lnu.sePublikasjoner
Endre søk
Begrens søket
1 - 43 of 43
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Braga, R.
    et al.
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Iglesias, Rodrigo S.
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Romio, Christiane
    Aarhus University, Denmark.
    Praeg, Daniel
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil;Géoazur, France.
    Miller, Dennis
    PETROBRAS, Brazil.
    Viana, Adriano
    PETROBRAS, Brazil.
    Ketzer, João Marcelo
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Modelling methane hydrate stability changes and gas release due to seasonal oscillations in bottom water temperatures on the Rio Grande cone, offshore southern Brazil2020Inngår i: Marine and Petroleum Geology, ISSN 0264-8172, E-ISSN 1873-4073, Vol. 112, s. 1-15, artikkel-id 104071Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The stability of methane hydrates on continental margins worldwide is sensitive to changes in temperature and pressure conditions. It has been shown how gradual increases in bottom water temperatures due to ocean warming over post-glacial timescales can destabilize shallow oceanic hydrate deposits, causing their dissociation and gas release into the ocean. However, bottom water temperatures (BWT) may also vary significantly over much shorter timescales, including due to seasonal temperature oscillations of the ocean bottom currents. In this study, we investigate how a shallow methane hydrate deposit responds to seasonal BWT oscillations with an amplitude of up to 1.5 °C. We use the TOUGH + HYDRATE code to model changes in the methane hydrate stability zone (MHSZ) using data from the Rio Grande Cone, in the South Atlantic Ocean off the Brazilian coast. In all the cases studied, BWT oscillations resulted in significant gaseous methane fluxes into the ocean for up to 10 years, followed by a short period of small fluxes of gaseous methane into the ocean, until they stopped completely. On the other hand, aqueous methane was released into the ocean during the 100 years simulated, for all the cases studied. During the temperature oscillations, the MHSZ recedes continuously both horizontally and, in a smaller scale, vertically, until a permanent and a seasonal region in MHSZ are defined. Sensitivity tests were carried out for parameters of porosity, thermal conductivity and initial hydrate saturation, which were shown to play an important role on the volume of methane released into the ocean and on the time interval in which such release occurs. Overall, the results indicate that in a system with no gas recharge from the bottom, seasonal temperature oscillations alone cannot account for long-term gas release into the ocean.

  • 2.
    Cedeno, Daniel Grings
    et al.
    Univ Fed Rio Grande do Sul, Brazil.
    Conceicao, Rommulo Vieira
    Univ Fed Rio Grande do Sul, Brazil.
    Wilbert de Souza, Marcio Roberto
    Univ Fed Rio Grande do Sul, Brazil..
    Schimdt Quinteiro, Roberto Vicente
    Univ Fed Rio Grande do Sul, Brazil.
    Carniel, Larissa Colombo
    Univ Fed Rio Grande do Sul, Brazil.
    Ketzer, João Marcelo
    Pontificia Univ Catolica Rio Grande Sul PUCRS, Brazil.
    Rodrigues, Frederico
    Pontificia Univ Catolica Rio Grande Sul PUCRS, Brazil.
    Bruzza, Eduardo do Canto
    Pontificia Univ Catolica Rio Grande Sul PUCRS, Brazil.
    An experimental study on smectites as nitrogen conveyors in subduction zones2019Inngår i: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 168, s. 409-420Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We performed high pressure and high temperature (HPHT) experiments on NH4-doped montmorillonite (similar to 2 wt % of NH4) under pressures of 2.5, 4.0, and 7.7 GPa and temperatures from 200 to 700 degrees C. Each experiment was analyzed with XRD, FTIR, CHN elemental analysis, and SEM in order to determine the NH4-Smectite phase changes and their morphology, and the presence of ammonium in the runs. Our results show that smectite can easily transport nitrogen, speciated as ammonium (NH4+), incorporated into the smectite interlayer in mildly reducing environments to deeper levels in the Earth through cold thermal regime subduction zones. NH4-Smectite transforms into NH4-enriched micaceous phase (tobelite) through a NH4+-enriched interlayered I/S phase in relatively low pressures and temperatures (around 2.5 GPa and 500 degrees C). Tobelite is stable until more extreme conditions (7.7 GPa and 700 degrees C), together with lesser amounts of buddingtonite (an ammonium-bearing feldspar) kyanite, and garnet. Our experiments also show the effect of nitrogen in the feldspar stability, as potassic and sodic feldspar are stable up to similar to 5 GPa, while buddingtonite, is observed to be stable up to 7.7 GPa. Nitrogen can return to the surface once the stability of these nitrogen-enriched minerals is reached due to pressure or temperature increasing.

