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23441. 题目: Aerobic granular sludge membrane bioreactor (AGMBR): Extracellular polymeric substances (EPS) analysis
文章编号: N19032001
期刊: Water Research
作者: Oliver T. Iorhemen, Rania A. Hamza, Mohamed S. Zaghloul, Joo Hwa Tay
更新时间: 2019-03-20
摘要: Aerobic granular sludge membrane bioreactor (AGMBR) has emerged with strong potential to overcome membrane fouling. There have been no extensive studies on extracellular polymeric substances (EPS) in AGMBR. The present work aimed at conducting an in-depth study of EPS and monitoring fouling development in AGMBR using a 2² factorial design having hydraulic retention time (HRT) and total organic carbon (TOC) as independent variables. HRT was tested at three levels of 6, 8 and 10 h while the TOC levels were 104 ± 13, 189 ± 17, and 266 ± 27 mg/L. AGMBR exhibited high proteins (PN) in the tightly-bound EPS (TB-EPS) resulting in high proteins/polysaccharides (PN/PS) ratios of 2–16. The PN in the LB-EPS was low, ranging from 0.01 to 1.92 mg/g MLVSS, but the range of PN/PS ratio was also of 2–16. Despite the high PN/PS ratio, TMP rise was low. Water jet easily sloughed off the developed membrane cake layer. The elimination of chemicals for membrane cleaning has significant cost savings. TOC had a significant main effect on both the PN and PS components of TB-EPS at α < 0.05. TB-EPS PN increased with increase in TOC. TB-EPS PN decreased as HRT increased from 6 h to 10 h at 104 ± 13 mg/L TOC but the change of HRT from 10 h to 6 h at 266 ± 27 mg/L TOC did not affect TB-EPS PN. The TMP increased with increasing HRT at 104 ± 13 and 266 ± 27 mg/L TOC. An increase in sEPS PN correlated well with increase in membrane fouling (r = 0.581). Three runs performed best: 266 ± 27 mg/L TOC and 10 h HRT; 104 ± 13 mg/L TOC and 6 h HR; and 266 ± 27 mg/L TOC and 6 h HRT as TMP was below the 50 kPa threshold. AGMBR achieved 98 ± 1%, 99 ± 1%, 52 ± 33% organics degradation, NH₃-N removal, total nitrogen removal, respectively.
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23442. 题目: Lignin catabolic pathways reveal unique characteristics of Dye‐decolorizing peroxidases in Pseudomonas putida
文章编号: N19031910
期刊: Environmental Microbiology
作者: Lu Lin, Xiaopeng Wang, Lanfang Cao, Meiying Xu
更新时间: 2019-03-19
摘要: Lignin is one of the largest carbon reservoirs in the environment, playing an important role in the global carbon cycle. However, lignin degradation in bacteria, especially non‐model organisms, has not been well characterized either enzymatically or genetically. Here, a lignin‐degrading bacterial strain, Pseudomonas putida A514, was used as the research model. Genomic and proteomic analyses suggested that two B subfamily dye‐decolorizing peroxidases (DypBs) were prominent in lignin depolymerization, while the classic O2‐dependent ring cleavage strategy was utilized in central pathways to catabolize lignin‐derived aromatic compounds that were funneled by peripheral pathways. These enzymes, together with a range of transporters, sequential and expression‐dose dependent regulation, and stress response systems coordinated for lignin metabolism. Catalytic assays indicated these DypBs show unique Mn2+ independent lignin depolymerization activity, while Mn2+ oxidation activity is absent. Furthermore, a high synergy between DypB enzymes and A514 cells was observed to promote cell growth (5 x 1012 CFUs/mL) and lignin degradation (27%). This suggested DypBs are competitive lignin biocatalysts and pinpointed limited extracellular secretion capacity as the rate‐limiting factor in bacterial lignin degradation. DypB production was, therefore, optimized in recombinant strains and a 14141‐fold increase in DypB activity (56565 U/L) was achieved, providing novel insights for lignin bioconversion.

