藻体部位、藻质量、碳源、水流对铁钉菜和羊栖菜营养盐吸收的影响     

孟伟杰  王萍  桂福坤  吴常文  梁君 《海洋与湖沼》2014,45(3):663-668

采用实验室生态学研究方法,进行了藻体部位、藻质量、碳源质量浓度及水流流速对铁钉菜(Ishige foliaceaokamurai)和羊栖菜(Sargassum fusiforme)氮磷营养盐吸收影响的研究。结果表明:2种大型海藻不同部位对营养盐的吸收速率不同,铁钉菜下部的吸收速率最大,其次是固着器;羊栖菜顶部的吸收速率最大,其次是中部。铁钉菜藻质量1.0g的吸收速率最大,其次是1.5g;羊栖菜藻质量0.5 g的吸收速率最大,其次是1.0g;2种藻类2.0g和2.5g的吸收速率相差不多。碳源质量浓度为1200mg/L时,铁钉菜的吸收速率最大,其次是碳源800mg/L;碳源质量浓度为800mg/L时,羊栖菜的吸收速率最大,其次是碳源400mg/L;2种海藻对照组的吸收速率均相对较低。相同流速下,2种海藻均以PO4-P对照组的吸收速率最大;NO3-N、NH4-N吸收速率在流速为50cm/s时最大。  相似文献   

Freshwater seepages and ephemeral macroalgae proliferation in an intertidal bay: II. Effect on benthic biomass and metabolism     

Aline Migné  Vincent Ouisse  Cédric Hubas  Dominique Davoult 《Estuarine, Coastal and Shelf Science》2011

Intertidal soft-sediments biomass and metabolism are naturally heterogeneous in time and space at different scales. Particular perturbations such as freshwater seepages and seasonal proliferation of ephemeral macroalgae can intermittently and/or locally create additional variability in these systems. Since the impacts of such environmental stresses on natural processes are not well understood, the hypothesis that they would affect the functioning of the benthic system was tested. An intertidal bay whose structure and functioning has been previously described and where a carbon budget has been calculated, was chosen. The results showed that the metabolism of the intertidal sediments was greatly impacted by the above perturbations. Freshwater seepage increased meiofauna and microalgae biomasses and enhanced the total benthic metabolism (increasing community respiration and gross primary production until 4 and 2 fold respectively) without altering its seasonal trend. Ephemeral macroalgae proliferation had a more important effect on the total benthic metabolism, increasing community respiration and gross primary production 8 and 12 fold respectively and leading to a change in the seasonal trend.  相似文献   

任务语言教学法在大学英语教学中的运用     

邓文英 《成都信息工程学院学报》2003,18(4):441-444

任务语言教学法注重语言的实际应用，旨在提高学生的交际能力。在大学英语教学实践中积极采用任务语言教学法，侧重培养学生的学习兴趣和交际能力。使用任务语言教学法有助于学生英语自学能力的培养和交际能力的提高。  相似文献   

探讨英语教学后发优势与学生英语交际能力的可持续提高     

申洪军 《成都信息工程学院学报》2004,19(1):131-134

从教学理论和课程模式方面对英语教学的后发优势进行研究,并详细探讨了后发优势对大学英语教学和学生语言交际能力提高的影响.一切从实际出发,发挥后发优势能促进教学各方面的创新和跨越式发展.  相似文献   

Remote sensing observations of biological material by LANDSAT along a tidal thermal front and their relevancy to the available field data     

Jacques Le Fèvre  Michel Viollier  Pierre Le Corre  Cécile Dupouy  Jean-René Grall 《Estuarine, Coastal and Shelf Science》1983,16(1):37-50

Two images recorded on two successive summer days by LANDSAT satellite over the western approaches to the English Channel show bright pattern of complex shape the origin of which is puzzling. Among the wavelength bands available on LANDSAT's multispectral scanner, these patterns are apparent only in the green region of the spectrum, and they are located towards the stratified side of a well marked tidal thermal front. Spectral signature analysis and available knowledge on hydrography and plankton in the area are used to derive a proposed interpretation. Phytoplankton would accordingly be the best candidate for being responsible for the observed patterns.  相似文献   

Legal implications of mobile shorelines in Great Britain     

Derek J McGlashan  Robert W Duck  Colin T Reid 《Area》2009,41(2):149-156

This paper highlights the three legally defined property areas that lie in the coastal zone in Great Britain (land, foreshore and seabed), and considers the mechanisms used by the two legal systems that operate on the mainland (Scots and English law) to cope with natural processes of erosion and accretion. The two legal systems are shown to be slightly different in how they accommodate erosion and accretion. However, they both have difficulty in coherently addressing the issues of coastal mobility and land ownership, which raises important questions of social justice, as they are based on the perceptions of judges in historic cases.  相似文献   

Quantifying Heterogeneity of Small Test Portion Masses of Geological Reference Materials by Portable XRF Spectrometry: Implications for Uncertainty of Reference Values          下载免费PDF全文

Peter D. Rostron  Michael H. Ramsey 《Geostandards and Geoanalytical Research》2017,41(3):459-473