  • 3.
    da S. Ramos, Alessandro
    et al.
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    de Araujo, Gabriel E.
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Siviero, Leonardo
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Ketzer, João Marcelo
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Heemann, Roberto
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Lourega, Rogerio V.
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Rodrigues, Luiz F.
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Comparative assessment between different sample preparation methodologies for PTGA CO2 adsorption assays—Pellet, powder, and fragment samples2018Inngår i: Adsorption Science and Technology, ISSN 0263-6174, E-ISSN 2048-4038, Vol. 36, nr 7-8, s. 1441-1455Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The carbon dioxide sorption process at coal seams is very important for understanding the trapping mechanisms of carbon capture and storage. The gas retention capacity of coal seams can be estimated using indirect methods based on the adsorption/desorption isotherms obtained in the laboratory. However, the gas sorption capacity can be overestimated or underestimated depending on the sample preparation. This work evaluates different sample preparations and their theoretical adsorption capacity using coal samples from the Cambui coal field (Parana Basin), southern Brazil. Experiments using a thermogravimetric balance were done to calculate the theoretical adsorption capacity, while sample characterization was done through immediate analysis, elementary analysis, and mineralogical studies. The sample preparations used in this work were powder, pellets, and fragments. While the powder form presents an average behavior, without any experimental complication, the pellet is extremely sensitive to any variation in the sample preparation, such as fractures, and the fragment requires a much longer experiment time than the other sample preparations, being impracticable for some cases.

  • 4.
    da Silva Ramos, Alessandro
    et al.
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Pires, Jessica Pereira
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Ketzer, João Marcelo
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    de Araujo, Gabriel Espindola
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Lourega, Rogerio Vescia
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Synthesis of new CO2 hydrate inhibitors2020Inngår i: Journal of Natural Gas Science and Engineering, ISSN 1875-5100, E-ISSN 2212-3865, Vol. 75, s. 1-6, artikkel-id 103166Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gas hydrate is a crystalline compound made of water and mainly of gases methane and carbon dioxide under specific conditions of pressure and temperature. Increasing worldwide petroleum exploitation in deep waters, where these conditions are encountered, favours the precipitation of gas hydrate in seafloor pipelines, resulting in partial or total obstruction of petroleum flow. Brazil's largest petroleum reserves of the pre-salt interval, for example, are located in ultra-deep waters (>1500 m) and may have a gas composition of up to 80% of CO2. Huge investments are necessary to inhibit the formation of gas hydrate and to assure petroleum flow in pipelines. Here we present the results of the synthesis of new organic compounds obtained from L-Threonine, which show a high potential to be used as CO2 hydrate inhibitors. This characteristic is related to the increase carbon chain in each molecule (higher hydrophobicity) leading to a reduction on CO2 solubility in water. In addition to that, our study also shows the occurrence of the “salting out effect” and reduced water activity coefficient.

