Palaeogene glendonites from Denmark

Pristinely preserved mineral pseudomorphs called glendonites, up to 1.6 m long, from the Palaeogene strata of Denmark allow detailed crystallographic characterisation and add to the understanding of the transformation of the precursor mineral, ikaite (CaCO3 center dot 6H(2)O), to calcite, which constitutes the glendonite. We describe Danish pseudomorphs after ikaite from two localities and formations: the Early Eocene Fur Formation and the Late Oligocene Brejning Formation. This detailed study highlights that key aspects such as morphology and mode of occurrence of these ancient glendonites are identical to those of their parent mineral ikaite, when it grows in marine sediments. Systematic distortion of the angles in glendonite and marine sedimentary ikaite relative to the ideal ikaite symmetry may arise due to the incorporation of organic matter into the crystal structure, and we demonstrate the similarity between modern and ancient ikaite formation zones in the marine sedimentary realm with respect to organic matter

The Global Stratotype Section and Point (GSSP) for the base of the Lutetian Stage at the Gorrondatxe section, Spain

The GSSP for the base of the Lutetian Stage (early/ middle Eocene boundary) is defined at 167.85 metres in the Gorrondatxe sea-cliff section (NW of Bilbao city, Basque Country, northern Spain; 43º22'46.47" N, 3º 00' 51.61" W). This dark marly level coincides with the lowest occurrence of the calcareous nannofossil Blackites inflatus (CP12a/b boundary), is in the middle of polarity Chron C21r, and has been interpreted as the maximumflooding surface of a depositional sequence that may be global in extent. The GSSP age is approximately 800 kyr (39 precession cycles) younger than the beginning of polarity Chron C21r, or ~47.8 Ma in the GTS04 time scale. The proposal was approved by the International Subcommission on Paleogene Stratigraphy in February 2010, approved by the International Commission of Stratigraphy in January 2011, and ratified by the International Union of Geological Sciences in April 2011.Published86-1082.2. Laboratorio di paleomagnetismoJCR Journalrestricte

The Global Stratotype Section and Point (GSSP) for the base of the Lutetian Stage at the Gorrondatxe section, Spain

The GSSP for the base of the Lutetian Stage (early/ middle Eocene boundary) is defined at 167.85 metres in the Gorrondatxe sea-cliff section (NW of Bilbao city, Basque Country, northern Spain; 43º22'46.47" N, 3º 00' 51.61" W). This dark marly level coincides with the lowest occurrence of the calcareous nannofossil Blackites inflatus (CP12a/b boundary), is in the middle of polarity Chron C21r, and has been interpreted as the maximumflooding surface of a depositional sequence that may be global in extent. The GSSP age is approximately 800 kyr (39 precession cycles) younger than the beginning of polarity Chron C21r, or ~47.8 Ma in the GTS04 time scale. The proposal was approved by the International Subcommission on Paleogene Stratigraphy in February 2010, approved by the International Commission of Stratigraphy in January 2011, and ratified by the International Union of Geological Sciences in April 2011.Published86-1082.2. Laboratorio di paleomagnetismoJCR Journalrestricte

Molerområdets geologi – sedimenter, fossiler, askelag og glaicaltektonik

Abstract in Danish I den vestlige del af Limfjorden findes en række kystklinter, hvor eocæne lag er blottet. Moler er en ca. 55-56 millioner år gammel diatomit, som indeholder lag af uforvitret vulkansk aske samt et stort antal velbevarede marine og terrestriske fossiler. Stolleklint Leret og Fur Formationen har et usædvanligt fossilselskab med mange repræsentanter for insekter, fisk, fugle og skildpadder men meget få kalkskallede, hvirvelløse dyr. De vulkanske askelag afspejler et stort antal gigantiske, eksplosive udbrud inden for en kort periode, hvor lavatilstrømningen var stor, samtidig med at udbruddene skete på lavt vand i den nydannede oceanbund. For ca. 25.000 år siden dannede fremrykkende iskapper folder og overskydninger i moler, askelag og glaciale sedimenter. Molerområdets geologi kan sammenfattes i følgende citat: ”…talrige tynde lag af sort vulkansk Aske...træde selv på lang Afstand tydelig frem i det hvide Moler …[Da de] ofte danner store Bugter og Folder, vil man forstaa, at de høje lyse Molerklinter i Solskin frembyde et malerisk og ejendommeligt Skue.” (N. V. Ussing i ’Danmarks Geologi’ 1904, s.143)

The absolute abundance calibration project: the <i>Lycopodium</i> marker-grain method put to the test

Traditionally, dinoflagellate cyst concentrations are calculated by adding an exotic marker or “spike” (such as Lycopodium clavatum) to each sample following the method of Stockmarr (1971). According to Maher (1981), the total error is controlled mainly by the error on the count of Lycopodium clavatum spores. In general, the more L. clavatum spores counted, the lower the error. A dinocyst / L. clavatum spore ratio of ~2 will give optimal results in terms of precision and time spent on a sample. It has also been proven that the use of the aliquot method yields comparable results to the marker-grain method (de Vernal et al., 1987). Critical evaluation of the effect of different laboratory procedures on the marker grain concentration in each sample has never been executed. Although, it has been reported that different processing methods (e.g. ultrasonication, oxidizing, etc.) are to a certain extent damaging to microfossils (e.g. Hodgkinson, 1991), it is not clear how this is translated into concentration calculations. It is wellknown from the literature that concentration calculations of dinoflagellate cysts from different laboratories are hard to resolve into a consistent picture. The aim of this study is to remove these inconsistencies and to make recommendations for the use of a standardized methodology. Sediment surface samples from four different localities (North Sea, Celtic Sea, NW Africa and Benguela) were macerated in different laboratories each using its own palynological maceration technique. A fixed amount of Lycopodium clavatum tablets was added to each sample. The uses of different preparation methodologies (sieving, ultrasonicating, oxidizing …) are compared using both concentrations – calculated from Lycopodium tablets - and relative abundances (more destructive methods will increase the amount of resistant taxa). Additionally, this study focuses on some important taxonomic issues, since obvious interlaboratorial differences in nomenclature are recorded

