SOC) preservation changes, so too should our representation of the underlying processes in soil models. Reactive transport models (RTMs) provide a framework capable of assessing the interactive influence of soil chemistry and transport processes on the accumulation and turnover of SOC. In this study, we present new developments in the isotopically enabled RTM “CrunchTope,” which is capable of explicitly tracking the three isotopes of carbon (12C, 13C, and 14C) and their fractionation between multiple coexisting and interacting solid, liquid and gas phases. This modeling framework opens the door to new applications of depth-resolved RTM models in application to SOC and deeper subsurface carbon reservoirs. Here, we demonstrate SOC accumulation and radiocarbon aging for long-timescale models of soil development in CrunchTope. Our goal is to assess advantages and limitations of such an approach and to identify the type and complexity of reaction networks that are required to adequately apply this model to SOC dynamics. We assess the behavior of this model relative to a high-resolution dataset of SOC content, stable isotope composition, and radiocarbon ages as well as physical and hydrologic data measured from a chronosequence of soils located near Santa Cruz, California. Starting from a previously published model using a simplified reaction network with a single class of carbon, we sequentially incorporate multiple carbon reservoirs subject to both reactivity and transport pathways. Our results indicate that multiple SOC pools with different mean ages of C do not inherently emerge as a result of including reactions which are conventionally expected to provide a diversity of transit times, i.e., sorption and complexation of SOC on mineral surfaces. Instead, transit times emerge as a result of the timescales of the reactions represented in the reaction network. For mineral associated C, the RTM framework imposes dynamic equilibrium with the fluid phase dissolved organic carbon, such that no distinction in radiocarbon ages is achieved between these pools. Aged C can be produced by including a solid-phase carbon reservoir, with a rate-limited solubilization coefficient. Aging of SOC in this way is more akin to selective preservation than to mineral protection and, while such a mechanism may be at play in many soils, mineral protection is thought to be at least as important. As such, our results indicate that additional parameterization is required to reproduce the heterogeneity of carbon transit times that result from organo-mineral interactions. These efforts show the promise of a modeling approach where the varied transit time of soil C emerges from the dynamic physical and hydrologic properties of the model rather than from the a priori assignment of operationally defined pools.

17351. 题目: Linkages between greenhouse gases (CO2, CH4, and N2O) and dissolved organic matter composition in a shallow estuary
文章编号: N21052114
期刊: Science of The Total Environment
作者: V. Amaral, T. Ortega, C. Romera-Castillo, J. Forja
更新时间: 2021-05-21
摘要: Estuarine systems receive large amounts of organic matter that enhance the production of greenhouse gases (GHGs), such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Despite considerable research on GHGs and dissolved organic matter (DOM) distribution in estuaries, little is known about the linkage between these gases and DOM composition. Here we evaluated the relationship between three GHGs (CO2, CH4, and N2O) and DOM composition, determined through optical properties, in Guadalete estuary (Bay of Cadiz, Spain). The partial pressure of CO2, and CH4 and N2O concentrations ranged between 332.8-6807.1 μatm, 19.9- 6440.1 nM, and 6.8- 283.9 nM, respectively. Thus, the Guadalete estuary was a source of CO2, CH4 and N2O to the atmosphere. We validated three PARAFAC components related to humic-like fluorescence from terrestrial, microbial and effluent sources, and one with protein-like material. Humic-like components accounted for 86% ± 6% of the total FDOM pool, indicating a predominantly allochthonous DOM origin. The three GHGs were significantly linked to DOC concentration and DOM composition, exhibiting different patterns in these linkages. Terrestrial and microbial humic-like substances with increasing aromaticity might enhance pCO2 in Guadalete estuary. Dissolved CH4 concentrations showed the strongest relationship with DOM composition, indicating that humic and protein-like material are linked with their distribution. In contrast, dissolved N2O was only related with the protein-like fraction and with humic-like material derived from anthropogenic activities (sewage and agriculture). Our results further indicate that a possible coupling between benthic fluxes of GHGs and DOM might be occurring in this shallow estuary. We conclude that it is important to account for DOM composition when studying GHGs distribution in estuarine systems to understand their roles and potential responses associated with climate change.

