Schäfer, Nadine

[["dc.bibliographiccitation.firstpage","1535"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Biogeosciences"],["dc.bibliographiccitation.lastpage","1548"],["dc.bibliographiccitation.volume","15"],["dc.contributor.author","Duda, Jan-Peter"],["dc.contributor.author","Thiel, Volker"],["dc.contributor.author","Bauersachs, Thorsten"],["dc.contributor.author","Mißbach, Helge"],["dc.contributor.author","Reinhardt, Manuel"],["dc.contributor.author","Schäfer, Nadine"],["dc.contributor.author","Van Kranendonk, Martin J."],["dc.contributor.author","Reitner, Joachim"],["dc.date.accessioned","2019-07-09T11:45:21Z"],["dc.date.available","2019-07-09T11:45:21Z"],["dc.date.issued","2018"],["dc.description.abstract","Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic). In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia). Catalytic hydropyrolysis (HyPy) of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution ( n-C18) is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer–Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface) environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (“hydrothermal pump hypothesis”)"],["dc.identifier.doi","10.5194/bg-15-1535-2018"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15113"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59212"],["dc.language.iso","en"],["dc.relation.issn","1726-4189"],["dc.relation.orgunit","Abteilung Geobiologie"],["dc.subject.ddc","550"],["dc.title","Ideas and perspectives: hydrothermally driven redistribution and sequestration of early Archaean biomass – the “hydrothermal pump hypothesis”"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e0177542"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","PLoS ONE"],["dc.bibliographiccitation.volume","12"],["dc.contributor.author","Heim, Christine N."],["dc.contributor.author","Quéric, Nadia Valérie"],["dc.contributor.author","Lonescu, Danny"],["dc.contributor.author","Schaefer, Nadine"],["dc.contributor.author","Reitner, Joachim"],["dc.date.accessioned","2018-11-07T10:23:44Z"],["dc.date.available","2018-11-07T10:23:44Z"],["dc.date.issued","2017"],["dc.description.abstract","Stromatolitic iron-rich structures have been reported from many ancient environments and are often described as Frutexites, a cryptic microfossil. Although microbial formation of such structures is likely, a clear relation to a microbial precursor is lacking so far. Here we report recent iron oxidizing biofilms which resemble the ancient Frutexites structures. The living Frutexites-like biofilms were sampled at 160 m depth in the Aspo Hard Rock Laboratory in Sweden. Investigations using microscopy, 454 pyrosequencing, FISH, Raman spectros-copy, biomarker and trace element analysis allowed a detailed view of the structural components of the mineralized biofilm. The most abundant bacterial groups were involved in nitrogen and iron cycling. Furthermore, Archaea are widely distributed in the Frutexites-like biofilm, even though their functional role remains unclear. Biomarker analysis revealed abundant sterols in the biofilm most likely from algal and fungal origins. Our results indicate that the Frutexites-like biofilm was built up by a complex microbial community. The functional role of each community member in the formation of the dendritic structures, as well as their potential relation to fossil Frutexites remains under investigation."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2017"],["dc.identifier.doi","10.1371/journal.pone.0177542"],["dc.identifier.isi","000401672600015"],["dc.identifier.pmid","28542238"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14488"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/42518"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","1932-6203"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0/"],["dc.title","Frutexites-like structures formed by iron oxidizing biofilms in the continental subsurface (Aspo Hard Rock Laboratory, Sweden)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","127"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","FOSSIL RECORD"],["dc.bibliographiccitation.lastpage","135"],["dc.bibliographiccitation.volume","18"],["dc.contributor.author","Hartl, C."],["dc.contributor.author","Schmidt, A. R."],["dc.contributor.author","Heinrichs, Jochen"],["dc.contributor.author","Seyfullah, Leyla J."],["dc.contributor.author","Schaefer, N."],["dc.contributor.author","Groehn, Carsten"],["dc.contributor.author","Rikkinen, Jouko"],["dc.contributor.author","Kaasalainen, Ulla"],["dc.date.accessioned","2018-11-07T10:02:30Z"],["dc.date.available","2018-11-07T10:02:30Z"],["dc.date.issued","2015"],["dc.description.abstract","The fossil record of lichens is scarce and many putative fossil lichens do not show an actual physiological relationship between mycobionts and photobionts or a typical habit, and are therefore disputed. Amber has preserved a huge variety of organisms in microscopic fidelity, and so the study of amber fossils is promising for elucidating the fossil history of lichens. However, so far it has not