Methane Fluxes and Associated Biogeochemical Processes in Cold Seep Ecosystems - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Methane Fluxes and Associated Biogeochemical Processes in Cold Seep Ecosystems write by Janine Felden. This book was released on 2009. Methane Fluxes and Associated Biogeochemical Processes in Cold Seep Ecosystems available in PDF, EPUB and Kindle. 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.
Chemical and Biogeochemical Processes at Methane and Other Cold Seeps
Chemical and Biogeochemical Processes at Methane and Other Cold Seeps - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Chemical and Biogeochemical Processes at Methane and Other Cold Seeps write by Davide Oppo. This book was released on 2023-10-31. Chemical and Biogeochemical Processes at Methane and Other Cold Seeps available in PDF, EPUB and Kindle. 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.
Physical and biogeochemical processes driving methane sources, sinks and emissions in aquatic systems: The past, present and future under global change
Physical and biogeochemical processes driving methane sources, sinks and emissions in aquatic systems: The past, present and future under global change - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Physical and biogeochemical processes driving methane sources, sinks and emissions in aquatic systems: The past, present and future under global change write by Daniel F. McGinnis. This book was released on 2023-06-08. Physical and biogeochemical processes driving methane sources, sinks and emissions in aquatic systems: The past, present and future under global change available in PDF, EPUB and Kindle.
Freshwater methane and carbon dioxide fluxes
Freshwater methane and carbon dioxide fluxes - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Freshwater methane and carbon dioxide fluxes write by Sivakiruthika Natchimuthu. This book was released on 2016-09-05. Freshwater methane and carbon dioxide fluxes available in PDF, EPUB and Kindle. Freshwater bodies such as lakes and streams release the greenhouse gases methane (CH4) and carbon dioxide (CO2) into the atmosphere. Global freshwater CH4 and CO2 emissions have been estimated to be of a similar magnitude to the global land or ocean carbon sink, and are thus significant components of global carbon budgets. However, the data supporting global estimates frequently lacks information regarding spatial and temporal variability and are thus highly inaccurate. In this thesis, detailed studies of the spatio-temporal variability of CH4 and CO2 fluxes were conducted in the open water areas of lakes and streams within a whole catchment in Sweden. One aim was also to evaluate the importance of spatio-temporal variability in lake and stream fluxes when making whole catchment aquatic or large scale assessments. Apart from the expected large spatio-temporal variability in lake fluxes, interactions between spatial and temporal variability in CH4 fluxes were found. Shallow lakes and shallow areas of lakes were observed to emit more CH4 as compared to their deeper counterparts. This spatial variability interacted with the temporal variability driven by an exponential temperature response of the fluxes, which meant that shallow waters were more sensitive to warming than deeper ones. Such interactions may be important for climate feedbacks. Surface water CO2 in lakes showed significant spatio-temporal variability and, when considering variability in both space and time, CO2 fluxes were largely controlled by concentrations, rather than gas transfer velocities. Stream fluxes were also highly variable in space and time and in particular, stream CH4 fluxes were surprisingly large and more variable than CO2 fluxes. Fluxes were large from stream areas with steep slopes and periods of high discharge which occupied a small fraction of the total stream area and the total measurement period, respectively, and a failure to account for these spatially distinct or episodic high fluxes could lead to underestimates. The total aquatic fluxes from the whole catchment were estimated by combining the measurements in open waters of lakes and streams. Using our data, recommendations on improved study designs for representative measurements in lakes and streams were provided for future studies. Thus, this thesis presents findings relating to flux regulation in lakes and streams, and urges forthcoming studies to better consider spatio-temporal variability so as to achieve unbiased large-scale estimates.
Systems Biogeochemistry of Major Marine Biomes
Systems Biogeochemistry of Major Marine Biomes - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Systems Biogeochemistry of Major Marine Biomes write by Aninda Mazumdar. This book was released on 2022-04-01. Systems Biogeochemistry of Major Marine Biomes available in PDF, EPUB and Kindle. 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.
