No ambiente marinho uma equação inversa entre a alcalinidade total e a salinidade, denominada de alcalinidade total normalizada (ATN) para mostrar uma relação linear entre esses parâmetros. O objetivo deste trabalho foi avaliar a distribuição superficial e vertical da ATN ao longo da Zona Econômica Exclusiva-ZEE da região Norte do Brasil, com os dados obtidos nas Operações Norte III e Norte IV, dentro do âmbito do Programa de Avaliação do Potencial Sustentável de Recursos Vivos na Zona Econômica Exclusiva (REVIZEE). Os dados demonstraram que o sistema do dióxido de carbono ao longo da ZEE Norte mantém o pH dentro da faixa esperada para o ambiente marinho. Os menores valores de pH (7,48 Norte III e 7,38 Norte IV), de AT (1971µmol kg-1, Norte III e 1878 µmol kg-1 Norte IV) e de ATN (2295 µmol kg-1 Norte III, 2293 µmol kg-1 Norte IV) na camada superficial, foram observados na área com influência da descarga do rio Amazonas, ou seja, com baixos valores de salinidade (28,31 Norte III e 24,00 Norte IV). As massas de águas na coluna de água, encontradas na região, tiveram diferenças na concentração de ATN. Essas diferenças podem ser associadas aos processos de degradação da matéria orgânica, e a formação ou dissolução do carbonato de cálcio. Pesquisas futuras englobando outras formas do sistema do dióxido de carbono, e também com a utilização de métodos mais precisos, irão servir para explicar a dinâmica desse sistema de forma mais precisa.

Forest biomass is an important variable for calculating carbon stocks and greenhouse gas emissions from deforestation and forest fires in Brazilian Amazonia. Its spatial distribution has caused controversy due to disagreements over the application of different calculation methodologies. Standardized networks of forest surveys provide an alternative to solve this problem. This study models the spatial distribution and original total stock of forest biomass (Aboveground + Belowground + Fine and coarse litter) in Brazil’s state of Roraima, taking advantage of data from georeferenced forest surveys in the region. Commercial volume (bole volume) from surveys was expanded to total biomass. Kriging techniques were used to model the spatial distribution of biomass stocks and generate a benchmark map. All results were associated with phytophysiognomic groups, climatic regions and land uses (protected areas; agricultural use). We estimate forest in the state of Roraima to have an original biomass stock of 6.32 × 109 Mg. Forest biomasses in areas with shorter dry seasons were higher as compared to forests in regions with longer dry seasons. The original vegetation in protected areas, independent of phytophysiognomic group, has higher biomass compared to areas currently under agricultural use. Protected areas support 65.8% of Roraima’s stock of forest biomass, indicating an important potential role in REDD projects for conservation of forest carbon. Information on spatial distribution of biomass stocks at a more refined scale is needed to reduce uncertainties about the regional character of carbon pools in Amazonia.

A relationship between oceanic conditions in the northwestern equatorial Atlantic (NWEA) and the seasonal rainfall over the northern part of Brazilian Northeast (NNEB) allows large climate events to be forecasted with a delay of a few months. Observed sea surface variables (sea surface temperature, wind stress and latent heat flux) and reanalyzed temperature and salinity profiles at depths of 0 – 150 m are used during 1974-2008. Perturbations in the Wind-Evaporation-SST mechanism over the NWEA during the last months of the year and the first months of the following year are of primary importance in evaluating the risk that strong climate events will affect the subsequent seasonal rainfall (in March-April) over the NNEB. Especially interesting are the Barrier Layer Thickness (BLT) and Ocean Heat Content (OHC) in the NWEA region from August-September through the subsequent months, during which a slow and steady evolution is apparent, with the highest signal occurring in October-November. Through their relationship with the local surface dynamic conditions, such BLT and OHC perturbations during the last months of the year can be used as a valuable indicator for forecasting wet or dry events over the NNEB during the subsequent rainfall season. A proposal is discussed to deploy additional temperature/conductivity sensors down to a depth of 140 m at three PIRATA moorings located in the NWEA region. That will be necessary if the BLT and other parameters of energy exchange between the ocean and atmosphere are to be estimated in real time and with a sufficiently high vertical resolution.

A forte relação das pessoas com o Rio Doce, bem como suas enchentes regulares, representam fator contínuo de exposição ao risco de doenças hídricas. Dada sua relevância epidemiológica, este estudo analisa a associação entre percepção de contaminação e uso do rio, bem como os mecanismos heurísticos empregados na formação da percepção de risco. Utilizou-se um modelo probit ordenado com variável instrumental e análise de redes temáticas aplicados a uma base de dados primária de 352 domicílios, representativa dos moradores de Tumiritinga, Minas Gerais, Brasil, para o ano de 2012. Os resultados indicam que embora a maioria (92,6%) dos moradores de Tumiritinga perceba o risco de contrair algum tipo de doença quando nada no Rio Doce, somente 11,4% informam não entrar na água. A análise de conteúdo sugere que esse paradoxo advém da falta de compreensão populacional sobre os mecanismos de transmissão de doenças hídricas, criando viés otimista sobre as chances de contaminação. Campanhas para promoção de comportamento preventivo devem, portanto, enfatizar as formas de contrair doenças hídricas na região.