17352. 题目: Using stable isotope probing and fluorescence spectroscopy to examine the roles of substrate and soluble microbial products in extracellular polymeric substance formation in activated sludge process
文章编号: N21052113
期刊: Science of The Total Environment
作者: Zeshan Arshad, Tahir Maqbool, Kyung Hoon Shin, Seung-Hee Kim, Jin Hur
更新时间: 2021-05-21
摘要: In this study, we used stable isotope-labeled soluble microbial products (SMP) and substrates to explore their assimilation into the formation of new biological products (i.e., extracellular polymeric substances and biomass) in two adjacent sequencing batch reactors. The isotope labeling approach along with fluorescence spectroscopy allowed us to distinguish between refractory and labile portions of SMP constituents as well as their roles in the formation of extracellular polymeric substances (EPS). Comparison of SMP fluorescence and the specific UV absorbance values between the two reactors revealed the presence of humic-like aromatic substances in the non-consumable part of SMP, which can be ultimately released as effluent organic matter. Parallel factor analysis modeling of fluorescence spectra showed that the hydrolysis of EPS contents mostly resulted in humic-like components in SMP rather than protein-like components, which were initially abundant in EPS (>80 %). From variations in carbon and nitrogen isotopic contents in EPS and biomass, it was found that carbon-containing substrates were enriched faster than their nitrogenous counterparts. The contributions to new EPS formation reached 87.5 % for carbon and 60.5 % for nitrogen. Meanwhile, the isotopic tracking of the labeled SMP revealed that only 11.0 % and 11.9 % of carbon and 13.3 % and 11.6% of nitrogen from the influent SMP were finally assimilated into EPS and biomass, respectively. In contrast, the isotopic enrichment in SMP was higher (~50 %) than that of EPS and biomass, indicating the low bioavailability and refractory nature of the feed SMP. This study proposed a promising approach for estimating the relative contributions of different forms of labile substrate and SMP to the formation of EPS in activated sludge processes. This approach could be suggested as a versatile method for establishing the kinetics, substrate element flow, mass balance on organic substrates and nutrients, as well as for tracking the consumption and uptake pathways of hazardous materials.

17353. 题目: Spatial–temporal variations in riverine carbon strongly influenced by local hydrological events in an alpine catchment
文章编号: N21052112
期刊: Biogeosciences
作者: Xin Wang, Ting Liu, Liang Wang, Zongguang Liu, Erxiong Zhu, Simin Wang, Yue Cai, Shanshan Zhu, Xiaojuan Feng
更新时间: 2021-05-21
摘要: 70 % of global land areas but are poorly monitored compared with large rivers. The small size and low water buffering capacity of headwater streams may result in a high sensitivity to local hydrological alterations and different carbon transport patterns from large rivers. Furthermore, alpine headwater streams on the “Asian water tower”, i.e., Qinghai–Tibetan Plateau, are heavily affected by thawing of frozen soils in spring as well as monsoonal precipitation in summer, which may present contrasting spatial–temporal variations in carbon transport compared to tropical and temperate streams and strongly influence the export of carbon locked in seasonally frozen soils. To illustrate the unique hydro-biogeochemistry of riverine carbon in Qinghai–Tibetan headwater streams, here we carry out a benchmark investigation on the riverine carbon transport in the Shaliu River (a small alpine river integrating headwater streams) based on annual flux monitoring, sampling at a high spatial resolution in two different seasons and hydrological event monitoring. We show that riverine carbon fluxes in the Shaliu River were dominated by dissolved inorganic carbon, peaking in the summer due to high discharge brought by the monsoon. Combining seasonal sampling along the river and monitoring of soil–river carbon transfer during spring thaw, we also show that both dissolved and particulate forms of riverine carbon increased downstream in the pre-monsoon season due to increasing contribution of organic matter derived from thawed soils along the river. By comparison, riverine carbon fluctuated in the summer, likely associated with sporadic inputs of organic matter supplied by local precipitation events during the monsoon season. Furthermore, using lignin phenol analysis for both riverine organic matter and soils in the basin, we show that the higher acid-to-aldehyde (Ad/Al) ratios