  • 5.
    Dano, Alexandre
    et al.
    UNS UPMC CNRS OCA, France.
    Praeg, Daniel
    OGS Ist Nazl Oceanog Geofis Sperimentale, Italy.
    Migeon, Sebastien
    UNS UPMC CNRS OCA, France.
    Augustin, Jean-Marie
    IFREMER, France.
    Ceramicola, Silvia
    OGS Ist Nazl Oceanog Geofis Sperimentale, Italy.
    Ketzer, João Marcelo
    Pontif Univ Rio Grande PUCRS, Brazil.
    Augustin, Adolpho Herbert
    Pontif Univ Rio Grande PUCRS, Brazil.
    Ducassou, Emmanuelle
    Univ Bordeaux 1, France.
    Mascle, Jean
    UNS UPMC CNRS OCA, France.
    Fluid Seepage in Relation to Seabed Deformation on the Central Nile Deep-Sea Fan, Part 1: Evidence from Sidescan Sonar Data2014Inngår i: Submarine Mass Movements and their Consequences: 6th International Symposium / [ed] Krastel, S Behrmann, JH Völker, D Stipp, M Berndt, C Urgeles, R Chaytor, J Huhn, K Strasser, M Harbitz, CB, Springer, 2014, s. 129-139Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The central Nile Deep-Sea Fan contains a broad area of seabed destabilisation in association with fluid seepage: slope-parallel sediment undulations are associated with multibeam high-backscatter patches (HBPs) related to authigenic carbonates. During the 2011 APINIL campaign, a deep-towed sidescan and profiling system (SAR) was used to acquire high-resolution data along three transects across water depths of 1,700-2,650 m. Three seabed domains are distinguished, all developed within stratified sediments overlying mass-transport deposits (MTDs). Upslope of the undulations (<1,950 m), sidescan HBPs record focused fluid seepage via seabed cracks. In the western area of undulations, sidescan HBPs are distinct from intermediate-backscatter patches (IBPs) that extend up to 850 m parallel to the undulations, mainly along their downslope flanks; some contain sub-circular HBPs up to 300 m wide, three associated with smaller (<10 m) hydroacoustic gas flares. Focused fluid seeps are inferred to have shifted over time to form elongate carbonate pavements, preferentially along the footwalls of faults beneath the undulations that provide pathways for fluid flow. In contrast, in the eastern area of undulations, sidescan imagery reveal only slope-transverse furrows formed by turbulent flows, interpreted to indicate that fossil carbonates sampled during submersible operations have been exhumed by erosion.

  • 6.
    de Castro Araujo Moreira, Andrea Cristina
    et al.
    PETROBRAS Petr Brasileiro SA Res Ctr CENPES, Brazil;Univ Estado Rio de Janeiro UERJ PPGMA, Brazil.
    Santana Musse, Ana Paula
    PETROBRAS Petr Brasileiro SA Res Ctr CENPES, Brazil.
    do Rosario, Fatima
    PETROBRAS Petr Brasileiro SA Res Ctr CENPES, Brazil.
    Chiaranda Lazzarin, Helen Simone
    Univ Fed Santa Catarina, Brazil.
    Cavelhao, Gabriel
    Univ Fed Santa Catarina, Brazil.
    Chang, Hung Kiang
    Univ Estadual Paulista UNESP, Brazil.
    Oliva, Andresa
    Univ Estadual Paulista UNESP, Brazil.
    Landulfo, Eduardo
    Inst Pesquisas Energet & Nucl IPEN CNEN SP, Brazil.
    Nakaema, Walter Morinobu
    Inst Pesquisas Energet & Nucl IPEN CNEN SP, Brazil.
    Melo, Clarissa Lovato
    Pontificia Univ Catolica Rio Grande Sul PUCRS CEP, Brazil.
    Bressan, Lia Weigert
    Pontificia Univ Catolica Rio Grande Sul PUCRS CEP, Brazil.
    Ketzer, João Marcelo
    Pontificia Univ Catolica Rio Grande Sul PUCRS CEP, Brazil.
    Constant, Marcelo Jardim
    Pontificia Univ Catolica Rio Grande Sul PUCRS CEP, Brazil.
    Spangler, Lee H.
    Montana State Univ, USA.
    Dobeck, Laura M.
    Montana State Univ, USA.
    The first Brazilian Field Lab fully dedicated to CO2 MMV experiments: from the start-up to the initial results2014Inngår i: 12th International Conference on Greenhouse Gas Control Technologies, GHGT-12 / [ed] Dixon, T Herzog, H Twinning, S, Elsevier, 2014, Vol. 63, s. 6227-6238Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Currently one of the main challenges in CO2 storage research is the development, testing and validation of accurate and efficient Measuring, Monitoring and Verification (MMV) techniques to be deployed at geological sequestration sites that are cost effective yet help minimize risk. This perspective motivated PETROBRAS, the National Oil Major in Brazil, through its R&D investments portfolio to prioritize research projects that would contribute to decreasing the technological gap in the area. The Company's periodic surveys indicated the lack of infrastructure, as well as expertise in CO2 MMV, as two of the most critical issues at the national level. In order to bridge that gap, initial steps were taken in 2010 for the start-up and development of the first CO2 MMV Field Lab in Brazil, fully sponsored by PETROBRAS, with a long term goal of enabling the ranking of the best, most cost-effective MMV technology alternatives to be deployed at commercial large scale CCGS sites scheduled to be installed in the country. In addition to providing basic infrastructure to carry out the CO2 injection and controlled release experiments, the facility was designed for the simultaneous testing of multiple measuring methodologies. Additional benefits of the initiative are the creation of expertise and the acceleration of the know-how in MMV in Brazil, as well as the development of a deeper and more practical knowledge of CO2 dynamics and impacts in a real world, open air scenario. Under the full support of the PETROBRAS R&D Center (CENPES), through its Climate Change Mitigation Technological Program (PROCLIMA), the Brazilian Pilot CO2 MMV Lab was made possible through a joint 4-year research Project, conceived and carried out by PETROBRAS and local academia in Brazil, in close cooperation with international experts. An overview of the Project and the multiple research areas encompassed will be presented, together with the preliminary results of the first CO2 injection campaign, which took place in 2013. (c) 2014 The Authors. Published by Elsevier

