Bacterial dominance of phototrophic communities in a High Arctic lake and its implications for paleoclimate analysis   总被引：1，自引：1，他引：0  

Dermot Antoniades  Julie Veillette  Marie-Josée Martineau  Claude Belzile  Jessica Tomkins  Reinhard Pienitz  Scott Lamoureux  Warwick F. Vincent 《Polar Science》2009,3(3):147-161

The phototrophic communities in meromictic, perennially ice-covered Lake A, on Ellesmere Island in the Canadian High Arctic, were characterized by pigment analysis using high performance liquid chromatography. Samples were taken to determine the vertical changes down the water column as well as a variation between years. These analyses showed that Lake A had distinct phototrophic communities in its oxic and anoxic layers. The pigment analyses indicated that phototrophic biomass in the upper, oxic waters was dominated by picocyanobacteria, while in the lower, anoxic layer photosynthetic green sulphur bacteria were dominant. Interannual variation in pigment concentrations was related to the penetration of photosynthetically active radiation in the water column, suggesting that light availability may be limiting the net accumulation of photosynthetic bacterial biomass in Lake A. Pigment analysis of the surface sediments indicated that deposition was dominated by the photosynthetic sulphur bacterial contribution. The sedimentary record of bacterial pigments in polar meromictic lakes offers a promising tool for the reconstruction of past changes in ice cover and therefore in climate.  相似文献   

Different Asian Monsoon Rainfall Responses to Idealized Orography Sensitivity Experiments in the HadGEM3-GA6 and FGOALS-FAMIL Global Climate Models     

Kai Chi WONG  Senfeng LIU  Andrew G.TURNER  Reinhard K.SCHIEMANN 《大气科学进展》2018,35(8):1049-1062

Recent work has shown the dominance of the Himalaya in supporting the Indian summer monsoon(ISM),perhaps by surface sensible heating along its southern slope and by mechanical blocking acting to separate moist tropical flow from drier midlatitude air.Previous studies have also shown that Indian summer rainfall is largely unaffected in sensitivity experiments that remove only the Tibetan Plateau.However,given the large biases in simulating the monsoon in CMIP5 models,such results may be model dependent.This study investigates the impact of orographic forcing from the Tibetan Plateau,Himalaya and Iranian Plateau on the ISM and East Asian summer monsoon(EASM) in the UK Met Office's Had GEM3-GA6 and China's Institute of Atmospheric Physics FGOALS-FAMIL global climate models.The models chosen feature oppositesigned biases in their simulation of the ISM rainfall and circulation climatology.The changes to ISM and EASM circulation across the sensitivity experiments are similar in both models and consistent with previous studies.However,considerable differences exist in the rainfall responses over India and China,and in the detailed aspects such as onset and retreat dates.In particular,the models show opposing changes in Indian monsoon rainfall when the Himalaya and Tibetan Plateau orography are removed.Our results show that a multi-model approach,as suggested in the forthcoming Global Monsoon Model Intercomparison Project(GMMIP) associated with CMIP6,is needed to clarify the impact of orographic forcing on the Asian monsoon and to fully understand the implications of model systematic error.  相似文献   

Regional geoid determination in Antarctica utilizing airborne gravity and topography data   总被引：2，自引：2，他引：0  

Mirko Scheinert  Jan Müller  Reinhard Dietrich  Detlef Damaske  Volkmar Damm 《Journal of Geodesy》2008,82(7):403-414