of riverine lignin in the monsoon season reflect a larger contribution of topsoil likely via increased surface runoff compared with the pre-monsoon season when soil leachate lignin Ad/Al ratios were closer to those in the subsoil than topsoil solutions. Overall, these findings highlight the unique patterns and strong links of carbon transport in alpine headwater catchments with local hydrological events. Given the projected climate warming on the Qinghai–Tibetan Plateau, thawing of frozen soils and alterations of precipitation regimes may significantly influence the alpine headwater carbon transport, with critical effects on the biogeochemical cycles of the downstream rivers. The alpine headwater catchments may also be utilized as sentinels for climate-induced changes in the hydrological pathways and/or biogeochemistry of the small basin.]]>

17354. 题目: In‐situ biochar production in paddies: direct involvement of farmers in greenhouse gases reduction policies besides increasing nutrients availability and rice production
文章编号: N21052111
期刊: Land Degradation & Development
作者: Mohammad Ghorbani, Elnaz Amirahmadi, Kazem Zamanian
更新时间: 2021-05-21
摘要: Treating soils with pyrolyzed biomass i.e. biochar is proposed as a conditioner and a carbon geoengineering measure. Rice is known as a strategic crop and rice husk is a cheap and available material in particular in Asia. We conducted a field experiment with laboratory biochar (LB) and in-situ biochar (IB) at 10 and 20 t ha-1 using a randomized block design in three replicates to examine the efficiency of in-situ biochar for improving soil condition for rice production, and to propose a cheap and in-farm applicable measure to decrease greenhouse gases (GHGs) emissions from agricultural sector. Grain yield significantly increased following biochar addition by 52.2%, 53.2%, 65.4% and 67.2% in LB10, IB10, LB20 and IB20, respectively. Total biomass in all biochar treatments had a significant difference (P<0.05) with control and the highest biomass belonged to LB20 and IB20 with 12.2 and 15.7 t ha1, respectively. The highest grain nitrogen, phosphorus, and potassium was in IB20. Compared to the control, IB20 significantly decreased emissions of CH4 by 72.3%, N2O by 85.8% and CO2 by 32.9%. In-situ production of biochar is as effective as laboratory biochar. In-situ biochar production and application provide a sustainable management for dealing with crop residues, improves soil conditions (aeration and nutrients availability) for crop growth and directly and in a practical way involves farmers in GHGs reduction policies.

17355. 题目: Oxygen Isotopic Fingerprints on the Phosphorus Cycle Within the Deep Subseafloor Biosphere
文章编号: N21052110
期刊: Geochimica et Cosmochimica Acta
作者: Mingyu Zhao, Ruth E. Blake, Yuhong Liang, Deren Dogru Ruf, Deb P. Jaisi, Sae Jung Chang, Noah J. Planavsky
更新时间: 2021-05-21
摘要: Phosphorus (P) is essential for all known forms of life. The oxygen isotopic composition of phosphate can carry a strong imprint from the metabolic processes on Earth’s surface environments, including the deep subseafloor biosphere extending to > 1 km beneath the seafloor. Here, we report the 18O/16O ratios (δ18O) of dissolved inorganic phosphate (DIP) to identify different pathways of P cycling in deep-sea sediments sampled up to 200 meters below the seafloor during Ocean Drilling Program (ODP) Leg 201. Our results, along with a diagenetic model, indicate that the δ18O of DIP (δ18ODIP) is mainly controlled by three pathways of P cycling at Site 1230: (1) release of DIP by extracellular enzymatic degradation of organic matter (i.e., organophosphate), (2) precipitation of authigenic apatite, (3) enzyme-catalyzed oxygen isotopic exchange between phosphate and water. Our diagenetic model quantitatively deconvolves the rates of the three P cycling pathways. In particular, a shift of δ18ODIP towards equilibrium around 140m below the seafloor corresponds well with a shift in microbial communities, suggesting that δ18ODIP has potential as a proxy for microbial activities in the deep subseafloor biosphere. We also find that the rate of oxygen isotopic exchange can be scaled with the rate of organic matter degradation, suggesting microbially controlled oxygen isotopic exchange. Further, the pattern of variation between authigenic phosphate in sediments and DIP in porewaters bolsters the case that authigenic phosphate (authigenic apatite and Fe-bound phosphate) should reflect the oxygen isotopic composition of contemporaneous porewater DIP and thus can be used to track biogeochemical cycling of P.

