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  • 1.
    Bengtson, Stefan
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Sallstedt, Therese
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Belivanova, Veneta
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Whitehouse, Martin
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Three-dimensional preservation of cellular and subcellular structures suggests 1.6 billion-year-old crown-group red algae2017Inngår i: PLoS biology, ISSN 1544-9173, E-ISSN 1545-7885, Vol. 15, nr 3, s. 1-38, artikkel-id e2000735Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ~1.6 Ga Tirohan Dolomite of the Lower Vindhyan in central India contains phosphatized stromatolitic microbialites. We report from there uniquely well-preserved fossils interpreted as probable crown-group rhodophytes (red algae). The filamentous form Rafatazmia chitrakootensis n. gen, n. sp. has uniserial rows of large cells and grows through diffusely distributed septation. Each cell has a centrally suspended, conspicuous rhomboidal disk interpreted as a pyrenoid. The septa between the cells have central structures that may represent pit connections and pit plugs. Another filamentous form, Denaricion mendax n. gen., n. sp., has coin-like cells reminiscent of those in large sulfur-oxidizing bacteria but much more recalcitrant than the liquid-vacuole-filled cells of the latter. There are also resemblances with oscillatoriacean cyanobacteria, although cell volumes in the latter are much smaller. The wider affinities of Denaricion are uncertain. Ramathallus lobatus n. gen., n. sp. is a lobate sessile alga with pseudoparenchymatous thallus, “cell fountains,” and apical growth, suggesting florideophycean affinity. If these inferences are correct, Rafatazmia and Ramathallus represent crown-group multicellular rhodophytes, antedating the oldest previously accepted red alga in the fossil record by about 400 million years.

    Fulltekst (pdf)
    fulltext
  • 2.
    Ivarsson, Lena Norbäck
    et al.
    Stockholm University.
    Ivarsson, Magnus
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Lundberg, Johannes
    Naturhistoriska riksmuseet, Enheten för botanik.
    Sallstedt, Therese
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Rydin, Catarina
    Stockholm University.
    Epilithic and aerophilic diatoms in the artificial environment of Kungsträdgården metro station, Stockholm, Sweden2013Inngår i: International Journal of Speleology, ISSN 0392-6672, E-ISSN 1827-806X, Vol. 42, nr 3, s. 289-297Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Kungsträdgården metro station is an artificial and urban subsurface environment illuminated with artificial light. Its ecosystem is almost completely unknown and as a first step to better understand the biology and rock wall habitats the diatom flora was investigated. A total of 12 species were found growing on the rock walls of Kungsträdgården metro station. The results show the diatom flora in Kungsträdgården to be dominated by e.g. Diadesmis contentaDiadesmis perpusillaPinnularia appendiculataNitzschia amphibiaNitzschia sinuata and Diploneis ovalis. One species, Caloneis cf. aerophila, has never been reported from Sweden before. Significant differences in the species composition between the sampling sites indicate Kungsträdgården metro station to be a heterogeneous habitat that provides different microhabitats.

