Download or read book Biochemical Processes at the Sediment Water Interface and Quantification of Metabolically Driven Calcite Dissolution in Deep Sea Sediments written by Frank Wenzhöfer and published by . This book was released on 1999 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biochemical Processes at the Sediment Water Interface and Qualification of Metabolically Driven Calcite Dissolution in Deep Sea Sedements written by and published by . This book was released on 1999 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biogeochemical Processes at the Sediment Water Interface and Quantification of Metabolically Driven Calcite Dissolution in Deep Sea Sediments written by Frank Wenzhöfer and published by . This book was released on 1999 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biogeochemical processes at the sediment water interfache and quantification of metabolically driven calcite dissolution in deep sea sediments written by Frank Wenzhöfer and published by . This book was released on 1999 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Public Roads of Tennessee written by and published by . This book was released on 1906 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ocean Chemistry and Deep sea Sediments written by Open University and published by . This book was released on 2003-05-21 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: After a brief introduction to the distribution of deep-sea sediments, we show how the activities of marine organisms cycle nutrients and other dissolved constituents within the oceans, and influence the rates at which both solid and dissolved material is removed to sediments. Chapter 3 reviews the carbonate system and ends with a brief excursion into palaeoceanography. We conclude by describing the biological and chemical processes that continue long after sediments have been deposited on the deep-sea floor.
Download or read book Calcite Dissolution Kinetics at the Sediment water Interface in an Acidifying Ocean written by Olivier Sulpis and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Carbon dioxide (CO2), produced and released to the atmosphere by human activities, has been accumulating in the oceans for approximately two centuries and will continue to do so well beyond the end of this century if emissions are not curbed. One direct consequence of CO2 build-up in the atmosphere and its transfer to the ocean is the acidification of seawater. Calcite, a mineral secreted by many organisms living in the surface ocean to produce their shells and skeletons, covers a large part of the seafloor and acts as a natural anti-acid, neutralizing CO2. Thus, a precise knowledge of the kinetics of this dissolution reaction is necessary to predict the ocean recovery time towards its pre-acidification state once anthropogenic CO2 emissions are curbed. This thesis combines laboratory experiments, oceanographic measurements and model outputs to explore and unravel the mechanisms that control calcite dissolution at the sediment-water interface (SWI) on the seafloor in the context of current anthropogenic ocean acidification. Using a newly developed temperature-controlled rotating-disk reactor, as well as a stirred reactor, we were able to measure the rate of dissolution of simulated and natural sediment disks of variable calcite content under environmental and hydrodynamic conditions representative of deep-sea benthic environments. These experiments revealed that, in contrast to the reigning paradigm that calcite dissolution kinetics in seawater is surface reaction-controlled and of high order, calcite dissolution at the SWI and under deep-sea conditions is linearly dependent on the undersaturation state of the overlying seawater with respect to calcite and controlled by the presence of a diffusive-boundary layer (DBL) above the sediment bed. Therefore, irrespective of the mineralogy and sediment properties, the dissolution rate is simply a function of the saturation state of the overlying seawater with respect to calcite, the calcite content of the sediment, and hydrodynamics at the seafloor. From these observations, using a compilation of seawater chemical variables in the global ocean, corresponding sediment calcite content and rain rates, as well as recently modeled bottom current velocities, we have been able to identify the loci of current anthropogenic calcite dissolution and its rate. We found that significant anthropogenic dissolution of calcite at the seafloor currently occurs in the western North Atlantic, where the bottom waters are youngest, and at various hot spots in the southern Atlantic, Indian and Pacific Oceans. Using model projections for the 21st century, under a “business as usual” scenario, we found that while seawater will become more corrosive to this mineral, calcite dissolution at the seafloor will decrease in intensity because bottom currents will slow down and the amount of calcite particles delivered to the seafloor will diminish. These results indicate that the neutralization of human-made CO2 by calcite dissolution at the seafloor may take longer than previously thought. These findings are of critical interest to the scientific community and the public, as these results have far reaching implications for ocean acidification mitigation, to the fate of benthic communities living under increasing environmental stress, and to geologists contemplating both present and past records of ocean acidification"--
Download or read book Chemistry of Marine Water and Sediments written by Antonio Gianguzza and published by Springer Science & Business Media. This book was released on 2002-05-28 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book deals with the processes in marine environment with particular emphasis on the interface processes (sediments- water and atmosphere-water) regarding organic matter and energy fluxes, carbon dioxide intake and transformation. Particular analytical methodologies concerning biosensors for analysis in situ are discussed.
