The dependence of organohalogen compound concentrations on herring age and size in the Bothnian Sea, northern Baltic     

Parmanne R  Hallikainen A  Isosaari P  Kiviranta H  Koistinen J  Laine O  Rantakokko P  Vuorinen PJ  Vartiainen T 《Marine pollution bulletin》2006,52(2):149-161

The concentrations and composition profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polybrominated diphenyl ethers and polychlorinated naphthalenes were determined in herring individuals collected from the commercial catches of the Bothnian Sea, northern Baltic. The median age of herring was 5.0 years and in the muscle the median toxic equivalent concentration of PCDD/Fs was 5.6 WHO(PCDD/F)-TEQ pg/g fresh weight (fw) and that of PCBs 2.7 WHO(PCB)-TEQ pg/g fw. The median sum concentration of PBDEs was 1.4 ng/g fw and that of PCNs 0.1 ng/g fw. Differences in age-dependent accumulation between the organohalogen groups and individual congeners were major. In the Bothnian Sea the content of organohalogen compounds in herring is obviously elevated due to the availability and large proportion of Mysis crustaceans in their diet. More intensive fishing could reduce the concentrations of organohalogens, including the abundant, accumulative and toxic 2,3,4,7,8-PeCDF congener in the Baltic herring catch.  相似文献   

The build-up of the colour–magnitude relation in galaxy clusters since z∼ 0.8     

Gabriella De Lucia  Bianca M. Poggianti  Alfonso Aragón-Salamanca  Simon D. M. White  Dennis Zaritsky  Douglas Clowe  Claire Halliday  Pascale Jablonka  Anja von der Linden  Bo Milvang-Jensen  Roser Pelló  Gregory Rudnick  Roberto P. Saglia  Luc Simard 《Monthly notices of the Royal Astronomical Society》2007,374(3):809-822

  相似文献   

The Auroral Station in Adventdalen, Svalbard     

T Svenφe 《极地研究(英文版)》2002,13(1)

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＡｕｒｏｒａｌＳｔａｔｉｏｎｉｎＡｄｖｅｎｔｄａｌｅｎｗａｓｂｕｉｌｔｉｎ 1 978ａｎｄｈａｓｗｏｒｋｅｄａｓａｎｏｐｔｉｃａｌｓｉｔｅｆｏｒｇｒｏｕｎｄ -ｂａｓｅｄｏｂｓｅｒｖａｔｉｏｎｓｏｆｔｈｅｄａｙｓｉｄｅａｎｄｎｉｇｈｔｓｉｄｅａｕｒｏｒａｉｎｔｈｅｐｏｌａｒｃａｐ .Ｆｉｇｕｒｅ 1ｓｈｏｗｓａｐｈｏｔｏｇｒａｐｈｏｆｔｈｅｓｔａｔｉｏｎｔｏｇｅｔｈｅｒｗｉｔｈａｔｙｐｉｃａｌｓｔｏｒｍｔｙｐｅａｕｒｏｒａ(Ｓｉｍｍｏｎｓｅｔａｌ.1 996) .Ｔｈｅｓｔａｔｉｏ…  相似文献   

Site-descriptive modelling for a final repository for spent nuclear fuel in Sweden   总被引：2，自引：0，他引：2  

Johan Andersson  Kristina Skagius  Anders Winberg  Tobias Lindborg  Anders Ström 《Environmental Earth Sciences》2013,69(3):1045-1060

  相似文献   

Response of Pediastrum in German floodplain lakes to Late Glacial climate changes   总被引：1，自引：0，他引：1  

Falko Turner  Richard Pott  Anja Schwarz  Antje Schwalb 《Journal of Paleolimnology》2014,52(4):293-310

Subfossil remains of the Pediastrum-algae group (Fam. Hydrodictyaceae) are frequently found in lake sediments, but very few studies have used them as palaeoclimate and palaeolimnological indicators. This study explored the species composition of Pediastrum assemblages in shallow floodplain lakes in northern Germany during two transitional periods from cold to temperate climate conditions (GS-2/GI-1 and GI-1/Holocene). We identified Pediastrum taxa to subspecies level and used multivariate statistics (constrained clustering, principal component analysis and redundancy analysis) to show that shifts in taxonomic composition reflected the strong Late Glacial climate oscillations. The Pediastrum assemblages indicate that climate amelioration already begun shortly before the main GS-2/GI-1 summer-temperature transition. In contrast to previous studies that identified trophic state as the main driver of change in Pediastrum species composition, we identified climate shifts and related factors as the major drivers of community change. Water depth and trophic state probably acted as secondary factors that were responsible for differences in Pediastrum response between the first and second investigated climate transitions. During cold periods, Pediastrum algae composition was controlled mainly by environmental variables, whereas during warm periods, Pediastrum assemblages may have been influenced to a greater extent by intra- and intergeneric competition. This study contributes to knowledge about ecological niches of Pediastrum species. Size-measurements on Pediastrum coenobia reveal that one response of Pediastrum algae to climate shifts probably was size change. Coenobia of Pseudopediastrum boryanum var. boryanum were significantly smaller during cold climate periods than during temperate periods. The shifts in Pediastrum species composition and coenobium size suggest this algae group has great potential for enabling palaeoecological and palaeoclimate inferences.  相似文献   

