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Book Ostracoda as Proxies for Quaternary Climate Change

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

Book Lake Records of Environmental and Climate Change on the Tibetan Plateau

Download or read book Lake Records of Environmental and Climate Change on the Tibetan Plateau written by Zhang Chengjun and published by Frontiers Media SA. This book was released on 2022-11-07 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Reconstructing Climate Variability on the Tibetan Plateau

Download or read book Reconstructing Climate Variability on the Tibetan Plateau written by Juliane Wischnewski and published by . This book was released on 2010 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spatial and temporal temperature and moisture patterns across the Tibetan Plateau are very complex. The onset and magnitude of the Holocene climate optimum in the Asian monsoon realm, in particular, is a subject of considerable debate as this time period is often used as an analogue for recent global warming. In the light of contradictory inferences regarding past climate and environmental change on the Tibetan Plateau, I have attempted to explain mismatches in the timing and magnitude of change. Therefore, I analysed the temporal variation of fossil pollen and diatom spectra and the geochemical record from palaeo-ecological records covering different time scales (late Quaternary and the last 200 years) from two core regions in the NE and SE Tibetan Plateau. For interpretation purposes I combined my data with other available palaeo-ecological data to set up corresponding aquatic and terrestrial proxy data sets of two lake pairs and two sets of sites. I focused on the direct comparison of proxies representing lacustrine response to climate signals (e.g., diatoms, ostracods, geochemical record) and proxies representing changes in the terrestrial environment (i.e., terrestrial pollen), in order to asses whether the lake and its catchments respond at similar times and magnitudes to environmental changes. Therefore, I introduced the established numerical technique procrustes rotation as a new approach in palaeoecology to quantitatively compare raw data of any two sedimentary records of interest in order to assess their degree of concordance. Focusing on the late Quaternary, sediment cores from two lakes (Kuhai Lake 35.3ʻN; 99.2ʻE; 4150 m asl; and Koucha Lake 34.0ʻN; 97.2ʻE; 4540 m asl) on the semi-arid northeastern Tibetan Plateau were analysed to identify post-glacial vegetation and environmental changes, and to investigate the responses of lake ecosystems to such changes. Based on the pollen record, five major vegetation and climate changes could be identified: (1) A shift from alpine desert to alpine steppe indicates a change from cold, dry conditions to warmer and more moist conditions at 14.8 cal. ka BP, (2) alpine steppe with tundra elements points to conditions of higher effective moisture and a stepwise warming climate at 13.6 cal. ka BP, (3) the appearance of high-alpine meadow vegetation indicates a further change towards increased moisture, but with colder temperatures, at 7.0 cal. ka BP, (4) the reoccurrence of alpine steppe with desert elements suggests a return to a significantly colder and drier phase at 6.3 cal. ka BP, and (5) the establishment of alpine steppe-meadow vegetation indicates a change back to relatively moist conditions at 2.2 cal. ka BP. To place the reconstructed climate inferences from the NE Tibetan Plateau into the context of Holocene moisture evolution across the Tibetan Plateau, I applied a five-scale moisture index and average link clustering to all available continuous pollen and non-pollen palaeoclimate records from the Tibetan Plateau, in an attempt to detect coherent regional and temporal patterns of moisture evolution on the Plateau. However, no common temporal or spatial pattern of moisture evolution during the Holocene could be detected, which can be assigned to the complex responses of different proxies to environmental changes in an already very heterogeneous mountain landscape, where minor differences in elevation can result in marked variations in microenvironments. Focusing on the past 200 years, I analysed the sedimentary records (LC6 Lake 29.5ʻN, 94.3ʻE, 4132 m asl; and Wuxu Lake 29.9ʻN, 101.1ʻE, 3705 m asl) from the southeastern Tibetan Plateau. I found that despite presumed significant temperature increases over that period, pollen and diatom records from the SE Tibetan Plateau reveal only very subtle changes throughout their profiles. The compositional species turnover investigated over the last 200 years appears relatively low in comparison to the species reorganisations during the Holocene. The results indicate that climatically induced ecological thresholds are not yet crossed, but that human activity has an increasing influence, particularly on the terrestrial ecosystem. Forest clearances and reforestation have not caused forest decline in our study area, but a conversion of natural forests to semi-natural secondary forests. The results from the numerical proxy comparison of the two sets of two pairs of Tibetan lakes indicate that the use of different proxies and the work with palaeo-ecological records from different lake types can cause deviant stories of inferred change. Irrespective of the timescale (Holocene or last 200 years) or region (SE or NE Tibetan Plateau) analysed, the agreement in terms of the direction, timing, and magnitude of change between the corresponding terrestrial data sets is generally better than the match between the corresponding lacustrine data sets, suggesting that lacustrine proxies may partly be influenced by in-lake or local catchment processes whereas the terrestrial proxy reflects a more regional climatic signal. The current disaccord on coherent temporal and spatial climate patterns on the Tibetan Plateau can partly be ascribed to the complexity of proxy response and lake systems on the Tibetan Plateau. Therefore, a multi-proxy, multi-site approach is important in order to gain a reliable climate interpretation for the complex mountain landscape of the Tibetan Plateau.

