Swedish Museum of Natural History
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Réchauffement climatique : quand la vase toxique asphyxieles eaux douces
No full text> De nombreux affleurements rocheux sur la planète portent la trace d’uncataclysme biologique, survenu il y a 252 millions d’années. Alors que lesfossiles y étaient nombreux auparavant, ils se fi rent alors très rares, toutcomme les pollens et les spores. > Au-dessus de ces couches presque stériles, la roche a enregistré uneprolifération d’algues d’eau douce et de bactéries photosynthétiques. Ladisparition massive d’espèces et des efflorescences microbiennestoxiques dans les eaux douces marquent la crise de la fi n du Permien,provoquée par un réchauffement très important de l’atmosphère. > La prolifération microbienne toxique dans les lacs et rivières estd’autant plus importante que la température est élevée, hier commeaujourd’hui. L’étude de la crise du Permien laisse entrevoir lesconséquences du réchauffement contemporain sur les écosystèmes d’eaudouce
Evolutionary contingency in lingulid brachiopods across mass extinctions
No full textMorphology usually serves as an effective proxy for functional ecology,1,2,3,4,5 and evaluating morphological, anatomical, and ecological changes permits a deeper understanding of the nature of diversification and macroevolution.5,6,7,8,9,10,11,12 Lingulid (order Lingulida) brachiopods are both diverse and abundant during the early Palaeozoic but decrease in diversity over time, with only a few genera of linguloids and discinoids present in modern marine ecosystems, resulting in them frequently being referred to as “living fossils.”13,14,15 The dynamics that drove this decline remain uncertain, and it has not been determined if there is an associated decline in morphological and ecological diversity. Here, we apply geometric morphometrics to reconstruct global morphospace occupation for lingulid brachiopods through the Phanerozoic, with results showing that maximum morphospace occupation was reached by the Early Ordovician. At this time of peak diversity, linguloids with a sub-rectangular shell shape already possessed several evolutionary features, such as the rearrangement of mantle canals and reduction of the pseudointerarea, common to all modern infaunal forms. The end Ordovician mass extinction has a differential effect on linguloids, disproportionally wiping out those forms with a rounded shell shape, while forms with sub-rectangular shells survived both the end Ordovician and the Permian-Triassic mass extinctions, leaving a fauna predominantly composed of infaunal forms. For discinoids, both morphospace occupation and epibenthic life strategies remain consistent through the Phanerozoic. Morphospace occupation over time, when considered using anatomical and ecological analyses, suggests that the limited morphological and ecological diversity of modern lingulid brachiopods reflects evolutionary contingency rather than deterministic processes
Graphic and statistical overview of temporal trends and spatial variations within the Swedish National Monitoring Programme for Contaminants in Marine Biota (until 2021 year’s data), 5:2023
No full textDark-coloured Mn-rich overgrowths in an elbaitic tourmaline crystal from the Rosina pegmatite, San Piero in Campo, Elba Island, Italy: witness of late-stage opening of the geochemical system
No full textPiccoliite, NaCaMn3+2(AsO4)2O(OH), a new arsenate from the manganese deposits of Montaldo di Mondovì and Valletta, Piedmont, Italy
No full textRik rundmaskfauna i Store Mosse nationalpark hittades med DNA-metastreckkodning
No full textTaxonomic and functional diversity of Nematode fauna of the Store Mosse National Park: a metabarcoding approac
Assessing the national burden of allergic asthma by web-search data, pollen counts, and drug prescriptions in Germany and Sweden
No full textChasing a ghost through Gondwana’s history – the fossil record of the 'seed fern' Komlopteris
No full textRecently, a 53 million year old pteridosperm species, Komlopteris cenozoicus, was discovered at the west coast of Tasmania near Strahan, post-dating the end-Cretaceous extinction by about 13 million years. The discovery of this 'ghost lineage' prompted new excavations at its type locality, which led to the recovery of 52 new leaf specimens of K. cenozoicus. Meticulous preparation of the retrieved hand samples revealed that the new Komlopteris specimens were more complete than those first described and offered the opportunity to study the frond architecture and micromorphology.This work was further supported by the University of Adelaide, Gostralia! [PhD scholarship to Miriam Slodownik]</p
The robustness of the Lu-Hf and Sm-Nd isotopic systems during metamorphism – A case study of the Åker metabasite in southern Sweden
No full textWhile whole-rock Lu-Hf isotope analysis remains one of the only ways to obtain initial Hf isotope signatures of old mafic rocks, Hf isotope analyses of more robust accessory zircon in intermediate to silicic rocks have largely replaced whole-rock analyses during the last decade. This has led to a discrepancy in the amount of existing data from mafic and felsic lithologies. However, especially in mafic, Si-poor rocks with a metamorphic imprint, Hf isotope data rely on whole-rock analysis since baddeleyite, commonly used for U-Pb age analyses of mafic rocks, is sensitive to alteration and metamorphism. Hence, to accurately evaluate the trace element and isotope signatures of altered mafic rocks, it is important to understand the mechanisms of element mobility during metamorphism. Here, we report whole-rock trace element compositions, Lu-Hf and Sm-Nd isotope data from variably deformed and metamorphosed samples of a mafic intrusion in southern Sweden, the Åker metabasite. These data suggest that trace elements were undisturbed on a whole-rock sample scale during deformation at upper amphibolite facies (at least 1000 MPa and 600 °C) metamorphism under hydrated conditions. Despite redistribution of Zr associated with the breakdown of baddeleyite and other igneous phases, the Åker metabasite has retained its chemical and isotopic integrity since igneous crystallisation at ca. 1565 Ma. This study demonstrates and strengthens the feasibility of whole-rock analyses of (meta-)mafic rocks for determining initial εNd and εHf values, despite deformation and metamorphism under hydrated amphibolite-grade metamorphic conditions. Testing the coherence of the calculated initial Nd and Hf isotope ratios by examining variably deformed and metamorphosed varieties of a rock in a single outcrop, could be used as a model for research on more complex Archean rocks
Beavers and flying squirrels (Rodentia: Castoridae, Pteromyini) from the Late Pliocene of Hambach 11C, Germany
No full textThis paper is a study of part of the rodent fauna collected at Hambach 11C, located in the Hambach lignite mine in north-western Germany. The deposits exposed here are fluvial channel fills of Late Pliocene age (MN16a) and the rodent material is compared to previously published material from the contemporaneous deposits of Hambach 11. Four species are discussed: two Castoridae, Castor fiber Linnaeus, 1758 and Trogontherium minus Newton, 1890 and two Sciuridae, Blackia miocaenica Mein, 1970 and Pliopetaurista pliocaenica Depéret, 1897. This new material is of great importance as the fossil records of T. minus and B. miocaenica are very scarce so far. Blackia is especially rare in the Late Pliocene and this occurrence is one of the three youngest of the genus. We also described the most complete juvenile material of Trogontherium minus. The fauna is indicative of fluvial environment surrounded by a forest of deciduous trees and of a temperate and humid climate.We would like to thank the RWE Power AG mining company (Cologne) for access to the Hambach mine. We grateful acknowledge financial support by the Special Research Project SFB 350 of the Deutsche Forschungsgemeinschaft, DFG (to TM).</p