De Carbono Research Articles

Condicionamento fisiológico de sementes em Clitoria ternatea L. com nanotubos de carbono de paredes múltiplas: Uma abordagem físico-química e morfológica

Abstract Clitoria ternatea L. is valued for its ornamental characteristics, medicinal properties, and culinary uses. However, efficient production of this species is constrained by seed coat dormancy, which impedes germination and seedling production. This study aimed to explore the physicochemical and morphological aspects of C. ternatea seeds, focusing on overcoming dormancy by applying multi-walled carbon nanotubes (MWCNTs) functionalized with carboxylic acid. The seeds were characterized by their physical, chemical, and mineral composition. Characterization included color dominance, geometry, thousand seed weight, and moisture content analyses. The seeds were treated with different concentrations (0, 100, 200, 400, 800 mg L-1) of multi-walled carbon nanotubes (MWCNT) during 24 hours of soaking. Then the germination rates were evaluated and morphological analysis was performed using scanning electron microscopy. Regarding the morphometry of the seeds, they were characterized by an oblong shape, a predominance of black tegument coloration, high levels of proteins, carbohydrates, lipids, fibers, and the presence of minerals such as potassium, magnesium, iron, and calcium. Seeds soaked in MWCNTs at a concentration of 200 mg L-1 exhibited an increase in germination percentage and the formation of normal seedlings compared to the control group (seeds soaked in water). The results suggest that MWCNTs can help to overcome seed dormancy and improve the quality of the resulting seedlings. Image analysis and scanning electron microscopy were crucial in understanding the physicochemical characteristics of the seeds and their changes upon exposure to MWCNTs.

Estoque de carbono e modelos aditivos na estimativa da biomassa de Ilex paraguariensis

ABSTRACT Ilex paraguariensis is an important non-timber forest product in southern Brazil, where it is cultivated in association with native species, given its demand for shading, which contributes to the conservation and carbon fixation in its biomass. However, determining this biomass is difficult, since the estimates do not guarantee additivity between the compartments and the total aboveground biomass. This study aimed to evaluate additive (seemingly unrelated regression - SUR) and non-additive (ordinary least squares - OLS) biomass models in an Ilex paraguariensis stand and comparing its carbon stock with other land use types, consolidating its potential in the face of climate change. A total of 30 trees were cut, compartmentalized and weighed on a digital scale, and four biomass models were adjusted. The carbon stocks were compared with values found in the literature. The bias in the SUR model was less than 2 %, except for the leaves, while the bias in the OLS model varied between 1 and 14 %. The error ranged between 23 and 49 % for SUR, and between 31 and 50 % for OLS. The models adjusted by SUR ensured the accuracy and additivity of the compartments. The Ilex paraguariensis stand stored more carbon than agriculture and pasture areas, removing more CO2, evidencing the sustainability of this system and favoring the climate stability.

Determinação dos Estoques de Carbono e Nitrogênio nas Frações Físicas da Matéria Orgânica em Solos Antrópicos (Terra Preta de Índio) e Não Antrópicos da Amazônia Central

The soil organic matter, as the Amazonian Dark Earths, have functional compartments with different characteristics concerning composition and dynamics and these fractions can be evaluated using physical fractionation, in which the fractions are separated by densimetric and granulometric methods. In the Amazon region, studies involving physical fractionation are scarce. This work aimed to identify the compartments and their carbon and nitrogen stocks, the effect of fallow time, and to evaluate the use of these fractions as indicators of soil quality, in soils collected in areas of Amazonian Dark Earths and non-anthropic soils. Physical fractionation of organic matter was carried out in soil samples from Amazonian Dark Earths and non-anthropic soils, with forest cover. The carbon and nitrogen contents in each fraction were determined, and their stocks. The fallow time influenced the dynamics of organic matter in the Amazonian Dark Earths. The light-free fraction proved to be a sensitive diagnostic attribute in the superficial layers. Fallow or the conversion of intensely cultivated Amazon areas to secondary forests can be a sustainable practice for mitigating carbon and nitrogen losses in the soil, especially in the most labile and reactive fractions present in the most superficial layers of the soil.

