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Introduction: Long-term stability of underground CO2 storage is partially affected by microbial activity but our knowledge of these effects is limited, mainly due to a lack of sites. A consistently high flux of mantle-derived CO2 makes the Eger Rift in the Czech Republic a natural analogue to underground CO2 storage. The Eger Rift is a seismically active region and H2 is produced abiotically during earthquakes, providing energy to indigenous microbial communities. Methods: To investigate the response of a microbial ecosystem to high levels of CO2 and H2, we enriched microorganisms from samples from a 239.5 m long drill core from the Eger Rift. Microbial abundance, diversity and community structure were assessed using qPCR and 16S rRNA gene sequencing. Enrichment cultures were set up with minimal mineral media and H2/CO2 headspace to simulate a seismically active period with elevated H2. Results and discussion: Methane headspace concentrations in the enrichments indicated that active methanogens were almost exclusively restricted to enrichment cultures from Miocene lacustrine deposits (50-60 m), for which we observed the most significant growth. Taxonomic assessment showed microbial communities in these enrichments to be less diverse than those with little or no growth. Active enrichments were especially abundant in methanogens of the taxa Methanobacterium and Methanosphaerula. Concurrent to the emergence of methanogenic archaea, we also observed sulfate reducers with the metabolic ability to utilize H2 and CO2, specifically the genus Desulfosporosinus, which were able to outcompete methanogens in several enrichments. Low microbial abundance and a diverse non-CO2 driven microbial community, similar to that in drill core samples, also reflect the inactivity in these cultures. Significant growth of sulfate reducing and methanogenic microbial taxa, which make up only a small fraction of the total microbial community, emphasize the need to account for rare biosphere taxa when assessing the metabolic potential of microbial subsurface populations. The observation that CO2 and H2-utilizing microorganisms could only be enriched from a narrow depth interval suggests that factors such as sediment heterogeneity may also be important. This study provides new insight on subsurface microbes under the influence of high CO2 concentrations, similar to those found in CCS sites. [ABSTRACT FROM AUTHOR]

Modern tropical rainforests (TRFs) are one of the most ecologically important and species-rich biomes on the planet. However, the origin of modern TRFs is still debated, especially due to the incongruence between the fossil record and molecular data. Here, we test whether Campanian assemblages from northeastern Africa could represent fossil TRF vegetation. In so doing, we compare the investigated assemblages with other assemblages known to represent temperate forests, subtropical forests, and TRF in terms of leaf physiognomy, species richness, and taxonomic composition. We conclude based on fossil leaves that modern-looking TRFs already existed since 80 Ma during the Campanian in northeastern Africa in an area corresponding to 10 % of the modern Amazonian or 25 % of the Congolese TRF. The apparent conflict between the fossil record and phylogenetic evidence is due to the nearly complete absence of published tropical floras for the Cretaceous. [ABSTRACT FROM AUTHOR]

Modern tropical rain forests (TRF) are one of the most ecologically important and species-rich biomes on the planet. However, the origin of modern TRF is still debated, especially due to the incongruence between the fossil record and molecular data. Here, we are testing whether Campanian assemblages from north-eastern Africa could represent fossil TRF vegetation. In so doing, we compare the investigated assemblages with other assemblages known to represent temperate forests, subtropical forests, and TRF in terms of leaf physiognomy, species richness, and taxonomic composition. We assume that modern-looking TRF already existed about 80 Ma ago during the Campanian in north-eastern Africa based on fossil leaves in an area corresponding to 10 % of the modern Amazonian or 25 % of the Congolese TRF. The apparent conflict between the fossil record and phylogenetic evidence is due to the more or less absence of published tropical floras for the Cretaceous. [ABSTRACT FROM AUTHOR]

Modern tropical rain forests (TRF) are one of the most ecologically important and species-rich biomes on the planet. However, the origin of modern TRF is still debated, especially due to the incongruence between the fossil record and molecular data. Here, we are testing whether Campanian assemblages from north-eastern Africa could represent fossil TRF vegetation. In so doing, we compare the investigated assemblages with other assemblages known to represent temperate forests, subtropical forests, and TRF in terms of leaf physiognomy, species richness, and taxonomic composition. We assume that modern-looking TRF already existed about 80 Ma ago during the Campanian in north-eastern Africa based on fossil leaves in an area corresponding to 10% of the modern Amazonian or 25% of the Congolese TRF. The apparent conflict between the fossil record and phylogenetic evidence is due to the more or less absence of published tropical floras for the Cretaceous. [ABSTRACT FROM AUTHOR]

Here we report on a new dyrosaurid from the latest Cretaceous Kababish Formation, Sudan, which was previously unknown to yield fossil macrovertebrates and had remained largely unstudied. The almost complete, partially articulated skeleton was recovered in situ near Jebel Abyad. The skeleton is almost 7 m in length and preserves an almost complete skull and partly articulated postcranium with several disarticulated osteoderms. The material is assigned to Dyrosauridae based on the presence of elongate supratemporal fenestrae, occipital tuberosities, and a reduced seventh alveolus on the mandible. Morphological features of the skull and mandible differ from other members of this family suggesting that this taxon represents a new genus and species of dyrosaurid. A unique feature of the new taxon is that the humerus is wedge-shaped and longer than femur. Phylogenetic analyses using parsimony and Bayesian inference posit that the new taxon is deeply nested in Dyrosauridae as a sister taxon to a clade including Arambourgisuchus, Dyrosaurus, Acherontisuchus, Hyposaurus, Congosaurus, Rhabdognathus, Atlantosuchus, and Guarinisuchus. The occurrence of the new dyrosaurid within the Kababish Formation potentially extends the temporal range of the Dyrosauridae to the Campanian and supports previous hypotheses of an African origin for this family. [ABSTRACT FROM AUTHOR]

The region around Tendaguru Hill in southeastern Tanzania has provided a rich, Late Jurassic dinosaur fauna. Among them, thousands of bones of the basal iguanodontian ornithopod Dysalotosaurus lettowvorbecki have been excavated in the Ig/WJ-quarry northwest of the Tendaguru Hill. The incomplete record of the taphonomic information from the excavation is the main reason for the still inconclusive interpretation of the assemblage as either catastrophic or attritional in origin. In this study, all available historical notes, sketches and field catalogues were analysed and combined with data from CT scans, new taphonomic observations and from bone histological as well as demographic analyses. According to these combined results, the mass accumulation of remains of D. lettowvorbecki consists of four closely associated bonebeds in at least three different stratigraphic levels. The bonebeds are classified as mixed, multitaxic, and monodominant. There is no evidence of abrasion and preburial weathering on the bones suggesting minimal transport distances and duration as well as short preburial exposure times. Although the size/age distributions are bimodally U-shaped, the bonebeds are interpreted as catastrophic in origin due to the restricted spatial extent and the overall uniform preservation of the bones. It is proposed that different herds of D. lettowvorbecki crossed a tidal channel several times during seasonal migration and that each time several to dozens of individuals died. The bodies decomposed and were buried at a barrier or a bend nearby. The demographic conditions as well as the modes of death and burial of D. lettowvorbecki are very similar to the observations made from the modern blue wildebeest in the Masai-Mara Reserve in Kenya. [ABSTRACT FROM AUTHOR]

The Hartoušov mofette system is a natural CO2 degassing site in the central Cheb Basin (Eger Rift, Central Europe). In early 2016 a 108 m deep core was obtained from this system to investigate the impact of ascending mantle-derived CO2 on indigenous deep microbial communities and their surrounding life habitat. During drilling, a CO2 blow out occurred at a depth of 78.5 meter below surface (mbs) suggesting a CO2 reservoir associated with a deep low-permeable CO2-saturated saline aquifer at the transition from Early Miocene terrestrial to lacustrine sediments. Past microbial communities were investigated by hopanoids and glycerol dialkyl glycerol tetraethers (GDGTs) reflecting the environmental conditions during the time of deposition rather than showing a signal of the current deep biosphere. The composition and distribution of the deep microbial community potentially stimulated by the upward migration of CO2 starting during Mid Pleistocene time was investigated by intact polar lipids (IPLs), quantitative polymerase chain reaction (qPCR), and deoxyribonucleic acid (DNA) analysis. The deep biosphere is characterized by microorganisms that are linked to the distribution and migration of the ascending CO2-saturated groundwater and the availability of organic matter instead of being linked to single lithological units of the investigated rock profile. Our findings revealed high relative abundances of common soil and water bacteria, in particular the facultative, anaerobic and potential iron-oxidizing Acidovorax and other members of the family Comamonadaceae across the whole recovered core. The results also highlighted the frequent detection of the putative sulfate-oxidizing and CO2-fixating genus Sulfuricurvum at certain depths. A set of new IPLs are suggested to be indicative for microorganisms associated to CO2 accumulation in the mofette system. [ABSTRACT FROM AUTHOR]