Durante as últimas décadas, com as fortes evidências do aquecimento global, ganham importância os estudos sobre o comportamento e as mudanças dos padrões em séries climáticas. Para a coerência nas análises de dados, o processo probabilístico gerador dos valores da variável aleatória ao longo do tempo deve permanecer o mesmo. No caso de dados de estações meteorológicas, este pressuposto de homogeneidade no processo estocástico pode ser violado a partir de perturbações como mudanças de posição da estação, mudança de instrumentos ou mudança climática.
Neste trabalho, o pacote Climatol-R foi aplicado a 122 séries mensais de temperatura mínima, cobrindo o interior do estado de São Paulo para os anos 1940 até 2012. Todas as estações estudadas apresentaram não homogeneidades. Uma das consequências deste trabalho de homogeneização foi a melhora da homogeneidade dos dados de temperatura mínima para a estação meteorológica IAC.00015 onde se obteve redução do desvio padrão de 0,86ºC para 0,81ºC. O pacote Climatol-R tende a melhorar espacialmente e temporalmente a série original, apresentando melhores resultados para a análise de variabilidade climatológica.

Research networks provide a framework for review, synthesis and systematic testing of theories by multiple scientists across international borders critical for addressing global-scale issues. In 2012, a GHG research network referred to as MAGGnet (Managing Agricultural Greenhouse Gases Network) was established within the Croplands Research Group of the Global Research Alliance on Agricultural Greenhouse Gases(GRA). With involvement from 46 alliance member countries, MAGGnet seeks to provide a platform for the inventory and analysis of agricultural GHG mitigation research throughout the world. To date, metadata from 315 experimental studies in 20 countries have been compiled using a standardized spreadsheet. Most studies were completed (74%) and conducted within a 1–3-year duration (68%). Soil carbon and nitrous oxide emissions were measured in over 80% of the studies. Among plant variables, grain yield was assessed across studies most frequently (56%), followed by stover (35%) and root (9%) biomass. MAGGnet has contributed to modeling efforts and has spurred other research groups in the GRA to collect experimental site metadata using an adapted spreadsheet. With continued growth and investment, MAGGnet will leverage limited-resource investments by any one country to produce an inclusive, globally shared meta-database focused on the science of GHG mitigation.

The recent article in this journal of Cerri et al. (2016) gives estimates of greenhouse gas (GHG) emissions for cattle production on extensively managed farms in the State of Mato Grosso, Brazil. The results are expressed as GHG emission per kg of animal in the herd, and not per kg of product. These estimates should not be referred to as “carbon footprints” as they do not reflect the estimate of the GHG emissions utilized in the production of 1 kg of animal or carcass, but the total emission per kg of the total mass of animals in the herd, whether calves, heifers, steers or mature bulls and cows. This leads to a large underestimation of the true GHG emissions for the production of Brazilian beef.

Hourly fCO2 is recorded at a time series at the PIRATA buoy located at 6°S 10°W in the eastern tropical Atlantic since June 2006. This site is located south and west of the seasonal Atlantic cold tongue and is affected by its propagation from June to September. Using an alkalinity–salinity relationship determined for the eastern tropical Atlantic and the observed fCO2, pH and the inorganic carbon concentration are calculated. The time series is investigated to explore the intraseasonal, seasonal and interannual timescales for these parameters, and to detect any long-term trends. At intraseasonal timescales, fCO2 and pH are strongly correlated. On seasonal timescales, the correlation still holds between fCO2 and pH and their variations are in agreement with those of sea surface salinity. At interannual timescales, some important differences appear in 2011–2012: lower fCO2 and fluxes are observed from September to December 2011 and are explained by higher advection of salty waters at the mooring, in agreement with the wind. In early 2012, the anomaly is still present and associated with lower sea surface temperatures. No significant long-term trend is detected over the period 2006–2013 on CO2 and any other physical parameter. However, as atmospheric fCO2 is increasing over time, the outgassing of CO2 is reduced over the period 2006–2013 as the flux is mainly controlled by the difference of fCO2 between the ocean and the atmosphere. A longer time series is required to determine if any significant trend exists in this region.

