Relationship between waterfowl and American coot abundance with submersed macrophytic vegetation in Currituck Sound,North Carolina     

Anton M. Wicker  Keith M. Endres 《Estuaries and Coasts》1995,18(2):428-431

Waterfowl and American coot data collected from aerial censusing on Currituck Sound were compared during three periods: before Eurasian watermilfoil (Myriophyllum spicatum) colonization (1961–1965); during Eurasian watermilfoil infestation (1968–1977); and following the near absence of submersed macrophytic vegetation after Eurasian watermilfoil decline (1981–1990). Numbers of dabbling ducks (Anas rubripes, Anas platyrhynchos, Anas acuta, Anas americana, Anas crecca), ring-necked ducks (Aythya collaris), and American coot (Fulica americana) were significantly different in Currituck Sound (p<0.05) in at least two of these periods and were highest during Eurasian watermilfoil infestation. These species also constituted higher percentages of the Atlantic Flyway counts during Eurasian watermilfoil infestation. than in periods before or after. Numbers of snow geese (Chen caerulescens), Canada geese (Branta canadensis), and canvasbacks (Aythya valisneria) were significantly different between periods; however, these birds exhibited a consistent decline from the early to the late period. This study suggests that submersed macrophytes, specifically Eurasian watermilfoil, support increased numbers of dabbling ducks, ring-necked ducks, and American coot.  相似文献   

Preface     

Anton L. Hales  Guest editor  Ziro Suzuki  Guest editor 《Tectonophysics》1982,85(1-2)

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Lithospheric thickness beneath the southern Kenya Rift: implications from basalt geochemistry     

Anton P. Roex  Andreas Späth  Robert E. Zartman 《Contributions to Mineralogy and Petrology》2001,142(1):89-106

Geochemical data are reported for samples from the flanks and floor of the southern Kenya Rift Valley in the Lake Magadi area, and from two central volcanoes located within the rift valley. Rift lavas include samples of Singaraini and Ol Tepesi basalts on the eastern flank, Kirikiti basalts from the western flank, and plateau trachytes from the rift valley floor. Central volcano samples are from Ol Esayeiti and Lenderut located on the eastern flank. The rift basalts are mildly ne-normative, moderately evolved (Mg#=0.39-0.62) alkali basalts and show an overall range in differentiation. Incompatible trace element abundances are moderately elevated (Nb=17-51; Zr=93-274; La=17-55 ppm) and show strongly coherent variations and constant inter-element ratios (e.g. Zr/Nb=4.2-5.5; Nb/Ta=17.5ǂ.4; (La/Sm)_n=7.3ǃ.1); isotope ratios are restricted in range (⁸⁷Sr/⁸⁶Sr=0.70393-0.70436; ¹⁴³Nd/¹⁴⁴Nd=0.51272-0.51280; ²⁰⁶Pb/²⁰⁴Pb=19.87-19.92; ²⁰⁷Pb/²⁰⁴Pb=15.68-15.70; ²⁰⁸Pb/²⁰⁴Pb=39.56-39.71). Central volcano lavas are more alkaline in character and include basanite (Ol Esayeiti; Mg# >60) and hawaiite to benmoreite (Lenderut; Mg#=0.48-0.38). Incompatible element ratio are similar to those of the rift basalts, although the chondrite normalised REE patterns are steeper (La/Sm)_n=17.4ǃ.2). ⁸⁷Sr/⁸⁶Sr (0.70358, 0.70391), ¹⁴³Nd/¹⁴⁴Nd (0.51280, 0.51267), ²⁰⁶Pb/²⁰⁴Pb (19.96,20.17), ²⁰⁷Pb/²⁰⁴Pb (15.66,15.76) and ²⁰⁸Pb/²⁰⁴Pb (39.80,40.00) ratios of Ol Esayeiti basanites are similar to the rift basalts, whereas the Lenderut lavas have unusually low¹⁴³Nd/¹⁴⁴Nd (0.512388-0.512453) ratios for their ⁸⁷Sr/⁸⁶Sr (0.70370-0.70481) ratios, and distinctly less radiogenic and variable Pb isotope compositions (²⁰⁶Pb/²⁰⁴Pb=17.93-19.01; ²⁰⁷Pb/²⁰⁴Pb=15.43-15.58; ²⁰⁸Pb/²⁰⁴Pb=37.91-39.14). An integrated model is developed in which the geochemical signature of the lavas is attributed to variable degrees of melting to depths within the garnet stability field, and in the presence of residual amphibole. The stability fields of these phases in P-T space indicates that the lavas must have formed within the sub-continental lithosphere rather than within the underlying ambient asthenosphere or a rising mantle plume. The subcontinental lithospheric mantle must therefore extend to a depth of at least 75 km beneath the Lake Magadi area, which contrasts with recent gravity models for the area, which infer that lithospheric mantle is absent beneath this section of the southern Kenya Rift.  相似文献   

