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Full-Text Articles in Physical Sciences and Mathematics
Understanding Biogeochemical And Physical Controls On Methane Air-Sea Exchange Fluxes In The Pacific Ocean, Sarah Raney
Understanding Biogeochemical And Physical Controls On Methane Air-Sea Exchange Fluxes In The Pacific Ocean, Sarah Raney
Master's Theses
Methane and trace element samples were collected on GEOTRACES GP15 Pacific Meridional Transect (PMT) cruise conducted between the Aleutian Islands (57 °N) and Tahiti (20 °S) from September to November 2018. Uncertainty in methane air-sea exchange fluxes was determined using a propagation of errors approach. Fluxes ranged from -0.88 to 4.9 µmol CH4 m-2 d-1. Average CH4 flux along the Alaskan margin was 2.2 ± 2.9 µmol CH4 m-2 d-1. Methane fluxes decreased moving southward and increased to their open ocean maximum around 20 °N before declining in equatorial waters. Near …
Nanoporous Carbon-Based Co2 Reduction Catalysts: Exploring The Combined Effects Of Surface Chemistry And Porosity, Wanlu Li
Dissertations, Theses, and Capstone Projects
For the first-time sulfur-doped, nitrogen-doped and sulfur, nitrogen-codoped nanoporous carbons were systematically studied as catalysts for CO2 electrochemical reduction reaction (CO2ERR). The Faradaic efficiencies (FE) of CO and CH4 formation were calculated to evaluate the performance of these carbons. The best catalysts showed the FE of CO and CH4 formation of 29% and 0.76%, respectively. It was found that the overall performance in CO2ERR dramatically increased upon the reduction pretreatment of the carbons in N2-saturated electrolyte before the CO2 reduction process. The pretreated carbon showed the maximum FE of CO …
Water Chemistry Dynamics In Four Vernal Pools In Maine, Usa, Lydia H. Kifner
Water Chemistry Dynamics In Four Vernal Pools In Maine, Usa, Lydia H. Kifner
Electronic Theses and Dissertations
Vernal pools are small seasonal wetlands that are a common landscape feature that contribute to biodiversity in northeastern North American forests. However, even basic information about their biogeochemical functions, such as carbon cycling, is limited. Dissolved gas concentrations (CH4, CO2) and other water chemistry parameters were monitored weekly at the bottom and surface of four vernal pools in central and eastern Maine, USA, from April to August 2016. The vernal pools were supersaturated with respect to CH4 and CO2 at all sampling dates and locations. Concentrations of dissolved CH4 and CO2 ranged …
Characterizing Groundwater Ch4 And 222rn In Relation To Hydraulic Fracturing And Other Environmental Processes In Letcher County, Ky, St. Thomas Majeau Ledoux
Characterizing Groundwater Ch4 And 222rn In Relation To Hydraulic Fracturing And Other Environmental Processes In Letcher County, Ky, St. Thomas Majeau Ledoux
Masters Theses
Hydraulic fracturing of shale deposits has greatly increased the productivity of the natural gas industry by allowing it to exploit previously inaccessible reservoirs. However, previous research has demonstrated that this practice can contaminate shallow aquifers with CH4 [methane] from deeper formations. This study compares concentrations and isotope compositions of CH4 sampled from domestic groundwater wells in Letcher County, Kentucky in order to characterize its occurrence and origins in relation to neighboring hydraulically fractured natural gas wells. Additionally, this study tests the reliability of 222Rn [radon] as an alternative tracer to CH4 in identifying processes of gas …
Carbon Sequestration In Tidal Salt Marshes And Mangrove Ecosystems, Carlos Eduardo Quintana-Alcantara
Carbon Sequestration In Tidal Salt Marshes And Mangrove Ecosystems, Carlos Eduardo Quintana-Alcantara
Master's Projects and Capstones
Wetlands are dynamic systems that provide support to vital environmental functions and services. Wetlands take part in the global carbon cycle by holding organic carbon in biomass, soils and sediments. In recent years, the wetland carbon sequestration capacity has been researched worldwide due to the increase of the concentrations of greenhouse gasses implicated in global warming and climate change. Although coastal wetlands release the greenhouse gasses carbon dioxide, methane and nitrous oxide, these ecosystems maintain high performance in offsetting significant amounts of atmospheric carbon. This paper investigated the carbon sequestration capacity of coastal wetland ecosystems summarizing the environmental conditions and …