Field Evaluation of Arid Soils Wetting Pattern in Subsurface Drip Irrigation Scheme     

Naji K. Al‐Mefleh  Majed Abu‐Zreig 《洁净——土壤、空气、水》2013,41(7):651-656

A field study evaluating wetted radius (Wr), downward depth (Dd), and upward movement (Um) under different emitter discharges and lateral depths was conducted. Four emitter discharges (2, 4, 8, and 16 L/h) and four lateral depths (0, 10, 20, and 30 cm) were tested in a clay loam soil. Relationships were found between the emitter discharge and lateral depth versus Wr, Dd, and Um. Wetting area at the surface occurs under different emitter discharges and lateral depths except at 30 cm lateral depth. At lateral depth of 0 and 10 cm, Wr and emitter discharge were positively correlated. The Dd was not affected by emitter discharge except for laterals installed at 20 cm depth. At 30 cm lateral depth, the correlations between each of Wr, Um, and Dd with emitter discharge were poor. The ratios of Wr/Dd and Um/Dd, with respect to emitter position, were less than unity over different emitter discharges and lateral depths. These results shed some light on the design of subsurface drip irrigation scheme so that the spacing between emitters should be determined based on the lateral depths and discharge of emitters. Evaporation losses were negligible for the 30‐cm‐lateral depth since the upward moisture movement has not reached the soil surface area at all discharge rates tested in the study.  相似文献   

Adsorption of Complex Pollutants from Aqueous Solutions by Nanocomposite Materials     

Yeoung‐Sheng Wang  Shu‐Huei Hsieh  Chang‐Hung Lee  Jao‐Jia Horng 《洁净——土壤、空气、水》2013,41(6):574-580

In view of water pollutants becoming more complex, both anionic and cationic pollutants need to be removed. The multi‐pollutants simultaneous removal is paid more and more attention. Hence, development composite materials for treatment complex wastewater are the aim of this study. In this research, iron–nickel nanoparticles deposited onto aluminum oxide (α‐Al₂O₃) and carbon nanotubes (CNTs) to form nanocomposite materials Fe–Ni/Al₂O₃ and Fe–Ni/CNTs, respectively, were used as adsorbents. The adsorption capacities of Fe–Ni/Al₂O₃ and Fe–Ni/CNTs for AO7, HSeO, and Pb²⁺ were observed to be 5.46, 8.28, 27.02, and 25.6 mg/g, 15.29 and 17.12 mg/g, separately. The composite materials with negative charges were superior in adsorption of anionic pollutants. Using orthogonal experimental design and analysis of variance to co‐treat dye AO7, HSeO and Pb²⁺ in aqueous solutions, seven testing factors were included: (1) adsorbent types, (2) amount of iron, (3) solution pHs, (4) AO7 concentrations, (5) Pb²⁺ concentrations, (6) HSeO concentrations and (7) reaction time. The experimental results showed that the removal of complex pollutants AO7, HSeO, and Pb²⁺ on Fe–Ni/CNTs could reach up to 90% in the optimal treatment conditions. When using Fe–Ni/CNTs as the adsorbent, the sorption isothermals were well fitted in the Freundlich isotherm, and R² could reach up to 0.98.  相似文献   

Simultaneous Determination of 11 Sulfonamides by HPLC–UV and Application for Fast Screening of Their Aerobic Elimination and Biodegradation in a Simple Test     

Waleed M. M. Mahmoud  Nareman D. H. Khaleel  Ghada M. Hadad  Randa A. Abdel‐Salam  Annette Haiß  Klaus Kümmerer 《洁净——土壤、空气、水》2013,41(9):907-916

Sulfonamides (SAs) are one of the most frequently used antibiotics. SAs have been found in various environmental compartments. If SAs are not degraded in the environment, they can affect bacteria by their antibiotic properties and contribute to bacterial antibiotic resistance. Therefore, the biodegradability of 11 SAs (sulfanilamide, sulfaguanidine monohydrate, sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethoxypyridazine, sulfachloropyridazine, sulfamethazine, sulfamethoxazole, and sulfadimethoxine) was studied. For this purpose, the Closed Bottle Test (CBT, OECD 301D) was performed, which includes a toxicity control. In order to monitor the environmental fate of the parent compound and to check for transformation products, a simple, efficient, and reliable HPLC–UV method for the simultaneous determination of these SAs has been developed. Acetonitrile and water (with 0.1% formic acid) were used as mobile phase solvents for gradient elution. The method was validated in terms of precision, detection and quantitation limits, selectivity, and analytical solution stability. In the CBT, none of these SAs was readily biodegradable. The HPLC–UV analysis confirmed that no degradation of any SA took place. In the toxicity control, these SAs showed no toxic effect in the used concentration of environmental bacteria applied in the test.  相似文献   

Plant Species Richness Increased Belowground Plant Biomass and Substrate Nitrogen Removal in a Constructed Wetland     

