| 51. |
- Rodrigues, L, et al.
(författare)
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An Alternative Gas Chromatography Setting for Geochemical Analysis.
- 2014
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Ingår i: Journal of Chemical Engineering & Process Technology. - : Omics Publishing Group. - 2157-7048. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Gas chromatography is one of the most important techniques used to characterize gas composition of geochemical samples. This work presents a new gas chromatography setting to characterize gaseous composition using three detectors: a Flame Ionization Detector (FID), a Thermal Conductivity Detector (TCD) and a Flame Photometric Detector (FPD). The new gas chromatography setting developed is able to quantify hydrocarbons gases (C1-C5) and non-hydrocarbons (H2S, CO, CO2, N2, O2 and H2) in only one injection and in the same analysis. This alternative gas chromatography is able to reduce time of analysis and save sample that can be used for other kind of analyses.
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| 52. |
- Rodrigues, Luiz F., et al.
(författare)
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High-Pressure and Automatized System for Study of Natural Gas Hydrates
- 2019
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Ingår i: Energies. - : MDPI. - 1996-1073. ; 12:16
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Tidskriftsartikel (refereegranskat)abstract
- Due to the declining of oil reserves in the world in the coming decades, gas hydrate (GH) is seen as the great promise to supply the planet's energy demand. With this, the importance of studying the behavior of GH, several researchers have been developing different systems that allow greater truthfulness in relation to the conditions where GH is found in nature. This work describes a new system to simulate formation (precipitation) and dissociation of GH primarily at natural conditions at deep-sea, lakes, and permafrost, but also applied for artificial gas hydrates studies (pipelines, and transport of hydrocarbons, CO2, and hydrogen). This system is fully automated and unique, allowing the simultaneous work in two independent reactors, built in Hastelloy C-22, with a capacity of 1 L and 10 L, facilitating rapid analyses when compared to higher-volume systems. The system can operate using different mixtures of gases (methane, ethane, propane, carbon dioxide, nitrogen, ammonia), high pressure (up to 200 bar) with high operating safety, temperature (-30 to 200 degrees C), pH controllers, stirring system, water and gas samplers, and hyphenated system with gas chromatograph (GC) to analyze the composition of the gases formed in the GH and was projected to possibility the visualizations of experiments (quartz windows).
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| 53. |
- Rodrigues, Luiz Frederico, et al.
(författare)
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The influence of methane fluxes on the sulfate/methane interface in sediments from the Rio Grande Cone Gas Hydrate Province, southern Brazil : A influência dos fluxos de metano na interface sulfato/metano em sedimentos de hidrato de gás do Cone do Rio Grande, Sul do Brasil
- 2017
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Ingår i: Brazilian Journal of Geology. - : FapUNIFESP (SciELO). - 2317-4692 .- 2317-4889. ; 47:3, s. 369-381
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Tidskriftsartikel (refereegranskat)abstract
- Much research has been published regarding the relation between major gas hydrate accumulations and the global carbon cycle. In this context, the determination of the sulfate/methane interface (SMI) depth is of primary importance in order to understand the dynamics of methane flux in the shallow section. This paper identifies the depth of the SMI in sediments based on sulfate and methane concentration profiles in cores recovered in the Rio Grande Cone Gas Hydrate Province, Pelotas Basin, southern Brazil. The shape of methane and sulfate concentration profiles in the sediments can be linked to the local methane flux rate as follows: (i) near linear, high upward-diffusing methane flux coupled with high sulfate diffusion from seawater; (ii) irregular, variable methane flux rates; and (iii) kink-type profile, which is indicative of variable rather than strictly high upward methane flux. The areas in which a high methane flux was identified are spatially associated with gas chimneys in sediments within pockmarks, whereas profiles with low methane flux are present in adjacent areas. These chimneys appear as acoustic blankings in seismic records and can therefore be mapped in subsurface. The wavy-like seismic reflection following the SMI coincides with the occurrence of authigenic carbonate nodules and concretions. In addition, high methane fluxes and the occurrence of concretions and nodules carbonates were correlated by stratigraphic position of the concretions bearing intervals and sulfate profiles
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| 54. |
- Rodrigues, Luiz, et al.