  • 7.
    dos Santos, Victor Hugo J. M.
    et al.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Ketzer, João Marcelo
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Rodrigues, Luiz F.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Classification of Fuel Blends Using Exploratory Analysis with Combined Data from Infrared Spectroscopy and Stable Isotope Analysis2017Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, nr 1, s. 523-532Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chemometric tools were applied for exploratory analysis and classification of fuel blends using the combined information on Fourier transform infrared spectroscopy and stable isotope analysis through isotope ratio mass spectrometry. Principal component analysisand hierarchical clustering analysis were applied for exploratory analysis, while support vector machine (SVM) was used to classify the biodiesel/diesel blends. All of the chemometric models used present better results from the combination of spectral information with isotopic data for biodiesel contents of over 10% in the mixture, with the best results being Obtained from the SVM classification. Therefore, the development presented in this paper could become an important technique to improve the discrimination of the feedstock used in biodiesel production and a resource for quality control in industry.

  • 8.
    dos Santos, Victor Hugo J. M.
    et al.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Ramos, Alessandro S.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Pires, Jessica P.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Engelmann, Pamela de M.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Lourega, Rogerio V.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Ketzer, João Marcelo
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Rodrigues, Luiz F.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Discriminant analysis of biodiesel fuel blends based on combined data from Fourier Transform Infrared Spectroscopy and stable carbon isotope analysis2017Inngår i: Chemometrics and Intelligent Laboratory Systems, ISSN 0169-7439, E-ISSN 1873-3239, Vol. 161, s. 70-78Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A multivariate approach was used for classification of fuel blends using the combined information from Fourier Transform Infrared Spectroscopy (FTIR) and stable carbon isotopes analysis by Isotope Ratio Mass Spectrometry (IRMS). Linear Discriminant Analysis (LDA) and Partial Least Squares Discriminant Analysis (PLS-DA) were applied to the classification of biodiesel/diesel fuel blends containing 0-100% (v/v) of biodiesel. The LDA and PLS-DA methods were able to discriminate samples ranging from 10% to 100% biodiesel (v/v) using the combined information from FTIR and IRMS. Since the global trend is toward a gradual increase in the percentage of biodiesel in fuel blends, the technique presented in this paper could be an important development in improving the traceability and identification of different raw materials used in biodiesel production.

