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  • 1
    Language: English
    In: Palaeogeography, Palaeoclimatology, Palaeoecology, 2013-02-01, Vol.371, pp.9-25
    Description: The Paleocene–Eocene Thermal Maximum (PETM; ~55.8 Ma) is considered as the most severe of a series of transient warming events (“hyperthermals”) that occurred during the Early Paleogene. However, the extent and magnitude of environmental changes during the short-lived warming events pre- and post-dating the PETM are still poorly constrained. In this study, we focus on the Latest Danian Event (LDE, ~61.7 Ma) and compare it to the PETM. We present high-resolution micropaleontological, geochemical, and mineralogical data of the PETM and the LDE in two adjacent sections from the Gebel Qreiya area in Egypt. There, both events are characterized by a distinct set of event beds overlying an unconformity. They are associated with intense carbonate dissolution and substantial changes in the benthic foraminifera fauna. Moreover, both show an abrupt drop of siliciclastic input (sediment starvation) correlative to the onset of black shale formation and a strong enrichment in redox-sensitive trace elements. The evidence for enhanced detrital input during the onset of the PETM and a longer recovery phase with enhanced phosphorus-sedimentation during the PETM attests a stronger environmental impact of this event compared to the LDE. According to Rock-Eval and elemental analysis, the PETM as well as the LDE event beds have up to 4 wt.% organic carbon, small amounts of volatile hydrocarbons, but high amounts of highly weathered and inert organic matter (“black carbon”). During pyrolysis, the extremely high temperatures for the maximum release of hydrocarbons of the PETMand LDE samples correspond to thermal heating of 〉170 °C,which is incompatible with the sediment burial history. Therefore, we suggest that the organic matter in both event deposits does not reflect well-preserved marine biomass but predominantly represents a mixture of heavily weathered autochthonous marine material and allochthonous combustion residues. Differences in preservation and/or type of organic matter are also likely to account for the divergent stable isotope anomalies of organic carbon: the well-known negative carbon isotope anomaly at the PETM and a positive anomaly at the LDE. Although warming, water column stratification, and enhanced nutrient input may have promoted anoxic conditions on the shelf during the LDE as well as during PETM, our results support rapid sea level rise and clastic starvation as one important mechanism for black shale formation and carbon sequestration for both events. This result underlines the similarity of both hyperthermal events in terms of environmental changes recorded on the Southern Tethyan margin, with the PETM showing an additional early phase of strong detrital input not revealed at the LDE.
    ISSN: 0031-0182
    Source: KU Leuven Association
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  • 2
    Language: English
    In: Phytochemistry, Feb, 2014, Vol.98, p.145(6)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.phytochem.2013.11.007 Byline: Thorsten Bauersachs, Opayi Mudimu, Rudiger Schulz, Lorenz Schwark Abstract: Long chain heterocyst glycolipids (HG32 triols and HG32 keto-diols) constitute a unique component of the heterocyst cell envelope of stigonematalean cyanobacteria. Article History: Received 4 September 2013; Revised 5 November 2013
    Keywords: Plant Lipids ; Cyanobacteria ; Membrane Lipids
    ISSN: 0031-9422
    Source: Cengage Learning, Inc.
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  • 3
    Language: English
    In: Earth and Planetary Science Letters, April 15, Vol.416, p.147(4)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.epsl.2015.02.022 Byline: Wolfgang Ruebsam, Petra Munzberger, Lorenz Schwark Author Affiliation: (a) Department of Organic Geochemistry, Institute of Geoscience, University of Kiel, Germany (b) Geological Survey Luxembourg, Luxembourg (c) WA-OIGC, Curtin University, Perth, Australia Article History: Received 11 February 2015; Accepted 13 February 2015 Article Note: (miscellaneous) Editor: J. Lynch-Stieglitz
    Keywords: Jurassic Period – Chronologies
    ISSN: 0012-821X
    Source: Cengage Learning, Inc.
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  • 4
    Language: English
    In: Earth and Planetary Science Letters, Oct 15, 2014, Vol.404, p.273(10)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.epsl.2014.08.005 Byline: Wolfgang Ruebsam, Petra Munzberger, Lorenz Schwark Abstract: Author Affiliation: (a) Department of Organic Geochemistry, Institute of Geoscience, University of Kiel, Germany (b) Geological Survey Luxembourg, Luxembourg (c) WA-OIGC, Curtin University, Perth, Australia Article History: Received 3 March 2014; Revised 30 July 2014; Accepted 3 August 2014 Article Note: (miscellaneous) Editor: J. Lynch-Stieglitz
    Keywords: Jurassic Period -- Chronologies ; Jurassic Period -- Environmental Aspects
    ISSN: 0012-821X
    Source: Cengage Learning, Inc.
