Stockholm University

About: Stockholm University is a education organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Population & Supernova. The organization has 21052 authors who have published 62567 publications receiving 2725859 citations. The organization is also known as: University of Stockholm & Stockholms universitet.

High‐resolution X‐ray fluorescence core scanning analysis of Les Echets (France) sedimentary sequence: new insights from chemical proxies

Abstract: The Les Echets sediment sequence has recently been the subject of a high-resolution, multi-proxy study which revealed shifts in lake productivity linked to Greenland stadials and interstadials over the last 40 ka (Wohlfarth et al., 2008. Rapid ecosystem response to abrupt climate changes during the last glacial period in western Europe, 40-16 ka. Geology 36: 407-410). Here we present new elemental data for this sequence as acquired using an X-ray fluorescence core scanning system which provides in situ high-resolution, continuous, multi-element analyses. It was found that the strength of associations between the studied elements (Ti, Rb, K, Zr, Si, Ca, Sr, Mn and Fe) varied over time with changes in lake status which are ultimately driven by changes in climate. Increases in fine-grained, detrital input (as indicated by Ti, Rb, K and Zr/Rb) overlap with independently established periods of lower lake productivity and are interpreted to represent more arid conditions. Several of these arid periods are coincident with low diatom concentrations and the timing of Heinrich events H4, H3 and H2. The duration of the environmental impacts linked to the H events varied by proxy with elemental data (Ti and Zr/Rb) estimating shorter events than the diatom data. Periods of lower detrital input and coarser grain sizes agreed in time with periods of higher lake productivity. The elemental data provide new insights into hydrological changes and related sediment processes within the catchment, and highlight the need for multi-element and multi-proxy approaches when reconstructing climate change using lacustrine sediment sequences. Copyright # 2011 John Wiley & Sons, Ltd.

Isozyme loci in brown trout (Salmo trutta L.): detection and interpretation from population data

Abstract: Previously reported results on natural populations of brown trout (Salmo trutta L.) urged further studies using additional electrophoretically detectable loci. Samples of brain, eye, heart, kidney, liver, and muscle from approximately 50 specimens from each of two populations and a large number of muscle samples from several additional populations were examined. Electrophoretic and staining methods for the 37 enzymes studied are given in detail. Of a total of 69 loci detected, 54 loci were considered usable in population genetics screenings. The expression of the loci coding for these enzymes is described and interpreted. The results presented will serve as a basis for a more detailed examination of genetic variation in brown trout populations.