Use of Proxies in Paleoceanography
Use of Proxies in Paleoceanography

Author: Gerhard Fischer

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 768

ISBN-13: 3642586465

DOWNLOAD EBOOK

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.

Rocas Alijos
Rocas Alijos

Author: Robert W. Schmieder

Publisher: Springer Science & Business Media

Published: 2013-03-09

Total Pages: 501

ISBN-13: 9401729174

DOWNLOAD EBOOK

Rocas Alijos lies 180 nautical miles west of Baja California. It comprises several exposed rocks that surmount a large oceanic volcano rising from the ocean floor well off the continental shelf. It is located at the transition zone between two major biologic provinces, at a latitude where the Pacific Current turns westward to form the north Pacific trans-oceanic current. In spite of its obvious importance for biogeographical studies, the remoteness of Rocas Alijos and its small size thwarted any major scientific work until very recently, and the topography, biota, and oceanographic conditions of the site remained largely unknown. During 1990, and again in 1993, Cordell Expeditions, a nonprofit research organization based in Walnut Creek, California, undertook expeditions to describe the site. A scientific team of 30 was onsite 31 October-7 November 1990, and a scientific team of 12 was onsite 10-15 February 1993. Since most of the Rocas Alijos site is subtidal, much of the examination and specimen collection was done by scuba, although several remote sampling techniques were also used. The exposed rocks were sampled by climbers, and megafauna were observed from shipboard.

Planktic Foraminifers in the Modern Ocean
Planktic Foraminifers in the Modern Ocean

Author: Ralf Schiebel

Publisher: Springer

Published: 2017-02-17

Total Pages: 366

ISBN-13: 3662502976

DOWNLOAD EBOOK

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.

The Micropalaeontology of Oceans
The Micropalaeontology of Oceans

Author: B. M. Funnell

Publisher: Cambridge University Press

Published: 1971-06-02

Total Pages: 842

ISBN-13: 0521076420

DOWNLOAD EBOOK

This 1971 volume presents the proceedings of a Symposium of Micropalaeontology of Marine Bottom Sediments held in Cambridge, England, in September 1967. The collection and paleontological interpretations of deep-sea sediments had only been carried out intensively for the twenty years preceding the book's publication, and it provides a summary of the state of knowledge in this field as it stood. Beginning with a consideration of the organisms in relation to the water in which they live, successive chapters deal with the descent of the skeletons to the sea floor, their entombment in the sediments and their interpretation to elucidate the history of the oceans. It is written by many of the specialists responsible for the development of this field and includes numerous Russian contributions. This book became the definitive compendium for students and workers in oceanography and palaeontology, and is still a useful resource today.