La importancia de las fuentes de carbono y nitrógeno en la síntesis de exopolisacáridos y su importancia industrial

Exopolysaccharides (EPSs) are classified in two groups, homopolysaccharides (HoPs) and heteropolysaccharides (HePs), are produced by lactic acid bacteria (LAB) and used in a range of industrial applications including the medical and food industries. HoPs are extracellular EPSs and their production depends on extracellular enzymes, while HePs are intracellular EPSs. Their nature (extra or intracellular) directly impacts production rates, HoPs having higher yields. The development of processes for producing EPSs has attracted great interest, since novel application trends have emerged due to the great diversity of recent information generated on EPSs properties. HoPs have been synthesized by fermentation using bacterial cells and a cell-free enzymatic process, while HePs have been produced only by fermentation. The analysis of the EPSs production processes indicates that macronutrients such as the carbon and nitrogen source used in the culture media are very important for the synthesis of EPSs and the enzymes involved, understanding their importance can assist to design processes for production of EPSs with desirable characteristics and yields according to the needs of the processes and products to which they are applicable. This review emphasized in the analyses of carbon and nitrogen sources used for EPSs production and their functional applications and productive aspects.

Estoque de carbono do estrato herbáceo em coberturas vegetais em fragmentos de Caatinga

Climate change and the extensive areas of dry tropical forests (DTF) used in the production of pasture determine the need to investigate alternative managements that would make it possible to increase carbon stock. As such, the aim of this research was to estimate the carbon stock in the herbaceous layer of two fragments of seasonally dry tropical forest: i) a fragment of dry tropical forest under 40 years of regeneration and ii) forest submitted to the thinning of trees with a diameter <10 cm. The research was carried out over nine years (2010-2018) in two micro basins inserted in a fragment of DTF in the district of Iguatu, Ceará. Herbaceous material was collected continuously every month in each micro basin, with 10 replications, giving a total of 2,160 samples (2 micro basins x 10 replications x 12 months x 9 years). The material was dried in an oven at 60 °C; the biomass content was then determined and later converted to carbon content. The carbon stock varied according to the rainfall in the region. The area under thinning recorded greater carbon stock for 80% of the months over the study period compared to the area under regeneration. It was found that the thinning management afforded the greatest amounts of carbon stock during both the rainy and the dry seasons, differing statistically from the area under regeneration (𝛼=0.05), and is one alternative for increasing the carbon stock of the herbaceous layer.

Análisis de cuatro sistemas silvopastoriles en Perú: Caracterización física y nutricional de pasturas, composición florística, reserva de carbono y CO2

Análisis de cuatro sistemas silvopastoriles en Perú: Caracterización física y nutricional de pasturas, composición florística, reserva de carbono y CO2

Diversity of indigenous arbuscular mycorrhizal fungi in rhizosphere of upland rice (Oryza sativa L.) varieties in Southwest Nigeria

Diversity of indigenous arbuscular mycorrhizal fungi in rhizosphere of upland rice (Oryza sativa L.) varieties in Southwest Nigeria

Calidad de poroto (Phaseolus vulgaris L.) almacenado en silobolsa en condiciones de intemperie en relación a la presencia de materias extrañas y granos partidos

El objetivo del trabajo fue estudiar el deterioro del poroto blanco alubia almacenado en silobolsa con la presencia de materias extrañas y granos partidos. Se evaluaron silobolsas con diferentes contenidos iniciales de humedad, materias extrañas, granos partidos y granos manchados. Se midió la evolución de estos parámetros y la concentración de dióxido de carbono. Se registró humedad relativa y temperatura del aire intergranario. Se utilizó la actividad acuosa como parámetro de actividad microbiana. Los resultados indican que el manchado de los granos aumentó con altos contenidos iniciales de manchado, humedad y materias extrañas, que coincidió con el incremento de microorganismos. Estos últimos se localizaron según la ubicación del material fino en la base de la bolsa, o en puntos húmedos del estrato superior producto de la condensación. Bajos valores de humedad y materias extrañas evidenciaron control microbiano por humedad relativa <70%. Se observó interacción entre los efectos de materias extrañas y granos partidos, que generó el manchado de los granos, favorecida por períodos prolongados y altas temperaturas. El efecto de los granos partidos se relacionó con el contenido de humedad y el efecto del material extraño con el tiempo. Se observó la estratificación de la humedad. La concentración de dióxido de carbono aumentó con el incremento de la temperatura. Los incrementos de la actividad acuosa se relacionaron con altas proporciones de materias extrañas y granos partidos presentes en el granel, y con elevados contenidos de humedad de los mismos y del grano, lo cual ocasiona mayor actividad microbiológica.

