Corrigendum: Higher Abundance of Sediment Methanogens and Methanotrophs Do Not Predict the Atmospheric Methane and Carbon Dioxide Flows in Eutrophic Tropical Freshwater Reservoirs

Emissions growth of carbon dioxide has suddenly slowed, but atmospheric methane concentrations continue to soar after a long hiatus. Both trends have a bearing on climate pacts sought this week.

Download Full-text

Atmospheric methane and carbon dioxide from SCIAMACHY satellite data: initial comparison with chemistry and transport models

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-4-7217-2004 ◽

2004 ◽

Vol 4 (6) ◽

pp. 7217-7279 ◽

Cited By ~ 4

Author(s):

M. Buchwitz ◽

R. de Beek ◽

J. P. Burrows ◽

H. Bovensmann ◽

T. Warneke ◽

...

Keyword(s):

Carbon Dioxide ◽

Reasonable Agreement ◽

Near Infrared ◽

Weighting Function ◽

Lower Surface ◽

Retrieval Algorithm ◽

Atmospheric Methane ◽

Mixing Ratios ◽

Data Products ◽

Carbon Dioxide Co2

Abstract. The remote sensing of the atmospheric greenhouse gases methane (CH4) and carbon dioxide (CO2) in the troposphere from instrumentation aboard satellites is a new area of research. In this manuscript, results obtained from observations of the up-welling radiation in the near-infrared by SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY), which flies on board ENVISAT, are presented. Vertical columns of CH4, CO2 and oxygen (O2) have been retrieved and the (air or) O2-normalized CH4 and CO2 column amounts, the dry air column averaged mixing ratios XCH4 and XCO2 derived. In this manuscript the first results, obtained by using the version 0.4 of the Weighting Function Modified (WFM) DOAS retrieval algorithm applied to SCIAMACHY data, are described and compared with global models. This is an important step in assessing the quality and information content of the data products derived from SCIAMACHY observations. This study investigates the behaviour of CO2 and CH4 in the period from January to October 2003. The SCIAMACHY greenhouse gas column amounts and their mixing ratios for cloud free scenes over land are shown to be in reasonable agreement with models. Over the ocean, as a result of the lower surface spectral reflectance and resultant low signal to noise with the exception of sun glint conditions, the accuracy of the individual data products is poorer. The measured methane column amounts agree with the model columns within a few percent. The inter-hemispheric difference of the methane mixing ratios, determined from single day cloud free measurements over land, is in the range 30–110 ppbv and in reasonable agreement with the corresponding model data (48–71 ppbv). For the set of individual measurements the standard deviations of the difference with respect to the models are in the range ~100–200 ppbv (5–10%) and ±14.4 ppmv (3.9%) for XCH

Download Full-text

Catalysts for the Simultaneous Production of Syngas and Carbon Nanofilaments Via Catalytic Decomposition of Biogas

10.5772/intechopen.101320 ◽

2022 ◽

Author(s):

Buthainah Ali Al-Timimi ◽

Zahira Yaakob

Keyword(s):

Carbon Dioxide ◽

Carbon Dioxide Emissions ◽

Heterogeneous Catalysts ◽

Fossil Fuels ◽

Raw Materials ◽

Catalytic Decomposition ◽

Atmospheric Methane ◽

Active Centers ◽

Carbon Dioxide Levels ◽

Scientific Attention

The possibility of alleviation of methane and carbon dioxide levels in the atmosphere are of major global interest. One of the alternatives that attracts much scientific attention is their chemical utilization, especially because both of these gases are components of the biogas. Thus, the rapid and extensive shale gas development makes them abundant raw materials. The development of an effective catalytic process that could be scaled-up for industrial purposes remains a great challenge for catalysis. As well, understanding of the mechanisms of molecular activation and the reaction pathways over active centers on heterogeneous catalysts needs to be advanced. It has been shown that biogas is a very interesting source of renewable energy. Because of its elevated methane content, biogas has excellent potential, as reflected in its year-over-year rise in production. This is because its manufacturing promotes the use of organic waste, prevents uncontrolled dumping and minimizes atmospheric methane and carbon dioxide emissions. Moreover, its use as an energy source is in some cases an alternative to fossil fuels and can help to minimize energy dependence. Another aspect of interest is that it can be used in situ, allowing agro-livestock farms or small industrial plants to achieve energy self-sufficiency.

Download Full-text

Carbon Dioxide and Methane Fluxes from Various Vegetation Communities of a Natural Tropical Freshwater Wetland in Different Seasons

Environmental Processes ◽

10.1007/s40710-021-00497-0 ◽

2021 ◽

Author(s):

David Were ◽

Frank Kansiime ◽

Tadesse Fetahi ◽

Thomas Hein

Keyword(s):

Carbon Dioxide ◽

Freshwater Wetland ◽

Vegetation Communities ◽

Methane Fluxes ◽

Different Seasons ◽

Tropical Freshwater

Download Full-text

Shipborne measurements of methane and carbon dioxide in the Middle East and Mediterranean areas and contribution from oil and gas emissions

10.5194/acp-2021-114 ◽

2021 ◽

Author(s):

Jean-Daniel Paris ◽

Aurélie Riandet ◽

Efstratios Bourtsoukidis ◽

Marc Delmotte ◽

Antoine Berchet ◽

...