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  • 5
    Language: English
    In: Palaeogeography, Palaeoclimatology, Palaeoecology, Sept 15, 2014, Vol.410, p.390(11)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.palaeo.2014.06.015 Byline: Thorsten Bauersachs, Stefan Schouten, Lorenz Schwark Abstract: We investigated a 150m thick drill core section of Messel oil shale using bulk geochemical and stable isotope techniques in order to determine the organic matter sources and the environmental conditions that prevailed during the deposition of the lacustrine sequence. High C.sub.org values (on average 27%) indicate that the Messel oil shale has likely been deposited under highly productive conditions and/or in an environment largely free of oxygen, which suggests a permanent stratification of the paleolake and prolonged periods of bottom water anoxia. Low stable nitrogen isotope values (ca. +1 to +2a[degrees]), observed at the transition from holomictic to meromictic conditions, suggest a brief period of an increased contribution of diazotrophic, possibly heterocystous, cyanobacteria that proliferated under the stagnant conditions. The basal oil shale unit (Lower Messel-Formation) is characterized by generally high HI values (〉570mg HC/g C.sub.org) and molar C.sub.org/N.sub.tot ratios (〉35) that evidence an increased loading of terrestrial organic matter to the lake system, which is hypothesized to be dominated by the lipid-rich constituents of vascular plants. The oil shale of the mid-section (Middle Messel-Formation) is characterized by carbon isotope excursions towards comparatively heavy [delta].sup.13C.sub.org values of -24a[degrees] that together with slightly lower C.sub.org/N.sub.tot ratios (ca. 30) of this interval are taken as evidence for a higher loading of aquatic-derived organic matter to the paleolake. The uppermost part of the Middle Messel-Formation displays decreasing [delta].sup.13C.sub.org and concomitantly high [delta].sup.15N.sub.tot values, which is interpreted to indicate an increased importance of bacterial driven processes (such as methanogenesis, methanotrophy and denitrification) in the paleolake system. Our results thus indicate that the Eocene maar lake received organic matter from various autochthonous and allochthonous sources with contributions of each source varying significantly over the lake's existence. Article History: Received 31 March 2014; Revised 6 June 2014; Accepted 9 June 2014
    Keywords: Shale Oils -- Chemical Properties ; Oil Shales -- Chemical Properties ; Denitrification -- Chemical Properties
    ISSN: 0031-0182
    Source: Cengage Learning, Inc.
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  • 6
    Language: English
    In: Palaeogeography, Palaeoclimatology, Palaeoecology, Feb 1, 2013, Vol.371, p.9(17)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.palaeo.2012.11.027 Byline: Peter Schulte, Lorenz Schwark, Peter Stassen, Tanja J. Kouwenhoven, Andre Bornemann, Robert P. Speijer Keywords: Paleocene; Eocene; Egypt; Tethyan shelf; Hyperthermals; PETM; LDE Abstract: The Paleocene-Eocene Thermal Maximum (PETM; ~55.8Ma) is considered as the most severe of a series of transient warming events ("hyperthermals") that occurred during the Early Paleogene. However, the extent and magnitude of environmental changes during the short-lived warming events pre- and post-dating the PETM are still poorly constrained. In this study, we focus on the Latest Danian Event (LDE, ~61.7Ma) and compare it to the PETM. We present high-resolution micropaleontological, geochemical, and mineralogical data of the PETM and the LDE in two adjacent sections from the Gebel Qreiya area in Egypt. There, both events are characterized by a distinct set of event beds overlying an unconformity. They are associated with intense carbonate dissolution and substantial changes in the benthic foraminifera fauna. Moreover, both show an abrupt drop of siliciclastic input (sediment starvation) correlative to the onset of black shale formation and a strong enrichment in redox-sensitive trace elements. The evidence for enhanced detrital input during the onset of the PETM and a longer recovery phase with enhanced phosphorus-sedimentation during the PETM attests a stronger environmental impact of this event compared to the LDE. According to Rock-Eval and elemental analysis, the PETM as well as the LDE event beds have up to 4wt.% organic carbon, small amounts of volatile hydrocarbons, but high amounts of highly weathered and inert organic matter ("black carbon"). During pyrolysis, the extremely high temperatures for the maximum release of hydrocarbons of the PETM and LDE samples correspond to thermal heating of 〉170[degrees]C, which is incompatible with the sediment burial history. Therefore, we suggest that the organic matter in both event deposits does not reflect well-preserved marine biomass but predominantly represents a mixture of heavily weathered autochthonous marine material and allochthonous combustion residues. Differences in preservation and/or type of organic matter are also likely to account for the divergent stable isotope anomalies of organic carbon: the well-known negative carbon isotope anomaly at the PETM and a positive anomaly at the LDE. Although warming, water column stratification, and enhanced nutrient input may have promoted anoxic conditions on the shelf during the LDE as well as during PETM, our results support rapid sea level rise and clastic starvation as one important mechanism for black shale formation and carbon sequestration for both events. This result underlines the similarity of both hyperthermal events in terms of environmental changes recorded on the Southern Tethyan margin, with the PETM showing an additional early phase of strong detrital input not revealed at the LDE. Article History: Received 31 March 2012; Revised 28 October 2012; Accepted 27 November 2012
    Keywords: Carbonates -- Analysis ; Paleogene Period -- Analysis ; Shales -- Analysis ; Pyrolysis -- Analysis
    ISSN: 0031-0182
    Source: Cengage Learning, Inc.
