CAROLINE KAKO OSTERMANN

CAROLINE KAKO OSTERMANN

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Assessment of 238U and 226Ra activity concentration along the Amazon Tall Tower Observatory site
2023 - TAPPIZ, B.; SILVA, P.S.C.; OSTERMANN, C.K.; LIMA, N.P.; BRAGUIN, L.N.M.; BOTIA, S.; LEVIN, I.; BUSTILLOS, O.V.
The Amazon Tall Tower Observatory (ATTO) site is a region located within the Uatumã Sustainable Development Reserve (USRD), approximately 150 km northeast of Manaus city, in the Brazilian state of Amazonas. At the ATTO site, there are 3 tall towers, which are used for studies on the Amazon rainforest and its interaction with the soil and the atmosphere. The activity concentration of 238U and 226Ra was determined in soil samples collected in the footprint of the ATTO site by gamma spectrometry. The activity concentration of these radionuclides is important for understanding the 222Rn exhalation rate and 222Rn flux from soils. Knowledge of the 222Rn flux at the ATTO site can be useful for applications in atmospheric research, e.g., the 222Rn tracer method can be used to estimate local and regional emissions of greenhouse gasses; simulating 222Rn transport is a powerful tool for evaluation and validation of transport schemes in atmospheric chemical transport models. In this study, 39 samples collected from 13 sampling sites along a transect from the ATTO site to the river were analyzed. The highest activity concentrations were found in the Igapó forest (69 ± 2 Bq/kg for 238U and 47 ± 5 Bq/kg for 226Ra), a region near the Uatumã river with prevailing flooded black-water forest, whereas the lowest activity concentrations occurred in the Campina (Savanna on white-sand soils) and Campinanara (white-sand forest) ecosystems (18 ± 1 Bq/kg for 238U and 13 ± 2 Bq/kg for 226Ra), a transition area located between river terraces and the Terra Firme forest.
Comparison of 238U mass fraction measured by ICP–MS and Instrumental Neutron Activation Analysis techniques
2022 - TAPPIZ, BRUNO; SILVA, PAULO S.C. da; OSTERMANN, CAROLINE; LIMA, NICOLE P. de; ANDRADE, MARIANA N. de; BUSTILLOS, OSCAR V.
Introduction: Uranium is an element present in ambient air, water, soil and rocks [1]. The most abundant natural radioisotope of this actinide (238U) produces in its chain decay the radionuclide 222Rn [2], which is a tracer for atmospheric mixing and transport model validations [3]. The 238U activity concentration in superficial soil samples is a crucial parameter for some 222Rn flux map modeling methodologies [4]. Methods: In this study, 18 superficial soil samples were analyzed. The content of 238U was assessed using two techniques: (i) by the comparative method of the Instrumental Neutron Activation Analysis (INAA) [5] and by ICP–MS (ELAN 6000, PerkinElmer) [6]. Certified Reference Materials (CRM) SRM 1646a Estuarine Sediment and USG STM–2 were used both as comparators in the INAA technique and to ensure quality control. The normality and homoscedasticity of the data were evaluated. Finally, the Mann- Whitney U test [7] was used to assess whether or not there is a significant difference (α = 0.05) between the two techniques. Results: The z-score was calculated to ensure quality control. Z-scores values was obtained by the Modified Horwitz Equation [8], which takes into account the order of magnitude of the content of the analyte and is independent of the CRM uncertainties, unavailable for the CRM used. The z-score values obtained (n = 3) for the radionuclide 238U were 0.5 for the CRM USG STM–2 and -0.4 for SRM 1646a. The z-scores obtained are smaller than 2 therefore they are considered satisfactory [9]. Regarding the statistical parameters of the comparison between the techniques, the normality (Shapiro Wilk) was not verified (p = 0.02 for ICP-MS and p = 0.03 for INAA). The p-value for the test for equal variances (F test) was 0.71 Mann-Whitney U test was used instead of Student’s test due to the non-verification of the normality parameter in the data. The p-value from the Mann-Whitney test (0.51) indicates that there is no significant difference between the 238U content measured by the two techniques. Conclusions: Statistical analysis showed that there is no significant difference between the 238U mass fraction measured by the ICP–MS and the INAA – comparative method. In the future, certified reference materials will also be assessed by ICP–MS in order to corroborate this statistical comparison from a metrological point of view.