  • 9.
    Engelmann, Pamela de Medeiros
    et al.
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    dos Santos, Victor Hugo Jacks Mendes
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Moser, Letícia Isabela
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    do Canto Bruzza, Eduardo
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Barbieri, Cristina Barazzetti
    General Institute of Forensics, Brazil.
    Barela, Pâmela Susin
    Federal University of Rio Grande do Sul, Brazil.
    Pompéu de Moraes, Diogo
    Federal University of Rio Grande do Sul, Brazil.
    Augustin, Adolpho Herbert
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Goudinho, Flávio Soares
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Melo, Clarissa Lovato
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Ketzer, João Marcelo
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Rodrigues, Luiz Frederico
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Environmental monitoring of water resources around a municipal landfill of the Rio Grande do Sul state, Brazil2017Inngår i: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 24, nr 26, s. 21398-21411Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In Brazil, landfills are commonly used as a method for the final disposal of waste that is compliant with the legislation. This technique, however, presents a risk to surface water and groundwater resources, owing to the leakage of metals, anions, and organic compounds. The geochemical monitoring of water resources is therefore extremely important, since the leachate can compromise the quality and use of surface water and groundwater close to landfills. In this paper, the results of analyses of metals, anions, ammonia, and physicochemical parameters were used to identify possible contamination of surface water and groundwater in a landfill area. A statistical multivariate approach was used. The values found for alkali metals, nitrate, and chloride indicate contamination in the regional groundwater and, moreover, surface waters also show variation when compared to the other background points, mainly for ammonia. Thus, the results of this study evidence the landfill leachate influence on the quality of groundwater and surface water in the study area.

  • 10.
    Engelmann, Pâmela de Medeiros
    et al.
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    dos Santos, Victor Hugo Jacks Mendes
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Barbieri, Cristina Barazzetti
    General Institute of Forensics, Brazil.
    Augustin, Adolpho Herbert
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Ketzer, João Marcelo
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Rodrigues, Luiz Frederico
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Environmental monitoring of a landfill area through the application of carbon stable isotopes, chemical parameters and multivariate analysis2018Inngår i: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 76, s. 591-605Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Leachate produced during an organic matter decomposition process has a complex composition and can cause contamination of surface and groundwaters adjacent to a landfill area. The monitoring of these areas is extremely important for the characterization of the leachate produced and to avoid or mitigate environmental damages. Thus, the present study has the objective of monitoring the area of a Brazilian landfill using conventional parameters (dissolved metals and anions in water) and alternative, stable carbon isotopes parameters (δ13C of dissolved organic and inorganic carbons in water) in addition to multivariate analysis techniques. The use of conventional and alternative parameters together with multivariate analysis showed that cells of the residues are at different phases of stabilization of the organic matter and probably already at C3 of the methanogenic phase of decomposition. In addition, the data showed that organic matter stabilization ponds present in the landfill are efficient and improve the quality of the leachate. Enrichment of the heavy 13C isotope in both surface and groundwater suggested contamination in two sampling sites.