Hai Wang  Zheng‐Xin Chen  Xiao‐Yu Zhang  Si‐Xi Zhu  Ying Ge  Scott‐X. Chang  Chong‐Bang Zhang  Cheng‐Cai Huang  Jie Chang 《洁净——土壤、空气、水》2013,41(7):657-664

The effects of plant species richness on both above‐ and belowground plant biomass, plant nitrogen (N) pool size, and substrate N concentrations were studied in a full‐scale subsurface vertical‐flow constructed wetland (CW). Results showed that (i) plant species richness increased belowground plant biomass and its N pool size but had no effect on aboveground plant biomass and its N pool size; (ii) plant species richness increased substrate N removal, especially ammonium N removal; and (iii) plant species richness had no effect on plant N use efficiency, suggesting that the N pool size increased with increasing plant species richness. More N accumulation could be removed through harvesting plant biomass. We concluded that the N removal performance of the CW improved by plant species richness through increasing belowground biomass and relevant N pool size.  相似文献   

Growth fold controls on carbonate distribution in mixed foreland basins: insights from the Amiran foreland basin (NW Zagros,Iran) and stratigraphic numerical modelling     

Eduard Saura  Jean‐Christophe Embry  Jaume Vergés  David W. Hunt  Emilio Casciello  Stéphane Homke 《Basin Research》2013,25(2):149-171

The evolution from Late Cretaceous to early Eocene of the well dated Amiran foreland basin in the NW Iranian Zagros Mountains is studied based on the reconstruction of successive thickness, palaeobathymetry and subsidence maps. These maps show the progressive forelandwards migration of the mixed carbonate‐siliciclastic system associated with a decrease in creation of accommodation. Carbonate facies variations across the basin suggest a structural control on the carbonate distribution in the Amiran foreland basin, which has been used as initial constraint to study the control exerted by syndepositional folding in basin architecture and evolution by means of stratigraphic numerical modelling. Modelled results show that shallow bathymetries on top of growing folds enhance carbonate production and basin compartmentalization. As a consequence, coarse clastics become restricted to the internal parts of the basin and only the fine sediments can by‐pass the bathymetric highs generated by folding. Additionally, the development of extensive carbonate platforms on top of the anticlines favours the basinwards migration of the depositional system, which progrades farther with higher fold uplift rates. In this scenario, build‐ups on top of anticlines record its growth and can be used as a dating method. Extrapolation of presented modelling results into the Amiran foreland basin is in agreement with an early folding stage in the SE Lurestan area, between the Khorramabad and Kabir Kuh anticlines. This folding stage would enhance the development of carbonate platforms on top of the anticlines, the south‐westward migration of the system and eventually, the complete filling of the basin north of the Chenareh anticline at the end of the Cuisian. Incremental thickness maps are consistent with a thin (0.4–2 km) ophiolite complex in the source area of the Amiran basin.  相似文献   

Strike‐slip tectonics and basin inversion in the Western Mediterranean: the Post‐Messinian evolution of the Alboran Sea     

P. Martínez‐García  M. Comas  J. I. Soto  L. Lonergan  A. B. Watts 《Basin Research》2013,25(4):361-387

A comprehensive interpretation of single and multichannel seismic reflection profiles integrated with biostratigraphical data and log information from nearby DSDP and ODP wells has been used to constrain the late Messinian to Quaternary basin evolution of the central part of the Alboran Sea Basin. We found that deformation is heterogeneously distributed in space and time and that three major shortening phases have affected the basin as a result of convergence between the Eurasian and African plates. During the Messinian salinity crisis, significant erosion and local subsidence resulted in the formation of small, isolated, basins with shallow marine and lacustrine sedimentation. The first shortening event occurred during the Early Pliocene (ca. 5.33–4.57 Ma) along the Alboran Ridge. This was followed by a major transgression that widened the basin and was accompanied by increased sediment accumulation rates. The second, and main, phase of shortening on the Alboran Ridge took place during the Late Pliocene (ca. 3.28–2.59 Ma) as a result of thrusting and folding which was accompanied by a change in the Eurasian/African plate convergence vector from NW‐SE to WNW‐ESE. This phase also caused uplift of the southern basins and right‐lateral transtension along the WNW‐ENE Yusuf fault zone. Deformation along the Yusuf and Alboran ridges continued during the early Pleistocene (ca. 1.81–1.19 Ma) and appears to continue at the present day together with the active NNE‐SSW trending Al‐Idrisi strike‐slip fault. The Alboran Sea Basin is a region of complex interplay between sediment supply from the surrounding Betic and Rif mountains and tectonics in a zone of transpression between the converging African and European plates. The partitioning of the deformation since the Pliocene, and the resulting subsidence and uplift in the basin was partially controlled by the inherited pre‐Messinian basin geometry.  相似文献   

Direct dating of thick‐ and thin‐skin thrusts in the Peruvian Subandean zone through apatite (U–Th)/He and fission track thermochronometry     

Cécile Gautheron  Nicolas Espurt  Jocelyn Barbarand  Martin Roddaz  Patrice Baby  Stéphane Brusset  Laurent Tassan‐Got  Eric Douville 《Basin Research》2013,25(4):419-435

