Hydrogen-isotopic variability in fatty acids from Yellowstone National Park hot spring microbial communities     

Magdalena R. Osburn  Alex L. Sessions  John R. Spear 《Geochimica et cosmochimica acta》2011,75(17):4830-4845

We report the abundances and hydrogen-isotopic compositions (D/H ratios) of fatty acids extracted from hot-spring microbial mats in Yellowstone National Park. The terrestrial hydrothermal environment provides a useful system for studying D/H fractionations because the numerous microbial communities in and around the springs are visually distinct, separable, and less complex than those in many other aquatic environments. D/H fractionations between lipids and water ranged from −374‰ to +41‰ and showed systematic variations between different types of microbial communities. Lipids produced by chemoautotrophic hyperthermophilic bacteria, such as icosenoic acid (20:1), generally exhibited the largest and most variable fractionations from water (−374‰ to −165‰). This was in contrast to lipids characteristic of heterotrophs, such as branched, odd chain-length fatty acids, which had the smallest fractionations (−163‰ to +41‰). Mats dominated by photoautotrophs exhibited intermediate fractionations similar in magnitude to those expressed by higher plants. These data support the hypothesis that variations in lipid D/H are strongly influenced by central metabolic pathways. Shifts in the isotopic compositions of individual fatty acids across known ecological boundaries show that the isotopic signature of specific metabolisms can be recognized in modern environmental samples, and potentially recorded in ancient ones. Considering all sampled springs, the total range in D/H ratios is similar to that observed in marine sediments, suggesting that the trends observed here are not exclusive to the hydrothermal environment.  相似文献   

Geoenergy: new concepts for utilization of geo-reservoirs as potential energy sources     

Magdalena Scheck-Wenderoth  Dieter Schmeißer  Maria Mutti  Olaf Kolditz  Ernst Huenges  Hans-Martin Schultz  Axel Liebscher  Michaela Bock 《Environmental Earth Sciences》2013,70(8):3427-3431

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On the choice of calibration periods and objective functions: A practical guide to model parameter identification   总被引：2，自引：0，他引：2  

Renata J. Romanowicz  Marzena Osuch  Magdalena Grabowiecka 《Acta Geophysica》2013,61(6):1477-1503

Despite the development of new measuring techniques, monitoring systems and advances in computer technology, rainfall-flow modelling is still a challenge. The reasons are multiple and fairly well known. They include the distributed, heterogeneous nature of the environmental variables affecting flow from the catchment. These are precipitation, evapotranspiration and in some seasons and catchments in Poland, snow melt also. This paper presents a review of work done on the calibration and validation of rainfall-runoff modelling, with a focus on the conceptual HBV model. We give a synthesis of the problems and propose a practical guide to the calibration and validation of rainfall-runoff models.  相似文献   

Paleomagnetism and magnetic mineralogy of metabasites and granulites from Orlica-Śnieżnik Dome (Central Sudetes)     

Magdalena Kądziałko-Hofmokl  Jacek Szczepański  Tomasz Werner  Maria Jeleńska  Krzysztof Nejbert 《Acta Geophysica》2013,61(3):535-568

The results of palaeomagnetic, rock magnetic, and microscopic study of Early Paleozoic metabasites and granulites from the Orlica?nie?nik Dome (OSD, Sudetes) have been combined with geochronological data. In the eastern part of the OSD (?nie?nik Massif, SM) ferrimagnetic pyrrhotite is prevalent, accompanied by various amounts of Fe-oxides. In the western part of the OSD (Orlica-Bystrzyca Massif, OBM) Fe-oxides dominate. All magnetic minerals originated during hydrothermal and weathering processes. The palaeomagnetic study revealed the presence of three secondary components of natural remanence: Late Carboniferous, Late Permian, and Mesozoic. Two Paleozoic components are related to volcanic activity in the Sudetes. They are carried by pyrrhotite and Fe-oxides and were isolated only in SM rocks. The Mesozoic component was determined in both parts of the OSD and is carried by Fe-oxides. It covers a time span, from ～160 to ～40 Ma, corresponding to a long period of alteration.  相似文献   

Post‐depositional bone destruction in cave sediments: a micromorphological study of the MIS 5a–d cave bear strata of Biśnik Cave,Poland     

Magdalena Krajcarz  Maciej T. Krajcarz 《第四纪科学杂志》2019,34(2):138-152

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Fluctuations of the Fennoscandian Ice Sheet recorded in the anisotropy of magnetic susceptibility of periglacial loess from Ukraine     

Jerzy Nawrocki  Andrij B. Bogucki  Petro Gozhik  Maria &#x;anczont  Magdalena Pa&#x;czyk  Karol Standzikowski  Maryna Komar  Olga Rosowiecka  Olena Tomeniuk 《Boreas: An International Journal of Quaternary Research》2019,48(4):940-952