23443. 题目: Organic matter content and type variation in the sequence stratigraphic context of the Upper Devonian New Albany Shale, Illinois Basin
文章编号: N19031909
期刊: Sedimentary Geology
作者: Bei Liu, Juergen Schieber, Maria Mastalerz, Juan Teng
更新时间: 2019-03-19
摘要: Organic matter quantity and type are important parameters in conventional source rock evaluation and unconventional shale oil/gas reservoir characterization. Understanding the stratigraphic distribution of organic matter content and type in black shale successions is critical for identifying potentially productive intervals, because organic matter can adsorb large amounts of oil and gas. Detailed examination of total organic carbon content, organic petrographic composition, and high-resolution (8 cm spacing) geochemical proxies in a sequence stratigraphic framework were conducted on an early mature (0.55% Ro) New Albany Shale core of the Illinois Basin to study the influence of relative sea-level fluctuations on paleoproductivity, clastic supply, bottom-water redox conditions, and their combined control on total organic carbon distribution pattern and organic maceral variation. Marine organic matter including amorphous organic matter and alginite (mainly derived from Tasmanites cysts) is the dominant organic matter in the New Albany Shale. Terrestrial organic matter accounts for <10% of total organic matter. Within a sequence stratigraphic context, total organic carbon content increases in transgressive systems tracts, reaches a maximum before the maximum flooding surface, and shows relatively low values in highstand systems tracts. Comparatively, low total organic carbon contents at maximum flooding surfaces reflect a combination of low sedimentation rates, elevated bottom-water oxygenation, and high biogenic silica dilution. Stratigraphically, amorphous organic matter content increases in transgressive systems tracts, reaches a maximum near the maximum flooding surface, and decreases in highstand systems tracts. Enrichment of broken Tasmanites cysts and their detrital infills are an indicator of high-energy environments and could possibly indicate lowstand systems tracts. The stratigraphic distribution of organic matter content and type may result in cyclic stratigraphic variations of hydrocarbon generation potential and oil saturation, and influence the development of secondary organic pores when the New Albany Shale is within the oil and gas windows.

23444. 题目: Interannual variability in the summer dissolved organic matter inventory of the North Sea: implications for the continental shelf pump
文章编号: N19031908
期刊: Biogeosciences
作者: Saisiri Chaichana, Tim Jickells, Martin Johnson
更新时间: 2019-03-19
摘要: We present the distribution and C:N stoichiometry of dissolved organic matter (DOM) in the North Sea in two summers (August 2011 and August 2012), with supporting data from the intervening winter (January 2012). These data demonstrate local variability superimposed on a general pattern of decreasing DOM with increasing distance from land, suggesting concentrations of DOM are controlled on large spatial scales by mixing between the open North Atlantic and either riverine sources or high DOM productivity in nearshore coastal waters driven by riverine nutrient discharge. Given the large size and long residence time of water in the North Sea, we find concentrations are commonly modified from simple conservative mixing between two endmembers. We observe differences in dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) concentrations and land–ocean gradients between the two summers, leading to an estimated 10–20 Tg difference in the DOC inventory between the two years, which is of the same order of magnitude as the annual uptake of atmospheric CO2 by the North Sea system, and thus significant for the carbon budget of the North Sea. This difference is not consistent with additional terrestrial loading and is more likely to be due to balancing of mixing and in situ production and loss processes across the North Sea. Differences were particularly pronounced in the bottom layer of the seasonally stratifying northern North Sea, with higher DOC and C:N ratio in 2011 than in 2012. Using other data, we consider the extent to which these differences in the concentrations and C:N ratio of DOM could be due to changes in the biogeochemistry or physical circulation in the two years, or a combination of both. The evidence we have is consistent with a flushing event in winter 2011/12 exchanging DOM-rich, high C:N shelf waters, which may have accumulated over more than 1 year, with deep North Atlantic waters with lower DOC and marginally higher DON. We discuss the implications of these observations for the shelf sea carbon pump and the export of carbon-rich organic matter off the shelf and hypothesise that intermittent flushing of temperate shelf systems may be a key mechanism in the maintenance of the continental shelf pump, via the accumulation and subsequent export of carbon-rich DOM.