Water and nutrient predictions in ungauged basins: set-up and evaluation of a model at the national scale     

Johan Strömqvist  Berit Arheimer  Joel Dahné  Chantal Donnelly  Göran Lindström 《水文科学杂志》2013,58(2):229-247

Abstract

A dynamic water quality model, HYPE, was applied to a large, data-sparse region to study whether reliable information on water quantity and water quality could be obtained for both gauged and ungauged waterbodies. The model (called S-HYPE) was set up for all of Sweden (～450 000 km²), divided into sub-basins with an average area of 28 km². Readily available national databases were used for physiographic data, emissions and agricultural practices, fixed values for representative years were used. Daily precipitation and temperature were used as the dynamic forcing of the model. Model evaluation was based on data from several hundred monitoring sites, of which approximately 90% had not been used in calibration on a daily scale. Results were evaluated using the Nash-Sutcliffe efficiency (NSE), correlation and relative errors: 92% of the spatial variation was explained for specific water discharge, and 88% and 59% for total nitrogen and total phosphorus concentrations, respectively. Day-to-day variations were modelled with satisfactory results for water discharge and the seasonal variation of nitrogen concentrations was also generally well captured. In 20 large, unregulated rivers the median NSE for water discharge was 0.84, and the corresponding number for 76 partly-regulated river basins was 0.52. In small basins, the NSE was typically above 0.6. These major achievements relative to previous similar experiments were ascribed to the step-wise calibration process using representative gauged basins and the use of a modelling concept, whereby coefficients are linked to physiographic variables rather than to specific sites.

Editor D. Koutsoyiannis

Citation Strömqvist, J., Arheimer, B., Dahné, J., Donnelly, C. and Lindström, G., 2012. Water and nutrient predictions in ungauged basins: set-up and evaluation of a model at the national scale. Hydrological Sciences Journal, 57 (2), 229–247.  相似文献   

Modelling indicators of water security,water pollution and aquatic biodiversity in Europe     

Egon Dumont  Richard Williams  Virginie Keller  Anja Voß  Sirkka Tattari 《水文科学杂志》2013,58(7):1378-1403

Abstract

The GWAVA (Global Water AVailability Assessment) model for indicating human water security has been extended with a newly developed module for calculating pollutant concentrations. This module is first described and then illustrated by being used to model nitrogen, phosphorus and organic matter concentrations. The module uses solely input variables that are likely to be available for future scenarios, making it possible to apply the module to such scenarios. The module first calculates pollutant loading from land to rivers, lakes and wetlands by considering drivers such as agriculture, industry and sewage treatment. Calculated loadings are subsequently converted to concentrations by considering aquatic processes, such as dilution, downstream transport, evaporation, human water abstraction and biophysical loss processes. Aquatic biodiversity is indicated to be at risk if modelled pollutant concentrations exceed certain water quality standards. This is indicated to be the case in about 35% of the European area, especially where lakes and wetlands are abundant. Human water security is indicated to be at risk where human water demands cannot be fulfilled during drought events. This is found to be the case in about 10% of the European area, especially in Mediterranean, arid and densely-populated areas. Modelled spatial variation in concentrations matches well with existing knowledge, and the temporal variability of concentrations is modelled reasonably well in some river basins. Therefore, we conclude that the updated GWAVA model can be used for indicating changes in human water security and aquatic biodiversity across Europe.

