Download or read book Chemical and Biogeochemical Processes at Methane and Other Cold Seeps written by Davide Oppo and published by Frontiers Media SA. This book was released on 2023-10-31 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methane is a strong climate-active gas, the concentration of which is rapidly increasing in the atmosphere. Vast methane reservoirs are hosted in seafloor sediments, both dissolved in pore fluids and trapped in gas hydrate. Cold seeps discharge significant amounts of this methane into the ocean. The rate of seabed methane discharge could be orders of magnitude higher than current estimates, creating considerable uncertainty. The extent of methane transfer from the seafloor to the water column and ultimately to the atmosphere is also uncertain. The seepage of methane and other hydrocarbons drives complex biogeochemical processes in marine sediments and the overlying water column. Seeps support chemosynthesis-based communities and impact the chemistry of the water column. Seeps may also play a critical role in ocean acidification and deoxygenation and can be geohazards, as well as a potential energy resource. Unraveling the complex and dynamic interactions and processes at marine seeps is crucial for our understanding of element cycling in the geo- and hydrosphere.

Download or read book Methane Fluxes and Associated Biogeochemical Processes in Cold Seep Ecosystems written by Janine Felden and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During this PhD study, methane efflux and consumption as well as related processes such as sulfate reduction were investigated at four different deep-sea cold seeps. The main focus was on in situ quantification of methane emission and oxygen consumption. The results showed that cold seeps are spatially heterogeneous ecosystems, which are controlled by variations of fluid flow intensity influencing benthic biogeochemical processes. The highest fluid flow velocities are found at the central outflow of mud volcanoes in combination with high methane emission but low methane consumption rates. Outside of these main emission sites, chemosynthetic organisms such as matforming thiotrophic bacteria or siboglinid tubeworms are observed. Here, medium to low fluid flow velocities with high methane oxidation and high sulfate reduction rates were measured. Within one seep ecosystem there are spatial variations in methane emission and consumption, but the benthic biological methane filter of the different seep habitats removes a significant fraction of the total methane flow (up to 90 %). For the methane budgets of geostructures and ocean basins, diffusive methane effluxes were previously not considered. However, based on the obtained data during this PhD study, diffusive methane discharge contributes significantly to the total methane emission. Considering the diffusive methane release of the investigated deep-sea mud volcanoes, only mud volcanoes would release up to 15 x 1012 g methane per year to the water column, which is a significant fraction of the total annual methane flux from the ocean to the atmosphere.

Download or read book Geobiology of Ancient and Modern Methane seeps written by Jörn Peckmann and published by . This book was released on 2005 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Systems Biogeochemistry of Major Marine Biomes written by Aninda Mazumdar and published by John Wiley & Sons. This book was released on 2022-04-01 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: Systems Biogeochemistry of Major Marine Biomes A comprehensive system-level discussion of the geomicrobiology of the Earth’s oceans In Systems Biogeochemistry of Major Marine Biomes, a team of distinguished researchers delivers a systemic overview of biogeochemistry across a number of major physiographies of the global ocean: the waters and sediments overlying continental margins; the deep sub-surfaces; the Arctic and Antarctic oceans; and the physicochemical extremes such as the hypersaline and sulfidic marine zones, cold methane seeps and hydrothermal ecosystems. The book explores state-of-the-art advances in marine geomicrobiology and investigates the drivers of biogeochemical processes. It highlights the imperatives of the unique, fringe, and cryptic processes while studying the geological manifestations and ecological feedbacks of in situ microbial metabolisms. Taking a holistic approach toward the understanding of marine biogeochemical provinces, this book emphasizes the centrality of culture-dependent and culture-independent (meta-omics-based) microbiological information within a systems biogeochemistry framework. Perfect for researchers and scientists in the fields of geochemistry, geophysics, geomicrobiology, oceanography, and marine science, Systems Biogeochemistry of Major Marine Biomes will also earn a place in the libraries of policymakers and advanced graduate students seeking a one-stop reference on marine biogeochemistry.

