Download or read book Combined Stable Isotope and Trace Element Analyses on Single Planktic Foraminifer Shells written by Lael Vetter and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Planktic foraminifers are abundant in the surface ocean, and the calcite shells of fossil foraminifers form a major component of deep sea sediments. These shells comprise a primary archive of sea surface conditions through the Cenozoic, and measurements of stable isotope and trace element ratios are frequently used in paleoclimate reconstructions. Each individual foraminifer calcifies over the course of days or weeks, and the environmental conditions during its life are locked into the geochemistry of the shell. Typically, measurements pool numerous individual shells in a single, bulk analysis to obtain an estimate of mean environmental conditions. However, observations of living foraminifers indicate that contemporaneous individuals may occupy different depth habitats, and individual foraminifers may migrate vertically during their life cycle. The potential thus exists for a population of foraminifers to capture a range of environmental conditions, and for daily-scale environmental variations to be recorded in the intrashell geochemical heterogeneity of a single individual. This research explores novel analytical methods of measuring geochemical heterogeneity in trace element ratios and stable oxygen and carbon isotope values in the shell calcite of the extant planktic foraminifer Orbulina universa through live culture experiments (Chapters 1 and 2) and measurements on fossil shells (Chapters 3 and 4). Chapter 1 describes the results of a live culture experiment in which oxygen isotope ([delta]18O) and trace element (Ba) labels in synthetic seawater were incorporated into shell calcite during calcification in the laboratory. Chapter 2 describes the results of a similar live culture experiment where O. universa calcified in seawater with modified trace element (Ba, 18Sr) and carbon isotope ([delta]13C) values. Intrashell geochemical measurements were performed using Secondary Ion Mass Spectrometry (SIMS) for [delta]18O and [delta]13C, and laser ablation inductively coupled mass spectrometry (LA-ICP-MS) for trace element analyses. Intrashell trace element analyses were accurately measured with sub-μm resolution using LA-ICP-MS depth profiling. We demonstrate that the full amplitude of isotopic values (labeled and ambient) are resolvable within the spatial resolution of SIMS measurements (3 [mu]m for [delta]18O; 6 [mu]m for [delta]13C). Together, these experimental results provide a quantitative framework for interpreting intrashell [delta]18O, [delta]13C) , and trace element ratio measurements in field samples, and open the possibility for reconstructing daily-scale environmental changes from fossil foraminifer shells.The combination of multiple different geochemical measurements on fragments of the same shell permits researchers to extract novel information from each individual foraminifer. Additionally, a suite of contemporaneous fossil foraminifer shells preserves a record of a range of environmental conditions from different depths in the water column. These types of measurements provide a new dimension of information about the hydrography or stratification of the surface ocean during transient events, such as glacial meltwater entering the ocean. Chapter 3 describes the results of an experiment conducted on fossil specimens of O. universa where each shell was split into fragments and each fragment was subjected to different reagent cleaning protocols. Intrashell LA-ICP-MS depth profiles on shell fragments illustrate the differences between cleaning techniques, and illustrate a method for computing whole-shell Mg/Ca and Ba/Ca ratios from collected depth profiles. In Chapter 4, [delta]18O, Mg/Ca, and Ba/Ca measurements were combined on multiple O. universa shells from selected 1 cm intervals from a core in the Orca Basin, Gulf of Mexico, deposited during the last deglacation (~18 to 11 ka). These combined measurements enable the calculation of [delta]18O(seawater) and salinity for each individual and the reconstruction of water column hydrography during meltwater pulses from the Laurentide Ice Sheet. Results yield computed [delta]18O(water) values of Laurentide Ice Sheet meltwater, and provide key insight into the dynamics of the ice sheet during its collapse.
Download or read book Stable Isotope Analyses of Individual Planktonic Foraminifera written by Katharina Billups and published by . This book was released on 1993 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geochemical Signals in Fossil Planktonic Foraminifera written by Rehemat Bhatia and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The stable isotope and trace element geochemistry of planktonic foraminifera is commonly used to reconstruct palaeoclimatic and palaeoceanographic parameters across recent and deeper timescales. However, aspects of their ecology, such as photosymbiont presence, ontogenetic growth and depth habitats, are suggested to alter these proxy signatures. Ecologies are additionally thought to change through time, creating further complications. Therefore, constraining foraminiferal palaeoecology, particularly during epochs which aid us in understanding future climate, is vital, to validate any proxy signals obtained. Two such epochs are the Eocene and Miocene, characterised by temperatures and CO2 levels comparable to a future warmer world. Many species within these periods have unresolved palaeoecologies. This thesis investigates the palaeoecology of multiple Eocene and Miocene planktonic foraminiferal species (from sites with well-preserved specimens) with unresolved palaeoecologies, using IÌ‚ Ì 13C, IÌ‚ Ì 18O, Mg/Ca, Sr/Ca and B/Ca. Whole and intra"â€shell geochemistry is investigated, using a combination of isotope ratio mass spectrometry and high resolution analytical techniques (laser ablation inductively coupled plasma mass spectrometry, electron microprobe analysis). It is shown for the first time that intra-chamber and size-segregated trace element/Ca data do not vary between Eocene foraminiferal species with differing ecologies (except Globigerina cf. bulloides and Pseudohastigerina wilcoxensis). Eocene and Miocene species EMPA data exhibit intra-shell Mg heterogeneity between species with varying depth habitats and photosymbiotic partnerships. Combining EMPA data with size-segregated IÌ‚ Ì 13C data is shown to be beneficial in distinguishing photosymbiotic species. Lastly, size-segregated IÌ‚ Ì 13C data from the species Globigerinatheka index indicate that it is possible for planktonic foraminifera to facultatively host photosymbionts in response to unfavourable environmental conditions. Having constrained the ecologies of various Eocene species, discrepancies between their inorganic proxy data are revealed and discussed. Overall, this thesis amplifies the importance of disentangling foraminiferal palaeoecology before constructing long-term downcore records, to mitigate the issues which vital effects can create.