Eletrodos de Carbono Cerâmico Modificados com Óxido Misto de Estanho e Nióbio com Potencial Aplicação como Sensores Eletroquímicos

A insercao de oxidos mistos em eletrodos de carbono cerâmico a partir do processo sol-gel pode proporcionar materiais com alta pureza e homogeneidade, sem a segregacao de fases e alta estabilidade, combinando as propriedades mecânicas e quimicas da silica gel com as propriedades quimicas dos oxidos metalicos (MxOy). Esse recurso pode fornecer ao dispositivo propriedades interessantes, uma vez que a distribuicao homogenea dos oxidos, pode minimizar a resistividade proporcionada pela rede de silica. Alem disso, a insercao de sitios acidos possibilita a imobilizacao de diferentes mediadores de eletrons, os quais permanecem estaveis sobre a superficie dos ECC, aumentando a seletividade e sensibilidade de tais eletrodos. Desta forma, neste trabalho teve-se como objetivo incorporar o pentoxido de niobio (Nb2O5) no ECC/SiO2-SnO2, de modo reduzir ainda mais a resistencia eletrica interna da matriz de silica, obtendo-se o eletrodo de carbono cerâmico, designado como ECC/SiO2-SnO2-Nb2O5. O material obtido foi caracterizado por espectroscopia de FTIR, a qual indicou que a rede de SiO2 e pouco perturbada pelo incorporacao dos oxidos, mostrando evidencias da formacao da ligacao Si-O-M (onde M=Sn ou Nb), a qual foi corroborada pela tecnica de XPS. Espectros Raman evidenciaram um aumento da relacao de intensidade entre as bandas D e G (ID/IG), indicando que a medida que os oxidos sao inseridos na estrutura da SiO2, ocorre um aumento do grau de desordem do sistema. A partir das tecnicas morfologicas, MEV e EDS evidenciou-se que o Sn e o Nb mostraram-se bem distribuidos pela superficie. O ECC/SiO2-SnO2 e o ECC/SiO2-SnO2-Nb2O5 apresentaram melhores respostas voltametricas que os sistemas sem a adicao destes (ECC/SiO2), apresentando um processo difusional de transferencia de massa e com respostas de corrente estaveis apos 100 ciclos voltametricos, com variacao de Ipa e Ipc abaixo de 5%. Tais resultados demonstram a potencialidade de utilizacao destes materiais no desenvolvimento de sensores.

Avances en electrodos y biosensores elaborados con nanotubos de carbono

espanolEl mejoramiento continuo en los procesos de fabricacion de electrodos y biosensores facilita la generacion de nuevas implementaciones en diversos sectores de la ciencia, tales como la fisica, la quimica y la biologia, asi como de la ingenieria, la electronica, la biomedica y la bioingenieria, en las que se requiere aplicar. Una amplia busqueda en articulos cientificos, bases de datos y revistas especializadas revela las nuevas tendencias en la inclusion de nanotubos de carbono (cnt) como material base de nuevos electrodos y biosensores altamente sensibles y menos susceptibles al ruido. La compresion de las nuevas metodologias de construccion que incluyen cnt y su funcionamiento final constituyen una oportunidad para la generacion de aplicaciones y el mejoramiento de las tecnicas de construccion actuales. EnglishContinuous improvement in manufacturing processes of electrodes and biosensors, facilitates the generation of new implementations in various fields of science and engineering where required applied. An extensive search of scientific articles unpublished research results, databases and journals reveal new trends in the inclusion of Carbon Nanotubes (cnt) as a base material of new electrodes and biosensors highly sensitive and less susceptible to noise. Compression of new construction methodologies including cnt and final operation constitute an opportunity for the generation of new applications and the improvement of actual construction techniques.

Mercado Voluntario de Carbono y su impacto socioeconómico en la Colonia La Amistad, Departamento de Itapúa, Paraguay. Periodo: 2010 - 2015