Download or read book Biogeochemistry of Marine Systems written by Kenneth D. Black and published by John Wiley & Sons. This book was released on 2009-02-12 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine systems vary in their sensitivities to perturbation.Perturbation may be insidious – such as increasingeutrophication of coastal areas – or it may be dramatic– such as a response to an oil spillage or some otheraccident. Climate change may occur incrementally or it may beabrupt, and ecosystem resilience is likely to be a complex functionof the interactions of those assemblages or species mediating keybiogeochemical processes. Biogeochemistry of Marine Systems considers issues ofmarine system resilience, focusing on a range of marine systemsthat exemplify major global province types but are also interestingand topical in their own right, on account of their sensitivity tonatural or anthropogenic change or their importance as ecologicalservice providers. Authors concentrate on advances of the lastdecade.

Download or read book Biogeochemical Processes at Marine Whale Falls and Methane Seeps written by David Vardeh and published by . This book was released on 2011 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interactions Between Macro and Microorganisms in Marine Sediments written by and published by American Geophysical Union. This book was released on 2005-01-14 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine sediments support complex interactions between macro-and microorganisms that have global implications for carbon and nutrient cycles. What is the state of the science on such interactions from coastal and estuarine environments to the deep sea? How does such knowledge effect environmental management? And what does future research hold in store for scientists, engineers, resource managers, and educators?Interactions between Macro- and Microorganisms in Marine Sediments responds to these questions, and more, by focusing on:? Interactions between plants, microorganisms, and marine sediment? Interactions between animals, microorganisms, and marine sediment? Interactions between macro- and microorganisms and the structuring of benthic communities? Impact of macrobenthic activity on microbially-mediated geochemical cycles in sediments? Conceptual and numeric models of diagenesis that incorporate interactions between macro- and microorganismsHere is an authoritative overview of the research, experimentation and modeling approaches now in use in our rapidly evolving understanding of life in marine sediments.

Download or read book The Response of Seep and Methane Hydrate Biogeochemical Systems to Variability in Climate Hydrogeology and Trace Metal Availability written by Theresa L. Whorley and published by . This book was released on 2021 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cold seeps are seafloor manifestations of fluid flow from deeper within marine sediments, and they are often locations where methane discharges into the ocean. These dynamic environments are typically found along continental margins and serve as biological oases for specialized seafloor macro- and meio-fauna as well as seafloor and subseafloor chemoautotrophic microorganisms. Microbial methanogenesis is ubiquitous in the upper few 100s of meters of sediments along continental margins and, as such, continental margin sediments constitute an enormous geologic reservoir of methane. Methane exists as a dissolved component of pore water within continental margin sediments and concentrations are often high enough that methane can also exist as a free gas or is stored in methane hydrates. Burial of dissolved methane in pore water and sequestration within methane hydrate represent two important sinks that prevent the release of this greenhouse gas into the ocean/atmosphere system. The largest sink of microbial methane within marine sediments is the anaerobic oxidation of methane (AOM) performed by a syntrophic consortium of bacteria and archaea within pore water. Bisulfide produced by this reaction is transported to the seafloor where it serves as a key metabolic component for thiotrophic organisms. The amount of methane oxidized through AOM is variable but can be up to 100% of the dissolved methane flux to the seafloor. The reasons for variability in the efficiency of this process remains a pivotal unknown impacting estimates of methane input to the ocean from marine sediments. This dissertation explores the response of cold seep and methane hydrate systems to environmental variability. Chapter 1 presents an introduction to microbially-mediated reactions in marine sediments including microbial methanogenesis and the anaerobic oxidation of methane, the global methane hydrate reservoir, and the importance and characteristics of the organisms involved in the vital process of AOM. In Chapter 2, pore water geochemical tracers are used to test the hypothesis that contemporary bottom water warming along the Washington sector of the Cascadia margin has induced widespread dissociation of buried methane hydrate along the upper continental slope where the reservoir is most sensitive to changes in bottom water temperature. This work reveals that fluid emitted at actively venting seeps in this region is largely sourced from deeper mineral dehydration reactions and from meteoric water discharge, and is not the result of modern methane hydrate dissociation. Chapter 3 presents the longest continuous record of time-series fluid flow rate and composition data at a cold seep to date. The time-series record documents the persistent downward flow of seawater directly beneath a Beggiatoa bacterial mat. Beggiaotoa is a filamentous bacterium common in reducing environments such as cold seeps that requires the upward flux of reduced sulfur for survival. Geochemical modeling shows that downward flow of fluid rich in electron acceptors stimulates enhanced rates of sulfate reduction and bisulfide production via AOM, driving a strong diffusional gradient of bisulfide to the seafloor. These results show that Beggiatoa can persist and thrive in regions of downward fluid advection, and that the shallow circulation of seawater at cold seeps increases the consumption of oxygen, nitrate, and sulfate from seawater, influencing local biogeochemical cycling The research presented in Chapter 4 explores the possibility that anaerobic methanotrophic (ANME) archaeal communities involved in AOM are limited by the bioavailability of nickel in cold seep pore water, thus potentially impacting the efficiency of AOM in oxidizing methane before it can escape to the water column. Data presented in this chapter show that higher concentrations of bioavailable nickel exist at non-cold seep settings compared to cold seep settings where there is likely greater uptake and utilization of nickel from pore water to fuel ANME communities. It may be that ANME have successfully developed an evolutionary adaptation to acquire nickel from non-bioavailable forms, such as the production of nickel-specific extracellular ligands similar to siderophores. One or more of the organic ligands characterized in this study may be the result of such ligand expression. This study is the first to measure the bioavailability of nickel in marine pore water as well as to quantify and characterize organic nickel-binding ligands.