23445. 题目: Effects of water erosion on soil organic carbon stability in the subtropical China
文章编号: N19031907
期刊: Journal of Soils and Sediments
作者: Xiaodong Nie, Zaijian Yuan, Bin Huang, Yishan Liao, Xuqin Zhang, Zhongwu Li, Dingqiang Li
更新时间: 2019-03-19
摘要: Purpose: How the stability of soil organic carbon (SOC) is affected by soil erosion is still not clear. The main purpose of this study was to characterize how SOC stability is affected by erosion and assess the effects of different soil properties on SOC stability. Materials and methods: Soils from eroding and depositional sites in a typical small watershed in subtropical China were collected, and soil samples from four different depths (0–5, 5–10, 20–30, and 120–150 cm) were selected to represent the profile. Soil physicochemical properties as well as soil organic matter (SOM) chemical structure were measured. Thermal analysis and mineralization incubation experiments were performed to study the SOM stability. The effects of the soil properties on the SOM stability were evaluated via redundancy analysis. Results and discussion: The results showed that the eroding and depositional sites had different SOC contents but had similar organic functional groups. Furthermore, the OC in the eroded soils was more stable than that in the deposited soils, but this difference was only observed in the surface layers (0–5 and 5–10 cm). The selected variables (including soil texture, bulk density, pH, SOC, dissolved organic carbon (DOC), iron, soil aggregates, depth, erosion, and deposition) significantly explained the variations in SOC stability. A total of 91.4% of the variation in the thermogravimetry (TG)-T₅₀ (the temperature resulting in 50% of SOM loss) and 98.9% of the variation in the CO₂ emissions were explained by these variables. SOC alone contributed to 68% of the variation in the TG-T₅₀, whereas DOC individually contributed 93.9% of the variation in the CO₂ emissions. Conclusions: SOC and DOC contents are the most important soil properties influencing SOC stability, and SOC stability affected by soil erosion is mainly by displacing SOM.

23446. 题目: Dissolved Organic Matter Sorption and Molecular Fractionation by Naturally Occurring Bacteriogenic Iron (Oxyhydr)oxides
文章编号: N19031906
期刊: Environmental Science & Technology
作者: Tyler D. Sowers, Kathryn L. Holden, Elizabeth K. Coward, Donald L. Sparks
更新时间: 2019-03-19
摘要: Iron (oxyhydr)oxides are highly reactive, environmentally ubiquitous organic matter (OM) sorbents that act as mediators of terrestrial and aqueous OM cycling. However, current understanding of environmental iron (oxyhydr)oxide affinity for OM is limited primarily to abiogenic oxides. Bacteriogenic iron (oxyhydr)oxides (BIOs), common to quiescent waterways and soil redox transitions, possess a high affinity for oxyanions (i.e., arsenate and chromate) and suggests that BIOs may be similarly reactive for OM. Using adsorption and desorption batch reactions, paired with Fourier transform infrared spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry, this work demonstrates that BIOs are capable of sorbing leaf litter-extracted DOM and Suwannee River Humic/Fulvic Acid (SRHA/SRFA) and have sorptive preference for distinct organic carbon compound classes at the biomineral interface. BIOs were found to sorb DOM and SRFA to half the extent of 2-line ferrihydrite per mass of sorbent and was resilient to desorption at high ionic strength and in the presence of a competitive ligand. We observed the preferential sorption of aromatic and carboxylic-containing species and concurrent solution enrichment of aliphatic groups unassociated with carboxylic acids. These findings suggest that DOM cycling may be significantly affected by BIOs, which may impact nutrient and contaminant transport in circumneutral environments.
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23447. 题目: Phosphorus enriched effluents increase eutrophication risks for mangrove systems in northeastern Brazil
文章编号: N19031905
期刊: Marine Pollution Bulletin
作者: Diego Barcellos, Hermano Melo Queiroz, Gabriel Nuto Nóbrega, Romildo Lopes de Oliveira Filho, Sandra Tedde Santaella, Xosé Luis Otero, Tiago Osório Ferreira
更新时间: 2019-03-19
摘要: Discharge of effluents loaded with phosphorus (P) from anthropogenic activities constitutes serious eutrophication risks in marine and terrestrial ecosystems, including mangroves. Three mangroves in NE-Brazil were studied to evaluate the impact of P-rich-effluents from shrimp farming and domestic sewage, in relation to a control area (natural mangrove). Soil phosphorus fractionation and water chemical analysis were performed to assess potential pollution. We observed the most labile P forms increased gradually and significantly from control to sewage to shrimp farm impacted mangroves as observed by increasingly dissolved orthophosphate (PO₄³⁻) content in water and the exchangeable/soluble P (Exch-P) extracted from soils, which is supported by the discriminant analysis. Exch-P results were correlated to Humic-Acid-P, which can release more labile P forms when mineralized. Our results demonstrate a substantial impact of aquiculture and sewage effluents in mangroves at both organic and inorganic P fractions, raising important concerns regarding pollution for these marine ecosystems.

