Orientations in Geochemistry - Softcover

US National Committee For Geochemistry

Softcover

ISBN 10: 0309021472 ISBN 13: 9780309021470

Publisher: National Academy of Sciences, 1973

Synopsis

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1974-01-01 edition. Excerpt: ...the forms in which transition metals occur in seawater. Although the concept of the ocean as a chemical system in an equilibrium or near-equilibrium state has led to major improvements in the methodology of marine geochemistry and will undoubtedly lead to a still better understanding of speciation of dissolved components in the future, results obtained during the past few years suggest that deviations from complete heterogeneous equilibrium are the rule, rather than the exception. The components most obviously out of equilibrium are those utilized by organisms. Both calcium carbonate and silica belong to this category and have been studied by geochemists for almost a century. In both cases, planktonic organisms fix these components at rates greatly in excess of the annual influx from rivers. Thus, if the ocean is not to be stripped, most of the biologically fixed material must re-dissolve in the water column or on the seafloor. The distribution of such components is, therefore, determined by the rates of fixation and dissolution, and by oceanic circulation. Many of the factors affecting the distribution of calcium carbonate and silica in the ocean and on the seafloor today have been identified, but there is little understanding of the mechanisms involved. It is one thing to know that the rate of dissolution of calcium carbonate increases with depth in the ocean, but quite another to estimate this rate solely from a set of physical and chemical parameters. Preliminary experiments with the carbonate and silica systems show promise of leading to predictive models for the dissolution rates of calcite and opaline silica, respectively. Much more work will be necessary, however, before the present patterns are fully understood, let alone before...

Edition details

• Publisher: National Academy of Sciences
• Publication date: 1973
• Language: English
• ISBN 10: 0309021472
• ISBN 13: 9780309021470
• Binding: Paperback
• Number of pages: 122