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  • 7
    Language: English
    In: Palaeogeography, Palaeoclimatology, Palaeoecology, 2006, Vol.240(1), pp.225-236
    Description: Algae are among the oldest organisms known to inhabit the Earth's biosphere with a record dating back some 2.7 Ga. Only few marine algae produce hard parts that can be preserved over geologic time and consequently their fossil record is incomplete. Molecular fossils or biomarkers add complementary information to the fossil palynomorph record. Steroids are important constituents of eukaryotic cell-membranes and are preserved in sediments as steranes. C - and C -steranes are indicators for the presence of green and C -steranes for the presence of red algae, respectively. The relative abundance of steranes allows the investigation of the fossil record for Palaeozoic algal diversification and evolution. In this study, 500 Palaeozoic rock samples, representing a broad facies variety from the Upper Ordovician to the P/T-boundary were investigated for sterane compositions. In addition three profiles covering the Hirnantian, the F/F and the Hangenberg-Event were analyzed for possible shifts in the sterane distribution associated with extinction events. A sharp increase of the C /C -sterane ratio from 〈 0.55 to 〉 0.70 at the Devonian/Carboniferous boundary implies a fundamental change in the green algae assemblage from more primitive, mainly C -sterane-producing algae, to modern C -sterane-producing algae. For all investigated extinction events a pronounced but short-lived rise in the C -sterane content occurs that is attributed to an episodic increase in prasinophytes. The gradual radiation of algae may have been triggered by frequent mass extinctions in the Upper Devonian culminating with the massive decline of acritarchs at the D/C-boundary. The coeval rise in the C /C -sterane ratio indicates the presence of an non-encysting algal group and coincides with the global augmentation of numerous filamentous Codiacea (Siphonales) and the rise of euspondyle and metaspondyle Dasycladales.
    Keywords: Green Algae ; Prasinophytes ; Steroid Biomarkers ; Steranes ; Palaeozoic ; Extinction Events ; Geology
    ISSN: 0031-0182
    E-ISSN: 1872-616X
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  • 8
    Language: English
    In: Science of the Total Environment, 15 April 2017, Vol.584-585, pp.19-28
    Description: In January 2011, fuel quality in inland water vessels was changed by EU regulation 2009/30/EC, aiming at improving air quality along waterways. We hypothesized that the implementation of this regulation both lowered the total deposition of polycyclic aromatic hydrocarbons (PAHs) and changed their composition in river valleys. We analyzed parent-, alkylated- and thio-PAHs in soil and vine leaves, at two waterways (Rhine and Moselle, Germany), as well as in one ship-free reference area (Ahr, Germany). Samples were taken annually (2010–2013) in transects perpendicular to the rivers. We did not find any relation of PAH concentration and composition on vine leaves to inland navigation, likely because atmospheric exchange processes distorted ship-specific accumulation patterns. We did find, however, an accumulation of ship-borne PAHs in topsoil near the waterways (1543 ± 788 and 581 ± 252 ng g at Moselle and Rhine, respectively), leading to larger PAH concentrations at the Moselle Valley than at the reference area (535 ± 404 ng g ) prior to EU fuel regulation. After fuel regulation, the PAH concentrations decreased in topsoils of the Moselle and Rhine Valley by 35 ± 9 and 62 ± 28%, respectively. These changes were accompanied by increasing proportions of dibenzothiophene (DBT) and low molecular weight PAHs. Both, changes in PAH concentrations and composition were traceable within 200 and 350 m distance to the river front of Moselle and Rhine, respectively, and likely favored by erosion of topsoil in vineyards. We conclude that the EU regulation was effective in improving soil and thus also air quality within only three years. The impact was greater and spatially more relevant at the Rhine, which may be attributed to the larger traffic volume of inland navigation.