Arthropod communities in fungal fruitbodies are weakly structured by climate and biogeography across European beech forests

Aim The tinder fungus Fomes fomentarius is a pivotal wood decomposer in European beech Fagus sylvatica forests. The fungus, however, has regionally declined due to centuries of logging. To unravel biogeographical drivers of arthropod communities associated with this fungus, we investigated how space, climate and habitat amount structure alpha and beta diversity of arthropod communities in fruitbodies of F. fomentarius. Location Temperate zone of Europe. Taxon Arthropods. Methods We reared arthropods from fruitbodies sampled from 61 sites throughout the range of European beech and identified 13 orders taxonomically or by metabarcoding. We estimated the total number of species occurring in fruitbodies of F. fomentarius in European beech forests using the Chao2 estimator and determined the relative importance of space, climate and habitat amount by hierarchical partitioning for alpha diversity and generalized dissimilarity models for beta diversity. A subset of fungi samples was sequenced for identification of the fungus’ genetic structure. Results The total number of arthropod species occurring in fruitbodies of F. fomentarius across European beech forests was estimated to be 600. Alpha diversity increased with increasing fruitbody biomass; it decreased with increasing longitude, temperature and latitude. Beta diversity was mainly composed by turnover. Patterns of beta diversity were only weakly linked to space and the overall explanatory power was low. We could distinguish two genotypes of F. fomentarius, which showed no spatial structuring. Main conclusion Fomes fomentarius hosts a large number of arthropods in European beech forests. The low biogeographical and climatic structure of the communities suggests that fruitbodies represent a habitat that offers similar conditions across large gradients of climate and space, but are characterized by high local variability in community composition and colonized by species with high dispersal ability. For European beech forests, retention of trees with F. fomentarius and promoting its recolonization where it had declined seems a promising conservation strategy

Open-source data reveal how collections?based fungal diversity is sensitive to global change

Premise of the Study: Fungal diversity (richness) trends at large scales are in urgent need of investigation, especially through novel situations that combine long-term observational with environmental and remotely sensed open-source data. Methods: We modeled fungal richness, with collections-based records of saprotrophic (decaying) and ectomycorrhizal (plant mutualistic) fungi, using an array of environmental variables across geographical gradients from northern to central Europe. Temporal differences in covariables granted insight into the impacts of the shorter- versus longer-term environment on fungal richness. Results: Fungal richness varied significantly across different land-use types, with highest richness in forests and lowest in urban areas. Latitudinal trends supported a unimodal pattern in diversity across Europe. Temperature, both annual mean and range, was positively correlated with richness, indicating the importance of seasonality in increasing richness amounts. Precipitation seasonality notably affected saprotrophic fungal diversity (a unimodal relationship), as did daily precipitation of the collection day (negatively correlated). Ectomycorrhizal fungal richness differed from that of saprotrophs by being positively associated with tree species richness. Discussion: Our results demonstrate that fungal richness is strongly correlated with land use and climate conditions, especially concerning seasonality, and that ongoing global change processes will affect fungal richness patterns at large scales.</p

Zur Modellierung des Fäulerisikos von Holzprodukten

International audienceAn empirical model for wood decay development which can be incorporated into a hygrothermal model of building physics is presented. The model is applied to the ERA-40 reanalysis data, based on six-hour weather observations in Europe, to estimate wood decay in different parts of Europe. These studies provide new tools for evaluating the durability and service life of wooden products and a preliminary European wood decay risk level map. The effects of the projected climate change on wood decay may also be considered by this methodology

Distance decay 2.0-A global synthesis of taxonomic and functional turnover in ecological communities

Aim: Understanding the variation in community composition and species abundances (i.e., beta-diversity) is at the heart of community ecology. A common approach to examine beta-diversity is to evaluate directional variation in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distance. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 148 datasets comprising different types of organisms and environments. Location: Global. Time period: 1990 to present. Major taxa studied: From diatoms to mammals. Method: We measured the strength of the decay using ranked Mantel tests (Mantel r) and the rate of distance decay as the slope of an exponential fit using generalized linear models. We used null models to test whether functional similarity decays faster or slower than expected given the taxonomic decay along the spatial and environmental distance. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm and organismal features. Results: Taxonomic distance decay was stronger than functional distance decay along both spatial and environmental distance. Functional distance decay was random given the taxonomic distance decay. The rate of taxonomic and functional spatial distance decay was fastest in the datasets from mid-latitudes. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distance but a higher rate of decay along environmental distance. Marine ecosystems had the slowest rate of decay along environmental distances. Main conclusions: In general, taxonomic distance decay is a useful tool for biogeographical research because it reflects dispersal-related factors in addition to species responses to climatic and environmental variables. Moreover, functional distance decay might be a cost-effective option for investigating community changes in heterogeneous environments