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 Biogeochemical Controls on Palaeoceanographic Environmental Proxies written by William E. N. Austin and published by Geological Society of London. This book was released on 2008 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most of our information about the evolution of Earth's ocean-climate system comes from the analysis of sediments laid down in the past. For example, the microfossil assemblage reflects the temperature, salinity and nutrient abundance of the water in which the organisms lived, while the chemical and isotopic composition of biogenic carbonates may be used to reconstruct past variations in the operation of the carbon cycle, as well as changes in ocean circulation. Nevertheless, understanding the link between these sediment variables (or 'proxies') and environmental conditions is not straightforward. This volume adopts a novel approach by bringing together palaeontologists, geochemists and palaeoceanographers, who contribute evidence that is required to better constrain these proxies. Topics include: (i) processes of biomineralization, and their effect on the chemical and isotopic composition of different organisms; (ii) proxy validation, including field, laboratory and theoretical studies; (iii) the links between modern and fossil organisms
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 Biostratigraphic and Geological Significance of Planktonic Foraminifera written by Marcelle K. BouDagher-Fadel and published by UCL Press. This book was released on 2015-10-02 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: The role of fossil planktonic foraminifera as markers for biostratigraphical zonation and correlation underpins most drilling of marine sedimentary sequences and is key to hydrocarbon exploration. The first - and only - book to synthesise the whole biostratigraphic and geological usefulness of planktonic foraminifera, Biostratigraphic and Geological Significance of Planktonic Foraminifera unifies existing biostratigraphic schemes and provides an improved correlation reflecting regional biogeographies.Renowned micropaleontologist Marcelle K. Boudagher-Fadel presents a comprehensive analysis of existing data on fossil planktonic foraminifera genera and their phylogenetic evolution in time and space. This important text, now in its Second Edition, is in considerable demand and is now being republished by UCL Press.
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 2012-12-06 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 Planktic Foraminifers in the Modern Ocean written by Ralf Schiebel and published by Springer. This book was released on 2017-02-24 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 Biostratigraphy and Shell Geochemistry of Quaternary Planktonic Foraminifera from the Cayman Trough written by Richard Thomas Kilbourne and published by . This book was released on 1974 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Boron Proxies in Paleoceanography and Paleoclimatology written by Bärbel Hönisch and published by John Wiley & Sons. This book was released on 2019-05-13 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic carbon dioxide emissions do not only warm our planet but also acidify our oceans. It is currently unclear to which degree Earth’s climate and marine life will be impacted by these changes but information from Earth history, particularly the geochemical signals of past environmental changes stored in the fossil remains of marine organisms, can help us predict possible future changes. This book aims to be a primer for scientists who seek to apply boron proxies in marine carbonates to estimate past seawater carbonate chemistry and atmospheric pCO2. Boron proxies (δ11B and B/Ca) were introduced nearly three decades ago, with subsequent strides being made in understanding their mechanistic functioning. This text reviews current knowledge about the aqueous systematics, the inorganic and biological controls on boron isotope fractionation and incorporation into marine carbonates, as well as the analytical techniques for measurement of boron proxies. Laboratory and field calibrations of the boron proxies are summarized, and similarities between modern calibrations are explored to suggest estimates for proxy sensitivities in marine calcifiers that are now extinct. Example applications illustrate the potential for reconstructing paleo-atmospheric pCO2 from boron isotopes. Also explored are the sensitivity of paleo-ocean acidity and pCO2 reconstructions to boron isotope proxy systematics that are currently less well understood, including the elemental and boron isotopic composition of seawater through time, seawater alkalinity, temperature and salinity, and their collective impact on the uncertainty of paleo-reconstructions. The B/Ca proxy is based on the same mechanistic principles as the boron isotope proxy, but empirical calibrations suggest seawater pH is not the only controlling factor. B/Ca therefore has the potential to provide a second carbonate parameter that could be paired with δ11B to fully constrain the ocean carbonate system, but the associated uncertainties are large. This text reviews and examines what is currently known about the B/Ca proxy systematics. As more scientists embark on characterizing past ocean acidity and atmospheric pCO2, Boron in Paleoceanography and Paleoclimatology provides a resource to introduce geoscientists to the opportunities and complications of boron proxies, including potential avenues to further refine them.