    Fulltekst (pdf)
    Diatoms in Kungsträdgården metro station.pdf
  • 3.
    Ivarsson, Magnus
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Nordic Center for Earth Evolution (NordCEE).
    Gustavsson, Lena
    Naturhistoriska riksmuseet, Enheten för zoologi.
    Hedenäs, Lars
    Naturhistoriska riksmuseet, Enheten för botanik.
    Kronestedt, Torbjörn
    Naturhistoriska riksmuseet, Enheten för zoologi.
    Lundberg, Johannes
    Naturhistoriska riksmuseet, Enheten för botanik.
    Norbäck Ivarsson, Lena
    Södertörn University.
    Sallstedt, Therese
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Nordic Center for Earth Evolution (NordCEE).
    Scheuerer, Manuela
    Sweco Rail.
    Thureborn, Olle
    Stockholm University.
    Wedin, Mats
    Naturhistoriska riksmuseet, Enheten för botanik.
    Unikt ekosystem i tunnelbanan vid Kungsträdgården2017Inngår i: Fauna och flora : populär tidskrift för biologi, ISSN 0014-8903, Vol. 112, nr 1, s. 2-9Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Fulltekst (pdf)
    fulltext
  • 4.
    Réblová, Martina
    et al.
    Department of Taxonomy, Institute of Botany of the Czech Academy of Sciences, 252 43, Pruhonice, Czech Republic.
    Hubka, Vit
    Department of Botany, Faculty of Science, Charles University in Prague, Benatska 2, 128 01 Prague 2, Czech Republic.
    Thureborn, Olle
    Institutionen för ekologi miljö och botanik, Stockholms Universitet.
    Lundberg, Johannes
    Naturhistoriska riksmuseet, Enheten för botanik.
    Sallstedt, Therese
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Nordic Center for Earth Evolution (NordCEE).
    Wedin, Mats
    Naturhistoriska riksmuseet, Enheten för botanik.
    Ivarsson, Magnus
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Nordic Center for Earth Evolution (NordCEE).
    From the tunnels into the treetops: new lineages of black yeasts from biofilm in the Stockholm metro system and their relatives among ant-associated fungi in the Chaetothyriales2016Inngår i: PLOS ONE, E-ISSN 1932-6203, Vol. 11, nr 10, s. e0163396-, artikkel-id e0163396Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rock-inhabiting fungi harbour species-rich, poorly differentiated, extremophilic taxa of polyphyletic origin. Their closest relatives are often well-known species from various biotopes with significant pathogenic potential. Speleothems represent a unique rock-dwelling habitat, whose mycobiota are largely unexplored. Isolation of fungi from speleothem biofilm covering bare granite walls in the Kungsträdgården metro station in Stockholm yielded axenic cultures of two distinct black yeast morphotypes. Phylogenetic analyses of DNA sequences from six nuclear loci, ITS, nuc18S and nuc28S rDNA, rpb1, rpb2 and β-tubulin, support their placement in the Chaetothyriales (Ascomycota). They are described as a new genus Bacillicladium with the type species Blobatum, and a new species Bradymyces graniticolaBacillicladium is distantly related to the known five chaetothyrialean families and is unique in the Chaetothyriales by variable morphology showing hyphal, meristematic and yeast-like growth in vitro. The nearest relatives of Bacillicladium are recruited among fungi isolated from cardboard-like construction material produced by arboricolous non-attine ants. Their sister relationship is weakly supported by the Maximum likelihood analysis, but strongly supported by Bayesian inference. The genus Bradymyces is placed amidst members of the Trichomeriaceae and is ecologically undefined; it includes an opportunistic animal pathogen while two other species inhabit rock surfaces. ITS rDNA sequences of three species accepted in Bradymyces and other undescribed species and environmental samples were subjected to phylogenetic analysis and in-depth comparative analysis of ITS1 and ITS2 secondary structures in order to study their intraspecific variability. Compensatory base change criterion in the ITS2 secondary structure supported delimitation of species in Bradymyces, which manifest a limited number of phenotypic features useful for species recognition. The role of fungi in the speleothem biofilm and relationships of Bacillicladium and Bradymyces with other members of the Chaetothyriales are discussed.