23448. 题目: Accelerating effects of humin on sulfide-mediated azo dye reduction
文章编号: N19031904
期刊: Ecotoxicology and Environmental Safety
作者: Guangfei Liu, Jiaqi Zhu, Ruofei Jin, Jiti Zhou, Zhanming Gao, Jing Wang
更新时间: 2019-03-19
摘要: As an important fraction of humic substances, humin has been found capable of stimulating bioreduction reactions. However, whether humin could promote abiotic reduction and the effects of coexisting soluble humic substance and insoluble mineral remained unsolved. In this study, a humin sample was isolated from a paddy soil. Cyclic voltammetry, electron paramagnetic resonance, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses of the humin indicated the existence of redox-active quinone moieties and other oxygen-containing groups. The humin could be reduced by sulfide and its presence stimulated the abiotic reduction of acid red 27 (AR27) and four other azo dyes by sulfide. In the presence of 100–1000 mg/L intact humin, the sulfide-mediated AR27 reduction efficiency in 7 d was enhanced from 56.3% to 92.5%. The stimulating behavior of intact humin was observed for 100–300 mg/L AR27 and increased with the increase of sulfide concentration (1.2–3.0 mM). Much higher stimulating effects were found with the presence of humin pre-reduced by sulfide. Moreover, for sulfide-mediated AR27 reduction, the coexistence of humin (500 mg/L) and humic acid (10–30 mg/L) or Wyoming sodium-montmorillonite (SWy-2, 1–4 g/L) led to better promotion activities than the presence of single component. And synergistic promotion of sulfide-mediated AR27 reduction was observed with coexisting humin and SWy-2 due to enhanced Fe(II) production. These findings extended our understanding of the influence of humin on reductive transformation of pollutants in the environment.

23449. 题目: Net ecosystem carbon balance of a peat bog undergoing restoration: integrating CO2 and CH4 fluxes from eddy covariance and aquatic evasion with DOC drainage fluxes
文章编号: N19031903
期刊: Journal of Geophysical Research: Biogeosciences
作者: Brenda D’Acunha, Laura Morillas, T. Andrew Black, Andreas Christen, Mark S. Johnson
更新时间: 2019-03-19
摘要: Peatland ecosystems are generally carbon (C) sinks. However, the role of dissolved organic C (DOC) relative to gaseous fluxes of CO₂ and CH₄ in the C balance of these ecosystems has not often been studied. Dissolved C fluxes are important for understanding C partitioning within the peatland and the potential C drainage from it. This research was conducted in Burns Bog, a heavily‐impacted ecosystem near Vancouver, Canada, undergoing ecological restoration efforts by rewetting. Here we present data on (i) ecosystem‐scale fluxes of CO₂ (net ecosystem exchange, NEE) and CH₄ (FCH₄) determined by eddy covariance (EC), (ii) evasion fluxes of CO₂ and CH₄ from the water surface to estimate the role of open water in ecosystem‐scale fluxes, and (iii) DOC flux (fDOC) in water draining from the peatland. Our results showed that open water areas inside the footprint were a continual C source, emitting 47.0 ± 2.4 g C m^‐2 yr^‐1. DOC export (15.6 g C m^‐2 yr^‐1) was significant to the net ecosystem carbon balance (NECB), decreasing the magnitude of the EC‐determined C balance (i.e., NEE + FCH₄) of ‐45.0 ± 16.8 g C m^‐2 yr^‐1 by 35%, resulting in an NECB (i.e., NEE + FCH₄ + fDOC) of ‐29.7 ± 17.0 g C m^‐2 yr^‐1. Most of this offset occurred during the wetter non‐growing season when GPP was low and fDOC was relatively high.

23450. 题目: Plant feedback aggravates soil organic carbon loss associated with wind erosion in Northwest China
文章编号: N19031902
期刊: Journal of Geophysical Research: Biogeosciences
作者: Lingjie Lei, Kesheng Zhang, Xuanze Zhang, Ying‐Ping Wang, Jianyang Xia, Shilong Piao, Dafeng Hui, Mingxing Zhong, Jingyi Ru, Zhenxing Zhou, Hongquan Song, Zhongling Yang, Dong Wang, Yuan Miao, Fan Yang, Bin Liu, Ang Zhang, Mengyang Yu, Xianghui Liu, Yongheng Song, Lili Zhu, Shiqiang Wan
更新时间: 2019-03-19
摘要: Soil organic carbon (SOC) loss caused by wind erosion can profoundly impact carbon (C) balance in arid and semiarid regions. Nevertheless, previous researches mainly focused on the direct effect of wind erosion through removing surface soil only, but ignored its indirect effects associated with soil nitrogen (N) loss and subsequent reductions of plant productivity. To better understand the wind erosion effect on SOC storage, we conducted a large‐scale field experiment by manipulating wind erosion at 371 sites in arid and semiarid regions of Northwest China from 2014 to 2016. We further integrated an observation‐based empirical equation of wind erosion process into a terrestrial biogeochemical model to evaluate the direct and indirect effects of wind erosion on SOC storage in Northwest China. Observed results showed that direct SOC losses increased linearly with square of wind speed but decreased nonlinearly with soil water content. Over the 34 years (1980‐2013), simulated cumulative SOC losses associated with wind erosion in Northwest China were 27.47 Tg C, among which the indirect effects contributed to 2.68 Tg C (9.76%). Indirect effect of wind erosion initially enhanced SOC storage by decreasing heterotrophic respiration from 1984 to 1988, but decreased SOC pool by reducing net primary productivity due to soil N loss under the long‐term wind erosion scenario. This work, for the first time, quantified the indirect impact of wind erosion on SOC storage via feedback of suppressed plant productivity, which is crucial for convincing assessment on SOC storage in arid and semiarid regions.