Keyword(s):

Carbon Dioxide ◽

Middle East ◽

Red Sea ◽

Oil And Gas ◽

Arabian Gulf ◽

Isomeric Ratio ◽

Anthropogenic Sources ◽

Lagrangian Model ◽

Atmospheric Methane ◽

Mixing Ratios

Abstract. The increase of atmospheric methane (CH4) and carbon dioxide (CO2), two main anthropogenic greenhouse gases, is largely driven by fossil sources. Sources and sinks remain insufficiently characterised in the Mediterranean and Middle East areas, where very few in situ measurements area available. We investigated the atmospheric distribution of CH4 and CO2 in the region through shipborne measurement in July and August 2017. High mixing ratios were observed over the Suez Canal, Red Sea and Arabian Gulf, while generally lower mixing ratios were observed over the Gulfs of Aden and Oman. We probe the origin of CO2 and CH4 excess mixing ratio by using correlations with light alkanes and through the use of a Lagrangian model coupled to two different emission inventories of anthropogenic sources. We find that the CO2 and especially the CH4 enhancements are mainly linked to nearby oil and gas (O&G) activities over the Arabian Gulf, and a mixture of other sources over the Red Sea. The isomeric ratio of pentane is shown to be a useful indicator of the O&G component of atmospheric CH4 at the regional level. Upstream emissions linked to oil in the Northern Arabian Gulf seem to be underestimated while gas-related emissions in the Southern Gulf are overestimated in our simulations. Our results highlight the need for improvement of inventories in the area to better characterize the changes in magnitude and the complex distribution of the O&G sources in the Middle East.

Download Full-text

Higher Abundance of Sediment Methanogens and Methanotrophs Do Not Predict the Atmospheric Methane and Carbon Dioxide Flows in Eutrophic Tropical Freshwater Reservoirs

Frontiers in Microbiology ◽

10.3389/fmicb.2021.647921 ◽

2021 ◽

Vol 12 ◽

Author(s):

Gabrielle Maria Fonseca Pierangeli ◽

Mercia Regina Domingues ◽

Tatiane Araujo de Jesus ◽

Lúcia Helena Gomes Coelho ◽

Werner Siegfried Hanisch ◽

...

Keyword(s):

Carbon Dioxide ◽

Global Warming ◽

Anthropogenic Pollution ◽

Total Carbon ◽

Anthropogenic Sources ◽

Atmospheric Methane ◽

Global Warming Impact ◽

Carbon Decomposition ◽

Untreated Sewage ◽

Gaseous Flows

Freshwater reservoirs emit greenhouse gases (GHGs) such as methane (CH4) and carbon dioxide (CO2), contributing to global warming, mainly when impacted by untreated sewage and other anthropogenic sources. These gases can be produced by microbial organic carbon decomposition, but little is known about the microbiota and its participation in GHG production and consumption in these environments. In this paper we analyzed the sediment microbiota of three eutrophic tropical urban freshwater reservoirs, in different seasons and evaluated the correlations between microorganisms and the atmospheric CH4 and CO2 flows, also correlating them to limnological variables. Our results showed that deeper water columns promote high methanogen abundance, with predominance of acetoclastic Methanosaeta spp. and hydrogenotrophs Methanoregula spp. and Methanolinea spp. The aerobic methanotrophic community was affected by dissolved total carbon (DTC) and was dominated by Crenothrix spp. However, both relative abundance of the total methanogenic and aerobic methanotrophic communities in sediments were uncoupled to CH4 and CO2 flows. Network based approach showed that fermentative microbiota, including Leptolinea spp. and Longilinea spp., which produces substrates for methanogenesis, influence CH4 flows and was favored by anthropogenic pollution, such as untreated sewage loads. Additionally, less polluted conditions favored probable anaerobic methanotrophs such as Candidatus Bathyarchaeota, Sva0485, NC10, and MBG-D/DHVEG-1, which promoted lower gaseous flows, confirming the importance of sanitation improvement to reduce these flows in tropical urban freshwater reservoirs and their local and global warming impact.

Download Full-text

Precision Heterodyne Oxygen-Calibration Spectrometry: Vertical Profiling of Water and Carbon Dioxide in the Troposphere and Lower Stratosphere

10.5194/egusphere-egu2020-18961 ◽

2020 ◽

Author(s):

J. Houston Miller ◽

Monica Flores ◽

David Bomse

Keyword(s):

Carbon Dioxide ◽

Low Noise ◽

Environmental Research ◽

Atmospheric Methane ◽

Heterodyne Receiver ◽

Noise Absorption ◽

Pressure Profiles ◽

Vertical Profiling ◽

Laser Heterodyne ◽

Oxygen Measurements

We describe the continued development of a new laser heterodyne radiometry (LHR) technique:&#160; Precision Heterodyne Oxygen-Calibration Spectrometry, or PHOCS. The prototype instrument is equipped with two active laser channels for oxygen and water (measured near 1.28 &#181;m) and carbon dioxide (near 1.57 &#181;m) determination. The latter may be substituted by a heterodyne receiver module equipped with a laser to monitor atmospheric methane near 1.65 &#181;m). Oxygen measurements provide dry gas corrections and &#8211; more importantly &#8211; determine accurate temperature and pressure profiles that, in turn, improve the precision of the CO2 and H2O column retrievals. Vertical profiling is enabled by interrogating the very low-noise, absorption lines shapes collected by the O(10-3 cm-1) instrument. The presentation will describe (1) the continued development of column concertation retrieval protocols and (2) the results of initial tests performed at the Smithsonian Environmental Research Center in Edgewater, Maryland during the summer/fall of 2019 and spring of 2020.

Download Full-text