Stable Isotope Analyses of Individual Planktonic Foraminifera PDF Download

Author: Katharina Billups
Publisher:
ISBN:
Category :
Languages : en
Pages : 552

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Author: Cynthia Elaine Schneider
Publisher:
ISBN:
Category :
Languages : en
Pages : 466

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Author: Vincent Jassey
Publisher: Frontiers Media SA
ISBN: 2889745007
Category : Science
Languages : en
Pages : 176

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Author: Christoph Hemleben
Publisher: Springer Science & Business Media
ISBN: 1461235448
Category : Science
Languages : en
Pages : 374

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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.

Author: Wade H. Shafer
Publisher: Springer Science & Business Media
ISBN: 1461519691
Category : Science
Languages : en
Pages : 426

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Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS)* at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volumes were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 38 (thesis year 1993) a total of 13,787 thesis titles from 22 Canadian and 164 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 38 reports theses submitted in 1993, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.

Author: Susan Elizabeth Alderman
Publisher:
ISBN:
Category :
Languages : en
Pages : 198

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Author: M. Kucera
Publisher: Elsevier
ISBN: 9780080447025
Category : Science
Languages : en
Pages : 318

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MARGO - Multiproxy Approach for the Reconstruction of the Glacial Ocean surface summarizes the results of the MARGO international working group, with the aim to develop an updated and harmonised reconstruction of sea surface temperatures and sea-ice extent of the Last Glacial Maximum oceans. The MARGO approach differs from previous efforts by developing and consistently applying measures of various aspects of reconstruction reliability, and by combining faunal and geochemical proxies. In 14 papers, the volume provides a comprehensive review of earlier work and a series of new, proxy-specific reconstructions based on census counts of planktonic foraminifera, diatoms, radiolaria and dinoflagellate cysts as well as on Mg/Ca measurements in planktonic foraminifera. The approach of harmonising the calibration and application of different proxies is described in detail, various paleothermometry techniques and their results are compared and the challenge of treating sparsely sampled data as the basis for ocean circulation models is addressed. The use of stable oxygen isotope composition of foraminiferal shells as a proxy for past sea water composition is comprehensively reassessed, and a new approach to the transfer function paleothermometer is presented. This volume represents a landmark contribution to the understanding of ice-age oceanography as well as the proxies used to reconstruct past ocean states. The results will form the basis for forcing and validation of ocean circulation models. New regional reconstructions of Last Glacial Maximum ocean temperatures and sea ice cover Compilation of new calibration and fossil datasets as well as documentation of techniques and approaches to paleoenvironmental reconstructions Comparison of techniques, proxies and modelling approaches

Author: U. Bleil
Publisher: Springer Science & Business Media
ISBN: 9400920296
Category : Science
Languages : en
Pages : 811

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Proceedings of the NATO Advanced Research Workshop, Bremen, Germany, October 10-14, 1988

Author: Gerhard Fischer
Publisher: Springer Science & Business Media
ISBN: 3642586465
Category : Science
Languages : en
Pages : 768

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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.

Author: Lael Vetter
Publisher:
ISBN: 9781303540998
Category :
Languages : en
Pages :

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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.