Development and Paleoceanographic Application of Planktonic Formanifera-bound Nitrogen Isotopes
Author: Haojia Ren
Publisher:
Published: 2010
Total Pages: 496
ISBN-13:
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Author: Haojia Ren
Publisher:
Published: 2010
Total Pages: 496
ISBN-13:
DOWNLOAD EBOOKAuthor: Marietta Straub
Publisher:
Published: 2012
Total Pages: 278
ISBN-13:
DOWNLOAD EBOOKAuthor: Emma Ruth Kast
Publisher:
Published: 2020
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKAs an essential nutrient required by all organisms, biologically available nitrogen (?fixed N?) plays an integral role in biogeochemical cycling at Earth?s surface. The nitrogen isotope ratio (15N/14N, ?15N) of fixed N is sensitive to biogeochemical transformations that constitute the nitrogen cycle. Additionally, the ?15N of organisms increases with trophic level. ?15N can be a powerful tool for reconstructing the N cycle and the trophic level of organisms, yet poor preservation of N in the geologic record have limited our ability to apply ?15N on million-year timescales. This dissertation focuses on million-year time scale nitrogen cycling and trophic ecology using biogenic mineral-bound organic matter ?15N.A foraminifera shell-bound organic matter ?15N (FB-?15N) record is presented for the early Cenozoic (66 million years ago until present). There is a large decrease (by ~15 ? in the Pacific and by ~ 6 ? in the Atlantic) between 57 and 50 million years ago, before Eocene global cooling. This indicates expanded ocean suboxia in the Paleocene, followed by its tectonically driven demise.Mineral-bound ?15N methods are adapted for use with tooth enamel and enameloid, abundant fossils that are widely used in geochemical and paleontological studies of the past. Enamel(oid)-bound organic matter ?15N (?15NEB) has a long-term method precision of 0.7 ? (1?) and there is substantial evidence for preservation on million-year time scales. Modern shark tooth ?15NEB shows that despite significant intra- and inter-individual differences (up to 3 ?), ?15NEB captures ocean inter- and intra-basin differences in fixed N ?15N. Modern bovid (cow and bison) ?15NEB shows a close correspondence to collagen ?15N, and reflects the dietary plant ?15N on the terrestrial landscape.Applying ?15NEB to the fossil record, the high ?15NEB of the ancient mega-tooth shark Otodus megalodon provides evidence for a remarkably high trophic position. A 100-million-year fossil shark ?15NEB record from the North Atlantic largely corroborates fixed N ?15N changes observed in FB-?15N.This dissertation expands our understanding of marine nitrogen cycling and the trophic position of ancient sharks. This work establishes new mineral-bound ?15N tools and initiates mineral-bound N isotope investigation of the million-year geologic record.
Author: Gerhard Fischer
Publisher: Springer Science & Business Media
Published: 1999-11-02
Total Pages: 768
ISBN-13: 9783540663409
DOWNLOAD EBOOKPaleoceanographic proxies provide infonnation for reconstructions of the past, including climate changes, global and regional oceanography, and the cycles of biochemical components in the ocean. These prox ies are measurable descriptors for desired but unobservable environmental variables such as tempera ture, salinity, primary productivity, nutrient content, or surface-water carbon dioxide concentrations. The proxies are employed in a manner analogous to oceanographic methods. The water masses are first characterized according to their specific physical and chemical properties, and then related to particular assemblages of certain organisms or to particular element or isotope distributions. We have a long-standing series of proven proxies available. Marine microfossil assemblages, for instance, are employed to reconstruct surface-water temperatures. The calcareous shells of planktonic and benthic microorgan isms contain a wealth of paleoceanographic information in their isotopic and elemental compositions. Stable oxygen isotope measurements are used to detennine ice volume, and MglCa ratios are related to water temperatures, to cite a few examples. Organic material may also provide valuable infonnation, e. g. , about past productivity conditions. Studying the stable carbon isotope composition of bulk organic matter or individual marine organic components may provide a measure of past surface-water CO 2 conditions within the bounds of certain assumptions. Within the scope of paleoceanographic investigations, the existing proxies are continuously evolving and improving, while new proxies are being studied and developed. The methodology is improved by analysis of samples from the water column and surface sediments, and through laboratory experiments.
Author: Bryan E. Bemis
Publisher:
Published: 2000
Total Pages: 450
ISBN-13:
DOWNLOAD EBOOKAuthor: Horst D. Schulz
Publisher: Springer Science & Business Media
Published: 2006-07-02
Total Pages: 583
ISBN-13: 3540321446
DOWNLOAD EBOOKSince 1980 a considerable amount of scientific research dealing with geochemical processes in marine sediments has been carried out. This textbook summarizes the state-of-the-art in this field of research providing a complete representation of the subject and including the most recent findings. The topics covered include the examination of sedimentological and physical properties of the sedimentary solid phase. A new chapter describes properties, occurrence and formation of gas hydrates in marine sediments. The textbook ends with a chapter on model conceptions and computer models to quantify processes of early diagenesis.
Author: Ralf Schiebel
Publisher: Springer
Published: 2017-02-17
Total Pages: 366
ISBN-13: 3662502976
DOWNLOAD EBOOKThis book provides a comprehensive overview of the taxonomy, biology, sedimentation, and carbonate geochemistry of modern species. Students, early career and advanced scientists alike will profit from a broad synthesis of the current understanding of planktic foraminifers as an ecological indicator, biogeochemical factories, and proxies in paleoceanography. The classification of modern species is amply illustrated with electron and light microscope images of morphotypes, addresses the state-of-the-art of molecular genetics of species, and provides a detailed guide for any laboratory analyses. The biology of planktic foraminifers is extensively discussed in chapters dedicated to the cellular ultrastructure, nutrition, symbionts, reproduction, ontogeny, and test architecture. Building on the biological prerequisites, the distribution of planktic foraminifers is discussed at regional to global scale. The geochemistry and sedimentation of tests are considered in relation to the ecology of the living animal. In the final chapter, which examines the most common methods in planktic foraminifer research, hands-on information is provided on sampling, processing and analyzing samples in the laboratory, as well as selected established methods for data interpretation. The various topics discussed in this book are aimed at the application of planktic foraminifers as sensitive indicators of the changing climate and marine environment.
Author: Gerard Johannes Augustinus Brummer
Publisher:
Published: 1988
Total Pages: 356
ISBN-13:
DOWNLOAD EBOOKAuthor: Heinrich D Holland
Publisher: Academic Press
Published: 2010-09-27
Total Pages: 689
ISBN-13: 0080967078
DOWNLOAD EBOOKGeochemistry of Earth Surface Systems offers an interdisciplinary reference for scientists, researchers and upper undergraduate and graduate level geochemistry students a sampling of articles on earth surface processes from The Treatise on Geochemistry that is more affordable than the full Treatise. For professionals, this volume will provide an overview of the field as a whole. For students, it will provide more in-depth introductory content than is found in broad-based geochemistry textbooks. Articles were selected from chapters across all volumes of the full Treatise, and include: Volcanic Degassing, Hydrothermal Processes, The Contemporary Carbon Cycle, Global Occurrence of Major Elements in Rivers, Organic Matter in the Contemporary Ocean, The Biological Pump, and Evolution of Sedimentary Rocks. Comprehensive, interdisciplinary and authoritative content selected by leading subject experts Robust illustrations, figures and tables Affordably priced sampling of content from the full Treatise on Geochemistry
Author: Katharina Billups
Publisher:
Published: 1993
Total Pages: 552
ISBN-13:
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