Although the structure of the central Peruvian Subandean zone is well defined, the timing of thrust‐related exhumation and Cenozoic sedimentation remain poorly constrained. In this study, we report new apatite (U–Th)/He (AHe) and fission track (AFT) ages from thrust‐belt and foreland strata along three published balanced cross sections. AHe data from the northern, thick‐skinned domain (i.e. Shira Mountain, Otishi Cordillera and Ucayali Basin) show young AHe ages (ranging from 2.6 ± 0.2 to 13.1 ± 0.8 Ma) compared with AFT ages (ranging from 101 ± 5 to 133 ± 11 Ma). In the southern Camisea Basin, where deformation is mainly thin‐skinned, AHe and AFT ages have been both reset and show young cooling ages (3.7 ± 0.8 Ma and 8 ± 2 Ma respectively). Using low‐temperature thermochronology data and the latest fission track annealing and He diffusion codes, the thermal history of the study area has been reconstructed using inverse modelling. This history includes two steps of erosion: Early Cretaceous and late Neogene, but only Neogene sedimentation and exhumation varies in the different sectors of the study area. From a methodological point of view, large AHe data dispersion point to the need for refinement of AHe damage and annealing models. The influence of grain chemistry on damage annealing, multiple age components and the possibility of fission tracks as traps for He need further consideration. For the central Peruvian Subandes, AHe and AFT ages combined with balanced cross sections emphasize the dominant control of Paleozoic inheritance rather than climate on Cenozoic infilling and exhumation histories. Finally, our data provide the first field example of how thick‐skinned thrust‐related deformation and exhumation in the Subandes can be directly dated through AHe thermochronology.  相似文献   

Mechanisms of tropical precipitation biases in climate models     

Kim  Hanjun  Kang  Sarah M.  Takahashi  Ken  Donohoe  Aaron  Pendergrass  Angeline G. 《Climate Dynamics》2021,56(1-2):17-27

Climate Dynamics - We investigate the possible causes for inter-model spread in tropical zonal-mean precipitation pattern, which is divided into hemispherically symmetric and anti-symmetric modes...  相似文献   

Sedimentological and ichnological signatures of changes in wave,river and tidal influence along a Neogene tropical deltaic shoreline     

LUIS A. BUATOIS  NUBIA SANTIAGO  MEYLIN HERRERA  PIRET PLINK‐BJÖRKLUND  RON STEEL  MARÍA ESPIN  KAOLU PARRA 《Sedimentology》2012,59(5):1568-1612

Analysis of Neogene cores from the Eastern Venezuela Basin along 65 km of a west–east trending shoreline allows characterization of the sedimentological and ichnological signatures of wave, river and tidal processes. The area displays deltas prograding northward from the Guyana Shield. Twenty‐three facies are defined and grouped into four categories (wave‐influenced, river‐influenced, tide‐influenced and basinal). Wave‐dominated deltaic deposits occur mostly in the Tácata Field. The delta plain was characterized by tide‐influenced distributary channels separated by interdistributary bays. Fluvial discharge in the delta front and prodelta was repeatedly interrupted by storm‐wave reworking and suspended sediment fallout. Delta‐front and prodelta deposits contain some ichnotaxa that typically do not occur in brackish water (for example, Chondrites and Phycosiphon). Amalgamated storm deposits are unburrowed or contain vertical Ophiomorpha. Lateral (especially on the updrift side) to the river mouths, waves caused nearly continuous accretion of the associated strandplains. These deposits are the most intensely bioturbated, and are dominated by the estenohaline echinoid‐generated ichnogenus Scolicia. River‐dominated deltaic deposits are present in the Santa Bárbara, Mulata, Carito and El Furrial Fields. Low‐sinuosity rivers characterized the alluvial plain, whereas the subaerial delta plain was occupied by higher‐sinuosity rivers. The subaqueous delta plain includes distributary channels and tide‐influenced interdistributary bays. Further seaward, successions are characterized by terminal distributary‐channel and distributary mouth‐bar deposits, as well as by delta‐front and prodelta deposits showing evidence of sediment gravity‐flow and fluid‐mud emplacement. Delta‐front and prodelta deposits are unbioturbated to sparsely bioturbated, suggesting extreme stress, mostly as a result of high fluvial discharge and generation of sediment gravity flows. Tidal influence is restricted to interdistributary bays, lagoons and some distributary channels. From an ichnological perspective, and in order of decreasing stress levels, four main depositional settings are identified: river‐dominated deltas, tide‐influenced delta plains, wave‐dominated deltas and wave‐dominated strandplain–offshore complexes.  相似文献   

Espacio,Ambiente y los Inicios de la Agricultura Indígena en el Noroeste Argentino: Un Enfoque Arqueológico. María Marta Sampietro Vattuone. 2010. JAS Arqueología Editorial S.L.U., Madrid. 188 pp., ISBN978‐84‐938146‐4‐9, 19€ (paperback).     

Manuel R. Palacios‐Fest 《Geoarchaeology》2012,27(2):183-184

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