23451. 题目: Spatial distribution of soil organic carbon stocks in Masson pine (Pinus massoniana) forests in subtropical China
文章编号: N19031901
期刊: CATENA
作者: Xiong Yao, Kunyong Yu, Yangbo Deng, Qi Zeng, Zhuangjie Lai, Jian Liu
更新时间: 2019-03-19
摘要: Masson pine (Pinus massoniana) is a typical reforestation species in subtropical China, which plays a key role in soil and water conservation. Site-specific forest management requires an accurate estimation of the soil organic carbon (SOC) stocks, and information about the spatial distribution of SOC stocks is essential for improving the soil quality and ecosystem productivity. We examined the spatial distribution of SOC stocks using 91 soil samples from Masson pine forests in subtropical China. Ordinary kriging (OK) and inverse distance weighting (IDW) methods were used to compare the spatial patterns of the SOC stocks. A moderate spatial dependence of the SOC stocks suggested that extrinsic and intrinsic factors affected the SOC stocks. Similar spatial distributions but different cross-validation accuracies indicated that OK outperformed IDW. The soil pools at a depth of 0–60 cm were 774.06 Gg and 761.61 Gg as determined by the OK and IDW methods, respectively, which were higher than that measured by the conventional method (CM, 734.22 Gg). This highlights the need to apply different methods when studying the regional SOC pools. On the basis of the comparison of OK, IDW, and CM methods, OK is recommended for determining nonhomogeneous sampling point distributions. The present results enhance our understanding of method selection when studying the spatial distribution of SOC stocks.

23452. 题目: Mineral elements uptake and physiological response of Amaranthus mangostanus (L.) as affected by biochar
文章编号: N19031811
期刊: Ecotoxicology and Environmental Safety
作者: Weili Jia, Cuiping Wang, Chuanxin Ma, Jicheng Wang, Hongwen Sun, Baoshan Xing
更新时间: 2019-03-18
摘要: Amaranthus mangostanus L. (amaranth) was hydroponically grown in different concentrations of biochar amended nutrient solution to investigate the mineral elements migration and physiological response of amaranth as affected by biochar. Our results showed that exposure to 26.6 g/L of biochar greatly increased the root and shoot K, Na and Al content, while 2.6 g/L of biochar greatly increased the root Ca and Mg content. The uptake of K and Al notably altered other elements' accumulation in shoots and roots upon the biochar exposure. The ratio of Ca: K in shoots and Mg: K in roots were negatively correlated to the biochar concentrations, while the ratio of Al: Ca and Al: Mg in roots were positively related to the biochar concentrations. The Al: Fe ratio was also polynomial correlated to the concentrations of biochar. The addition of biochar beyond 2.6 g/L resulted in the cell membrane and DNA damages in roots. The activity of SOD and CAT in 6.7 g/L biochar treated roots was significantly elevated as compared to the ones in other biochar treatments and was almost 2-fold of the control. The photosynthetic F_v/F_m intensity and subcellular structure in leaves were also compromised upon exposure to 26.6 g/L biochar. Taken together, biochar could significantly alter the mineral migration in amaranth and physiologically damage in the plants. It is essential to study the effect of biochar within appropriate concentrations on plants prior to wide application in agriculture.