Download or read book Methods for the Study of Deep Sea Sediments Their Functioning and Biodiversity written by Roberto Danovaro and published by CRC Press. This book was released on 2009-12-21 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: For years scientists viewed the deep sea as calm, quiet, and undisturbed, with marine species existing in an ecologically stable and uniform environment. Recent discoveries have completely transformed that understanding and the deep sea is recognized as a complicated and dynamic environment with a rich diversity of marine species. Carefully designe
Download or read book Sediment Diagenesis written by A. Parker and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: The topic of sediment diagenesis is of fundamental importance to industry in the evaluation of hydrocarbon and water reservoir rocks. Detailed knowledge of the diagenetic textures, fabrics, and minerals, and a prediction of the regional diagenetic response, partly controls hydrocarbon recovery programmes. In other words, knowledge of the diagenesis can aid (or even control) conservation policy. Similarly, facies and diagenetic trends w.ithin basins can influence exploration policy. This volume incorporates the majority of the principal contributions given to the NATO Advanced Study Institute held in the University of Reading, U.K., from July 12th-25th, 1981, at which the major themes of carbonate and terrigenous clastic sediments were treated sequentially from deposition to deep burial. Eighty selected scientists from twelve NATO and three other countries participated in the Institute. The keynote addresses which acted as the touchstones for discussion are presented here in the expectation that they will stimulate a still wider audience. We gratefully acknowledge the award of a grant from the Scientific Affairs Division of NATO to run the Institute, and also the cooperation of the University of Reading. Mrs. D. M. Powell helped in many ways with the organisation, and also retyped the entire manuscript of this book. A. Parker B. lv. Sellwood vii FACIES, SEQUENCES AND SAND-BODIES OF THE PRINCIPAL CLASTIC DEPOSITIONAL ENVIRONMENTS T.Elliott Department of Geology University College of Swansea Singleton Park, Swansea SA 2 8PP Wales, U.K.
Download or read book The Dissolution of Calcite in Deep Sea Sediments written by David E. Archer and published by . This book was released on 1990 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Calcium Carbonate Dissolution History in Late Quaternary Deep sea Sediments Western Gulf of Mexico written by Robert C. Thunell and published by . This book was released on 1975 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deep Sea Sediments written by H. Huneke and published by Elsevier. This book was released on 2011-02-08 with total page 865 pages. Available in PDF, EPUB and Kindle. Book excerpt: '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.
Download or read book The Role of Labile Dissolved Organic Carbon in Influencing Fluxes Across the Sediment water Interface written by Deborah J. Read and published by . This book was released on 2008 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sediment diagenesis in aquatic systems is usually understood to be controlled by the concentrations of both organic carbon and the oxidant. However, the concept that sediment respiration may be limited by the supply of organic carbon, even in systems with moderate concentrations of organic carbon in the water column, has yet to be fully explored. Typically we assume that a direct coupling between water column and sediment diagenesis processes occurs and the chemical evolution of porewater and surface water are linked through fluxes of chemical species across the sediment-water interface. While the dynamics of supply of particulate organic carbon (POC) to the sediments via plankton deposition and resuspension, has previously been examined, the fate of dissolved organic carbon (DOC) once in the sediments, has rarely been investigated. A series of experiments comprising batch tests, microcosms and sediment cores were conducted on sediment and water from four diverse field sites in which sediment respiration was considered to be carbon limited. Three sites were oligotrophic, acidic lakes and the fourth an oligotrophic coastal embayment. During each experiment dissolved organic carbon was added and measurements were undertaken of solutes that were considered participants in diagenetic processes. While each system differed in its chemical, biological and geological makeup, a key commonality was the rapid onset of anoxic conditions in the sediments irrespective of the overlying water oxygen concentrations, indicating lack of direct coupling between biogeochemical processes in the water column and sediments. Also, similar apparent DOC remineralisation rates were observed, measured solute fluxes after the addition of DOC indicated adherence to the ecological redox sequence, and increased ammonium concentrations were measured in the overlying waters of the acidic microcosms. In marine system experiments it was noted that diagenetic respiration, as indicated by decreasing concentrations of oxygen in the overlying water, increased rapidly after labile DOC was added. To explore the influence of geochemical processes on sediment respiration, a diagenetic model was tested against the laboratory data. The model was able to capture the rapid changes observed in the microcosms after addition of DOC in both the marine and acidic systems experiments. The model has the potential to serve as an essential tool for quantifying sediment organic matter decomposition and dissolved chemical fluxes. This work has focussed our attention on the control of DOC availability on sediment respiration and thus its ultimate control on solute fluxes across the sediment water interface. The results highlight the need to understand and quantify the supply of DOC to the sediment (as POC or already as the dissolved form), its transport through the sediment and its eventual remineralisation. This understanding is critical for improved management of aquatic systems, possibly even in systems where water column organic carbon is plentiful but sediment respiration is constrained by high organic carbon turnover rates in the water column and a resulting low flux of organic carbon to the sediment.
Download or read book Kinetics of Carbonate seawater Interactions written by Francois Pesret and published by . This book was released on 1972 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most of the calcium carbonate removed from the oceans is precipitated out by pelagic organisms living in the upper layers of the world's oceans. However, only a small fraction of that amount accumulates on the ocean floor as sediments. Thus, there is the question of where the dissolution takes place. This question will not be finally answered until the chemical process of the dissolution in seawater is fully understood. Since most oceanic waters are out of equilibrium with the calcium carbonate system, it is more important to consider the kinetics of the reaction, rather than the equilibrium itself. Using the spinning disk method, an experimental set-up was devised to study the rate of dissolution of calcite in aqueous solutions. Different models were developed to describe the reaction and to estimate what chemical processes may take place. The object of this study was to compare the relative influence of individual seawater constituents such as Mg(++), Sr(++), Ba(++), Ca(++), SO4( -- ), PO4(3- ), and dissolved organic matter, on the rate of calcite solution. (Author).
Download or read book Diagenetic Models and Their Implementation written by Bernard Paul Boudreau and published by Berlin : Springer. This book was released on 1997 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Organic Substances and Sediments in Water Processes and analytical written by and published by . This book was released on 1991 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: V.1. Humics and soils. v.2. Processes and analytical. v.3. Biological.
