Organic Phosphorus in Marine Sediments


Book Description

Phosphorus, an essential nutrient, is removed from the oceans only through burial with marine sediments. Organic phosphorus (Porg) constitutes an important fraction (ca. 25%) of total-P in marine sediments. However, given the inherent lability of primary Porg biochemicals, it is a puzzle that any Porg is preserved in marine sediments. The goal of this thesis was to address this apparent paradox by linking bulk and molecular-level Porg information. A newly-developed sequential extraction method, which isolates sedimentary Porg reservoirs based on solubility, was used in concert with 31P nuclear magnetic resonance spectroscopy (31P-NMR) to quantify Porg functional group concentrations. The coupled extraction/31P-NMR method was applied to three sediment cores from the Santa Barbara Basin, and the first-ever high-resolution depth profiles of molecular-level Porg distribution during diagenesis were generated. These depth profiles were used to consider regulation of Porg distribution by biomass abundance, chemical structure, and physical protection mechanisms. Biomass cannot account for more than a few percent of sedimentary Porg. No evidence for direct structural control on remineralization of Porg was found. Instead, sorptive protection appears to be an important mechanism for Porg preservation, and structure may act as a secondary control due to preferential sorption of specific Porg compound classes.




Interactions of C, N, P and S Biogeochemical Cycles and Global Change


Book Description

This book is a natural extension of the SCOPE (Scientific Committee of Problems on the Environment) volumes on the carbon (C), nitrogen (N), phosphorus (P) and sulfur (S) biogeochemical cycles and their interactions (Likens, 1981; Bolin and Cook, 1983). Substantial progress in the knowledge of these cycles has been made since publication of those volumes. In particular, the nature and extent of biological and inorganic interactions between these cycles have been identified, positive and negative feedbacks recognized and the relationship between the cycles and global environmental change preliminarily elucidated. In March 1991, a NATO Advanced Research Workshop was held for one week in Melreux, Belgium to reexamine the biogeochemical cycles of C, N, P and S on a variety of time and space scales from a holistic point of view. This book is the result of that workshop. The biogeochemical cycles of C, N, P and S are intimately tied to each other through biological productivity and subsequently to problems of global environmental change. These problems may be the most challenging facing humanity in the 21 st century. In the broadest sense, "global change" encompasses both changes to the status of the large, globally connected atmospheric, oceanic and terrestrial environments (e. g. tropospheric temperature increase) and change occurring as the result of nearly simultaneous local changes in many regions of the world (e. g. eutrophication).













Geochemistry of Marine Sediments


Book Description

The processes occurring in surface marine sediments have a profound effect on the local and global cycling of many elements. This graduate text presents the fundamentals of marine sediment geochemistry by examining the complex chemical, biological, and physical processes that contribute to the conversion of these sediments to rock, a process known as early diagenesis. Research over the past three decades has uncovered the fact that the oxidation of organic matter deposited in sediment acts as a causative agent for many early diagenetic changes. Summarizing and discussing these findings and providing a much-needed update to Robert Berner's Early Diagenesis: A Theoretical Approach, David J. Burdige describes the ways to quantify geochemical processes in marine sediment. By doing so, he offers a deeper understanding of the cycling of elements such as carbon, nitrogen, and phosphorus, along with important metals such as iron and manganese. No other book presents such an in-depth look at marine sediment geochemistry. Including the most up-to-date research, a complete survey of the subject, explanatory text, and the most recent mathematical formulations that have contributed to our greater understanding of early diagenesis, Geochemistry of Marine Sediments will interest graduate students of geology, geochemistry, and oceanography, as well as the broader community of earth scientists. It is poised to become the standard text on the subject for years to come.







Deep-Sea Sediments


Book Description

'Deep-Sea Sediments' focuses on the sedimentary processes operating within the various modern and ancient deep-sea environments. The chapters track the way of sedimentary particles from continental erosion or production in the marine realm, to transport into the deep sea, to final deposition on the sea floor.