23453. 题目: Plant presence reduces root and shoot litter decomposition rates of crops and wild relatives
文章编号: N19031810
期刊: Plant and Soil
作者: Janna M. Barel, Thomas W. Kuyper, Wietse de Boer, Gerlinde B. De Deyn
更新时间: 2019-03-18
摘要: Aims: Roots contribute greatly to carbon cycling in agriculture. Measuring aboveground litter decomposition could approximate belowground turn-over if drivers of decomposition, f.e. litter traits and plant presence, influence shoot and root decomposition in a comparable manner. We tested coordination of above- and belowground litter traits and decomposition rates for six pairs of crops and closely related wild plants and studied the influence of plant presence on decomposition. Methods: Above- and belowground traits were measured, compared and related to decomposition rates. Shoot and root litters were incubated in presence of the same plant species as the litter species (own) or in presence of two other plant species (a grass or forb). Results: Shoots decomposed 1.43–1.98 times faster than (resp.) wild plant and crop roots. Decomposition correlated negatively with litter carbon and lignin concentrations, except crop root decomposition which correlated negatively with nitrogen concentration. Unexpectedly, plant presence reduced litter decomposition, with strongest effects for root litters in presence of forbs. Conclusions: Carbon cycling might be slower than predicted solely based on shoots decomposition rates, especially in presence of growing plants. While root decomposition of wild plants can be approximated by shoot decomposition, crop shoots are a poor proxy for crop root decomposition.

23454. 题目: Anthropogenic influence on the sediment chemistry and diatom assemblages of Balamtetik Lake, Chiapas, Mexico
文章编号: N19031809
期刊: Environmental Science and Pollution Research
作者: Margarita Caballero, Lucy Mora, Esperanza Muñoz, Oscar Escolero, Roberto Bonifaz, Carolina Ruiz, Blanca Prado
更新时间: 2019-03-18
摘要: Balamtetik is the receiving body of the Rio Grande de Comitán and is located just at the outskirts of the Montebello National Park, Chiapas, México. Multi-elemental, infrared spectra, ¹³⁷Cs, ²¹⁰Pb, and diatom analyses in a 75-cm sediment core were used to reconstruct the recent disturbance history of the lake. The sequence chronology, based mostly on ¹³⁷Cs profiles, allowed to infer high sedimentation rates in Balamtetik (~ 7 mm/year) and a nearly cyclic series of disturbance events that can be related to anthropogenic causes such as deforestation and increased development of agriculture and urban areas at local and regional scale. These disturbance events show high local and regional erosion (high Ca, TIC, and Ti), soil organic matter (IR spectra), eutrophication (high P and diatoms), and anoxic bottom water conditions (low Mn) and can be dated to the early 1950s, the late 1950s, and from the 1980s until the 2000s. The entrance of wastewaters is related with an increase in salinity inferred by the diatom record and the organic matter type. The first two disturbance events are related to changes in land use during the agrarian reform that started during the 1940s; the last event is related with the increase in local population and the introduction of intensive agriculture. This last phase of disturbance corresponds with the reports of fish mortality events around 2003; however, high lake turbidity and anoxic bottom waters seem to have been established since the 1980s. The record from Lake Balamtetik also shows that during the intermediate periods, there was a recovery of the lake and its catchment; however, the future trends might be different, as the increase in the speed of organic matter and nutrients arrival to the lake reduces its resilience.

23455. 题目: Long-term soil biological fertility, volatile organic compounds and chemical properties in a vineyard soil after biochar amendment
文章编号: N19031808
期刊: Geoderma
作者: Laura Giagnoni, Anita Maienza, Silvia Baronti, Francesco Primo Vaccari, Lorenzo Genesio, Cosimo Taiti, Tania Martellini, Roberto Scodellini, Alessandra Cincinelli, Corrado Costa, Stefano Mancuso, Giancarlo Renella
更新时间: 2019-03-18
摘要: The agronomic management of vineyards, aimed at the maximization of grape yields, is intensive and includes repeated tillage, crop residues removal, strict weed and pest control treatments. In viticulture, healthy soils and a suitable climate are the key factors that influence the quality of the produced wine. Even under intensive agronomic practices, typical of conventional viticulture, the choice of appropriate soil management strategies can preserve soil quality in the long term. The use of biochar as soil amendment has been suggested as a potential practice that allows restoration of the functionality of degraded soils in terms of water retention, chemical and biological fertility. In this paper we report the results of a long field trial on biochar amendment of a vineyard, assessing the impact on soil functionality, VOC emission and fertility. Our results show that biochar effects on soil functions and fertility are maintained in the long term (seven years) after a one-time application.