17356. 题目: Sewage treatment sludge biochar activated blast furnace slag as a low carbon binder for soft soil stabilisation
文章编号: N21052109
期刊: Journal of Cleaner Production
作者: J. Gonzalez, P. Sargent, C. Ennis
更新时间: 2021-05-21
摘要: Portland cement forms the basis of most binders used in deep dry soil mixing, significantly improving the shear strength and compressibility properties of soils. However, due to the high environmental and socio-economic impacts of cement production, there is great interest in developing alternative low-carbon binders for soil stabilisation. One of the most desirable routes involves the use of industrial by-products, such as ground granulated blast furnace slag, whose pozzolanic properties require activation by alkali agents. This paper assesses the feasibility of using sewage treatment sludge biochar as a low-carbon 100% waste-based alternative to traditional alkali agents. Two biochar:slag ratios (0.5:0.5 and 0.67:0.33) were added to an artificial soil at dosages of 7.5 and 10% by dry weight and cured for up to 56 days. The engineering performance of these stabilised soil mixtures was assessed by performing a suite of compressive strength, pH, water content, mineralogical and microstructural analyses. Results were compared with those of untreated and CEM-II stabilised alluvium, along with data published in the literature. Biochar was observed to successfully activate the pozzolanic properties of the slag, whereby the studied mixtures resulted in 28-day strengths that met European soil stabilisation standards requirements. Binder mixtures with higher biochar concentrations achieved greater strengths. The best performing mixture had a biochar-slag ratio of 0.67:0.33 and dosage of 10%, which produced strengths up to 1,243 kPa. This study suggests that the biochar-slag binder has encouraging prospects for replacing Portland cements in soil stabilisation, reducing the carbon footprint of the construction sector and improving the circular economy.

17357. 题目: Abundance and diversity of carbon-fixing bacterial communities in karst wetland soil ecosystems
文章编号: N21052108
期刊: CATENA
作者: Xiayu Wang, Wei Li, Yutian Xiao, Aoqi Cheng, Taiming Shen, Min Zhu, Longjiang Yu
更新时间: 2021-05-21
摘要: Autotrophic carbon-fixing bacteria are the main drivers of carbon sequestration and elemental cycle in wetland ecosystems. Their relationship with environmental factors in karst soils such as soil organic carbon (SOC) fractions, which are affected by natural degradation and human disturbance, is key to understanding the biological mechanisms of karst wetland ecosystem deterioration and restoration. In this study, the abundances of the Calvin cycle functional genes cbbL and cbbM as well as the characteristics of carbon-fixing bacterial communities were compared in soil samples from a native wetland, naturally degraded wetland, and reclaimed farmland wetland in the Huixian karst wetland, Guilin, China. The abundances of the cbbL gene in the degraded wetland and reclaimed wetland soils varied significantly among the seasons (P < 0.05, summer > winter). The influence of the season on the abundances of the cbbL and cbbM genes was more significant than that of the wetland state. The structures of carbon-fixing bacterial communities were similar in the three states of karst wetland soils, mainly consisting of Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria in the phylum Proteobacteria. However, the relative abundances of some dominant bacterial genera were significantly different. Thiomonas and Bradyrhizobium had a relatively high abundance in the native wetland soil and the degraded wetland soil, respectively, while Ferriphaselus and Sulfuricaulis were more abundant in the reclaimed farmland wetland soil. The main soil factors affecting the structure of the carbon-fixing bacterial communities were the SOC and its fractions dissolved organic carbon (DOC), microbial biomass carbon (MBC) and readily oxidizable organic carbon (ROC), as well as the soil temperature. Anthropogenic activities such as wetland transition to farmland have caused significant changes in karst soils and the characteristics of carbon-fixing bacterial community in this karst wetland soil ecosystem.