La presente investigacion tiene por objetivo analizar el Mercado Voluntario de Carbono y su impacto socioeconomico en la Colonia La Amistad del Departamento de Itapua, Paraguay, desde su implementacion en el ano 2010 hasta el ano 2015. El marco metodologico seguido contempla el bibliografico documental y el de campo. El resultado de la investigacion describe y analiza el primer proyecto aprobado y financiado para el Mercado Voluntario de Carbono en el Paraguay, el cual es impulsado por la Asociacion Guyra Paraguay. Dicha organizacion, desde el ano 2010 mantiene areas boscosas a cambio de un incentivo economico. Esta conservacion es posible debido a que la compania naviera asiatica Swire Pacific Offshore (proponente del proyecto), mediante la intermediacion de World Land Trust, contrata a Guyra Paraguay para que esta desembolse anualmente un montodeterminado de dinero a cada familia de la Colonia que haya decidido participar del proyecto a cambio de que las mismas conserven las hectareas de bosques que le quedan, renunciando a emplearlas para obtener beneficios economicos derivados de su explotacion. Puede calificarse como una experiencia exitosa hasta el momento, a pesar de las multiples dificultades atravesadas para su implementacion. Asi mismo se demuestra que en Paraguay se esta dando un paso importante en la promocion del financiamiento de actividades que permitan la conservacion de bosques y rentabilidad economica. Finalmente, es una alternativa viable para que familias generen renta mediante la conservacion y manejo sostenible de los bosques.

Spatial patterns of carbon, biodiversity, deforestation threat, and REDD+ projects in Indonesia.

There are concerns that Reduced Emissions from Deforestation and forest Degradation (REDD+) may fail to deliver potential biodiversity cobenefits if it is focused on high carbon areas. We explored the spatial overlaps between carbon stocks, biodiversity, projected deforestation threats, and the location of REDD+ projects in Indonesia, a tropical country at the forefront of REDD+ development. For biodiversity, we assembled data on the distribution of terrestrial vertebrates (ranges of amphibians, mammals, birds, reptiles) and plants (species distribution models for 8 families). We then investigated congruence between different measures of biodiversity richness and carbon stocks at the national and subnational scales. Finally, we mapped active REDD+ projects and investigated the carbon density and potential biodiversity richness and modeled deforestation pressures within these forests relative to protected areas and unprotected forests. There was little internal overlap among the different hotspots (richest 10% of cells) of species richness. There was also no consistent spatial congruence between carbon stocks and the biodiversity measures: a weak negative correlation at the national scale masked highly variable and nonlinear relationships island by island. Current REDD+ projects were preferentially located in areas with higher total species richness and threatened species richness but lower carbon densities than protected areas and unprotected forests. Although a quarter of the total area of these REDD+ projects is under relatively high deforestation pressure, the majority of the REDD+ area is not. In Indonesia at least, first-generation REDD+ projects are located where they are likely to deliver biodiversity benefits. However, if REDD+ is to deliver additional gains for climate and biodiversity, projects will need to focus on forests with the highest threat to deforestation, which will have cost implications for future REDD+ implementation.Los Patrones Espaciales del Carbono, la Biodiversidad, la Amenaza de Deforestación y los Proyectos REDD+ en IndonesiaResumenActualmente hay preocupación por que las Emisiones Reducidas de la Deforestación y Degradación del Bosque (REDD+, en inglés) puedan fallar en la entrega de co–beneficios potenciales de la biodiversidad si se enfocan en áreas de alto carbono. Exploramos los traslapes espaciales entre los stocks de carbono, la biodiversidad, las amenazas proyectadas de deforestación y la ubicación de proyectos REDD+ en Indonesia, un país tropical a la vanguardia del desarrollo REDD+. Para la biodiversidad, reunimos datos sobre la distribución de vertebrados terrestres (hábitats de anfibios, mamíferos, aves y reptiles) y plantas (modelos de distribución de especies para ocho familia). Después investigamos la congruencia entre las diferentes medidas de la riqueza de la biodiversidad y los stocks de carbono en la escala nacional y sub–nacional. Finalmente mapeamos proyectos REDD+ activos e investigamos la densidad de carbono y la riqueza potencial de la biodiversidad y modelamos presiones de deforestación dentro de estos bosques en relación con áreas protegidas y no protegidas. Hubo poco traslape interno entre los diferentes hotspots (el 10% más rico de las celdas) de riqueza de especies. Tampoco hubo congruencia espacial consecuente entre los stocks de carbono y las medidas de la biodiversidad: una correlación negativa débil en la escala nacional enmascaró las relaciones altamente variables y no-lineales isla por isla. Los proyectos REDD+ actuales estuvieron ubicados preferencialmente en áreas con una riqueza total de especies y con una riqueza de especies amenazadas más altas pero con densidades de carbono más bajas que en las áreas protegidas y los bosques sin protección. Aunque un cuarto del área total de estos proyectos REDD+ está bajo una presión de deforestación relativamente alta, la mayoría del área REDD+ no lo está. Por lo menos en Indonesia, los proyectos REDD+ de primera generación están ubicados en donde tengan probabilidad de entregar beneficios para la biodiversidad. Sin embargo, si se espera que REDD+ entregue beneficios adicionales para el clima y la biodiversidad, los proyectos necesitarán enfocarse en los bosques con la mayor amenaza de deforestación, lo que tendrá implicaciones de costo para la implementación futura de REDD+.