23456. 题目: Topographic influences on soil properties and aboveground biomass in lucerne-rich vegetation in a semi-arid environment
文章编号: N19031807
期刊: Geoderma
作者: Zi-Qiang Yuan, Chao Fang, Rong Zhang, Feng-Min Li, Muhammad Mansoor Javaid, Ivan A. Janssens
更新时间: 2019-03-18
摘要: Lucerne (Medicago sativa L.) is widely planted on the semi-arid Loess Plateau in China to control soil erosion, yet the extent to which topography affects the productivity of lucerne still remains poorly understood. This study aimed to evaluate how topographic position influences soil properties and aboveground biomass in lucerne-rich vegetation. A total of 112 quadrats were established in 28 fields covered with 11-year-old lucerne vegetation. In each quadrat, the slope, slope position, slope aspect, altitude, soil properties (soil moisture content, organic carbon, total nitrogen [N] and phosphorus [P], available P and inorganic N), and aboveground biomass were measured. Redundancy and multiple regression analyses were performed to determine the relationships among topographic factors, soil properties and aboveground biomass. A modest proportion of variation in soil variables was explained by topographic variables. The altitude, slope and slope position, rather than the slope aspect, were the key factors that influencing soil variables. Soil organic carbon, total N, inorganic N, the ratio of organic carbon to available P (C/P), and the ratio of total N to available P were positively correlated with altitude, whereas available P was negatively correlated with altitude. The soil moisture content was primarily affected by the slope and slope position. The topographic factors did not directly affect the total and lucerne aboveground biomass. The total and lucerne aboveground biomass were positively correlated to soil moisture content, inorganic N and C/P. Therefore, the aboveground biomass of lucerne-rich vegetation could be indirectly regulated by the slope and slope position through the effect on the soil moisture content and by altitude through the effect on soil inorganic N and C/P. This work highlighted the importance of soil properties such as soil moisture and P dynamics in the revegetation process of lucerne in this semi-arid region. As soil properties can be directly governed by topography, considering topography could enhance the quality of vegetation restoration in the large hilly region of the Loess Plateau.

23457. 题目: Collapse and failure of ancient agricultural stone terraces: On-site geomorphic processes, pedogenic mechanisms, and soil quality
文章编号: N19031806
期刊: Geoderma
作者: Ilan Stavi, Yulia Gusarov, Rares Halbac-Cotoara-Zamfir
更新时间: 2019-03-18
摘要: Water is the major limiting factor for primary productivity in drylands. In ancient times, stone terraces aimed at runoff harvesting and soil erosion control were established, allowing agricultural crop production. Land abandonment and cease of maintenance have led to the collapse and failure of terraces in the hinterlands of the Roman/Byzantine city of Avdat in the arid Negev Desert, Israel. The objective of this study was to assess the geomorphic processes and pedogenic mechanisms related to terrace collapse, and their on-site impact on soil quality. We studied key properties of the top 10 cm of soil in intact-terrace plots and partially-collapsed terrace plots, as well as in ‘natural’ lands. Unexpectedly, the soil texture was finer in the partially collapsed-terrace plots (clay loam) than that in the intact-terrace plots (loam). This was attributed to transportation of mineral material by rolling, which sorts out the large primary particles. This process, which characterizes rill erosion of high erosive power, is probably the predominant surface process in this study. The soil penetration resistance was significantly greater in the partially-collapsed terrace plots, and was attributed to the continuous removal of recently deposited loose sediments and exposure of the underlying, compacted older sediments. Soil stoniness, which was 16-fold greater in the partially-collapsed terrace plots, was also attributed to soil erosion. Unexpectedly, the total organic carbon was similar in both terrace states. Yet, labile organic carbon was 41% lower in soil of the partially-collapsed terrace plots, suggesting greater susceptibility of this fraction to erosional processes. The low electrical conductivity in the soil of the intact-terrace plots, was attributed to the better leaching of salts. The soil's calculated available water capacity was 42% greater in the intact-terrace plots. The study suggests that these processes and mechanisms strengthen each other through a chain of feedbacks, resulting in accelerated degradation of the collapsed-terrace lands.
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23458. 题目: Exploring sediment porewater dissolved organic matter (DOM) in a mud volcano: Clues of a thermogenic DOM source from fluorescence spectroscopy
文章编号: N19031805
期刊: Marine Chemistry
作者: Simona Retelletti Brogi, Ji-Hoon Kim, Jong-Sik Ryu, Young Keun Jin, Yun Kyung Lee, Jin Hur
更新时间: 2019-03-18
摘要: Mud volcanoes (MVs) are potential conduit migration pathways for deep thermogenic DOM. In this study, we investigated the dissolved organic matter (DOM) of porewater in a MV in the Canadian Beaufort Sea and compared dissolved organic carbon (DOC) and fluorescent DOM (FDOM) between the MV and a reference site (RS). The chemical and isotopic compositions (Cl⁻, δ¹⁸O and δD) of porewater from the MVs indicated that these fluids are derived from a mixture of seawater, meteoric water, and clay dehydration, causing a freshening of the porewaters. Interestingly, the porewaters in the MV exhibited DOC concentrations up to 14 times higher than those in the RS. This high DOC concentration was attributed to a higher concentration in the deep fluid moving upwards through the MV, and in minor part to processes such as particulate organic matter sulfate reduction, anaerobic oxidation of methane and higher biological activity in the MV sediments. The fluorescence results showed the presence of four components in both MV and RS sites, which included two humic-like, one microbial humic-like, and a protein-like component. All the four fluorescent components increased with depth, showing a good linear relationship with DOC. However, the DOC-normalized fluorescence in the porewater DOM was on average 3 to 7 times lower in the MV, suggesting that the DOM molecules have undergone thermogenic processes in the deep sediments, and that shallow processes do not affect significantly to FDOM composition. Our results highlight that fluids migrating from the deep sediment through the MV can be an important source of thermogenically altered DOM to the shallow sediments and overlaying water column.