The azimuth of imbrication of minimum magnetic susceptibility axes in the youngest loess from Ukraine defines prevailing wind directions during aeolian sedimentation. It changes along the studied sections. These changes can be directly correlated with the fluctuations of the Fennoscandian Ice Sheet. The northern and northeastern winds noted in the loess succession separated by a period when southwestern to southeastern winds were predominant may be correlated with two main phases of ice‐sheet advance during the Last Glacial Maximum. The ice‐sheet advances towards the areas of loess deposition generated katabatic winds that influenced aeolian sedimentation in the periglacial zone. A period of relatively stable wind directions during a younger phase of the Last Glacial Maximum was interrupted by periods with more chaotic wind regime most probably caused by fluctuations of the Fennoscandian Ice Sheet during its retreat from the peri‐Baltic part of Europe. These intervals occur where initial soils developed. The distribution of anisotropy of magnetic susceptibility axes defined along the periglacial loess sections from central and eastern Europe can serve to constrain fluctuations of the Fennoscandian Ice Sheet.  相似文献   

Water vapour mixing ratio profiles over Hornsund, Arctic. Intercomparison of lidar and AIRS results     

Magdalena Bloch  Grzegorz Karasiński 《Acta Geophysica》2014,62(2):290-301

Since October 2009, a ground-based Raman lidar system has been deployed to perform a regular, night-time, vertical sounding of a water vapour content in the lower and middle troposphere above Polish Polar Station at Hornsund (77.00°N, 15.55°E, 10 m a.s.l.) in the Arctic. The water vapour mixing ratio profiles were obtained for the atmosphere up to 6 km altitude, based on analysis of inelastic Raman backscattering signals from nitrogen molecules (at 387 nm) and water vapour particles (at 407 nm), calibrated with the data from a local Vaisala’s automatic meteorological station. The results obtained for winter seasons in the years 2009–2012 are in a good general agreement with the results obtained from the atmospheric infrared sounder (AIRS) on the Aqua satellite.  相似文献   

Monazite RW-1: a homogenous natural reference material for SIMS U–Pb and Th–Pb isotopic analysis     

Ling  Xiao-Xiao  Huyskens  Magdalena H.  Li  Qiu-Li  Yin  Qin-Zhu  Werner  Ronald  Liu  Yu  Tang  Guo-Qiang  Yang  Ya-Nan  Li  Xian-Hua 《Mineralogy and Petrology》2017,111(2):163-172

Mineralogy and Petrology - Well-characterized matrix-matched natural mineral references of known age are an important prerequisite for SIMS (secondary ion mass spectrometry) U–Th–Pb...  相似文献   

An ensemble estimation of the variability of upper-ocean heat content over the tropical Atlantic Ocean with multi-ocean reanalysis products   总被引：2，自引：2，他引：0  

Jieshun Zhu  Bohua Huang  Magdalena A. Balmaseda 《Climate Dynamics》2012,39(3-4):1001-1020

Current ocean reanalysis systems contain considerable uncertainty in estimating the subsurface oceanic state, especially in the tropical Atlantic Ocean. Given this level of uncertainty, it is important to develop useful strategies to identify realistic low-frequency signals optimally from these analyses. In this paper, we present an “ensemble” method to estimate the variability of upper-ocean heat content (HC) in the tropical Atlantic based on multiple-ocean reanalysis products. Six state-of-the-art global ocean reanalaysis products, all of which are widely used in the climate research community, are examined in terms of their HC variability from 1979 to 2007. The conventional empirical orthogonal function (EOF) analysis of the HC anomalies from each individual analysis indicates that their leading modes show significant qualitative differences among analyses, especially for the first modes, although some common characteristics are discernable. Then, the simple arithmetic average (or ensemble mean) is applied to produce an ensemble dataset, i.e., the EM analysis. The leading EOF modes of the EM analysis show quantitatively consistent spatial–temporal patterns with those derived from an alternative EOF technique that maximizes signal-to-noise ratio of the six analyses, which suggests that the ensemble mean generates HC fields with the noise reduced to an acceptable level. The quality of the EM analysis is further validated against AVISO altimetry sea level anomaly (SLA) data and PIRATA mooring station data. A regression analysis with the AVISO SLA data proved that the leading modes in the EM analysis are realistic. It also demonstrated that some reanalysis products might contain higher level of intrinsic noise than others. A quantitative correlation analysis indicates that the HC fields are more realistic in the EM analysis than in individual products, especially over the equatorial regions, with signals contributed from all ensemble members. A direct comparison with the HC anomalies derived from in situ temperature measurements showed that the EM analysis generally gets realistic HC variability at the five chosen PIRATA mooring stations. Overall, these results demonstrate that the EM analysis is a promising alternative for studying physical processes and possibly for initializing climate predictions.  相似文献   

Modeling of the 3D thermal field in the northeast German basin     

U. Bayer  M. Scheck  M. Koehler 《International Journal of Earth Sciences》1997,86(2):241-251

The regional thermal field of the NE-German basin is modeled by a three-dimensional finite-element approach and is compared to classical one-dimensional extrapolations. Two alternative boundary conditions are assumed at the approximate depth of the Moho: a constant temperature distribution and a constant heat flow. Surprisingly, both results are almost identical down to approximately 10?km depth. Based on the models presented, the results are due to a complex interaction of different strata and the related regional variability of conductivities. In addition, the available temperature maps for different depths (Hurtig et al. 1992) indicate a relative high heat flow at the basin margins especially at the southern and eastern boundary. The models are able to reproduce the generalized pattern by regarding only a conductive heat flow. However, because both models are successful at shallow depth, we conclude that the current techniques of thermal modeling require improvement, even on the theoretical aspects of depth continuation and inversion.  相似文献