(författare)
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Molecular and Isotopic Composition of Hydrate-Bound, Dissolved and Free Gases in the Amazon Deep-Sea Fan and Slope Sediments, Brazil
- 2019
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Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 9:2, s. 1-15
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, we investigated the molecular stable isotope compositions of hydrate-bound and dissolved gases in sediments of the Amazon deep-sea fan and adjacent continental slope, Foz do Amazonas Basin, Brazil. Some cores were obtained in places with active gas venting on the seafloor and, in one of the locations, the venting gas is probably associated with the dissociation of hydrates near the edge of their stability zone. Results of the methane stable isotopes (δ13C and δD) of hydrate-bound and dissolved gases in sediments for the Amazon fan indicated the dominant microbial origin of methane via carbon dioxide reduction, in which 13C and deuterium isotopes were highly depleted (δ13C and δD of −102.2% to −74.2% V-PDB and −190 to −150% V-SMOW, respectively). The combination of C1/(C2+C3) versus δ13C plot also suggested a biogenic origin for methane in all analysed samples (commonly >1000). However, a mixture of thermogenic and microbial gases was suggested for the hydrate-bound and dissolved gases in the continental slope adjacent to the Amazon fan, in which the combination of chemical and isotopic gas compositions in the C1/(C2+C3) versus δ13C plot were <100 in one of the recovered cores. Moreover, the δ13C-ethane of −30.0% indicates a thermogenic origin.
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| 55. |
- Santarosa, Cristian S., et al.
(författare)
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CO2 sequestration potential of Charqueadas coal field in Brazil
- 2013
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Ingår i: International Journal of Coal Geology. - : Elsevier. - 0166-5162 .- 1872-7840. ; 106, s. 25-34
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Tidskriftsartikel (refereegranskat)abstract
- Although coal is not the primary source of energy in Brazil there is growing interest to evaluate the potential of coal from the south of the country for various activities. The I2B coal seam in the Charqueadas coal field has been considered a target for enhanced coal bed methane production and CO2 sequestration. A detailed experimental study of the samples from this seam was conducted at the NETL with assistance from the Pontificia Universidade Catolica Do Rio Grande Do Sul. Such properties as sorption capacity, internal structure of the samples, porosity and permeability were of primary interest in this characterization study. The samples used were low rank coals (high volatile bituminous and sub-bituminous) obtained from the I2B seam. It was observed that the temperature effect on adsorption capacity correlates negatively with as-received water and mineral content. Langmuir CO2 adsorption capacity of the coal samples ranged 0.61-2.09 mmol/g. The upper I2B seam appears to be overall more heterogeneous and less permeable than the lower I2B seam. The lower seam coal appears to have a large amount of micro-fractures that do not close even at 11 MPa of confining pressure. Published by Elsevier B.V.
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| 56. |
- Santos, Victor Hugo Jacks Mendes dos, et al.
(författare)
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Exploratory analysis of the microbial community profile of the municipal solid waste leachate treatment system : A case study
- 2022
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Ingår i: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 141, s. 125-135
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Tidskriftsartikel (refereegranskat)abstract
- Studies on the degradation dynamics of landfill leachate indicate that the microbial community profile is a valuable and sensitive tool for landfill monitoring programs. Although knowledge about the microbial community can improve the efficiency of leachate treatment systems, little is known about the microbial profile changes that occur throughout the leachate attenuation process. In the present work, an exploratory analysis of the microbial community profile of the MSW leachate treatment system in the municipality of Osório (Brazil) was conducted. In this way, a comprehensive analysis of chemical parameters, isotopic signature and microbial profile data were applied to monitor the changes in the structure of the microbial community throughout the leachate attenuation process and to describe the relationship between the microbial community structure and the attenuation of chemical and isotopic parameters. From data analysis, it was possible to assess the microbial community structure and relate it to the attenuation of chemical and isotopic parameters. Based on massive parallel 16S rRNA gene sequencing, it was possible to observe that each leachate treatment unit has a specific microbial consortium, reflecting the adaptation of different microorganisms to changes in leachate characteristics throughout treatment. From our results, we concluded that the structure of the microbial community is sensitive to the leachate composition and can be applied to study the municipal solid waste management system.
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| 57. |
- Schütz, Marta K., et al.
(författare)
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Influence of Alkaline Additives and Buffers on Mineral Trapping of CO2 under Mild Conditions
- 2018
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Ingår i: Chemical Engineering & Technology. - : John Wiley & Sons. - 0930-7516 .- 1521-4125. ; 41:3, s. 573-579
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Tidskriftsartikel (refereegranskat)abstract
- Carbon dioxide (CO2) gas is the main contributor to climate change. CO2 storage in underground brines and oil‐field brines by mineral trapping has been considered as a promising alternative in order to reduce CO2 emissions. However, permanent storage of CO2 in stable carbonate minerals is greatly dependent on brine pH, being favored over an alkaline pH. The effect of alkaline additives (NaOH, KOH, CaO) and buffer solutions (NaHCO3/NaOH, Na2HPO4/NaOH, NH4Cl/NH4OH) on the mineral trapping of CO2 under mild conditions using a synthetic brine is investigated. The results indicate that both NaOH+NH4Cl/NH4OH and KOH+NH4Cl/NH4OH mixtures promote precipitation mainly of calcium carbonate (CaCO3).
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| 58. |
- Seidel, Laura, et al.