Download or read book Modern Foraminifera written by Barun K. Sen Gupta and published by Springer Science & Business Media. This book was released on 2007-05-08 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the reviews: "This is now the definitive, authoritative text on applied foraminiferal micropaleontology and should be in the library of all practicing micropaleontologists." (William A. Berggren, Woods Hole Oceanographic Institution in Micropaleontology, 47:1 (2001)"During the last 20 years there has been an explosion of publications about foraminifera from an amazing variety of disciplines: basic cell biology, algal symbiosis, biomineralization, biogeography, ecology, pollution, chemical oceanography, geochemistry, paleoceanography, and geology. This book summarizes contributions by leading researchers in these diverse fields. It is not just another text on the biology of foraminifera. Rather, Barun Sen Gupta has accomplished his objective to "write an advanced text for university students that would also serve as a reference book for professionals"." (Howard J. Spero, University of California at Davis in Limnology and Oceanography, 45:8 (2000).
Download or read book Controls on the Oxygen and Carbon Isotopic Composition of Planktonic Foraminifera written by Bryan E. Bemis and published by . This book was released on 2000 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Encyclopedia of Quaternary Science written by Cary Mock and published by Newnes. This book was released on 2013-03-25 with total page 3883 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second revised edition of the Encyclopedia of Quaternary Science, Four Volume Set, provides both students and professionals with an up-to-date reference work on this important and highly varied area of research. There are lots of new articles, and many of the articles that appeared in the first edition have been updated to reflect advances in knowledge since 2006, when the original articles were written. The second edition will contain about 375 articles, written by leading experts around the world. This major reference work is richly illustrated with more than 3,000 illustrations, most of them in colour. Research in the Quaternary sciences has advanced greatly in the last 10 years, especially since topics like global climate change, geologic hazards and soil erosion were put high on the political agenda. This second edition builds upon its award-winning predecessor to provide the reader assured quality along with essential updated coverage Contains 357 broad-ranging articles (4310 pages) written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource for information in the field. Facilitates teaching and learning The first edition was regarded by many as the most significant single overview of Quaternary science ever, yet Editor-in-Chief, Scott Elias, has managed to surpass that in this second edition by securing even more expert reviews whilst retaining his renowned editorial consistency that enables readers to navigates seamlessly from one unfamiliar topic to the next
Download or read book Journal of the Palaeontological Society of India written by Palaeontological Society of India and published by . This book was released on 2008 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proxies in Late Cenozoic Paleoceanography written by C. Hillaire-Marcel and published by Elsevier. This book was released on 2007-05-25 with total page 863 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present volume is the first in a series of two books dedicated to the paleoceanography of the Late Cenozoic ocean. The need for an updated synthesis on paleoceanographic science is urgent, owing to the huge and very diversified progress made in this domain during the last decade. In addition, no comprehensive monography still exists in this domain. This is quite incomprehensible in view of the contribution of paleoceanographic research to our present understanding of the dynamics of the climate-ocean system. The focus on the Late Cenozoic ocean responds to two constraints. Firstly, most quantitative methods, notably those based on micropaleontological approaches, cannot be used back in time beyond a few million years at most. Secondly, the last few million years, with their strong climate oscillations, show specific high frequency changes of the ocean with a relatively reduced influcence of tectonics. The first volume addresses quantitative methodologies to reconstruct the dynamics of the ocean andthe second, major aspects of the ocean system (thermohaline circulation, carbon cycle, productivity, sea level etc.) and will also present regional synthesis about the paleoceanography of major the oceanic basins. In both cases, the focus is the "open ocean leaving aside nearshore processes that depend too much onlocal conditions. In this first volume, we have gathered up-to-date methodologies for the measurement and quantitative interpretation of tracers and proxies in deep sea sediments that allow reconstruction of a few key past-properties of the ocean( temperature, salinity, sea-ice cover, seasonal gradients, pH, ventilation, oceanic currents, thermohaline circulation, and paleoproductivity). Chapters encompass physical methods (conventional