Evaluation of two statements methods by TD-GC-MS/TOF to BVOCs concentrations above the Amazon canopy
2022 - ROVELO, BEATRIZ S.; OSTERMANN, CAROLINE; WILLIAMS, JONATHAN; TAPPIZ, BRUNO; ZANNONI, NORA; GUENTHER, ALEX; VEGA, OSCAR
Introduction: Many biogenic volatile organic compounds (BVOCs) are chiral, meaning they naturally occur as two mirror images of the same molecule. Past and current studies on chiral BVOCs have highlighted the existence of regiospecific patterns [1] and their variability with time of the day, season and height [2]. To better elucidate the role of the tropical forest as a source or a sink of chiral VOC was determined the concentration in two distinctive GC-MS/TOF methods in Amazon rainforest. Methods: Air samples were collected in the Amazon Tall Tower Observatory (ATTO), located 150 km NE of Manaus, Brazil (02°08.752’S, 59°00.335’W) [3]. The site was chosen for having a tower enclosed into the canopy allowing it to measure above the canopy height. Samples were taken at 40m height during July/2019 and 2022 (wet season). The concentration of VOC in each sample was determined through GC-TOF-MS (Markes International, UK) at the Max Planck Institute for Chemistry and at University of California Irvine with the same type of detector. The GC-TOF-MS in Germany [4] is equipped with a thermal desorption unit, a chiral column and a TOF MS which operates in tandem mode and the TD-GC-MS/TOF in the USA is equipped with just one column [5]. Results: Data obtained from the chiral method shows that the concentration of enantiomeric compounds must be different than the simple column method used by the same analyser and mass detector. Conclusions: The second column in addition to TD-GC-MS/TOF can allow the enantiomeric BVOCs identification related to the amount of concentration measured in the Amazon rainforest.
Chiral BVOCs composition over the Amazon and Atlantic Rainforest by TD-GCxGC-TOF/MS
2022 - OSTERMANN, CAROLINE; WILLIAMS, JONATHAN; ZANONNI, NORA; KESSELMEIER, JURGEN; TAPPIZ, BRUNO; GUENTHER, ALEX; VEGA, OSCAR
Introduction: Many BVOCs are chiral, meaning they exist in two non-superimposable mirror image forms termed enantiomers. Enantiomers have identical physical properties, such as boiling point, density, and reactivity to atmospheric oxidants; however, they differ in their specific biological activity. Since most monoterpene measurements do not distinguish enantiomers, relatively little is known about the natural abundance and behavior of the chiral speciated molecules. Previous studies have reported regiospecific patterns across Tropical and Boreal ecosystems for α-pinene [1] and have used them as tracers of secondary processes in air and soil [2][3], highlighting the potential use of chiral compounds in air to decipher processes linking the biosphere with the atmosphere. To better understand the sources, dynamics and sinks of BVOC in the forest environment we have investigated chiral BVOC in the pristine Amazonian rainforest environment at Amazon Tall Tower Observatory (ATTO) is located 150 km from Manaus/BR and in Atlantic Forest located in the Ecological Immigrant Park (PEI) at São Paulo/BR in 2019. Methods: Samples collected in 2019, were thermally desorbed, separated and analyzed through a Bench-TOF select (TD-GCxGC-TOF/MS tandem ionization-14eV and -70eV) from Markes International, UK. First, all samples through to Thermo-Desorption, that one we separated in two desorption: Primary one we use at the cartridges during 10 min in 250°C and in the second one is for trap during 10 min with 250°C. In the GC the column is Dimethyl TBS Cyclodextrin based so the oven was settled in 5 min at 40°C and 1.5°C/min during the temperature increase from 40°C until 150°C and then 30°C/min from 150°C until 200°C. Results: The VOCs and their chirals analyzed are: (-/+) α- Pinene, (-/+) Camphene, (-/+) β- Pinene, (-/+) Limonene, these chiral are of extreme importance because the fact of obtaining the same chemical composition, but different geometries the (-) and (+) differ in nature in their function/aroma, for example the ( -) α- Pinene is found in pine and (+) α- Pinene is found in eucalyptus, such as (-) Limonene emitted by orange and (+) Limonene emitted by lemon. The separation method was specifically designed for the separation of chiral monoterpenes (C H ) and sesquiterpenes (C H ). A chiral column is therefore needed to separate the two enantiomers, standard columns for GC-MS, comparing to an online PTR-MS would not allow enantiomeric separation. Conclusions: It was concluded that the ratio between the pairs of enantiomeric concentrations show a temporal and spatial variability. In forests not disturbed by humans, was found a significant amount of (-) α-Pinene, and due to human interference located in the metropolitan region of São Paulo, (+) Limonene was the BVOC with the highest concentration.