Antarctica is the only continent that suffers major gaps in terrestrial gravity data coverage. To overcome this problem and to close these gaps as well as to densify the global satellite gravity field solutions, the International Association of Geodesy (IAG) Commission Project 2.4 “Antarctic Geoid” was set into action. This paper reviews the current situation concerning the gravity field in Antarctica. It is shown that airborne geophysical surveys are the most promising tools to gain new gravity data in Antarctica. In this context, a number of projects to be carried out during the International Polar Year 2007/2008 will contribute to this goal. To demonstrate the feasibility of the regional geoid improvement in Antarctica, we present a case study using gravity and topography data of the southern Prince Charles Mountains, East Antarctica. During the processing, the remove–compute– restore (RCR) technique and least-squares collocation (LSC) were applied. Adding signal parts of up to 6 m to the global gravity field model that was used as a basis, the calculated regional quasigeoid reveals the dominant features of bedrock topography in that region, namely the graben structure of the Lambert glacier system. The accuracy of the improved regional quasigeoid is estimated to be at the level of 15 cm.  相似文献   

Co-ordinated traffic in a transponder based co-operative system. presentation of the NADAKOS- project     

Reinhard Müller  Thoralf Weißflog  Anke ZÖlder 《Ocean Dynamics》1997,49(4):499-510

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Secondary Ion Mass Spectrometry Bias on Isotope Ratios in Dolomite–Ankerite,Part II: δ13C Matrix Effects          下载免费PDF全文

Maciej G. Śliwiński  Kouki Kitajima  Reinhard Kozdon  Michael J. Spicuzza  John H. Fournelle  Adam Denny  John W. Valley 《Geostandards and Geoanalytical Research》2016,40(2):173-184

This study is Part II of a series that documents the development of a suite of calibration reference materials for in situ SIMS analysis of stable isotope ratios in Ca‐Mg‐Fe carbonates. Part I explored the effects of Fe²⁺ substitution on SIMS δ¹⁸O bias measured from the dolomite–ankerite solid solution series [CaMg(CO₃)₂–CaFe(CO₃)₂], whereas this complementary work explores the compositional dependence of SIMS δ¹³C bias (calibrated range: Fe# = 0.004–0.789, where Fe# = molar Fe/(Mg+Fe)). Under routine operating conditions for carbonate δ¹³C analysis at WiscSIMS (CAMECA IMS 1280), the magnitude of instrumental bias increased exponentially by 2.5–5.5‰ (session‐specific) with increasing Fe‐content in the dolomite structure, but appeared insensitive to minor Mn substitution [< 2.6 mole % Mn/(Ca+Mg+Fe+Mn)]. The compositional dependence of bias (i.e., the matrix effect) was expressed using the Hill equation, yielding calibration residual values ≤ 0.3‰ relative to CRM NBS‐19 for eleven carbonate reference materials (6‐μm‐diameter spot size measurements). Based on the spot‐to‐spot repeatability of a drift monitor material that ‘bracketed’ each set of ten sample‐spot analyses, the analytical precision was ± 0.6–1.2‰ (2s, standard deviations). The analytical uncertainty for individual sample analyses was approximated by combining the precision and calibration residual values (propagated in quadrature), suggesting an uncertainty of ± 1.0–1.5‰ (2s).  相似文献   

Modular development of an inline monitoring system for waterborne pathogens in raw and drinking water     

Daniel Karthe  Ole Behrmann  Verena Blättel  Dennis Elsässer  Christian Heese  Matthias Hügle  Frank Hufert  Andreas Kunze  Reinhard Niessner  Johannes Ho  Buren Scharaw  Matthias Spoo  Andreas Tiehm  Gerald Urban  Silvia Vosseler  Thomas Westerhoff  Gregory Dame  Michael Seidel 《Environmental Earth Sciences》2016,75(23):1481

The state-of-the-art monitoring of drinking water hygiene is based on the cultivation and enumeration of indicator bacteria. Despite its proven reliability, this approach has the disadvantages of being (a) relatively slow and (b) limited to a small number of indicator bacteria. Ideally, alternative methods would be less time-consuming while providing information about a larger set of hygienically relevant microorganisms including viruses. In this paper, we present insights into the design of a modular concentration and detection system for bacteria, bacteriophages and viruses. Following further validation, this or similar techniques have the potential to extend and speed up the monitoring of raw and drinking water hygiene in the future. The system consists of different modules for the concentration of microorganisms, an amplification and detection unit that includes a module for the differentiation between live and dead microorganisms, and an automated system for decision support and self-diagnosis. The ongoing testing under controlled laboratory conditions and real-life conditions in the water supply industry yields further system improvements. Moreover, the increased sensitivity and broader range of microbiological parameters emphasize the need for a reconsideration of the currently used criteria for the assessment of (drinking) water hygiene.  相似文献   