    Keywords: Inland Waterways ; Polycyclic Aromatic Hydrocarbons ; Diesel Combustion ; Thioaromatics ; Passive Samplers ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 9
    Language: English
    In: Phytochemistry, February 2014, Vol.98, pp.145-150
    Description: Long chain heterocyst glycolipids (HG32 triols and HG32 keto-diols) constitute a unique component of the heterocyst cell envelope of stigonematalean cyanobacteria. N -fixing heterocystous cyanobacteria have been shown to hold a suite of unique glycolipids, so-called heterocyst glycolipids (HGs), as part of the heterocyst cell envelope. It was also demonstrated that the distribution of these components bears a high level of chemotaxonomic information, which allows distinguishing heterocystous cyanobacteria of the order Nostocales on a family or even genus level. Here we report the heterocyst glycolipid composition of five representatives of the order Stigonematales ( , sp., , and sp.), which have largely escaped a detailed investigation of their HG content so far. All analyzed strains contained a similar qualitative mixture of HGs with 1-( -hexose)-3,29,31-dotriacontanetriol (HG triol) dominating over minor quantities of 1-( -hexose)-29-keto-3,31-dotriacontanediol (HG keto-diol). When viewed in conjunction with previous culture studies on the HG composition of heterocystous cyanobacteria, our results demonstrate that HG triols and their corresponding keto-diol varieties are characteristic biological markers for heterocystous cyanobacteria of the order Stigonematales. Given that these N -fixers primarily occur in tropical to subtropical freshwater lakes and subaerial habitats, the presence of HG triols and keto-diols in sedimentary sequences may offer additional information on climatic conditions in palaeoenvironmental studies.
    Keywords: Fischerella Muscicola ; Nostochopsis Lobatus ; Westiellopsis Prolifica ; Fischerellaceae ; Nostochopsidaceae ; Stigonemataceae ; Hplc–MS/MS ; Intact Polar Lipids ; Chemotaxonomy ; Diazotrophs ; Botany
    ISSN: 0031-9422
    E-ISSN: 1873-3700
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  • 10
    Language: English
    In: Palaeogeography, Palaeoclimatology, Palaeoecology, 15 September 2014, Vol.410, pp.390-400
    Description: We investigated a 150 m thick drill core section of Messel oil shale using bulk geochemical and stable isotope techniques in order to determine the organic matter sources and the environmental conditions that prevailed during the deposition of the lacustrine sequence. High C values (on average 27%) indicate that the Messel oil shale has likely been deposited under highly productive conditions and/or in an environment largely free of oxygen, which suggests a permanent stratification of the paleolake and prolonged periods of bottom water anoxia. Low stable nitrogen isotope values (ca. + 1 to + 2‰), observed at the transition from holomictic to meromictic conditions, suggest a brief period of an increased contribution of diazotrophic, possibly heterocystous, cyanobacteria that proliferated under the stagnant conditions. The basal oil shale unit (Lower Messel-Formation) is characterized by generally high HI values (〉 570 mg HC/g C ) and molar C /N ratios (〉 35) that evidence an increased loading of terrestrial organic matter to the lake system, which is hypothesized to be dominated by the lipid-rich constituents of vascular plants. The oil shale of the mid-section (Middle Messel-Formation) is characterized by carbon isotope excursions towards comparatively heavy δ C values of − 24‰ that together with slightly lower C /N ratios (ca. 30) of this interval are taken as evidence for a higher loading of aquatic-derived organic matter to the paleolake. The uppermost part of the Middle Messel-Formation displays decreasing δ C and concomitantly high δ N values, which is interpreted to indicate an increased importance of bacterial driven processes (such as methanogenesis, methanotrophy and denitrification) in the paleolake system. Our results thus indicate that the Eocene maar lake received organic matter from various autochthonous and allochthonous sources with contributions of each source varying significantly over the lake's existence.
    Keywords: Eocene ; Lacustrine Sediments ; Maar Lake ; Paleoenvironmental Reconstruction ; Terrestrial Organic Matter ; Tetraedron Minimum ; Geology
    ISSN: 0031-0182
    E-ISSN: 1872-616X
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