Few grass genotypes with high yield potential are used as fodder in Brazil, making it necessary to develop new cultivars. In this study, we compared tiller density, forage mass, and agronomic traits across 12 Elephant grass (Pennisetum purpureum Schum.) genotypes under free-growth and conventional cutting systems at the Agência Paulista de Técnologia dos Agronegócios (APTA), Andradina, São Paulo, Brazil. The experimental design of the two trials was three replicates of a randomized complete block, each experimental unit consisting of 37.5-m2 plots with five rows spaced 1.5 m apart. We estimated tiller density 30, 60, and 150 days after planting (DAP), and 90 days after cut (DAC), and harvested the grass 150 DAP and 90 DAC for determination of forage mass and agronomic traits. In the free-growth system, forage mass was highest in genotypes CNPGL 00-155-2, CNPGL 92-41-1, CNPGL 92-51-1, and CNPGL 96-21-1 and in cultivar Guaçu. After cutting and regrowth, forage mass was highest in genotypes CNPGL 93-41-1, CNPGL 92-41-1, and CNPGL 91-11-2 and in cultivars Mineiro IPEACO, Guaçu, and Pioneiro. Stem mass was higher than leaf mass in the two trials, with leaf/stem ratio in most genotypes below 1.0. Aerial tiller density was highest for genotypes Pioneiro and CNPGL 00-155-2, and stem diameter was smallest in cv. Pioneiro in the free-growth and in the cutting and regrowth systems (9.7 and 7.62 mm, respectively). After regrowth, plant height ranged from 0.56 m in cv. Guaçu to 2.0 m in cv. Mineiro IPEACO and the mean number of internodes.stem-1 ranged from 2.1 in cv. Guaçu to 7.4 in cv. Pioneiro. Forage mass correlated positively with basal tiller density (r =0.4096) and negatively with stem diameter (r =-0.4879) in the free-growth trial, but relationships were not significant after regrowth.

The intense rainfall in the tropical Atlantic spatially overlaps with the spread of the Amazon plume. Based on remote-sensed sea surface salinity and rainfall, we removed the contribution of rainfall to the apparent Amazon plume area, thus refining the quantification of its extension (0.84 ± 0.06 × 106 km2 to 0.89 ± 0.06 × 106 km2). Despite the previous overestimation of the Amazon plume area due to the influence of rainfall (>16%), our calculated annual CO2 flux based on rainfall-corrected sea surface CO2 fugacity confirms that the Amazon River plume is an atmospheric CO2 sink of global importance (−7.61 ± 1.01 to −7.85 ± 1.02 Tg C yr−1). Yet we show that current sea-air CO2 flux assessments for the tropical Atlantic could be overestimated in about 10% by neglecting the CO2 sink associated to the Amazon plume. Thus, including the Amazon plume, the sea-air CO2 exchange for the tropical Atlantic is estimated to be 81.1 ± 1.1 to 81.5 ± 1.1 Tg C yr−1.

The variability of sea surface Total Alkalinity (TA) and sea surface Total Inorganic Carbon (CT) is examined using all available data in the western tropical Atlantic (WTA: 20°S-20°N, 60°W-20°W). Lowest TA and CT are observed for the region located between 0°N-15°N/60°W-50°W and are explained by the influence of the Amazon plume during boreal summer. In the southern part of the area, 20°S-10°S/40°W-60°W, the highest values of TA and CT are linked to the CO2–rich waters due to the equatorial upwelling, which are transported by the South Equatorial Current (SEC) flowing from the African coast to the Brazilian shore. An increase of CT of 0.9 ± 0.3 μmol kg−1yr−1 has been observed in the SEC region and is consistent with previous published estimates. A revised CT-Sea Surface Salinity (SSS) relationship is proposed for the WTA to take into account the variability of CT at low salinities. This new CT-SSS relationship together with a published TA-SSS relationship allow to calculate pCO2 values that compare well with observed pCO2 (R2 = 0.90).

Tropical forests harbor a significant portion of global biodiversity and are a critical component of the climate system. Reducing deforestation and forest degradation contributes to global climate-change mitigation efforts, yet emissions and removals from forest dynamics are still poorly quantified. We reviewed the main challenges to estimate changes in carbon stocks and biodiversity due to degradation and recovery of tropical forests, focusing on three main areas: (1) the combination of field surveys and remote sensing; (2) evaluation of biodiversity and carbon values under a unified strategy; and (3) research efforts needed to understand and quantify forest degradation and recovery. The improvement of models and estimates of changes of forest carbon can foster process-oriented monitoring of forest dynamics, including different variables and using spatially explicit algorithms that account for regional and local differences, such as variation in climate, soil, nutrient content, topography, biodiversity, disturbance history, recovery pathways, and socioeconomic factors. Generating the data for these models requires affordable large-scale remote-sensing tools associated with a robust network of field plots that can generate spatially explicit information on a range of variables through time. By combining ecosystem models, multiscale remote sensing, and networks of field plots, we will be able to evaluate forest degradation and recovery and their interactions with biodiversity and carbon cycling. Improving monitoring strategies will allow a better understanding of the role of forest dynamics in climate-change mitigation, adaptation, and carbon cycle feedbacks, thereby reducing uncertainties in models of the key processes in the carbon cycle, including their impacts on biodiversity, which are fundamental to support forest governance policies, such as Reducing Emissions from Deforestation and Forest Degradation.