23459. 题目: A new software of calculating the pH values of coastal seawater: Considering the effects of low molecular weight organic acids
文章编号: N19031804
期刊: Marine Chemistry
作者: Li-Na Lyu, Daoming Lu, Chengjun Sun, Haibing Ding, Liang-Min Yu, Gui-Peng Yang
更新时间: 2019-03-18
摘要: Effects of low molecular weight organic acids (LMWOAs) on the pH value of seawater were investigated in the surface seawater of the Jiaozhou Bay, China. The new software of Org·TCO2TA was developed to calculate the pH values of seawater based on the alkalinity (Alk) equation where organic acid Alk (Org-Alk) was separated into LMWOA Alk (LMWOA-Alk) and humic acid Alk (HA-Alk). In the calculations, all dissociation constants of organic acids were from previous literature. In our study, the average concentration of total LMWOAs was 14.5 ± 11.2 μmol·kg⁻¹ SW. pH values from the Org·TCO2TA software were closer to the pH values from spectrophotometric measurement than those from the CO2SYS program, indicating pH values can be influenced by high concentrations of LMWOAs in coastal seawater of the Jiaozhou Bay. Although the differences still existed between the pH values from the spectrophotometric method and the calculated pH values from the Org·TCO2TA software due to the influence of various factors, including the analytical errors of dissolved inorganic carbon and nutrients, the new software can calculate the pH values of coastal seawater more accurately by considering the effects of LMWOAs.

23460. 题目: Diagenetic transformation of organic matter in sapropel sediments of small lakes (southern West Siberia and eastern Transbaikalia)
文章编号: N19031803
期刊: Quaternary International
作者: G.A. Leonova, A.E. Maltsev, V.N. Melenevsky, S.K. Krivonogov, L.M. Kondratyeva, V.A. Bobrov, M.Y. Suslova
更新时间: 2019-03-18
摘要: Sapropels, biogenic lake sediments, are characterized by a reduction type of diagenesis, during which decomposition of organic compounds, modification of the pore water chemical composition and precipitation of authigenic minerals, mostly pyrite, occur. Pyrolysis data indicate that organic matter undergoes radical transformations already in the uppermost sapropel layers, and composition of the organic matter in the sediments is principally different from the composition of the organic matter of live organisms, which produce the sediments. The sapropels lose labile protein–carbohydrate compounds in the horizon of unconsolidated sediment (0–5 cm), and kerogen appears, whose macromolecular structures start to develop in the very early stages of diagenesis. Various physiological groups of microorganisms provide diagenetic transformations of the organic matter, where heterotrophic, ammonifying and sulfate-reducing bacteria play key role. Their effect is well-seen from the pore water transformation: a decrease in concentrations of SO₄^2– and consequent increase of reduced Fe and S as pyrite in the solid phase of the sediment. Comparative analysis shows that, unlike in lakes of the Baikal area, sapropels in southern West Siberia are affected by more active sulfate reduction, which can depend on both the composition of the organic matter and the SO₄^2– concentration in the pore waters.