17358. 题目: Combustion ash addition promotes the production of K-enriched biochar and K release characteristics
文章编号: N21052107
期刊: Journal of Cleaner Production
作者: Wenzhu Wu, Beibei Yan, Lei Zhong, Rui Zhang, Xiang Guo, Xiaoqiang Cui, Wenlong Lu, Guanyi Chen
更新时间: 2021-05-21
摘要: Biogas residues (BR) and maize silage (MS) from biogas plants were mixed with biomass combustion ash (ASH) for K-enriched biochar preparation. The characteristics and nutrient contents of biochar were determined by thermo-gravimetric apparatus, Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, and chemical extraction methods, respectively. The desorption kinetics and slow release mechanism of K in biochar were evaluated after an incubation experiment for 28 days. Results showed that biochar yields were improved from 36.6% to 49.0% for BR-based biochars (BRCs) and 24.9% to 38.2% for MS-based biochars (MSCs) with the addition of ASH during pyrolysis. The total potassium (TK) content of composite biochar increased to the highest TK content of 37.29 mg/g in biochar derived from MS with 20 wt% ash (MSCA20%). Furthermore, slow-available K content increased from 0.86 mg/g and 1.62 mg/g of primary biochar derived from BR and MS to 6.88 mg/g and 7.8 mg/g in composite biochar with 20 wt% ash respectively. The formation of K-Si-Al-O species involved unstable clay minerals and stable insoluble minerals during the catalytic pyrolysis improved slow release performance. The composite biochar showed a slower and continuable K+ release property in the incubation experiment, releasing less than 80% of the total available K into water in 28 days. The K+ desorption kinetics fitted the Power function well, indicating release of K+ was a complex reaction process. This lab-scale work showed that the pyrolytic composite biochar from wastes in biogas plants with combustion ash addition has the potential to be slow release fertilizer. The combined thermal conversion of solid wastes provides a sustainable strategy to simultaneously achieve the reclamation of nutrients and generation of environmental benefits via the production of biochar fertilizer.

17359. 题目: Woody peat addition increases soil organic matter but its mineralization is affected by soil clay in the four degenerated erodible soils
文章编号: N21052106
期刊: Agriculture, Ecosystems & Environment
作者: Wei Fu, Jun Fan, Sheng Wang, Huan Wang, Zijun Dai, Xu Zhao, Mingde Hao
更新时间: 2021-05-21
摘要: Soil erosion exacerbates the reduction of soil organic matter (SOM) and destruction of soil physical structure in agricultural systems, which seriously threatens agricultural ecological environment and global sustainable agriculture development. Owing to rich SOM and nutrients of woody peat results in it’s widely applied in degraded soil for improving land productivity. But how the impacted of woody peat addition on crop growth and soil organic matter (SOM) in different textured degenerated erodible soils are not well understood. Here, along the latitudinal gradient from north to south of China, four typical regional soils collected in Northeast (black soil), Northwest (loessial soil), Central (lou soil) and South (red soil) of China, where suffered strongly soil erosion. Soil clay content was 37.0%, 16.9%, 29.6%, and 38.5% for the black, loessial, lou, and red soils, respectively. We conducted a plot incubation experiment in a fully ventilated, rainproof outdoor greenhouse for planting wheat (Triticum aestivum L.). The study is aimed to investigate the response of different texture eroded soil to crop growth and physiology, soil evaporation and soil organic matter after woody peat addition. Eight treatments have been designed for four soils with two groups. (i) the control group with no woody peat addition, B0, H0, L0 and R0; (ii) woody peat addition group, BW, HW, LW and RW. Overall, the SOM concentration altered wheat growth characteristic and grain yield in the four typical erosion degraded soils. The highest grain