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Intro -- Carbon Mineralization in Coastal Wetlands: From Litter Decomposition to Greenhouse Gas Dynamics -- Copyright -- Contents -- Contributors -- Acknowledgments -- Chapter 1: Introduction -- 1.1. Concepts and background -- 1.2. Potential climatic and anthropogenic drivers for carbon mineralization -- 1.3. Conceptual model on carbon mineralization and related processes -- 1.4. Motivation for writing the book -- References -- Chapter 2: Decomposition of vascular plants and carbon mineralization in coastal wetlands -- 2.1. Introduction -- 2.2. Kinetics of litter decomposition -- 2.2.1. Residence time (Tr) -- 2.2.2. Decomposition rate (Rd) -- 2.2.3. Half-life (t1/2) -- 2.3. Factors affecting litter decomposition in coastal wetlands -- 2.3.1. Priori knowledge of influential factors -- 2.3.2. A metaanalysis of litter decomposition patterns -- 2.4. Refractory compounds -- 2.5. Sinks of mineral carbon -- 2.6. Conclusions -- References -- Chapter 3: CO2 and CH4 emissions from coastal wetland soils -- 3.1. Introduction -- 3.2. Methods to quantify GHG emissions from coastal wetland soils -- 3.3. Magnitude of GHG emissions from coastal wetland soils -- 3.4. Influence of physical parameters on GHG emissions from coastal wetland soils -- 3.4.1. Temperature -- 3.4.2. Soil water content -- 3.4.3. Nutrient inputs -- 3.5. Biological controls of GHG emissions from coastal wetland soils -- 3.5.1. Benthic biofilm -- 3.5.2. Biogenic structures -- 3.6. Synthesis and research directions -- Acknowledgments -- References -- Chapter 4: Biosphere-atmosphere exchange of CO2 and CH4 in mangrove forests and salt marshes -- 4.1. Overview of the eddy covariance technique -- 4.1.1. Principles of the eddy covariance technique -- 4.1.2. Advantages of eddy covariance measurements -- 4.1.3. Disadvantages of eddy covariance measurements.

Subterranean ecosystems play an active role in the global carbon cycle, yet only a few studies using indirect methods have focused on the role of the cave microbiota in this critical cycle. Here we present pioneering research based on in situ real-time monitoring of CO2 and CH4 diffusive fluxes and concurrent δ13C geochemical tracing in caves, combined with 16S microbiome analysis. Our findings show that cave sediments are promoting continuous CH4 consumption from cave atmosphere, resulting in a significant removal of 65% to 90%. This research reveals the most effective taxa and metabolic pathways in consumption and uptake of greenhouse gases. Methanotrophic bacteria were the most effective group involved in CH4 consumption, namely within the families Methylomonaceae, Methylomirabilaceae and Methylacidiphilaceae. In addition, Crossiella and Nitrosococcaceae wb1-P19 could be one of the main responsible of CO2 uptake, which occurs via the Calvin-Benson-Bassham cycle and reversible hydration of CO2. Thus, syntrophic relationships exist between Crossiella and nitrifying bacteria that capture CO2, consume inorganic N produced by heterotrophic ammonification in the surface of sediments, and induce moonmilk formation. Moonmilk is found as the most evolved phase of the microbial processes in cave sediments that fixes CO2 as calcite and intensifies CH4 oxidation. From an ecological perspective, cave sediments act qualitatively as soils, providing fundamental ecosystem services (e.g. nutrient cycling and carbon sequestration) with direct influence on greenhouse gas emissions. ; This work was supported by the Spanish Ministry of Science, Innovation through project PID2019-110603RB-I00, MCIN/AEI/FEDER UE/10.13039/501100011033 and with collaboration of projects RTI2018-099052-B-I00 and PID2020-114978GB-I00. This research has also received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 844535 — MIFLUKE. ; Peer reviewed

Subterranean ecosystems play an active role in the global carbon cycle, yet only a few studies using indirect methods have focused on the role of the cave microbiota in this critical cycle. Here we present pioneering research based on in situ real-time monitoring of CO2 and CH4 diffusive fluxes and concurrent δ13C geochemical tracing in caves, combined with 16S microbiome analysis. Our findings show that cave sediments are promoting continuous CH4 consumption from cave atmosphere, resulting in a significant removal of 65% to 90%. This research reveals the most effective taxa and metabolic pathways in consumption and uptake of greenhouse gases. Methanotrophic bacteria were the most effective group involved in CH4 consumption, namely within the families Methylomonaceae, Methylomirabilaceae and Methylacidiphilaceae. In addition, Crossiella and Nitrosococcaceae wb1-P19 could be one of the main responsible of CO2 uptake, which occurs via the Calvin-Benson-Bassham cycle and reversible hydration of CO2. Thus, syntrophic relationships exist between Crossiella and nitrifying bacteria that capture CO2, consume inorganic N produced by heterotrophic ammonification in the surface of sediments, and induce moonmilk formation. Moonmilk is found as the most evolved phase of the microbial processes in cave sediments that fixes CO2 as calcite and intensifies CH4 oxidation. From an ecological perspective, cave sediments act qualitatively as soils, providing fundamental ecosystem services (e.g. nutrient cycling and carbon sequestration) with direct influence on greenhouse gas emissions. ; This work was supported by the Spanish Ministry of Science, Innovation through project PID2019-110603RB-I00, MCIN/AEI/FEDER, UE/10.13039/501100011033 and with collaboration of projects RTI2018-099052-B-I00 and PID2020-114978GB-I00. This research has also received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 844535 — MIFLUKE.