Book Cenozoic Climatic and Environmental Changes in the Qaidam Basin

Download or read book Cenozoic Climatic and Environmental Changes in the Qaidam Basin written by Yuanyuan Sun and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Cenozoic Climatic and Environmental Changes in the Qaidam Basin" by Yuanyuan, Sun, 孙嫒嫒, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Large discrepancies remain regarding the timing of Cenozoic paleoclimatic and paleoenvironmental transitions in the central Asia. The first order driving force behind these changes has been intensively debated. Global climate change, the uplift of Tibetan Plateau, and the evolution of Paratethys sea have been proposed as three major candidates. To understand the evolutionary history of climate and environment of the region and controlling factors responsible for these paleoclimatic and paleoenvironmental changes, a combined study utilizing multiple proxies, including microfossils, bulk carbonate carbon and oxygen isotopes, long chain alkenones, plant n-alkane-based indices (carbon preference index, average chain length and Paq) and compound-specific carbon and hydrogen isotopes of higher plant n-alkanes, was carried out on a long, continuous and well-dated section in Dahonggou, Qaidam Basin, northern Tibetan Plateau. A parallel study was also carried out in another relatively shorter section in the Xunhua Basin, northern Tibetan Plateau. Six intervals of paleoclimatic and paleoenvironmental transitions over an interval of 35 Myr can be recognized in the studied sections, including Late Eocene-Early Oligocene gradual drying (prior to 30 Ma), Middle Oligocene aridification ( 30-26 Ma), Late Oligocene-Early Miocene wetting ( 26-21 Ma), Early Miocene drying ( 21-17 Ma), Middle Miocene climatic optimum ( 17-13 Ma), and deteriorated climate since the late Middle Miocene ( 13 Ma onwards). The reconstructed onsite C4 plant abundance including occurrence of C4 plants and their thriving and the followed decreasing, a sensitive indicator of available moisture level in the environment, agrees well with these intervals. Microfossils and long-chain alkenones suggest that a relic sea existed in the Qaidam Basin during the Middle Miocene, thus falsifying any hypothesis of significant variations in elevations of northern Tibetan Plateau prior to the Middle Miocene. The relatively stable elevations since the Eocene and before the Middle Miocene of, respectively, the central-southern part and northern part of the Plateau reveals an insignificant role of Tibetan Plateau uplift in controlling the evolution of central Asian climate and environment during the early Cenozoic. However, the Middle Miocene marine transgression and the rapid plateau-scale uplift since the late Middle Miocene probably contributed to the Middle Miocene climatic optimum and the initiated aridification afterwards in the central Asia. A comparison of proxy records in the northern Tibetan Plateau with the global benthic oxygen isotope record suggests a tight relation between the climatic/environmental transitions in the central Asia and global climatic changes. This lends support to the hypothesis that global climate, by controlling the moisture supply to the continental interior, played the dominant role in the evolution of climate and environment of central Asia during the Cenozoic time. DOI: 10.5353/th_b5223961 Subjects: Climatic changes - China - Tsaidam Basin Paleoclimatology - Cenozoic

Book Ostracoda in the Earth Sciences

Download or read book Ostracoda in the Earth Sciences written by Patrick De Deckker and published by Elsevier Publishing Company. This book was released on 1988 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ostracods belong to a group of microfossils found in nearly all types of aquatic environments. These microcrustaceans, characterized by a bivalved, calcitic carapace, are used to reconstruct ancient environments. For example, they can help to provide information on palaeoclimates, palaeogeography, the formation of deep oceans, sea level changes, etc. This book endeavours to bring about a greater understanding of their usefulness in many aspects of geological sciences, and provides suggestions for future research. It is principally intended for the non-specialist, and shows many applications of ostracods to help solve geological problems and phenomena. Topics reviewed assume no prior knowledge of palaeontology, and thus terminology is kept simple. There is an exhaustive index, and an appendix supplying additional references on significant sources of information on ostracods. This book aims to deliver information on ostracods to those people not usually interested in the literature of palaeontology and also to awaken an interest in the Ostracoda by referring to more specialized articles published elsewhere.

Book Non marine Ostracods as Indicators of Holocene Environmental Change in Central Mexico

Download or read book Non marine Ostracods as Indicators of Holocene Environmental Change in Central Mexico written by Nigel Derrick Bridgwater and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Natural Climate Variability on Decade to Century Time Scales

Download or read book Natural Climate Variability on Decade to Century Time Scales written by National Research Council and published by National Academies Press. This book was released on 1996-08-30 with total page 645 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reflects the current state of scientific knowledge about natural climate variability on decade-to-century time scales. It covers a wide range of relevant subjects, including the characteristics of the atmosphere and ocean environments as well as the methods used to describe and analyze them, such as proxy data and numerical models. They clearly demonstrate the range, persistence, and magnitude of climate variability as represented by many different indicators. Not only do natural climate variations have important socioeconomic effects, but they must be better understood before possible anthropogenic effects (from greenhouse gas emissions, for instance) can be evaluated. A topical essay introduces each of the disciplines represented, providing the nonscientist with a perspective on the field and linking the papers to the larger issues in climate research. In its conclusions section, the book evaluates progress in the different areas and makes recommendations for the direction and conduct of future climate research. This book, while consisting of technical papers, is also accessible to the interested layperson.