yield of winter wheat is 6.5 ± 1.3 g per plot in B0 and 6.5 ± 1.1 g per plot in BW, and the lowest is 0.4 ± 0.1 g per plot in R0 in red soil. But woody peat addition increased the wheat yield or yield variation, the wheat gain yield increased four times with woody peat addition (RW) than control (R0) in red soil. In addition, the results revealed that the SOM content were increased in black soil by 40.4%, in loessial soil by 40.0%, in lou soil by 101.3%, and in red soil by 94.6% when compared to the control treatments at harvest. From sowing to harvest, SOM decreased by 5.1 ± 1.8 g kg-1 (black soil), 9.9 ± 0.9 g kg-1 (loessial soil), 7.6 ± 1.8 g kg-1 (lou soil), and 6.2 ± 1.0 g kg-1 (red soil) in the soils with woody peat addition. Without woody peat addition, SOM decreased by 5.6 g kg-1 (black soil), 4.7 g kg-1 (lou soil), and 0.6 g kg-1 (red soil), but increased by 0.4 g kg-1 in loessial soil. In conclusion, woody peat addition resulted in wheat yield increasing in the degenerated soils, but it’s significant in the red soil with adequate nutrient supply and increased soil acid buffering capacity. Woody peat addition increased the SOM concentration in the four degenerated soils, but a faster decreasing rate of the ΔSOM in coarse-textured loessial soil than others medium-fine texture soils. Therefore, appropriate woody peat application and clay content is more conducive to the protection of SOM. More deeply research should have been focused on the impact of woody peat addition in coarse-textured soil on the soil environment (such as the clay type, content, and soil priming effect, etc.).

17360. 题目: Rain-fed streams dilute inorganic nutrients but subsidise organic-matter-associated nutrients in coastal waters of the northeast Pacific Ocean
文章编号: N21052105
期刊: Biogeosciences
作者: Kyra A. St. Pierre, Brian P. V. Hunt, Suzanne E. Tank, Ian Giesbrecht, Maartje C. Korver, William C. Floyd, Allison A. Oliver, Kenneth P. Lertzman
更新时间: 2021-05-21
摘要: In coastal regions, rivers and streams may be important sources of nutrients limiting to primary production in marine waters; however, sampling is still rarely conducted across the land-to-ocean aquatic continuum, precluding conclusions from being drawn about connectivity between freshwater and marine systems. Here we use a more-than-4-year dataset (2014–2018) of nutrients (nitrogen, phosphorus, silica, iron) and dissolved organic carbon spanning streams draining coastal watersheds and nearshore marine surface waters along the Central Coast of British Columbia, Canada, at the heart of the North Pacific coastal temperate rainforest region. Mean freshwater and surface marine N:Si:P ratios were 5:20:1 (P:Fe = 1:67) and 6:11:1, respectively, showing relative consistency across the land–ocean interface but deviation from the extended Redfield ratio. Inorganic nutrient concentrations (NO−3+NO−2, PO3−4, Si(OH)4) in fresh waters were less than in the receiving marine environment, indicating that freshwater nutrient inputs in this region were of little importance to – or even diluted – the pool of readily available inorganic nutrients in nearshore waters. Conversely, fresh waters increased the pool of organic-matter-associated nutrients, namely dissolved organic nitrogen and iron. The organic-matter-rich landscapes of the region yielded globally significant quantities of dissolved organic nitrogen (304–381 kg km−2 yr−1) and iron (463–596 kg km−2 yr−1), thus acting as important sources of potentially limiting nutrients to both nearshore and offshore waters. These exports may subsidise heterotrophic microbial communities capable of directly consuming and remineralising these nutrients, potentially compensating for the dilution of inorganic nutrients by freshwater inputs. We highlight the need to better understand nutrient limitation in coastal waters and for concerted research efforts to study the spatial and temporal dynamism at the land–ocean interface along the northeast Pacific coast.