Comparing Eulerian and Lagrangian eddy census for a tide-less,semi-enclosed basin,the Baltic Sea     

Vortmeyer-Kley  Rahel  Holtermann  Peter  Feudel  Ulrike  Gräwe  Ulf 《Ocean Dynamics》2019,69(6):701-717

Ocean Dynamics - Eddies in the global and coastal ocean play a key role in mixing and transport processes. Here, we present an eddy census for the Baltic Sea covering the years 2008–2010. The...  相似文献   

Geostandards and Geoanalytical Research Bibliographic Review 2018     

Ulrike Weis  Jodok Arns  Viktoria Kaiser  Anna Reichstein  Lea Reichstein  Brigitte Stoll  Klaus Peter Jochum 《Geostandards and Geoanalytical Research》2020,44(1):51-56

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Investigation of the geochemical impact of CO2 on shallow groundwater: design and implementation of a CO2 injection test in Northeast Germany     

Anita Peter  Hendrik Lamert  Matthias Beyer  G?tz Hornbruch  Ben Heinrich  Alexandra Schulz  Helmut Geistlinger  Ben Schreiber  Peter Dietrich  Ulrike Werban  Carsten Vogt  Hans-Hermann Richnow  Jochen Gro?mann  Andreas Dahmke 《Environmental Earth Sciences》2012,67(2):335-349

A small scale and temporally limited CO₂ injection test was performed in a shallow aquifer to investigate the geochemical impact of CO₂ upon such aquifers and to apply and verify different monitoring methods. Detailed site investigation coupled with multiphase simulations were necessary to design the injection experiment and to set up the monitoring network, before CO₂ was injected over a ten-day period at three injection wells, at a depth of 18?m below surface level into a quaternary sand aquifer located close to the town of Wittstock in Northeast Germany. Monitoring methods comprised groundwater sampling and standard analyses, as well as trace element analyses and isotope analyses; geoelectrical borehole monitoring; passive samplers to analyse temporally integrated for cations and multi-parameter probes that can measure continuously for dissolved CO₂, pH and electrical conductivity. Due to CO₂ injection, total inorganic carbon concentrations increased and pH decreased down to a level of 5.1. Associated reactions comprised the release of major cations and trace elements. Geoelectrical monitoring, as well as isotope analyses and multi-parameter probes proved to be suitable methods for monitoring injected CO₂ and/or the alteration of groundwater.  相似文献   

GGR Biennial Critical Review: Analytical Developments Since 2010     

Michael Wiedenbeck  Roxana Bugoi  M. John M. Duke  Tibor Dunai  Jacinta Enzweiler  Mary Horan  Klaus Peter Jochum  Kathryn Linge  Jan Košler  Silke Merchel  Luiz F.G. Morales  Lutz Nasdala  Roland Stalder  Paul Sylvester  Ulrike Weis  Arnaud Zoubir 《Geostandards and Geoanalytical Research》2012,36(4):337-398

Advances in the chemical and isotopic characterisation of geological and environmental materials can often be ascribed to technological improvements in analytical hardware. Equally, the creation of novel methods of data acquisition and interpretation, including access to better reference materials, can also be crucial components enabling important breakthroughs. This biennial review highlights key advances in either instrumentation or data acquisition and treatment, which have appeared since January 2010. This review is based on the assessments by scientists prominent in each of the given analytical fields; it is not intended as an exhaustive summary, but rather provides insight from experts of the most significant advances and trends in their given field of expertise. In contrast to earlier reviews, this presentation has been formulated into a unified work, providing a single source covering a broad spectrum of geoanalytical techniques. Additionally, some themes that were not previously emphasised, in particular thermal ionisation mass spectrometry, accelerator‐based methods and vibrational spectroscopy, are also presented in detail.  相似文献   

Late Holocene thermokarst variability inferred from diatoms in a lake sediment record from the Lena Delta, Siberian Arctic     

B. K. Biskaborn  U. Herzschuh  D. Bolshiyanov  L. Savelieva  R. Zibulski  B. Diekmann 《Journal of Paleolimnology》2013,49(2):155-170

Thermokarst lakes in the Siberian Arctic contain sediment archives that can be used for paleoenvironmental inference. Until now, however, there has been no study from the inner Lena River Delta with a focus on diatoms. The objective of this study was to investigate how the diatom community in a thermokarst lake responded to past limnogeological changes and what specific factors drove variations in the diatom assemblage. We analysed fossil diatom species, organic content, grain-size distribution and elemental composition in a sediment core retrieved in 2009 from a shallow thermokarst lake in the Arga Complex, western Lena River Delta. The core contains a 3,000-year record of sediment accumulation. Shifts in the predominantly benthic and epiphytic diatom species composition parallel changes in sediment characteristics. Paleoenvironmental and limnogeological development, inferred from multiple biological and sedimentological variables, are discussed in the context of four diatom zones, and indicate a strong relation between changes in the diatom assemblage and thermokarst processes. We conclude that limnogeological and thermokarst processes such as lake drainage, rather than direct climate forcing, were the main factors that altered the aquatic ecosystem by influencing, for example, habitat availability, hydrochemistry, and water level.  相似文献   

Recently induced anoxia leading to the preservation of seasonal laminae in two NE-German lakes     

Ulrike Kienel  Peter Dulski  Florian Ott  Sebastian Lorenz  Achim Brauer 《Journal of Paleolimnology》2013,50(4):535-544