Optical imaging techniques are ubiquitous for the resolution of non-uniformities in gas flows. Planar imaging techniques such as laser-induced fluorescence are well established and applied extensively in turbulent reactive flows, offering both high temporal and spatial resolutions. However, planar imaging suffers from a critical disadvantage, the requirement for spatially continuous optical access over large solid angles in both the excitation and detection paths and this precludes their application in many practical situations, for example those encountered in engine testing. Tomographic absorption spectroscopy, TAS, on the other hand, shares many of the advantages of planar imaging techniques but reduces the demands for optical access, because high quality data can be obtained with sparsely sampled volumes. The technique has unrivalled potential for imaging in harsh environments, for example for in-cylinder/in-chamber engine measurements. TAS is beginning to mature as a technique for the simultaneous imaging of temperature and species concentration, and is experiencing a surge of interest due to progress in laser technology, spectroscopy, and theoretical developments of nonlinear tomography techniques. The recent advancements in broad bandwidth, frequency-agile laser sources massively enrich the spectral information obtainable in TAS. Furthermore, nonlinear tomography enables the recovery of multiplexed information from a single tomographic inversion. The utilization of multispectral information improves the immunity of TAS to experimental noise and makes possible the simultaneous imaging of temperature, pressure, and multiple species. Nonlinear tomography can also be used to empower the imaging potential of sensitive and robust absorption techniques, such as wavelength modulation spectroscopy, for use in harsh and even optically dense environments. In combination, this greatly extends the applicability of TAS for more general and harsh scenarios in combustion technology. In this article we review basic concepts and mathematical foundations of classical absorption tomography, proceeding to more advanced recent concepts based on nonlinear tomography, and providing an extensive review of experimental demonstrations and practical applications in the context of state-of-the-art combustion research. ; European Commission under Grant No. ASHTCSC 330840; Chinese Government 'Thousand Youth Talent Program'; Engineering and Physical Sciences Research Council (EPSRC) (Grant EP/ L015889/1).

Aims. We present observations from the Gaia-ESO Survey in the lines of Hα, [N II], [S II], and He I of nebular emission in the central part of the Carina nebula. Methods. We investigate the properties of the two already known kinematic components (approaching and receding), which account for the bulk of emission. Moreover, we investigate the features of the much less known low-intensity high-velocity (absolute RV >50 km s) gas emission. Results. We show that gas giving rise to Hα and He I emission is dynamically well correlated with but not identical to gas seen through forbidden-line emission. Gas temperatures are derived from line-width ratios, and densities from [S II] doublet ratios. The spatial variation of N ionization is also studied, and found to differ between the approaching and receding components. The main result is that the bulk of the emission lines in the central part of Carina arise from several distinct shell-like expanding regions, the most evident found around η Car, the Trumpler 14 core, and the star WR25. These >shells> are non-spherical and show distortions probably caused by collisions with other shells or colder, higher-density gas. Some of them are also partially obscured by foreground dust lanes, while very little dust is found in their interior. Preferential directions, parallel to the dark dust lanes, are found in the shell geometries and physical properties, probably related to strong density gradients in the studied region. We also find evidence that the ionizing flux emerging from η Car and the surrounding Homunculus nebula varies with polar angle. The high-velocity components in the wings of Hα are found to arise from expanding dust reflecting the η Car spectrum. © ESO, 2016. ; This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541 ; Peer Reviewed

Aims. We present observations from the Gaia-ESO Survey in the lines of Hα, [N II], [S II], and He I of nebular emission in the central part of the Carina nebula. Methods. We investigate the properties of the two already known kinematic components (approaching and receding), which account for the bulk of emission. Moreover, we investigate the features of the much less known low-intensity high-velocity (absolute RV >50 km s-1) gas emission. Results. We show that gas giving rise to Hα and He I emission is dynamically well correlated with but not identical to gas seen through forbidden-line emission. Gas temperatures are derived from line-width ratios, and densities from [S II] doublet ratios. The spatial variation of N ionization is also studied, and found to differ between the approaching and receding components. The main result is that the bulk of the emission lines in the central part of Carina arise from several distinct shell-like expanding regions, the most evident found around η Car, the Trumpler 14 core, and the star WR25. These "shells" are non-spherical and show distortions probably caused by collisions with other shells or colder, higher-density gas. Some of them are also partially obscured by foreground dust lanes, while very little dust is found in their interior. Preferential directions, parallel to the dark dust lanes, are found in the shell geometries and physical properties, probably related to strong density gradients in the studied region. We also find evidence that the ionizing flux emerging from η Car and the surrounding Homunculus nebula varies with polar angle. The high-velocity components in the wings of Hα are found to arise from expanding dust reflecting the η Car spectrum. ; This work was partly supported by the European Union FP7 programme through ERC grant number 320360 and by the Leverhulme Trust through grant RPG-2012-541.