grain-size studies, tomodensitometry, magnetic and mineralogical properties), most current biological proxies (planktic and benthic foraminifers, deep sea corals, diatoms, coccoliths, dinocysts and biomarkers) and key geochemical tracers (trace elements, stable isotopes, radiogenic isotopes, and U-series). Contributors to the book and members of the review panel are among the best scientists in their specialty. They represent major European and North American laboratories and thus provide a priori guarantees to the quality and updat of the entire book. Scientists and graduate students in paleoclimatology, paleoceanography, climate modeling, and undergraduate and graduate students in marine geology represent the target audience. This volume should be of interest for scientists involved in several international programs, such as those linked to the IPCC (IODP – Integrated Ocean Drilling Program; PAGES – Past Global Changes; IMAGES – Marine Global Changes; PMIP: Paleoclimate Intercomparison Project; several IGCP projects etc.), That is, all programs that require access to time series illustrating changes in the climate-ocean system. - Presents updated techniques and methods in paleoceanography - Reviews the state-of-the-art interpretation of proxies used for quantitative reconstruction of the climate-ocean system - Acts as a supplement for undergraduate and graduate courses in paleoceanography and marine geology
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 Climate Change and Marine Geological Dynamics written by George Kontakiotis and published by Mdpi AG. This book was released on 2021-11-11 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tendency for climate to change has been one of the most surprising outcomes of the study of Earth's history. Marine geoscience can reveal valuable information about past environments, climates, and biota just before, during and after each climate perturbation. Particularly, certain intervals of geological records are windows to key episodes in the climate history of the Earth-life system. Ιn this regard, the detailed analyses of such time intervals are challenging and rewarding for environmental reconstruction and climate modelling, because they provide documentation and better understanding of a warmer-than-present world, and opportunities to test and refine the predictive ability of climate models. Marine geological dynamics such as sea-level changes, hydrographic parameters, water quality, sedimentary cyclicity, and (paleo)climate are strongly related through a direct exchange between the oceanographic and atmospheric systems. The increasing attention paid to this wide topic is also motivated by the interplay of these processes across a variety of settings (coastal to open marine) and timescales (early Cenozoic to modern). In order to realize the full predictive value of these warm (fresh)/cold (salty) intervals in Earth's history, it is important to have reliable tools (e.g., integrated geochemical, paleontological and/or paleoceanographic proxies) through the application of multiple, independent, and novel techniques (e.g., TEX86, UK'37, Mg/Ca, Na/Ca, Δ47, and μCT) for providing reliable hydroclimate reconstructions at both local and global scales.
Download or read book Neogene Planktonic Foraminifera written by James P. Kennett and published by . This book was released on 1983 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CO2 in Seawater Equilibrium Kinetics Isotopes written by R.E. Zeebe and published by Elsevier. This book was released on 2001-10-15 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon dioxide is the most important greenhouse gas after water vapor in the atmosphere of the earth. More than 98% of the carbon of the atmosphere-ocean system is stored in the oceans as dissolved inorganic carbon. The key for understanding critical processes of the marine carbon cycle is a sound knowledge of the seawater carbonate chemistry, including equilibrium and nonequilibrium properties as well as stable isotope fractionation.Presenting the first coherent text describing equilibrium and nonequilibrium properties and stable isotope fractionation among the elements of the carbonate system. This volume presents an overview and a synthesis of these subjects which should be useful for graduate students and researchers in various fields such as biogeochemistry, chemical oceanography, paleoceanography, marine biology, marine chemistry, marine geology, and others.The volume includes an introduction to the equilibrium properties of the carbonate system in which basic concepts such as equilibrium constants, alkalinity, pH scales, and buffering are discussed. It also deals with the nonequilibrium properties of the seawater carbonate chemistry. Whereas principle of chemical kinetics are recapitulated, reaction rates and relaxation times of the carbonate system are considered in details. The book also provides a general introduction to stable isotope fractionation and describes the partitioning of carbon, oxygen, and boron isotopes between the species of the carbonate system. The appendix contains formulas for the equilibrium constants of the carbonate system, mathematical expressions to calculate carbonate system parameters, answers to exercises and more.