(författare)
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Climate change induces shifts in coastal Baltic Sea surface water microorganism stress and photosynthesis gene expression
- 2024
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- The world's oceans are challenged by climate change linked warming with typically highly populated coastal areas being particularly susceptible to these effects. Many studies of climate change on the marine environment use large, short-term temperature manipulations that neglect factors such as long-term adaptation and seasonal cycles. In this study, a Baltic Sea 'heated' bay influenced by thermal discharge since the 1970s from a nuclear reactor (in relation to an unaffected nearby 'control' bay) was used to investigate how elevated temperature impacts surface water microbial communities and activities. 16S rRNA gene amplicon based microbial diversity and population structure showed no difference in alpha diversity in surface water microbial communities, while the beta diversity showed a dissimilarity between the bays. Amplicon sequencing variant relative abundances between the bays showed statistically higher values for, e.g., Ilumatobacteraceae and Burkholderiaceae in the heated and control bays, respectively. RNA transcript-derived activities followed a similar pattern in alpha and beta diversity with no effect on Shannon's H diversity but a significant difference in the beta diversity between the bays. The RNA data further showed more elevated transcript counts assigned to stress related genes in the heated bay that included heat shock protein genes dnaKJ, the co-chaperonin groS, and the nucleotide exchange factor heat shock protein grpE. The RNA data also showed elevated oxidative phosphorylation transcripts in the heated (e.g., atpHG) compared to control (e.g., atpAEFB) bay. Furthermore, genes related to photosynthesis had generally higher transcript numbers in the control bay, such as photosystem I (psaAC) and II genes (psbABCEH). These increased stress gene responses in the heated bay will likely have additional cascading effects on marine carbon cycling and ecosystem services.
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| 59. |
- Seidel, Laura, 1989-, et al.
(författare)
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Climate change-related warming reduces thermal sensitivity and modifies metabolic activity of coastal benthic bacterial communities
- 2023
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Ingår i: The ISME Journal. - : Springer Nature. - 1751-7362 .- 1751-7370. ; 17, s. 855-869
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Tidskriftsartikel (refereegranskat)abstract
- Besides long-term average temperature increases, climate change is projected to result in a higher frequency of marine heatwaves. Coastal zones are some of the most productive and vulnerable ecosystems, with many stretches already under anthropogenic pressure. Microorganisms in coastal areas are central to marine energy and nutrient cycling and therefore, it is important to understand how climate change will alter these ecosystems. Using a long-term heated bay (warmed for 50 years) in comparison with an unaffected adjacent control bay and an experimental short-term thermal (9 days at 6–35 °C) incubation experiment, this study provides new insights into how coastal benthic water and surface sediment bacterial communities respond to temperature change. Benthic bacterial communities in the two bays reacted differently to temperature increases with productivity in the heated bay having a broader thermal tolerance compared with that in the control bay. Furthermore, the transcriptional analysis showed that the heated bay benthic bacteria had higher transcript numbers related to energy metabolism and stress compared to the control bay, while short-term elevated temperatures in the control bay incubation experiment induced a transcript response resembling that observed in the heated bay field conditions. In contrast, a reciprocal response was not observed for the heated bay community RNA transcripts exposed to lower temperatures indicating a potential tipping point in community response may have been reached. In summary, long-term warming modulates the performance, productivity, and resilience of bacterial communities in response to warming.
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| 60. |
- Seidel, Laura, et al.
(författare)
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Long-term warming modulates diversity, vertical structuring of microbial communities, and sulfate reduction in coastal Baltic Sea sediments
- 2023
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- Coastal waters such as those found in the Baltic Sea already suffer from anthropogenic related problems including increased algal blooming and hypoxia while ongoing and future climate change will likely worsen these effects. Microbial communities in sediments play a crucial role in the marine energy- and nutrient cycling, and how they are affected by climate change and shape the environment in the future is of great interest. The aims of this study were to investigate potential effects of prolonged warming on microbial community composition and nutrient cycling including sulfate reduction in surface (similar to 0.5 cm) to deeper sediments (similar to 24 cm). To investigate this, 16S rRNA gene amplicon sequencing was performed, and sulfate concentrations were measured and compared between sediments in a heated bay (which has been used as a cooling water outlet from a nearby nuclear power plant for approximately 50 years) and a nearby but unaffected control bay. The results showed variation in overall microbial diversity according to sediment depth and higher sulfate flux in the heated bay compared to the control bay. A difference in vertical community structure reflected increased relative abundances of sulfur oxidizing- and sulfate reducing bacteria along with a higher proportion of archaea, such as Bathyarchaeota, in the heated compared to the control bay. This was particularly evident closer to the sediment surface, indicating a compression of geochemical zones in the heated bay. These results corroborate findings in previous studies and additionally point to an amplified effect of prolonged warming deeper in the sediment, which could result in elevated concentrations of toxic compounds and greenhouse gases closer to the sediment surface.
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