Download or read book Environmental and Biological Controls on the Shell Geochemistry of the Planktic Foraminifera Orbulina Universa written by Katherine Davina Holland and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foraminifera make excellent archives of past oceans and climate because they grow calcium carbonate shells which incorporate trace element and stable isotopes that reflect the seawater conditions in which they grow. This study aims to: (i) improve understanding of the factors that influence trace element and stable isotope incorporation into foraminifera shells, and (ii) improve proxy calibrations for reconstructing past ocean carbonate system parameters and temperature. To do this, I have cultured living foraminifers in seawaters that have a wide range of cation and carbonate chemistry compositions. The shells produced by these foraminifers have been analysed by a laser ablation ICP-MS microanalysis techniques. The study has focused on three specific objectives: (i) formalising the sensitivity of shell trace element to calcium (TE/Ca) ratios to changes in seawater composition, (ii) establishing the response of bulk shell TE/Ca compositions to carbonate system chemistry and shell growth rates linked to the calcite saturation state of seawater, and (iii) characterising the responses of intra-shell TE/Ca and boron isotope composition to changes in the carbonate system chemistry of the foraminiferal microenvironment over diurnal cycles due to variation in respiration, calcification, and symbiont photosynthesis. To quantify the effect that changes in the Mg/Ca ratio of seawater has on the foraminifer shell Mg/Ca thermometer, both seawater [Mg] and [Ca] concentrations were varied independently in culture experiments. Results from these experiments has permitted the shell Mg/Ca thermometer to be recalibrated to account for the effects of past changes in seawater Mg/Ca ratio and [Ca] concentration. Culture experiments on Orbulina universa were also used to investigate the effects of different carbonate system parameters; pH, DIC, carbonate ion, seawater [Ca] and calcite saturation state on shell B/Ca, Mg/Ca, Mn/Ca, Sr/Ca and U/Ca compositions. Seawater DIC concentration was found to form significant correlations with B/Ca, Sr/Ca and Mg/Ca shell compositions, and seawater carbonate ion concentration had the dominant effect on U/Ca. Orbulina universa exhibits a narrow range in shell growth rates over a wide range in calcite saturation state of experimental seawaters, indicating shell growth is highly regulated. Intra-shell B/Ca and U/Ca ratios record significant changes in carbonate system chemistry of the foraminiferal microenvironment over diurnal time scales due to the net effects of photosynthesis-respiration and calcification of the foraminifer and its algal symbionts. Orbulina universa shell composition was also explored for internal variation in boron isotope composition. The resolution of the laser ablation MC-ICP-MS technique used is near the precision limits of modelled changes in microenvironment carbonate system chemistry. The measured bulk shell boron isotope compositions are significantly offset from the predicted boron isotope composition of the seawater borate ion. In summary, this thesis provides new insights into the factors controlling trace element and isotope incorporation into foraminiferal calcite, including the extent to which biological factor influence the composition of precipitated shell calcite relative to external seawater chemistry.
Download or read book Trace Element Ratios and Stable Isotopic Compositions of Planktonic Foraminiferal Shell Collected from the South China Sea Geochemical Calibration and Paleoceanographic Implication written by 黃國芳 and published by . This book was released on 2007 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stable isotope and Trace element Composition on Ostracode Shells and Their Application to Paleoclimatic Reconstruction in the Northern Great Plains written by Juanjuan Xia and published by . This book was released on 1996 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Use of Proxies in Paleoceanography written by Gerhard Fischer and published by Springer Science & Business Media. This book was released on 1999-11-02 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: Paleoceanographic 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.