MODELAGEM DO ESTOQUE DE CARBONO PARA MIMOSA SCABRELLA BENTH. LOCALIZADAS NO PARANÁ Modeling of carbon stock for Mimosa scabrella Benth. located in Paraná, Brazil

A grande quantidade de poluentes emitidos diariamente na atmosfera tem ocasionado à intensificação dos gases de efeito estufa (GEE). Esses gases, somados ao desmatamento e às queimadas, contribuem com as alterações climáticas. A alternativa mais conhecida para combater essa mudança do clima é a fixação de carbono na biomassa florestal, seja pelo plantio de florestas, podendo ser associado com a recuperação de áreas degradadas, ou a simples conservação dos estoques existentes em florestas naturais. Essas ações são conhecidas como sequestro de carbono. Neste sentido, o presente trabalho teve como objetivo modelar o estoque de carbono por meio de ajustes de diferentes modelos para a espécie Mimosa scabrella Benth., realizando também a determinação do fator de expansão de biomassa e a razão de raízes. A equação que apresentou melhor ajuste foi com base no modelo proposto por Schumacher-Hall, obtendo boas estatísticas, apresentando um R²aj de 0,991 e Sxy% de 10,541%. De acordo com análise realizada no presente trabalho, o FEB médio (1,41) não apresentou aumento em função da idade, seguindo uma tendência média ao longo dos anos, tendo poucas oscilações durante o período. A mesma observação pode ser feita com o R, que apresentou valor médio de 0,18. Desse modo, recomenda-se a utilização da modelagem para estimativa do estoque de carbono para a espécie Mimosa scabrella. Contudo, a utilização do FEB e R proporcionam estimativas confiáveis para obtenção da biomassa, podendo assim, utilizar o teor médio ponderado de carbono para a estimativa do estoque do mesmo para a espécie em questão.

Estoque volumétrico, de biomassa e de carbono em uma floresta estacional semidecidual em viçosa, minas gerais

Este trabalho teve por objetivo estimar o estoque volumétrico, de biomassa e de carbono das árvores (nível 1), sub-bosque (nível 2) e serapilheira (nível 3), em uma Floresta Estacional Semidecidual em Viçosa, estado de Minas Gerais.Os dados para o nível 1 de abordagem foram obtidos em 15 parcelas de 0,1ha cada. Para o nível 2 e 3 foram utilizadas 15 parcelas de 25 m² e 6,25 m², respectivamente, localizadas dentro das parcelas do nível 1.O volume total com casca nas árvores vivas foi de 281,51 ±105,80m³ ha-1, sendo que 15,2% deste valor corresponderam à casca. O fuste com casca contribuiu com 80,30% do volume total e a copa com 19,70%.O total de biomassa foi igual a 227,40 ± 77,81 t ha-1. As árvores vivas contribuíram em média com 82,8% deste total, seguido da serapilheira (5,1%); espécies não arbóreas (4,2%); árvores mortas (3,5%); arvoretas (2,9%); mudas (1,5%). Do total de biomassa, 181,48 t ha-1 (79,8%) estavam acima do solo; 34,3 t ha-1 (15,1%) nas raízes e 11,62 t ha-1 (5,1%) na serapilheira.O estoque total de carbono foi de 108,98 ± 35,33 t ha-1. As árvores vivas contribuíram com 82,6%; serapilheira 5,2%; espécies não arbóreas 4,2%; árvores mortas 3,5%; arvoretas 3,0%; mudas 1,5%. Do estoque total de carbono, 86,93 t ha-1 (79,7%) estavam acima do solo; 16,41 t ha-1 (15,1%) nas raízes e 5,64 t ha-1 (5,2%) na serapilheira.

Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning

Abstract. In this study, we identify a biomass-burning signal in molecular hydrogen (H2) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H2 and several other species as well as the H2 isotopic composition in air samples that were collected in the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) aircraft campaign during the dry season. We derive a relative H2 emission ratio with respect to carbon monoxide (CO) of 0.31 ± 0.04 ppb ppb−1 and an isotopic source signature of −280 ± 41‰ in the air masses influenced by tropical biomass burning. In order to retrieve a clear source signal that is not influenced by the soil uptake of H2, we exclude samples from the atmospheric boundary layer. This procedure is supported by data from a global chemistry transport model. The ΔH2 / ΔCO emission ratio is significantly lower than some earlier estimates for the tropical rainforest. In addition, our results confirm the lower values of the previously conflicting estimates of the H2 isotopic source signature from biomass burning. These values for the emission ratio and isotopic source signatures of H2 from tropical biomass burning can be used in future bottom-up and top-down approaches aiming to constrain the strength of the biomass-burning source for H2. Hitherto, these two quantities relied only on combustion experiments or on statistical relations, since no direct signal had been obtained from in-situ observations.

WRF-Chem simulations in the Amazon region during wet and dry season transitions: evaluation of methane models and wetland inundation maps

Abstract. The Amazon region, being a large source of methane (CH4), contributes significantly to the global annual CH4 budget. For the first time, a forward and inverse modelling framework on regional scale for the purpose of assessing the CH4 budget of the Amazon region is implemented. Here, we present forward simulations of CH4 as part of the forward and inverse modelling framework based on a modified version of the Weather Research and Forecasting model with chemistry that allows for passive tracer transport of CH4, carbon monoxide, and carbon dioxide (WRF-GHG), in combination with two different process-based bottom-up models of CH4 emissions from anaerobic microbial production in wetlands and additional datasets prescribing CH4 emissions from other sources such as biomass burning, termites, or other anthropogenic emissions. We compare WRF-GHG simulations on 10 km horizontal resolution to flask and continuous CH4 observations obtained during two airborne measurement campaigns within the Balanço Atmosférico Regional de Carbono na Amazônia (BARCA) project in November 2008 and May 2009. In addition, three different wetland inundation maps, prescribing the fraction of inundated area per grid cell, are evaluated. Our results indicate that the wetland inundation maps based on remote-sensing data represent the observations best except for the northern part of the Amazon basin and the Manaus area. WRF-GHG was able to represent the observed CH4 mixing ratios best at days with less convective activity. After adjusting wetland emissions to match the averaged observed mixing ratios of flights with little convective activity, the monthly CH4 budget for the Amazon basin obtained from four different simulations ranges from 1.5 to 4.8 Tg for November 2008 and from 1.3 to 5.5 Tg for May 2009. This corresponds to an average CH4 flux of 9–31 mg m−2 d−1 for November 2008 and 8–36 mg m−2 d−1 for May 2009.

Methane airborne measurements and comparison to global models during BARCA

Tropical regions, especially the Amazon region, account for large emissions of methane (CH4). Here, we present CH4 observations from two airborne campaigns conducted within the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) project in the Amazon basin in November 2008 (end of the dry season) and May 2009 (end of the wet season). We performed continuous measurements of CH4 onboard an aircraft for the first time in the Amazon region, covering the whole Amazon basin with over 150 vertical profiles between altitudes of 500 m and 4000 m. The observations support the finding of previous ground‐based, airborne, and satellite measurements that the Amazon basin is a large source of atmospheric CH4. Isotope analysis verified that the majority of emissions can be attributed to CH4 emissions from wetlands, while urban CH4 emissions could be also traced back to biogenic origin. A comparison of five TM5 based global CH4 inversions with the observations clearly indicates that the inversions using SCIAMACHY observations represent the BARCA observations best. The calculated CH4 flux estimate obtained from the mismatch between observations and TM5‐modeled CH4 fields ranges from 36 to 43 mg m−2 d−1 for the Amazon lowland region.

Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

Abstract. We present the results of airborne measurements of carbon monoxide (CO) and aerosol particle number concentration (CN) made during the Balanço Atmosférico Regional de Carbono na Amazônia (BARCA) program. The primary goal of BARCA is to address the question of basin-scale sources and sinks of CO2 and other atmospheric carbon species, a central issue of the Large-scale Biosphere-Atmosphere (LBA) program. The experiment consisted of two aircraft campaigns during November–December 2008 (BARCA-A) and May–June 2009 (BARCA-B), which covered the altitude range from the surface up to about 4500 m, and spanned most of the Amazon Basin. Based on meteorological analysis and measurements of the tracer, SF6, we found that airmasses over the Amazon Basin during the late dry season (BARCA-A, November 2008) originated predominantly from the Southern Hemisphere, while during the late wet season (BARCA-B, May 2009) low-level airmasses were dominated by northern-hemispheric inflow and mid-tropospheric airmasses were of mixed origin. In BARCA-A we found strong influence of biomass burning emissions on the composition of the atmosphere over much of the Amazon Basin, with CO enhancements up to 300 ppb and CN concentrations approaching 10 000 cm−3; the highest values were in the southern part of the Basin at altitudes of 1–3 km. The ΔCN/ΔCO ratios were diagnostic for biomass burning emissions, and were lower in aged than in fresh smoke. Fresh emissions indicated CO/CO2 and CN/CO emission ratios in good agreement with previous work, but our results also highlight the need to consider the residual smoldering combustion that takes place after the active flaming phase of deforestation fires. During the late wet season, in contrast, there was little evidence for a significant presence of biomass smoke. Low CN concentrations (300–500 cm−3) prevailed basinwide, and CO mixing ratios were enhanced by only ~10 ppb above the mixing line between Northern and Southern Hemisphere air. There was no detectable trend in CO with distance from the coast, but there was a small enhancement of CO in the boundary layer suggesting diffuse biogenic sources from photochemical degradation of biogenic volatile organic compounds or direct biological emission. Simulations of CO distributions during BARCA-A using a range of models yielded general agreement in spatial distribution and confirm the important contribution from biomass burning emissions, but the models evidence some systematic quantitative differences compared to observed CO concentrations. These mismatches appear to be related to problems with the accuracy of the global background fields, the role of vertical transport and biomass smoke injection height, the choice of model resolution, and reliability and temporal resolution of the emissions data base.

High-accuracy continuous airborne measurements of greenhouse gases (CO<sub>2</sub> and CH<sub>4</sub>) using the cavity ring-down spectroscopy (CRDS) technique

Abstract. High-accuracy continuous measurements of greenhouse gases (CO2 and CH4) during the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) phase B campaign in Brazil in May 2009 were accomplished using a newly available analyzer based on the cavity ring-down spectroscopy (CRDS) technique. This analyzer was flown without a drying system or any in-flight calibration gases. Water vapor corrections associated with dilution and pressure-broadening effects for CO2 and CH4 were derived from laboratory experiments employing measurements of water vapor by the CRDS analyzer. Before the campaign, the stability of the analyzer was assessed by laboratory tests under simulated flight conditions. During the campaign, a comparison of CO2 measurements between the CRDS analyzer and a nondispersive infrared (NDIR) analyzer on board the same aircraft showed a mean difference of 0.22±0.09 ppm for all flights over the Amazon rain forest. At the end of the campaign, CO2 concentrations of the synthetic calibration gases used by the NDIR analyzer were determined by the CRDS analyzer. After correcting for the isotope and the pressure-broadening effects that resulted from changes of the composition of synthetic vs. ambient air, and applying those concentrations as calibrated values of the calibration gases to reprocess the CO2 measurements made by the NDIR, the mean difference between the CRDS and the NDIR during BARCA was reduced to 0.05±0.09 ppm, with the mean standard deviation of 0.23±0.05 ppm. The results clearly show that the CRDS is sufficiently stable to be used in flight without drying the air or calibrating in flight and the water corrections are fully adequate for high-accuracy continuous airborne measurements of CO2 and CH4.

Virological evaluation of domestic water purification devices commonly used in India emphasizes inadequate quality and need for virological standards

To evaluate the performance of domestic water purification units with respect to contaminating enteric viruses. Eight domestic water purification systems widely used in India were evaluated using hepatitis E virus (HEV) as a model virus. For HEV concentration and detection, membrane filtration and real-time PCR were used respectively. Viral log reduction value (LRV) was calculated for each unit. Viral log reduction value was 0.21 for unit 6 (polyester + carbon), 1.45 for unit 4 (filter + UV), 1.52 for unit 3 (filter + chlorine), 1.70 for a carbon + exhaust indication contact disinfection unit, 2.20 for an iodine resin unit, 2.51 for a dual filter unit and 6.53 for a hollow fibre membrane unit and a gravity-fed filter unit. Thus, only the technologies employed by the latter two were efficient in complete removal of HEV. The majority of the water purifiers under use are inadequate. Virological standards in evaluating such devices need to be established urgently, in order to help manufacturers to improve the performance of such products and most importantly, to help consumers.