Download or read book Methane and Climate Change written by Dave Reay and published by Routledge. This book was released on 2010-08-12 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methane is a powerful greenhouse gas and is estimated to be responsible for approximately one-fifth of man-made global warming. Per kilogram, it is 25 times more powerful than carbon dioxide over a 100-year time horizon -- and global warming is likely to enhance methane release from a number of sources. Current natural and man-made sources include many where methane-producing micro-organisms can thrive in anaerobic conditions, particularly ruminant livestock, rice cultivation, landfill, wastewater, wetlands and marine sediments. This timely and authoritative book provides the only comprehensive and balanced overview of our current knowledge of sources of methane and how these might be controlled to limit future climate change. It describes how methane is derived from the anaerobic metabolism of micro-organisms, whether in wetlands or rice fields, manure, landfill or wastewater, or the digestive systems of cattle and other ruminant animals. It highlights how sources of methane might themselves be affected by climate change. It is shown how numerous point sources of methane have the potential to be more easily addressed than sources of carbon dioxide and therefore contribute significantly to climate change mitigation in the 21st century.

Download or read book Encyclopedia of Marine Geosciences written by Jan Harff and published by Springer. This book was released on 2021-01-14 with total page 1000 pages. Available in PDF, EPUB and Kindle. Book excerpt: Globally growing demand of energy and mineral resources, reliable future projection of climate processes and the protection of coasts to mitigate the threats of disasters and hazards require a comprehensive understanding of the structure, ongoing processes and genesis of the marine geosphere. Beyond the “classical” research fields in marine geology in current time more general concepts have been evolved integrating marine geophysics, hydrography, marine biology, climatology and ecology. As an umbrella the term “marine geosciences” has been broadly accepted for this new complex field of research and the solutions of practical tasks in the marine realm. The “Encyclopedia of Marine Geosciences” comprises the current knowledge in marine geosciences whereby not only basic but also applied and technical sciences are covered. Through this concept a broad scale of users in the field of marine sciences and techniques is addressed from students and scholars in academia to engineers and decision makers in industry and politics.