Editor Z.W. Kundzewicz

Citation Dumont, E., Williams, R., Keller, V., Voss, A., and Tattari, S., 2012. Modelling indicators of water security, water pollution and aquatic biodiversity in Europe. Hydrological Sciences Journal, 57 (7), 1378–1403.  相似文献   

Coarse clast ridge sequences as suitable archives for past storm events? Case study on the Houtman Abrolhos,Western Australia     

Anja M. Scheffers  Sander R. Scheffers  Dieter H. Kelletat  Peter Squire  Lindsay Collins  Yuexing Feng  Jian‐Xin Zhao  Renaud Joannes‐Boyau  Simon Matthias May  Gerhard Schellmann  Heather Freeman 《第四纪科学杂志》2012,27(7):713-724

Prehistoric storm records are relatively scarce in most parts of the world. This article presents storm records derived from coral rubble‐based geological archives of the Houtman Abrolhos Archipelago located off the west coast of Australia, where the southernmost coral reefs of the Indian Ocean are found. Winter storm swell from the circum‐Antarctic ‘Brave Westerlies’, as well as tropical cyclone waves, have left numerous ridge systems on dozens of islands of the archipelago, all composed of coral rubble from adjacent reefs. At three islands, seven ridge systems were dated by three different methods: U‐series (68 dates), radiocarbon (64 dates), electron spin resonance (7 dates); 139 radiometric dates span the last 5500 years of the Holocene. In contrast to the geomorphological interpretation, the age sequences show ‘inversions’, hiatuses and different ages for the same ridge, all pointing to complicated ridge formation processes. Time gaps, some exceeding 1000 years, are interpreted as phases of erosion and not as phases without storm activity. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Insights into rock avalanche emplacement processes from detailed morpho‐lithological studies of the Tschirgant deposit (Tyrol,Austria)          下载免费PDF全文

Anja Dufresne  Christoph Prager  Annette Bösmeier 《地球表面变化过程与地形》2016,41(5):587-602

Large, rapid rockslope failures generate deposits with complex morphologies due to a number of causal and influencing factors. To investigate these, we conducted a detailed case study at the carbonate Tschirgant deposit (Tyrol, Austria). It preserved evidence of simultaneous rock sliding (very large, coherent hummocks) and rock avalanche spreading (smaller, more scattered hummocks and ridges). Motion indicators, such as longitudinal ridges furthermore pinpoint the transition between linear sliding and radial spreading. The lithological distribution in the Tschirgant deposit shows that it retained source stratigraphy despite being split into two accumulation lobes by a high bedrock ridge. Furthermore, lithology had a very strong control on the final deposit morphology in that the different lithologic units form individual deposit surfaces. River erosion has created fortuitous outcrops that reveal the basal rock avalanche contact. The underlying valley‐fill sediments (substrates) have been intricately involved in shaping the rock avalanche morphology and, where entrained, highlight internal rock avalanche deformation features. This study shows that intrinsic dynamic properties of granular media (e.g. tendency for longitudinal alignments), emplacement mode, lithology (and source predisposition), runout path topography, and substrates form the quintet of causal factors that shape rock avalanche morphology. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Dynamic adjustment of training sets (‘moving-window’ reconstruction) by using transfer functions in paleolimnology—a new approach   总被引：1，自引：0，他引：1  

Thomas Hübener  Mirko Dreßler  Anja Schwarz  Kirsten Langner  Sven Adler 《Journal of Paleolimnology》2008,40(1):79-95

This paper presents a new method (moving-windows) that optimizes diatom-based paleolimnological reconstructions of past environmental conditions from supra-regional training sets. The moving-window method identifies the best number of nearest neighbours (window size) from a merged supra-regional EDDI and local (MV) training set (n = 429) for each fossil diatom assemblage and the best type of transfer function (ML, WA-PLS) based on the error statistic of each transfer function (highest cross-validated R ², lowest cross-validated average bias, maximum bias and RMSEP). At first we evaluated the moving-window approach by comparing measured TP-values with inferred TP-values using both the moving-window approach and the WA-PLS method. The relative errors of the moving-window approach were not significantly different for 208 samples that had an error <15 μg/l TP using the WA-PLS method. However, for the remaining 221 samples with errors >>15 μg/l TP using the WA-PLS method, the moving window approach significantly reduced the relative error of the inferred TP levels. Secondly, the moving- window approach was used to reconstruct epilimnetic total phosphorous (TP) for Lake Dudinghausen, Lake Rugensee, Lake Tiefer See and Lake Drewitzer See (Northern Germany) using both the supra-regional EDDI training set and a local training set from Northern Germany (MV training set). The moving-window inferred TP-levels of the four study lakes were compared with published reconstructed TP-values and with inferred TP-values based on the local MV training set. Overall, the moving-window and the published TP-trends agree well with each other. However, the moving-window reconstructions generally indicated lower TP-levels throughout the past ∼5,000 to 12,000 years, including past maxima. Thus, the moving-window method seems to generate more realistic absolute TP levels due to the optimized window size (highest number of modern analogues, best error statistics). The identification of more realistic absolute historic TP-values is important for the validation of reference conditions for inland waters. This study also demonstrates that a robust local training set may, similar to moving-window training sets, also lead to reliable reconstructions, if the geological settings of the local training set lakes and the study lakes are similar.  相似文献