There is an increasing use of analytical macro‐beam techniques (such as portable XRF, PXRF) for geochemical measurements, as a result of their convenience and relatively low cost per measurement. Reference materials (RMs) are essential for validation, and sometimes calibration, of beam measurements, just as they are for the traditional analytical techniques that use bulk powders. RMs are typically supplied with data sheets that tabulate uncertainties in the reference values by element, for which purpose they also specify a minimum recommended mass of material to be used in the chemical analysis. This minimum mass may not be achievable using analytical beam techniques. In this study, the mass of the test portion interrogated by a handheld PXRF within pellets made from three silicate RMs (SdAR L2, M2 and H1) was estimated using a theoretical approach. It was found to vary from 0.001 to 0.3 g for an 8 mm beam size and 0.0001 to 0.045 g for a 3 mm beam. These test portion masses are mainly well below the recommended minimum mass for these particular RMs (0.2 g), but were found to increase as a function of atomic number (as might be expected). The uncertainties caused by heterogeneity (U_HET) in PXRF measurements of the three RMs were experimentally estimated using two different beam diameters for eighteen elements. The elements showing the highest levels of heterogeneity (U_HET > 5%) seem generally to be those usually associated with either an accessory mineral (e.g., Zr in zircon, As in pyrite) or low test portion mass (associated with low atomic number). When the beam size was changed from nominally 8 to 3 mm, the uncertainty caused by heterogeneity was seen to increase for most elements by an average ratio of 2.2. These values of U_HET were used to calculate revised uncertainties of the reference values that would be appropriate for measurements made using a PXRF with these beam sizes. The methods used here to estimate U_HET in PXRF measurements have a potential application to other analytical beam techniques.  相似文献   

Shore platform lowering due to frost shattering during the 2009 winter at mesnil Val,English channel coast,NW France          下载免费PDF全文

T. J. B. Dewez  V. Regard  A. Duperret  E. Lasseur 《地球表面变化过程与地形》2015,40(12):1688-1700

In 2008–2009, a severe cold snap affected the otherwise temperate mid‐latitude coasts of the English Channel of France. In March 2009, we gathered rock spalling observations at Mesnil Val, NW France, to document the effect of frost on platform lowering in macro‐tidal environments. Six epochs of frost were recorded in 2 months, the two longest lasted 16 and 8 days, with minimum air temperature dropping to –9.5°C. Semi‐diurnal tides flood the entire platform, imposing up to 25 freeze–thaw cycles below –2.5°C, the freezing temperature of seawater. 19 cycles occurred at neap tidal elevation lasting at most 3.5 h. Our integrated observations indicate that these frost cycles were responsible for a platform lowering of about 0.8±0.5 mm during a single winter. No clear spatial trend appears, nor do macroscopic chalk types clearly stand out as being more susceptible to erosion. Assuming that the long‐term platform retreat model preserves a constant slope, frost shattering would then account for 10 to 20% of the expected annual platform erosion rate. Under more contrasted climates, frost is thus likely to be a prominent shaping process for rocky coastal platforms. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Characterization of Chlorination By-products in Cooling Effluents of Coastal Nuclear Power Stations   总被引：3，自引：0，他引：3  

Anne-Sophie Allonier  Michel Khalanski  Valrie Camel  Alain Bermond 《Marine pollution bulletin》1999,38(12):214-1241

In power stations, the cooling effluents are chlorinated to avoid excessive biofouling. Yet, this disinfecting treatment leads to the formation of halogenated by-products. In spite of possible toxicity of such compounds towards aquatic organisms, there is an evident lack of information on the formation of halogenated compounds in chlorinated seawater samples. So, this study was undertaken to identify and quantify halogenated compounds (i.e. trihalomethanes, haloacetonitriles, halophenols and haloacetic acids) in effluents from three French nuclear power stations. In addition, experiments conducted in the laboratory allowed the determination of the kinetics of formation of the main compounds detected: bromoform, dihaloacetonitrile, 2,4,6-tribromophenol and dibromoacetic acid. Good agreement was obtained between the experiments conducted either on site or in the laboratory. In particular, evidence was given on the formation of brominated compounds (due to the high concentrations of bromide ions in seawater).  相似文献   

“韧性”的词义解析及其应用          下载免费PDF全文

薄景山    段玉石    王玉婷    郭子辉  李琪  陈亚男 《世界地震工程》2023,39(1):038-48

英文“Resilience”和汉语“韧性”这两个词汇被广泛应用在不同的学科领域。在中国的生态学和工程学领域“Resilience”一词常被翻译成“恢复力、弹性、韧性和韧弹性”等,正确的理解和解析英文“Resilience”和汉语“韧性”十分必要。本文主要依据现有英文和汉语辞典、辞书以及相关的中外科技文献,对英文“Resilience”和汉语“韧性”这两个词汇的含义进行全面的词义辨析和清理,认为英文“Resilience”翻译成汉语“韧性”比较合适,符合汉语的词义和语言环境,韧性在一定程度上涵盖了恢复、弹回和弹性的含义;在此基础上,总结和厘定了韧性的起源、定义和内涵;比较全面的梳理和评述了“Resilience”和“韧性”这两个词在不同学科领域的发展和演化。这一研究工作对正确的使用英文“Resilience”和汉语“韧性”有重要意义,对从事韧性城市研究、城市规划、城市抗震韧性研究和建筑抗震韧性研究的科技人员有一定的参考价值。  相似文献