  • 11.
    Giongo, Adriana
    et al.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Haag, Taiana
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Lopes Simao, Taiz L.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Medina-Silva, Renata
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Utz, Laura R. P.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Bogo, Mauricio R.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Bonatto, Sandro L.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Zamberlan, Priscilla M.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Augustin, Adolpho H.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Lourega, Rogerio V.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Rodrigues, Luiz F.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Sbrissa, Gesiane F.
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Kowsmann, Renato O.
    Petrobras SA, Brazil.
    Freire, Antonio F. M.
    Petrobras SA, Brazil.
    Miller, Dennis J.
    Petrobras SA, Brazil.
    Viana, Adriano R.
    Petrobras SA, Brazil.
    Ketzer, João Marcelo
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Eizirik, Eduardo
    Pontificia Univ Catolica Rio Grande do Sul, Brazil.
    Discovery of a chemosynthesis-based community in the western South Atlantic Ocean2016Inngår i: Deep Sea Research Part I: Oceanographic Research Papers, ISSN 0967-0637, E-ISSN 1879-0119, Vol. 112, s. 45-56Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chemosynthetic communities have been described from a variety of deep-sea environments across the world's oceans. They constitute very interesting biological systems in terms of their ecology, evolution and biogeography, and also given their potential as indicators of the presence and abundance of consistent hydrocarbon-based nutritional sources. Up to now such peculiar biotic assemblages have not been reported for the western South Atlantic Ocean, leaving this large region undocumented with respect to the presence, composition and history of such communities. Here we report on the presence of a chemosynthetic community off the coast of southern Brazil, in an area where high-levels of methane and the presence of gas hydrates have been detected. We performed metagenomic analyses of the microbial community present at this site, and also employed molecular approaches to identify components of its benthic fauna. We conducted phylogenetic analyses comparing the components of this assemblage to those found elsewhere in the world, which allowed a historical assessment of the structure and dynamics of these systems. Our results revealed that the microbial community at this site is quite diverse, and contains many components that are very closely related to lineages previously sampled in ecologically similar environments across the globe. Anaerobic methanotrophic (ANME) archaeal groups were found to be very abundant at this site, suggesting that methane is indeed an important source of nutrition for this community. In addition, we document the presence at this site of a vestimentiferan siboglinid polychaete and the bivalve Acharax sp., both of which are typical components of deep-sea chemosynthetic communities. The remarkable similarity in biotic composition between this area and other deep-sea communities across the world supports the interpretation that these assemblages are historically connected across the global oceans, undergoing colonization from distant sites and influenced by local ecological features that select a stereotyped suite of specifically adapted organisms. (C) 2015 Elsevier Ltd. All rights reserved.

  • 12.
    Giongo, Adriana
    et al.
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil;Universidade Regional de Blumenau, Brazil.
    Haag, Taiana
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Medina-Silva, Renata
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Heemann, Roberto
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Pereira, Leandro M.
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Zamberlan, Priscilla M.
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Valdez, Fernanda P.
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Oliveira, Rafael R.
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Eizirik, Eduardo
    Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Viana, Adriano R.
    PETROBRAS, Brazil.
    Ketzer, João Marcelo
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM). Pontifícia Universidade Católica do Rio Grande do Sul, Brazil.
    Distinct deep subsurface microbial communities in two sandstone units separated by a mudstone layer2020Inngår i: Geosciences Journal, ISSN 1226-4806, Vol. 24, s. 267-274Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Deep subsurface microbial communities are more abundant in coarse-grained sedimentary rocks such as sandstones than in fine-grained mudstones. The low porosity and low permeability of mudstones are believed to restrict microbial life. Then, it is expected that distinct, isolated microbial communities may form in sandstones separated by mudstones. In this context, the connectivity between microbial communities in different sandstone units can be investigated to infer evolutionary patterns of diversification in space-time, which may potentially contribute with relevant data for analyses of hydraulic connectivity and stratigraphic correlation. In this work, we used high throughput DNA sequencing of a ribosomal 16S gene fragment to characterize the prokaryotic communities found in Permian sandstone samples of the same core that are separated by one mudstone interval, in the Charqueadas coal field, Parana Basin (Southern Brazil). Our samples were collected at ∌300 m deep, in porous sandstones separated by a thick mudstone package. Differences in the bacterial community structure between samples were observed for the classified OTUs, from phylum to genus. Molecular biology might be further applied as a possible tool to help to understand the spatial and temporal distribution of depositional facies, and the efficiency of low permeability rocks to compartmentalize reservoirs. Ongoing studies aim to extend the present investigation into further analyses regarding lateral changes in microbial communities present in the same sandstone units.

  • 13.
    Iglesias, Rodrigo S.
    et al.
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Ketzer, João Marcelo
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Maraschin, Anderson J.
    Pontifical Catholic University of Rio Grande do Sul, Brazil.
    Sbrissa, Gesiane
    Toho University, Japan.