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In this study, organic petrology and Osmium isotope (187Os/188Os) stratigraphy, major and trace element, and programmed pyrolysis analysis were performed on five outcrop samples from western New York, USA. Seawater Os isotope composition is controlled by radiogenic input from weathering of the ancient land and nonradiogenic input from extraterrestrial and hydrothermal sources (Peucker-Ehrenbrink and Ravizza, 2000). Os is complexed by the organic matter present at the time of deposition without isotope fractionation. Seawater Os isotope composition is reconstructed by analysing the Os isotope composition of the organic-rich sedimentary rock (Turgeon et al., 2007). The short residence time of Os (10 – 50 kyrs) in...
Whole-plant and leaf nitrogen isotope composition are determined by the isotope ratio of the external nitrogen source and physiological mechanisms within the plant. Whole-plant isotope composition can reflect that of the nitrogen source when plant demand exceeds nitrogen supply. Uptake by mycorrhizae can cause the isotope ratio of the plant to deviate from the source. Intra-plant variation in isotope composition can be caused by multiple assimilation events, organ-specific loss of nitrogen, and resorption and reallocation of nitrogen. Future work must address acquisition of organic nitrogen from the soil solution, the role of mycorrhizae, and internal transformations within the plant. Published in Trends in Plant...
    map background search result map search result map Enhanced wildfire at the Frasnian-Famennian boundary and its implications for O2 level and F-F mass extinction: evidence from organic petrology and Os isotope stratigraphy Enhanced wildfire at the Frasnian-Famennian boundary and its implications for O2 level and F-F mass extinction: evidence from organic petrology and Os isotope stratigraphy