been tested as to how amber inclusions of lichens are preserved regarding their internal characters, ultrastructure, and chemofossils. Here, we apply light microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Raman spectroscopy to an amber-preserved Eocene lichen in order to gain information about the preservation of the fossil. The lichen thallus displays lifelike tissue preservation including the upper and lower cortex, medulla, photobiont layer, apothecia, and soredia. SEM analysis revealed globular photobiont cells in contact with the fungal hyphae, as well as impressions of possible former crystals of lichen compounds. EDX analysis permitted the differentiation between halite and pyrite crystals inside the lichen which were likely formed during the later diagenesis of the amber piece. Raman spectroscopy revealed the preservation of organic compounds and a difference between the composition of the cortex and the medulla of the fossil."],["dc.description.sponsorship","Alexander von Humboldt Foundation"],["dc.identifier.doi","10.5194/fr-18-127-2015"],["dc.identifier.isi","000371181900004"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/12566"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/38236"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Copernicus Gesellschaft Mbh"],["dc.relation.issn","2193-0074"],["dc.relation.issn","2193-0066"],["dc.rights","CC BY 3.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/3.0/"],["dc.title","Lichen preservation in amber: morphology, ultrastructure, chemofossils, and taphonomic alteration"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e0147629"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","PLoS ONE"],["dc.bibliographiccitation.volume","11"],["dc.contributor.author","Duda, Jan-Peter"],["dc.contributor.author","Van Kranendonk, Martin J."],["dc.contributor.author","Thiel, Volker"],["dc.contributor.author","Ionescu, Danny"],["dc.contributor.author","Strauss, Harald"],["dc.contributor.author","Schaefer, Nadine"],["dc.contributor.author","Reitner, Joachim"],["dc.date.accessioned","2018-11-07T10:19:12Z"],["dc.date.available","2018-11-07T10:19:12Z"],["dc.date.issued","2016"],["dc.description.abstract","Paleoarchean rocks from the Pilbara Craton of Western Australia provide a variety of clues to the existence of early life on Earth, such as stromatolites, putative microfossils and geo-chemical signatures of microbial activity. However, some of these features have also been explained by non-biological processes. Further lines of evidence are therefore required to convincingly argue for the presence of microbial life. Here we describe a new type of microbial mat facies from the 3.4 Ga Strelley Pool Formation, which directly overlies well known stromatolitic carbonates from the same formation. This microbial mat facies consists of laminated, very fine-grained black cherts with discontinuous white quartz layers and lenses, and contains small domical stromatolites and wind-blown crescentic ripples. Light-and cathodoluminescence microscopy, Raman spectroscopy, and time of flight-secondary ion mass spectrometry (ToF-SIMS) reveal a spatial association of carbonates, organic material, and highly abundant framboidal pyrite within the black cherts. Nano secondary ion mass spectrometry (NanoSIMS) confirmed the presence of distinct spheroidal carbonate bodies up to several tens of mu m that are surrounded by organic material and pyrite. These aggregates are interpreted as biogenic. Comparison with Phanerozoic analogues indicates that the facies represents microbial mats formed in a shallow marine environment. Carbonate precipitation and silicification by hydrothermal fluids occurred during sedimentation and earliest diagenesis. The deciphered environment, as well as the delta C-13 signature of bulk organic matter (-35.3 parts per thousand), are in accord with the presence of photoautotrophs. At the same time, highly abundant framboidal pyrite exhibits a sulfur isotopic signature (delta S-34 = +3.05 parts per thousand;Delta S-33 = 0.268 parts per thousand; and Delta S-36 = -0.282 parts per thousand) that is consistent with microbial sulfate reduction. Taken together, our results strongly support a microbial mat origin of the black chert facies, thus providing another line of evidence for life in the 3.4 Ga Strelley Pool Formation."],["dc.description.sponsorship","Open-Access Publikationsfonds 2016"],["dc.identifier.doi","10.1371/journal.pone.0147629"],["dc.identifier.isi","000369527800155"],["dc.identifier.pmid","26807732"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/12848"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/41616"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1932-6203"],["dc.relation.orgunit","Fakultät für Geowissenschaften und Geographie"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0/"],["dc.title","A Rare Glimpse of Paleoarchean Life: Geobiology of an Exceptionally Preserved Microbial Mat Facies from the 3.4 Ga Strelley Pool Formation, Western Australia"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]