Avaliação de fluxos dos COVBs quirais das Florestas Amazônica e Mata Atlântica pelo método de Acumuladores de Vórtices Estacionários (REA)
2021 - OSTERMANN, CAROLINE K.
O estudo da interação Biosfera-Atmosfera em florestas tropicais é de extrema importância para a compreensão das mudanças climáticas globais. O objetivo deste trabalho é correlacionar os fluxos ascendentes e descendentes de Compostos Orgânicos Voláteis Biogênicos (COVB) e seus quirais em dois locais: na Floresta Amazônica, a maior floresta intacta do mundo, e na Mata Atlântica, com a maior influência antropogênica, restando somente 7% de mata. As duas florestas estão conectadas pela célula Hadley-Walker, ou "rios voadores". Muitos dos COVB presentes nestas florestas são quirais, o que significa que ocorrem naturalmente como duas imagens espelhadas da mesma molécula. Neste contexto, os dados atmosféricos foram medidos por um amostrador de "Fluxo de Ar na Direção Vertical" denominado em inglês como Acumulador de Vórtices Estacionários (REA), o qual processa dados pelo método de acumulação de vórtices turbulentos, instalado no Observatório da Torre Alta da Amazônia (ATTO) e no corredor ecológico suspenso na Mata Atlântica, situado no Parque Ecológico dos Imigrantes (PEI), São Bernardo do Campo, SP. O REA diferencia o fluxo de ar ascendente e descendente por um anemômetro sônico conectado a um painel eletrônico acoplado a cartuchos revestidos de Carbotrap/ TENAX. As análises foram realizadas por dessorção térmica acoplada a um cromatógrafo a gás de duas colunas com detecção por espectrômetro de massa por Tempo de Voo (TD-GCxGC/TOF), fornecido em parceria com o Instituto Max Planck, Mainz, Alemanha. Os resultados mostraram que a especiação de COVBs e seus quirais em ambas as florestas se correlacionam com o aumento do fluxo de ar entre as árvores, diferindo diretamente na proporção e identidade da floresta sendo maior fluxo de (-) α- Pineno (2,98404333 mgC/m2h) na Amazônia e (+) Limoneno (0,53536872 mgC/m2h) na mata Atlântica, como também revelaram uma distinção de comportamento do gradiente de fluxo de calor pelo método REA, entre sazonalidade e perfil diurno, resultando na possível construção de um mecanismo químico entre biosfera - atmosfera.
Determination of 238-U and 232-Th in soil samples collected near the Amazon Tall Tower Observatory, Brazilian Amazon
2021 - TAPPIZ, B.; SILVA, P.S.C.; CARVALHO, E.F.; BOTIA, S.; LINHARES, H.M.S.M.D.; OSTERMANN, C.K.; BUSTILLOS, O.V.
Exploratory study on chiral BVOC fluxes from tropical forests by REA method
2019 - OSTERMANN, CAROLINE; ZANNONI, NORA; CARVALHO, ELIAS F. de; WILLIAMS, JONATHAN; VEGA, OSCAR
Vertical profile analysis of wind flow to obtain optimal eddy covariance parameters
2019 - CARVALHO, ELIAS F.; OSTERMANN, CAROLINE K.; BUSTILLOS, JOSE O.V.
Exploring chiral BVOCs in Amazon and Atlantic forest by TENAX® and Carbograph® sorbent
2019 - OSTERMANN, CAROLINE; ZANNONI, NORA; CARVALHO, ELIAS; NOVAES, MARIANA; WILLIAMS, JONATHAN; VEGA, OSCAR