Book Quaternary Deserts and Climatic Change

Download or read book Quaternary Deserts and Climatic Change written by A.S. Alsharhan and published by CRC Press. This book was released on 2020-08-26 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings record the results of climate change in many areas which are hyper-arid deserts today but which, almost cyclically, at intervals of thousands or even hundreds of thousands of years, have had a much more humid climate.

Book Tibetan Plateau Uplift and Environmental Impacts New Progress and Perspectives

Download or read book Tibetan Plateau Uplift and Environmental Impacts New Progress and Perspectives written by Yibo Yang and published by Frontiers Media SA. This book was released on 2022-10-20 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Asian Summer Monsoon

Download or read book The Asian Summer Monsoon written by Yunyun Liu and published by Elsevier. This book was released on 2019-07-13 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Asian Summer Monsoon: Characteristics, Variability, Teleconnections and Projection focuses on the connections between the Indian Summer and East Asian Summer Monsoons, also including the South China Sea Summer Monsoon. While these systems have profound differences, their interactions have significant impacts on the climatic regimes in the region and throughout the world. In summer, the ASM engine pumps moisture transported across thousands of miles from the Indian and Pacific Oceans to the monsoon regions, producing heavy rains over south and east Asia and its adjacent marginal seas. This book reviews the different subsystems and their impact, providing guidance to enhance prediction models. Synthesizes the connections between the East Asian Summer Monsoon, the Indian Summer Monsoon and the Asian Summer Monsoon system Includes subsections on holistic characteristics, sub-seasonal and interannual variability, teleconnection patterns, and projections of future change Connects current theory and practice on Asian Monsoon forecasting, providing researchers with new skills and information to use in climate and weather forecasting

Book Tracking Environmental Change Using Lake Sediments

Download or read book Tracking Environmental Change Using Lake Sediments written by William M. Last and published by Springer Science & Business Media. This book was released on 2006-04-11 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theory Instrumentation NIR analysis of sediment samples Uses of NIRS in palaeolimnology Future perspectives Summary References Fly-ash particles. Neil Rose 319 12. Introduction A brief history Methods of extraction and enumeration Temporal distribution Spatial distribution Source apportionment The future Summary Acknowledgements References Part III: Stable Isotope Techniques 13. Application of stable isotope techniques to inorganic and biogenic carbonates. Emi Ito 351 Introduction Nomenclature and systematics of lake-water Mg/Ca and Sr/Ca ratios of lake-water of dissolved inorganic carbon (DIC) Carbonates in lake-sediments Mollusks Ostracodes Charaphytes Isotope analysis Preparation of carbonate samples for isotope analysis Conclusions Summary Acknowledgments References 14. Carbon and oxygen isotope analysis of lake sediment cellulose: methods and applications. Brent B. Wolfe, Thomas W. D. Edwards, Richard J. Elgood & Kristina R. M. Beuning 373 xi Introduction Stable isotope tracers in lake Historical development Methods Key criteria for paleohydrologic reconstruction Applications Future research directions Summary Acknowledgements References Nitrogen isotopes in palaeolimnology. Michael R. Talbot 15. 401 Introduction Nitrogen in lakes: forms and distribution Nitrogen isotopes Nitrogen isotope studies in palaeolimnology: sampling and measurement Some examples Closing remarks Summary Acknowledgments References Glossary, acronyms and abbreviations 441 Index 493 xiii PREFACE The explosive growth of paleolimnology over the past two decades has provided impetus for the publication of this series of monographs detailing the numerous advances and new techniques being applied to the interpretation of lake histories. This is the second volume in the series and deals mainly with physical and geochemical analytical techniques.

Book Aquatic Bioindicators of Late Holocene Environmental Change on the South Central Tibetan Plateau

Download or read book Aquatic Bioindicators of Late Holocene Environmental Change on the South Central Tibetan Plateau written by Paula Gabriela Echeverría Galindo and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Introduction to Cryospheric Science

Download or read book Introduction to Cryospheric Science written by Dahe Qin and published by Springer Nature. This book was released on 2021-10-15 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces systematically the cryospheric science, covering the formation, development, evolution, and research methods of each component of the cryosphere, the interaction between the cryosphere and the other spheres of the climate system and the anthroposphere, and the hot topics of social and economic sustainable development and geopolitics. The authors are world-renowned experts and scientists working in the related fields. They have a deep understanding and accurate grasp of the basic theory, evolution mechanism, and international frontiers of the cryosphere, as well as rich teaching experience, which makes this book suitable also as textbook for graduate students. It is also the first book that introduces the knowledge of cryospheric science systematically. In addition to theoretical knowledge, the book also introduces field work and experimental analysis. It should be of interests for the scholars and graduate student working in the fields of geography, hydrology, geology, geomorphology, atmosphere, ecology, environment, oceanography, and regional economic and social sustainable development.