Download or read book Ostracoda as Proxies for Quaternary Climate Change written by and published by Newnes. This book was released on 2012-12-31 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ostracod crustaceans, common microfossils in marine and freshwater sedimentary records, supply evidence of past climatic conditions via indicator species, transfer function and mutual climatic range approaches as well as the trace element and stable isotope geochemistry of their shells. As methods of using ostracods as Quaternary palaeoclimate proxies have developed, so too has a critical awareness of their complexities, potential and limitations. This book combines up-to-date reviews (covering previous work and summarising the state of the art) with presentations of new, cutting-edge science (data and interpretations as well as methodological developments) to form a major reference work that will constitute a durable bench-mark in the science of Ostracoda and Quaternary climate change. - In-depth and focused treatment of palaeoclimate applications - Provides durable benchmark and guide for all future work on ostracods - Presents new, cutting-edge science
Download or read book Modern Planktonic Foraminifera written by Christoph Hemleben and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a single volume, the authors bring together a review of current biological understanding of planktonic foraminifera and apply it to developments in sedimentology. With the growing interest in the shells of this class of protozoa as indicators of the history of the earth, revealed through the sedimentary record, a comprehensive analysis of the biology of contemporary foraminifera has become necessary. Main topics covered include Taxonomy, Collecting and Culture Methods, Cellular Ultrastructure, Host and Symbiont Relationships, Trophic Activity and Nutrition, Reproduction, Shell Ontogeny and Architecture, Ecology and Sedimentation and Settlement of Shells.
Download or read book LA ICP MS Trace Element Analysis of Planktonic Foraminifera and Application to Marine Isotope Stage 31 in the Southwest Pacific Ocean written by Annette Bolton and published by . This book was released on 2011 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Encyclopedia of Ocean Sciences written by and published by Academic Press. This book was released on 2019-04-12 with total page 4318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oceans cover 70% of the Earth’s surface, and are critical components of Earth’s climate system. This new edition of Encyclopedia of Ocean Sciences, Six Volume Set summarizes the breadth of knowledge about them, providing revised, up to date entries as well coverage of new topics in the field. New and expanded sections include microbial ecology, high latitude systems and the cryosphere, climate and climate change, hydrothermal and cold seep systems. The structure of the work provides a modern presentation of the field, reflecting the input and different perspective of chemical, physical and biological oceanography, the specialized area of expertise of each of the three Editors-in-Chief. In this framework maximum attention has been devoted to making this an organic and unified reference. Represents a one-stop. organic information resource on the breadth of ocean science research Reflects the input and different perspective of chemical, physical and biological oceanography, the specialized area of expertise of each of the three Editors-in-Chief New and expanded sections include microbial ecology, high latitude systems and climate change Provides scientifically reliable information at a foundational level, making this work a resource for students as well as active researches
Download or read book Spring Meeting written by American Geophysical Union. Meeting and published by . This book was released on 1999 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Micropaleontology written by Pratul Kumar Saraswati and published by Springer. This book was released on 2015-12-17 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will help readers learn the basic skills needed to study microfossils especially those without a formal background in paleontology. It details key principles, explains how to identify different groups of microfossils, and provides insight into their potential applications in solving geologic problems. Basic principles are addressed with examples that explore the strengths and limitations of microfossils and their geological records. This overview provides an understanding of taphonomy and quality of the fossil records, biomineralization and biogeochemistry, taxonomy, concepts of species, and basic concepts of ecology. Readers learn about the major groups of microfossils, including their morphology, ecology, and geologic history. Coverage includes: foraminifera, ostracoda, coccolithophores, pteropods, radiolaria, diatoms, silicoflagellates, conodonts, dinoflagellates, acritarch, and spores and pollens. In this coverage, marine microfossils, and particularly foraminifera, are discussed in more detail compared with the other groups as they continue to play a major role in most scientific investigations. Among the various tracers of earth history, microfossils provide the most diverse kinds of information to earth scientists. This richly illustrated volume will help students and professionals understand microfossils, and provide insight on how to work with them to better understand evolution of life, and age and the paleoenvironment of sedimentary strata.
Download or read book Planktic Foraminifers in the Modern Ocean written by Ralf Schiebel and published by Springer. This book was released on 2017-02-17 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 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.
Download or read book The Trace Element and Lithium Isotope Composition of Planktonic Foraminifera written by Edmund Charles Hathorne and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Marine Protists written by Susumu Ohtsuka and published by Springer. This book was released on 2015-09-28 with total page 637 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive book provides a unique overview of advances in the biology and ecology of marine protists. Nowadays marine protistology is a hot spot in science to disclose life phenomena using the latest techniques. Although many protistological textbooks deal with the cytology, genetics, ecology, and pathology of specific organisms, none keeps up with the quick pace of new discoveries on the diversity and dynamics of marine protists in general. The bookMarine Protists: Diversity and Dynamics gives an overview of current research on the phylogeny, cytology, genomics, biology, ecology, fisheries, applied sciences, geology and pathology of marine free-living and symbiotic protists. Poorly known but ecologically important protists such as labyrinthulids and apostome ciliates are also presented in detail. Special attention is paid to complex interactions between marine protists and other organisms including human beings. An understanding of the ecological roles of marine protists is essential for conservation of nature and human welfare. This book will be of great interest not only to scientists and students but also to a larger audience, to give a better understanding of protists’ diverse roles in marine ecosystems.
Download or read book Larger Benthic Foraminifera Through Space and Time written by Pratul Kumar Saraswati and published by Springer Nature. This book was released on with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