Assimilationszahlen submerser Phanerogamen und ihre Beziehung zur Kohlensäureversorgung     

Anton Hammann 《Aquatic Sciences - Research Across Boundaries》1957,19(2):579-612

Ohne Zusammenfassung  相似文献   

Magnetospheric regions of amplification of VLF emissions and micropulsations     

Antonín Hruśka 《Studia Geophysica et Geodaetica》1967,11(2):235-240

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Detecting patterns of climate change in long-term forecasts of marine environmental parameters     

Gianpaolo Coro  Pasquale Pagano  Anton Ellenbroek 《International Journal of Digital Earth》2020,13(5):567-585

ABSTRACT

Forecasting environmental parameters in the distant future requires complex modelling and large computational resources. Due to the sensitivity and complexity of forecast models, long-term parameter forecasts (e.g. up to 2100) are uncommon and only produced by a few organisations, in heterogeneous formats and based on different assumptions of greenhouse gases emissions. However, data mining techniques can be used to coerce the data to a uniform time and spatial representation, which facilitates their use in many applications. In this paper, streams of big data coming from AquaMaps and NASA collections of 126 long-term forecasts of nine types of environmental parameters are processed through a cloud computing platform in order to (i) standardise and harmonise the data representations, (ii) produce intermediate scenarios and new informative parameters, and (iii) align all sets on a common time and spatial resolution. Time series cross-correlation applied to these aligned datasets reveals patterns of climate change and similarities between parameter trends in 10 marine areas. Our results highlight that (i) the Mediterranean Sea may have a standalone ‘response’ to climate change with respect to other areas, (ii) the Poles are most representative of global forecasted change, and (iii) the trends are generally alarming for most oceans.  相似文献   

Principles and measurements in environmental biology: F. I. Woodward and J. E. Sheehy. Butterworth Group,Kent, 1983, 263 pp. Price £30.00 Hardcover. ISBN 0-408-106379     

A.J. McLachlan 《Marine pollution bulletin》1983,14(11):432-433

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A unified approach to array-factor synthesis for line arrays with nonuniformly positioned elements     

Anton  J. Rockmore  A. 《Oceanic Engineering, IEEE Journal of》1976,1(1):14-21

An approach for the design of line arrays which synthesizes array factors having desired attributes is developed. This approach draws upon, clarifies, and expands earlier developments in nonuniformly positioned line-array design. A new array with important characteristics, called the square-root design, is derived. The approach is also applied to formulation and evaluation of design tradeoff studies. Specific examples are given for exponential and square-root arrays.  相似文献   

DEVEX-disdrometer evaluation experiment: Basic results and implications for hydrologic studies   总被引：1，自引：0，他引：1  

Witold F. Krajewski  Anton Kruger  Clelia Caracciolo  Peter Golé  Laurent Barthes  Jean-Dominique Creutin  Jean-Yves Delahaye  Efthymios I. Nikolopoulos  Fred Ogden  Jean-Paul Vinson 《Advances in water resources》2006

Increasing our understanding of the small scale variability of drop size distributions (DSD), and therefore of several bulk characteristics of rainfall processes, has major implications for our interpretation of the remote sensing based estimates of precipitation and its uncertainty. During the spring and summer of 2002 the authors conducted the DEVEX experiment (disdrometer evaluation experiment) to compare measurements of natural rain made with three different types of disdrometers collocated at the Iowa City Municipal Airport in Iowa City, Iowa in the Midwestern United States. This paper focuses on the evaluation of the instruments rather than analysis of the hydrometeorological aspects of the observed events. The comparison demonstrates discrepancies between instruments. The authors discuss the systematic and random effects in terms of rainfall quantities, drop size distribution properties, and the observed drop size vs. velocity relationships. Since the instruments were collocated, the effects of the natural variability of rain are reduced some with time integration, isolating the instrumental differences. The authors discuss the status of DSD measurement technologies and the implications for a range of hydrologic applications from remote sensing of rainfall to atmospheric deposition to soil erosion and sediment transport in the environment. The data set collected during the DEVEX experiment is made available to the research community.  相似文献   

铝钒土中有效铝和活性硅的测定          下载免费PDF全文

奥地利安东帕公司 《岩矿测试》2007,26(2):170-170

《岩矿测试》杂志由中国地质学会岩矿测试专业委员会和国家地质实验测试中心共同主办,各省地勘局中心实验室协办,中国科学技术协会主管,反映分析测试技术的专业性科技期刊(ISSN 0254-5357,CODEN码YACEEK,国内统一刊号CN 11-2131/TD)。  相似文献