Download or read book Physical and biogeochemical processes driving methane sources sinks and emissions in aquatic systems The past present and future under global change written by Daniel F. McGinnis and published by Frontiers Media SA. This book was released on 2023-06-08 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Recent Advances in Natural Methane Seep and Gas Hydrate Systems written by Tamara Baumberger and published by Frontiers Media SA. This book was released on 2023-02-13 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Biogeochemistry of Methane Isotopologues in Marine and Lacustrine Sediments written by Ellen Lalk and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methane is a globally significant greenhouse gas, energy resource, and it is a product and reactant of microbial metabolisms. Multiple sources and sinks of methane can be challenging to distinguish from each other, thus complicating the understanding of methane budgets and the effects of microbes on mediating Earth's carbon cycle. The relative abundances of methane isotopologues (e.g., 12CH4, 13CH4, 12CH3D, and 13CH3D) record process-based information about the formation conditions, transport, and fate of methane, and in select environments can serve as a temperature proxy. This geochemical tool is herein applied to methane from marine and lacustrine sediments to test assumptions about prevailing mechanisms of its formation and consumption in these settings. This thesis describes 1) three studies about biogeochemical insights gained by quantifying the relative abundance of clumped methane isotopologue, 13CH3D, in samples from marine and lacustrine sediments, and 2) one foray into method development to improve the quantification of methane in these environments. Chapter 2 presents a global survey of marine gas hydrates where isotope-based temperatures are used to assess whether linkages between methane sources and seepage-associated seafloor features match putative geologic models. Chapter 3 describes two kilometer-scale profiles of methane isotopologues from marine sediments, where the relationship between expected sediment temperature and isotope-based temperature is used to evaluate the temperature limit of microbial processing and abiotic re-equilibration mechanisms. Chapter 4 reports the largest set of methane isotopologue data from ebullition in a single lake basin, which is used to gauge the relative importance of aerobic and anaerobic methane oxidation in the study site and recommend a general sampling strategy to constrain methane source signatures in similar lake settings. Chapter 5 explains the development of a method to quantify the in situ concentration of methane based on ratios of dissolved gases, and its comparison to four other methane quantification methods for surface sediments from marine cold seeps. The findings from this research contribute to ongoing efforts to understand the sedimentary carbon cycle and microbial activity in remote environments.

Download or read book Geobiology of Ancient and Modern Methane Seeps written by Jörn Peckmann and published by . This book was released on 2005 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Habitats and Biota of the Gulf of Mexico Before the Deepwater Horizon Oil Spill written by C. Herb Ward and published by Springer. This book was released on 2017-06-26 with total page 917 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is open access under a CC BY-NC 2.5 license. The Gulf of Mexico is an open and dynamic marine ecosystem rich in natural resources but heavily impacted by human activities, including agricultural, industrial, commercial and coastal development. The Gulf of Mexico has been continuously exposed to petroleum hydrocarbons for millions of years from natural oil and gas seeps on the sea floor, and more recently from oil drilling and production activities located in the water near and far from shore. Major accidental oil spills in the Gulf are infrequent; two of the most significant include the Ixtoc I blowout in the Bay of Campeche in 1979 and the Deepwater Horizon Oil Spill in 2010. Unfortunately, baseline assessments of the status of habitats and biota in the Gulf of Mexico before these spills either were not available, or the data had not been systematically compiled in a way that would help scientists assess the potential short-term and long-term effects of such events. This 2-volume series compiles and summarizes thousands of data sets showing the status of habitats and biota in the Gulf of Mexico before the Deepwater Horizon Oil Spill. Volume 1 covers: water and sediment quality and contaminants in the Gulf; natural oil and gas seeps in the Gulf of Mexico; coastal habitats, including flora and fauna and coastal geology; offshore benthos and plankton, with an analysis of current knowledge on energy capture and energy flows in the Gulf; and shellfish and finfish resources that provide the basis for commercial and recreational fisheries.

Download or read book In Situ Quantification of Biogeochemical Processes at Cold Seeps written by Anna Lichtschlag and published by . This book was released on 2009 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biogeochemistry of Marine Systems written by Kenneth D. Black and published by CRC Press. This book was released on 2020-02-03 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine systems vary in their sensitivities to perturbation. Perturbation may be insidious - such as increasing eutrophication of coastal areas - or it may be dramatic - such as a response to an oil spill or some other accident. Climate change may occur incrementally or it may be abrupt, and ecosystem resilience is likely to be a complex function of the interactions of the factors and species mediating key biogeochemical processes. Biogeochemistry of Marine Systems considers issues of marine system resilience, focusing on a range of marine systems that exemplify major global province types. Each system is interesting in its own right, on account of its sensitivity to natural or anthropogenic change or its importance as an ecological service provider. Each contributing author concentrates on advances of the last decade. This prime reference source for marine biogeochemists, marine ecologists, and global systems scientists provides a strong foundation for the study of the multiple marine systems undergoing change because of natural biochemical or anthropogenic factors.