In recent anoxic sediments manganese(II)carbonate minerals (e.g., rhodochrosite, kutnohorite) der... more In recent anoxic sediments manganese(II)carbonate minerals (e.g., rhodochrosite, kutnohorite) derive mainly from the reduction of manganese(IV) compounds by microbial anaerobic respiration. Small particles of rhodochrosite in stromatolite-like features in the Dresser chert Fm (Pilbara supergroup, W-Australia), associated with small flakes of kerogen, account for biogenic formation of the mineral in this early Archaean setting. Contrastingly, the formation of huge manganese-rich (carbonate) deposits requires effective manganese redox cycling, also conducted by various microbial processes, mainly requiring conditions of the early and late Proterozoic (Kirschvink et al., 2000; Nealson and Saffrani 1994). However, putative anaerobic pathways like microbial nitrate-dependent manganese oxidation (Hulth et al., 1999), anoxygenic photosynthesis (Johnson et al., 2013) and oxidation in UV light may facilitate manganese cycling even in a reducing atmosphere. Thus manganese redox cycling might ...
Following the collapse of the early Cambrian calcimicrobial-archaeocyathan reef consortium, metaz... more Following the collapse of the early Cambrian calcimicrobial-archaeocyathan reef consortium, metazoans played little part in reef construction through the latter half of the Cambrian and earliest Ordovician. This interval was dominated by microbial reefs. Nevertheless, exceptional metazoan-moderated reefs have been reported from peri-Gondwanan Iran and Laurentia, and more recently from North China. The metazoan participants in these reefs were primarily spiculate sponges, which increasingly participated in reef construction over time. Two northern Australian examples provide further documentation of metazoan-moderated reefs immediately following the early Cambrian reef collapse. In the Ranken Limestone of the Georgina Basin (probably late Drumian-early Guzhangian), reefs were constructed by a calcimicrobial consortium including Angulocellularia and minor Taninia; these encrusted a scaffold of the anthaspidellid spiculate sponge Rankenella, as well as other skeletal metazoans. Older, ...
In recent years, a large diversity of sponge-microbe associations has been described: sponges can... more In recent years, a large diversity of sponge-microbe associations has been described: sponges can harbour archaea, eubacteria (including cyanobacteria), microalgae, fungi and probably also protozoa. The current paper gives a brief overview of the different types of associations and describes the potential influence of symbiotic micro-organisms on bioprocess design for the biotechnological production of sponge-associated natural compounds. It is concluded
Based on preliminary observations and fossil records a new subdivision of the Plattenkalk Group o... more Based on preliminary observations and fossil records a new subdivision of the Plattenkalk Group of the Taygetos Mountains of the Peloponnesus is proposed. Furthermore in this work we present the first record of relics of lithistid demosponges from tertiary ...
The aftermath of the Permian – Triassic crisis is characterized by ubiquitous occurrences of micr... more The aftermath of the Permian – Triassic crisis is characterized by ubiquitous occurrences of microbial sediments around the world. For instance, Triassic deposits of the Germanic Basin have shown to provide a rich record of stromatolites as well as of microbe-metazoan build-ups with non-spicular demosponges. Despite their paleoecological significance, however, all of these microbialites have only rarely been studied. This study aims to fill this gap by examining and comparing microbialites from the Upper Buntsandstein (Olenekian, Early Triassic) and the lower Middle Muschelkalk (Anisian, Middle Triassic). By combining analytical petrography (optical microscopy, micro X-ray fluorescence, Raman spectroscopy) and geochemistry (δ13Ccarb, δ18Ocarb), we show that all studied microbialites formed in hypersaline lagoons to sabkha environments. Olenekian deposits in Jena and surroundings and Anisian strata at Werbach contain stromatolites. Anisian successions at Hardheim, in contrast, host m...
In recent anoxic sediments manganese(II)carbonate minerals (e.g., rhodochrosite, kutnohorite) der... more In recent anoxic sediments manganese(II)carbonate minerals (e.g., rhodochrosite, kutnohorite) derive mainly from the reduction of manganese(IV) compounds by microbial anaerobic respiration. Small particles of rhodochrosite in stromatolite-like features in the Dresser chert Fm (Pilbara supergroup, W-Australia), associated with small flakes of kerogen, account for biogenic formation of the mineral in this early Archaean setting. Contrastingly, the formation of huge manganese-rich (carbonate) deposits requires effective manganese redox cycling, also conducted by various microbial processes, mainly requiring conditions of the early and late Proterozoic (Kirschvink et al., 2000; Nealson and Saffrani 1994). However, putative anaerobic pathways like microbial nitrate-dependent manganese oxidation (Hulth et al., 1999), anoxygenic photosynthesis (Johnson et al., 2013) and oxidation in UV light may facilitate manganese cycling even in a reducing atmosphere. Thus manganese redox cycling might ...
Following the collapse of the early Cambrian calcimicrobial-archaeocyathan reef consortium, metaz... more Following the collapse of the early Cambrian calcimicrobial-archaeocyathan reef consortium, metazoans played little part in reef construction through the latter half of the Cambrian and earliest Ordovician. This interval was dominated by microbial reefs. Nevertheless, exceptional metazoan-moderated reefs have been reported from peri-Gondwanan Iran and Laurentia, and more recently from North China. The metazoan participants in these reefs were primarily spiculate sponges, which increasingly participated in reef construction over time. Two northern Australian examples provide further documentation of metazoan-moderated reefs immediately following the early Cambrian reef collapse. In the Ranken Limestone of the Georgina Basin (probably late Drumian-early Guzhangian), reefs were constructed by a calcimicrobial consortium including Angulocellularia and minor Taninia; these encrusted a scaffold of the anthaspidellid spiculate sponge Rankenella, as well as other skeletal metazoans. Older, ...
In recent years, a large diversity of sponge-microbe associations has been described: sponges can... more In recent years, a large diversity of sponge-microbe associations has been described: sponges can harbour archaea, eubacteria (including cyanobacteria), microalgae, fungi and probably also protozoa. The current paper gives a brief overview of the different types of associations and describes the potential influence of symbiotic micro-organisms on bioprocess design for the biotechnological production of sponge-associated natural compounds. It is concluded
Based on preliminary observations and fossil records a new subdivision of the Plattenkalk Group o... more Based on preliminary observations and fossil records a new subdivision of the Plattenkalk Group of the Taygetos Mountains of the Peloponnesus is proposed. Furthermore in this work we present the first record of relics of lithistid demosponges from tertiary ...
The aftermath of the Permian – Triassic crisis is characterized by ubiquitous occurrences of micr... more The aftermath of the Permian – Triassic crisis is characterized by ubiquitous occurrences of microbial sediments around the world. For instance, Triassic deposits of the Germanic Basin have shown to provide a rich record of stromatolites as well as of microbe-metazoan build-ups with non-spicular demosponges. Despite their paleoecological significance, however, all of these microbialites have only rarely been studied. This study aims to fill this gap by examining and comparing microbialites from the Upper Buntsandstein (Olenekian, Early Triassic) and the lower Middle Muschelkalk (Anisian, Middle Triassic). By combining analytical petrography (optical microscopy, micro X-ray fluorescence, Raman spectroscopy) and geochemistry (δ13Ccarb, δ18Ocarb), we show that all studied microbialites formed in hypersaline lagoons to sabkha environments. Olenekian deposits in Jena and surroundings and Anisian strata at Werbach contain stromatolites. Anisian successions at Hardheim, in contrast, host m...
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Papers by Joachim Reitner