The recent sediments of two lakes in the NE German lowland became seasonally laminated at different times. Anoxic bottom conditions resulted from a surplus of organic matter (OM), in the early stage indicated by irregularly laminated sediments comprising abundant iron-sulfide framboids. Their diagenetic formation predates the preservation of biochemical calcite varves. In the larger, deeper Lake Tiefer See near Klocksin, anoxia developed stepwise. A first anoxic pulse was contemporary with inflow narrowing by railway-dam construction and accumulation of OM. It was favored by a decrease of the intensity of lake circulation (turnover). Nutrients introduced from artificial fertilizer then increased the primary production (diatoms) to the point of OM surplus and seasonal laminae formation started 40 years later in 1924. In the smaller, shallower Lake Tiefer See in the Uckermark, a massive pulse of iron sulfide was centered around 1960, seven years after installation of piped field drainage into the lake. Anoxia developed rapidly with the nutrients drained from a fertilized groundwater catchment that is 10 times larger than the surface catchment, while surface erosion was reduced. Reducing bottom conditions became regular and the seasonal lamination was preserved after 1967. Morphological criteria to screen lakes for varved sediments should include reductions of natural lake inflow and catchment increase, such as by inflow of field drainage. Similar developments of increased nutrient input or intensity decrease of lake circulation may result from historical human activities but also from natural processes.  相似文献   

Geostandards and Geoanalytical Research Bibliographic Review 2010     

Klaus Peter Jochum  Xiaohong Wang  Uwe Nohl  Steffen Schmidt  Beate Schwager  Brigitte Stoll  Qichao Yang  Ulrike Weis 《Geostandards and Geoanalytical Research》2011,35(4):485-488

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Chironomid-based inference models for estimating mean July air temperature and water depth from lakes in Yakutia,northeastern Russia     

Larisa Nazarova  Ulrike Herzschuh  Sebastian Wetterich  Thomas Kumke  Ludmila Pestryakova 《Journal of Paleolimnology》2011,45(1):57-71

We investigated the subfossil chironomid fauna of 150 lakes situated in Yakutia, northeastern Russia. The objective of this study was to assess the relationship between chironomid assemblage composition and the environment and to develop chironomid inference models for quantifying past regional climate and environmental changes in this poorly investigated area of northern Russia. The environmental data and sediment samples for chironomid analysis were collected in 5 consecutive years, 2003–2007, from several regions of Yakutia. The lakes spanned wide latitudinal and longitudinal ranges and were distributed through several environmental zones (arctic tundra, typical tundra, steppe-tundra, boreal coniferous forest), but all were situated within the zone of continuous permafrost. Mean July temperature (T_July) varied from 3.4°C in the Laptev Sea region to 18.8°C in central Yakutia near Yakutsk. Water depth (WD) varied from 0.1 to 17.1 m. T_July and WD were identified as the strongest predictor variables explaining the chironomid communitiy composition and distribution of the taxa in our data set. Quantitative transfer functions were developed using two unimodal regression calibration techniques: simple weighted averaging (WA) and weighted averaging partial least squares (WA-PLS). The two-component T_July WA-PLS model had the best performance. It produced a strong coefficient of determination (r ² _boot = 0.87), root mean square error of prediction (RMSEP = 1.93), and max bias (max bias_boot = 2.17). For WD, the one-component WA-PLS model had the best performance (r ² _boot = 0.62, RMSEP = 0.35, max bias_boot = 0.47).  相似文献   

Geostandards and Geoanalytical Research Bibliographic Review 2013     

Klaus Peter Jochum  Uwe Nohl  Beate Schwager  Brigitte Stoll  Philip Suesser  Ulrike Weis 《Geostandards and Geoanalytical Research》2014,38(4):513-515

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Non‐Matrix‐Matched Calibration for the Multi‐Element Analysis of Geological and Environmental Samples Using 200 nm Femtosecond LA‐ICP‐MS: A Comparison with Nanosecond Lasers     

Klaus Peter Jochum  Brigitte Stoll  Ulrike Weis  Dorrit E. Jacob  Regina Mertz‐Kraus  Meinrat O. Andreae 《Geostandards and Geoanalytical Research》2014,38(3):265-292

LA‐ICP‐MS is one of the most promising techniques for in situ analysis of geological and environmental samples. However, there are some limitations with respect to measurement accuracy, in particular for volatile and siderophile/chalcophile elements, when using non‐matrix‐matched calibration. We therefore investigated matrix‐related effects with a new 200 nm femtosecond (fs) laser ablation system (NWRFemto200) using reference materials with different matrices and spot sizes from 10 to 55 μm. We also performed similar experiments with two nanosecond (ns) lasers, a 193 nm excimer (ESI NWR 193) and a 213 nm Nd:YAG (NWR UP‐213) laser. The ion intensity of the 200 nm fs laser ablation was much lower than that of the 213 nm Nd:YAG laser, because the ablation rate was a factor of about 30 lower. Our experiments did not show significant matrix dependency with the 200 nm fs laser. Therefore, a non‐matrix‐matched calibration for the multi‐element analysis of quite different matrices could be performed. This is demonstrated with analytical results from twenty‐two international synthetic silicate glass, geological glass, mineral, phosphate and carbonate reference materials. Calibration was performed with the certified NIST SRM 610 glass, exclusively. Within overall analytical uncertainties, the 200 nm fs LA‐ICP‐MS data agreed with available reference values.  相似文献