    Fulltekst (pdf)
    fulltext
  • 5.
    Sallstedt, Therese
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Nordic Center for Earth Evolution (NordCEE); Department of Biology, University of Southern Denmark.
    Ivarsson, Magnus
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Nordic Center for Earth Evolution (NordCEE).
    Lundberg, Johannes
    Naturhistoriska riksmuseet, Enheten för botanik.
    Sjöberg, Rabbe
    Vidal Romaní, Juan Ramón
    University of Coruña, Campus de Elviña, ES-15071 Coruña, Spain.
    Speleothem and biofilm formation in a granite/dolerite cave, Northern Sweden2014Inngår i: International Journal of Speleology, ISSN 0392-6672, E-ISSN 1827-806X, Vol. 43, nr 3, s. 305-313Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tjuv-Antes grotta (Tjuv-Ante's Cave) located in northern Sweden is a round-abraded sea cave ('tunnel cave'), about 30 m in length, formed by rock-water abrasion in a dolerite dyke in granite gneiss. Abundant speleothems are restricted to the inner, mafic parts of the cave and absent on granite parts. The speleothems are of two types: cylindrical (coralloid, popcorn-like), and flowstone (thin crusts). Coralloids correspond to terrestrial stromatolite speleothems in which layers of light calcite alternate with dark, silica-rich laminae. The dark laminae are also enriched in carbon and contain incorporated remains of microorganisms. Two types of microbial communities can be distinguished associated with the speleothems: an Actinobacteria-like biofilm and a fungal community. Actinobacteria seem to play an important role in the formation of speleothem while the fungal community acts as both a constructive and a destructive agent. A modern biofilm dominated by Actinobacteria is present in the speleothem-free parts of the dolerite and located in cave ceiling cracks. These biofilms may represent sites of early speleothem formation. Because of its unusual position in between two types of host rock, Tjuv-Ante's Cave represents a unique environment in which to study differences in microbe-rock interactions and speleothem genesis between the granite and dolerite host rock. Our study shows that the mafic rock is superior to the granite in hosting a microbial community and to support formation of speleothems.

    Fulltekst (pdf)
    Sallstedt et al 2014 Int J Speleology
  • 6.
    Zepeda Mendoza, Marie Lisandra
    et al.
    Natural History Museum of Denmark.
    Lundberg, Johannes
    Naturhistoriska riksmuseet, Enheten för botanik.
    Ivarsson, Magnus
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Nordic Center for Earth Evolution (NordCEE).
    Campos, Paula
    University of Copenhagen.
    Nylander, Johan A. A.
    Naturhistoriska riksmuseet, Enheten för bioinformatik och genetik.
    Sallstedt, Thereese
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Nordic Center for Earth Evolution (NordCEE).
    Dalén, Love
    Naturhistoriska riksmuseet, Enheten för bioinformatik och genetik.
    Metagenomic Analysis from the Interior of a Speleothem in Tjuv-Ante's Cave, Northern Sweden2016Inngår i: PLOS ONE, E-ISSN 1932-6203, Vol. 11, nr 3, s. 1-23, artikkel-id e015177Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Speleothems are secondary mineral deposits normally formed by water supersaturated with calcium carbonate percolating into underground caves, and are often associated with low-nutrient and mostly non-phototrophic conditions. Tjuv-Ante’s cave is a shallow-depth cave formed by the action of waves, with granite and dolerite as major components, and opal-A and calcite as part of the speleothems, making it a rare kind of cave. We generated two DNA shotgun sequencing metagenomic datasets from the interior of a speleothem from Tjuv-Ante’s cave representing areas of old and relatively recent speleothem formation. We used these datasets to perform i) an evaluation of the use of these speleothems as past biodiversity archives, ii) functional and taxonomic profiling of the speleothem’s different formation periods, and iii) taxonomic comparison of the metagenomic results to previous microscopic analyses from a nearby speleothem of the same cave. Our analyses confirm the abundance of Actinobacteria and fungi as previously reported by microscopic analyses on this cave, however we also discovered a larger biodiversity. Interestingly, we identified photosynthetic genes, as well as genes related to iron and sulphur metabolism, suggesting the presence of chemoautotrophs. Furthermore, we identified taxa and functions related to biomineralization. However, we could not confidently establish the use of this type of speleothems as biological paleoarchives due to the potential leaching from the outside of the cave and the DNA damage that we propose has been caused by the fungal chemical etching.

    Fulltekst (pdf)
    fulltext
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