The resolution sensitivity of the South Asian monsoon and Indo-Pacific in a global 0.35° AGCM     

Stephanie J. Johnson  Richard C. Levine  Andrew G. Turner  Gill M. Martin  Steven J. Woolnough  Reinhard Schiemann  Matthew S. Mizielinski  Malcolm J. Roberts  Pier Luigi Vidale  Marie-Estelle Demory  Jane Strachan 《Climate Dynamics》2016,46(3-4):807-831

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Höhenwindverhältnisse im Gebiete des Ärmelkanals     

H. Reinhard 《Theoretical and Applied Climatology》1951,3(1):110-122

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The role of sediments in the phosphorus cycle in Lake Lugano. II. Seasonal and spatial variability of microbiological processes at the sediment-water interface   总被引：1，自引：1，他引：0  

Maja A. Lazzaretti  Kurt W. Hanselmann  Helmut Brandl  Daniel Span  Reinhard Bachofen 《Aquatic Sciences - Research Across Boundaries》1992,54(3-4):285-299

P, Fe, Mn, and S species were analyzed in water samples from the sediment-water interface collected at four seasonally different times during the course of a year at two sampling sites in the southern basin of Lake Lugano (Lago di Lugano). The results reveal the strong influence of the biogeochemical processes in the sediment on the chemical composition of the lake water above. Consumption of oxygen and nitrate under oxic to microoxic conditions in the water column as well as sequential release of reduced manganese and iron under anoxic conditions was observed as a direct or indirect consequence of microbially mediated degradation of organic matter. The seasonal pattern observed for the release and the retainment of dissolved reduced iron and manganese correlates well with the one for dissolved phosphate. Iron, manganese and phosphorus cycling are coupled tightly in these sediments. Both sediment types act as sinks for hydrogen sulfide and sulfate. An inner-sedimentary sulfur cycle is proposed to couple iron, manganese and phosphorus cycling with the degradation of organic matter. Nutrient cycling at the sediment-water interface might thus be driven by a microbially regulated electron pumping mechanism. The results contribute to a better understanding of the role of sediment processes in the lake's internal phosphorus cycle and its seasonal dynamics.  相似文献   

Stellarv sini and optical emission line widths in Be stars     

Reinhard W. Hanuschik 《Astrophysics and Space Science》1989,161(1):61-73

I re-investigate empirical correlations between line widths of photospheric absorption lines — as a measure of the stellar projected rotational velocityv sini- and of circumstellar emission lines in Be stars. The degree of this correlation is a measure for the kinematic, i.e., rotational, contribution to the total emission line broadening.From the literature and from additional data, I have collected a sample of photoelectric measurements of Balmer and Feii emission lines of the 115 brightest Be stars in the sky, most of them observed several times during the past decade. I investigate the following emission line widths parameters: full width at half maximum, total width at the base, and double-peak separation. I find from the FWHM that the basic origin of emission line broadening in Be stars is undoubtedly rotational, the correlations withv sini being best for weaker emission lines while H shows considerable scatter. Total width at the base is uncorrelated withv sini except for the Feii lines. Peak separation is found to be a function both ofv sini and of equivalent width. The latter dependence can straightforwardly be understood by the fact that within Huang's disk model peak separation, normalized tov sini, is governed by the outer envelope radius.I conclude that observational evidence leaves no doubt that Be star envelopes as visible in optical emission lines are rotationally supported and have axisymmetric geometry.Partly based on observations obtained at the European Southern Observatory, La Silla, Chile.  相似文献