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 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 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 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 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 Dissolution of Abiogenic and Biogenic Calcium Carbonate Under Ocean Acidification Conditions written by Zhaleh Adhamijamnani and published by . This book was released on 2017 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: Under ocean acidification conditions, the chemistry of the seawater will change including a decrease in pH, a decrease in carbonate ion concentration and a decrease in the calcium carbonate saturation state of the water (Ω). This has implications for solid marine calcium carbonates including calcifying organisms and carbonate sediments. The dissolution kinetics of marine carbonates are poorly understood, therefore modelling of the future ocean under ocean acidification scenarios is hampered.

Download or read book Chemical Kinetics and Process Dynamics in Aquatic Systems written by PatrickL. Brezonik and published by Routledge. This book was released on 2018-05-08 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical Kinetics and Process Dynamics in Aquatic Systems is devoted to chemical reactions and biogeochemical processes in aquatic systems. The book provides a thorough analysis of the principles, mathematics, and analytical tools used in chemical, microbial, and reactor kinetics. It also presents a comprehensive, up-to-date description of the kinetics of important chemical processes in aquatic environments. Aquatic photochemistry and correlation methods (e.g., LFERs and QSARs) to predict process rates are covered. Numerous examples are included, and each chapter has a detailed bibliography and problems sets. The book will be an excellent text/reference for professionals and students in such fields as aquatic chemistry, limnology, aqueous geochemistry, microbial ecology, marine science, environmental and water resources engineering, and geochemistry.

Download or read book Dissolution Dynamics of the Calcite water Interface Observed in Situ by Glancing incidence X ray Scattering written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Glancing-incidence X-ray scattering measurements made at the National Synchrotron Light Source were used to investigate dissolution dynamics in situ at the calcite-water interface. The relation between calcite saturation state and roughness of the calcite (1014) cleavage surface as a function of time was examined during pH titrations of an initially calcite-saturated solution. Systematic variations in roughness were observed as a function of saturation state as pH was titrated to values below that of calcite saturation. Different steady-state values of roughness were evident at fixed values of [Delta]G[sub r], and these were correlated with the extent of undersaturation. A significant increase in roughness begins to occur with increasing undersaturation at a [Delta]G[sub r] value of approximately [minus]2.0 kcal/mol. The dissolution rate corresponding to this increase is about 1.5 x 10[sup 7] mmol/cm [center-dot] sec. This increase in roughness is attributed to a transition in the principal rate-determining dissolution mechanism, and is consistent with both powder-reaction studies of dissolution kinetics and single-crystal dissolution studies by atomic force microscopy. These data indicate some important potential applications of GIXS in the study of mineral-water interface geochemistry.

Download or read book Treatise on Geochemistry written by and published by Newnes. This book was released on 2013-10-19 with total page 14787 pages. Available in PDF, EPUB and Kindle. Book excerpt: This extensively updated new edition of the widely acclaimed Treatise on Geochemistry has increased its coverage beyond the wide range of geochemical subject areas in the first edition, with five new volumes which include: the history of the atmosphere, geochemistry of mineral deposits, archaeology and anthropology, organic geochemistry and analytical geochemistry. In addition, the original Volume 1 on "Meteorites, Comets, and Planets" was expanded into two separate volumes dealing with meteorites and planets, respectively. These additions increased the number of volumes in the Treatise from 9 to 15 with the index/appendices volume remaining as the last volume (Volume 16). Each of the original volumes was scrutinized by the appropriate volume editors, with respect to necessary revisions as well as additions and deletions. As a result, 27% were republished without major changes, 66% were revised and 126 new chapters were added. In a many-faceted field such as Geochemistry, explaining and understanding how one sub-field relates to another is key. Instructors will find the complete overviews with extensive cross-referencing useful additions to their course packs and students will benefit from the contextual organization of the subject matter Six new volumes added and 66% updated from 1st edition. The Editors of this work have taken every measure to include the many suggestions received from readers and ensure comprehensiveness of coverage and added value in this 2nd edition The esteemed Board of Volume Editors and Editors-in-Chief worked cohesively to ensure a uniform and consistent approach to the content, which is an amazing accomplishment for a 15-volume work (16 volumes including index volume)!

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 Ocean Acidification written by Jean-Pierre Gattuso and published by Oxford University Press. This book was released on 2011-09-15 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ocean helps moderate climate change thanks to its considerable capacity to store CO2, through the combined actions of ocean physics, chemistry, and biology. This storage capacity limits the amount of human-released CO2 remaining in the atmosphere. As CO2 reacts with seawater, it generates dramatic changes in carbonate chemistry, including decreases in pH and carbonate ions and an increase in bicarbonate ions. The consequences of this overall process, known as "ocean acidification", are raising concerns for the biological, ecological, and biogeochemical health of the world's oceans, as well as for the potential societal implications. This research level text is the first to synthesize the very latest understanding of the consequences of ocean acidification, with the intention of informing both future research agendas and marine management policy. A prestigious list of authors has been assembled, among them the coordinators of major national and international projects on ocean acidification.

Download or read book Kinetics and Mechanism of Calcite Dissolution in Aqueous Solutions at Low Temperatures written by E. Lennart Sjöberg and published by . This book was released on 1978 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Calcite dissolution kinetics and lake neutralization written by Harald Ulrik Sverdrup and published by . This book was released on 1985 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Dissolution Kinetics of Calcite Dolomite and Dolomitic Rocks in the Carbon Dioxide water System written by Janet Suzanne Herman and published by . This book was released on 1982 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissolution kinetics of natural calcite minerals in CO2 water systems approaching calcite equilibrium written by U. Svensson and published by . This book was released on 1992 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Dissolution Kinetics of Calcite Dolomite and Dolomitic Rocks in the CO2 water System written by Janet S. Herman and published by . This book was released on 1982 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Guide to Best Practices for Ocean Acidification Research and Data Reporting written by and published by . This book was released on 2011 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: