The low natural fertility of Oxisols in the Cerrado region makes some crops in this region very dependent on high rates of synthetic N-fertilizers, which are of growing environmental concern as a major source of N₂O emissions in agriculture. In a field experiment, we quantified direct N₂O emissions and NH₃ volatilization (a source of indirect N₂O emissions) from surface-applied N fertilizer on a no-till maize (Zea maysL.) crop in Cerrado biome. We used four fertilizers at the rate of 120 kg N ha⁻¹ as topdress-N (V4–V6 growth stage), which were regular urea, urea + zeolite, calcium nitrate and ammonium sulfate, and a non-topdressed control. The total N losses as volatilized NH₃ ranged from 2.2% (calcium nitrate) to 4.5% (urea + zeolite). The N loss as volatilized NH₃ from urea was very low (3.2%), with no significant difference between urea + zeolite, ammonium sulfate and calcium nitrate. Significantly, higher cumulated N₂O emissions were observed with ammonium sulfate than with the control. No significant differences among fertilizers were found for emission factor (EF), which was 0.20% on average (0.14–0.26%), indicating that use of IPCC default EF (1.00%) would substantially overestimate N₂O emission. Free drainage and acidity of Oxisols and occurrence of dry spells, known as ‘veranicos’, are characteristics of Cerrado biome that may naturally mitigate N₂O emissions.

Resumo: A partir de uma oficina realizada em uma escola pública de Florianópolis (SC), o texto explora aspectos da filosofia prática de Gilles Deleuze e Félix Guattari no encontro com a Educação Ambiental. Na primeira parte são apresentadas as ideias de ‘começo’, ‘criação’ e ‘experimentação’ e sua relação com o presente atual e o campo da Educação Ambiental. Na segunda parte apresentam-se as etapas da oficina e o modo pelo qual se esboça um campo problemático onde o ambiental se singulariza a partir de questões eminentemente vitais. Na parte final do texto, destacam-se alguns aspectos apresentados na segunda parte e de que maneira eles nos abrem e ao campo ambiental para novas regiões do viver.

Abstract: As from a workshop held in a public school in Florianópolis (SC), the text explores aspects of the practical philosophy of Gilles Deleuze and Félix Guattari in the meeting with the Environmental Education. In the first part we present the ideas of ‘beginning’, ‘creation’ and ‘experimentation’ and its relation to the actual present and the field of Environmental Education. The second part presents the steps of the workshop and the way in which it outlines a problematic field where the environment is singularized from an eminently vital issues. At the end of the text highlights some aspects presented in the second part and in what way they open us and open the environmental field to new regions of living.

Maize production accounts for the largest proportion of synthetic fertilizer-N used in Brazil, with most of it being urea. The use of this fertilizer raises significant agronomic and environmental concerns due to an elevated risk of gaseous N losses, resulting in low fertilizer-N recovery by plants and increasing anthropogenic greenhouse gas (GHG) emissions. In a field trial on a tropical Acrisol, we quantified the N losses caused by the gaseous emissions of NH3 and N2O and the grain yield and recovery of 15N-fertilizer by maize plants treated with urea with added nitrapyrin or N-(n-butyl) thiophosphoric triamide (NBPT). Under conditions favorable for gaseous N loss from fertilizers, nitrapyrin reduced the cumulative N2O emission by 49% over a period of 30days after the subsurface application of side-banded urea (50kgNha−1) during maize sowing. The use of NBPT delayed urea hydrolysis and reduced the NH3 volatilization by 35%, which represents a significant reduction in indirect N2O emission due to subsequent atmospheric deposition. The use of nitrapyrin during sowing and NBPT during the V5 stage of maize growth enhanced urea-15N recovery by 53% and increased maize grain yield by 1.5tha−1 compared to regular urea. Our results indicate that considering the main potential N losses according to timing and placement of fertilizer, the specific use of inhibitors represents an efficient strategy to improve the urea-N recovery and the maize grain yield. The use of nitrification inhibitors can play an effective role in mitigating N2O emissions from typical N fertilization practices in maize-producing areas in Brazil. This study also indicates the need for considering indirect emissions in the overall balance of N2O emissions derived from enhanced-efficiency fertilizers.

Pacific and Atlantic sea surface temperature (SST) variability strongly influences rainfall changes in the Amazon River basin, which impacts on the river discharge and consequently the sea surface salinity (SSS) in the Amazon plume. An Empirical Orthogonal Function (EOF) analysis was performed using 46 years of SST, rainfall, and SSS datasets, in order to establish the relationship between these variables. The first three modes of SST/rainfall explained 87.83% of the total covariance. Pacific and Atlantic SSTs led Amazon basin rainfall events by 4 months. The resultant SSS in the western tropical North Atlantic (WTNA) lagged behind basin rainfall by 3 months, with 75.04% of the total covariance corresponding to the first four EOF modes. The first EOF mode indicated a strong SSS pattern along the coast that was connected to negative rainfall anomalies covering the Amazon basin, linked to El Niño events. A second pattern also presented positive SSS anomalies, when the rainfall was predominantly over the northwestern part of the Amazon basin, with low rainfall around the Amazon River mouth. The pattern with negative SSS anomalies in the WTNA was associated with the fourth mode, when positive rainfall anomalies were concentrated in the northwest part of South America. The spatial rainfall structure of this fourth mode was associated with the spatial rainfall distribution found in the third EOF mode of SST vs. rainfall, which was a response to La Niña Modoki events. A statistical analysis for the 46 year period and monthly anomaly composites for 2008 and 2009 indicated that La Niña Modoki events can be used for the prediction of low SSS patterns in the WNTA.

The Amazon generates the world’s largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly NO3− and SiO2−, were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m−3). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO2 fugacity (fCO2sw), calculated from total alkalinity (1,450 < TA < 2,394 μmol kg−1) and dissolved inorganic carbon (1,303 < DIC < 2,062 μmol kg−1) measurements, confirms that the Amazon River plume is a sink of atmospheric CO2 in areas with salinities <35 psu, whereas, in regions with salinities >35 and higher-intensity winds, the CO2 flux is reversed. Lower fCO2sw values were observed in the NECC area. The ΔfCO2 in this region was less than 5 μatm (−0.3 mmol m−2 d−1), while the ΔfCO2 in the coastal region was approximately 50 μatm (+3.7 mmol m−2 d−1). During the cruise, heterotrophic and autotrophic processes were observed and are indicative of the influences of terrestrial material and biological activity, respectively.

By 2014 approximately 2.2 million km2 (~43%) ofBrazil’s Legal Amazonia region had been incorporated into anextensive network of 718 protected areas, which are com-prised by 372 indigenous lands, 313 federal, state and munic-ipal (county) conservation units, and 33 Maroon territories(Quilombos). Although protected areas occupy vast expansesin Amazonia, their importance as carbon reserves needs to bebetter understood. In this study, we estimate the total carbon in2014 held in protected areas in Brazil’s BLegal Amazonia^and BAmazonia biome^ regions, and the carbon loss in theportions of these protected areas that were cleared by 2014. In 2014, a total of 33.4 Pg C or 57.0% of all carbon stored inLegal Amazonia was held in protected areas and 32.7 Pg C or58.5% of all the carbon stored in the Amazonia biome washeld in protected areas. By 2014, carbon lost due to clearing inprotected areas in Legal Amazonia and the Amazonia biometotaled, respectively, 0.787 (or 2.3%) and 0.702 (or 2.1%)Pg C if one assumes that previously each protected area wasentirely covered by native vegetation. If the protection of theseareas is effective, about half of the carbon in BrazilianAmazonia will be maintained. Carbon in protected areas hasstrategic value for environmental conservation and for mitiga-tion of climate change because these areas are under lower riskof being emitted to the atmosphere than carbon stored in veg-etation located outside of protected areas, although the effec-tiveness of protected areas varies.

In the present study a simplified multiscale atmosphere–ocean coupled model for the tropical interactions among synoptic, intraseasonal, and interannual scales is developed. Two nonlinear equatorial β-plane shallow-water equations are considered: one for the ocean and the other for the atmosphere. The nonlinear terms are the intrinsic advective nonlinearity and the air–sea coupling fluxes. To mimic the main differences between the fast atmosphere and the slow ocean, suitable anisotropic multispace/multitime scalings are applied, yielding a balanced synoptic–intraseasonal–interannual–El Niño (SInEN) regime. In this distinguished balanced regime, the synoptic scale is the fastest atmospheric time scale, the intraseasonal scale is the intermediate air–sea coupling time scale (common to both fluid flows), and El Niño refers to the slowest interannual ocean time scale. The asymptotic SInEN equations reveal that the slow wave amplitude evolution depends on both types of nonlinearities. Analytic solutions of the reduced SInEN equations for a single atmosphere–ocean resonant triad illustrate the potential of the model to understand slow-frequency variability in the tropics. The resonant nonlinear wind stress allows a mechanism for the synoptic-scale atmospheric waves to force intraseasonal variability in the ocean. The intraseasonal ocean temperature anomaly coupled with the atmosphere through evaporation forces synoptic and intraseasonal atmospheric variability. The wave–convection coupling provides another source for higher-order atmospheric variability. Nonlinear interactions of intraseasonal ocean perturbations may also force interannual oceanic variability. The constrains that determine the establishment of the atmosphere–ocean resonant coupling can be viewed as selection rules for the excitation of intraseasonal variability (MJO) or even slower interannual variability (El Niño).

Hourly data of CO2 fugacity (fCO2) at 8°N-38°W were analyzed from 2008 to 2011. Analyses of wind, rainfall, temperature and salinity data from the buoy indicated two distinct seasonal periods. The first period (January to July) had a mean fCO2 of 378.9 μatm (n = 7512). During this period, in which the study area was characterized by small salinity variations, the fCO2 is mainly controlled by sea surface temperature (SST) variations (fCO2 = 24.4*SST-281.1, r2 = 0.8). During the second period (August-December), the mean fCO2 was 421.9 μatm (n = 11571). During these months, the region is subjected to the simultaneous action of (a) rainfall induced by the presence of the Intertropical Convergence Zone (ITCZ); (b) arrival of fresh water from the Amazon River plume that is transported to the east by the North Equatorial Countercurrent (NECC) after the retroflection of the North Brazil Current (NBC); and (c) vertical input of CO2-rich water due to Ekman pumping. The data indicated the existence of high-frequency fCO2 variability (periods less than 24 h). This high variability is related to two different mechanisms. In the first mechanism, fCO2 increases are associated to rapid increases in SST and are attributed to the diurnal cycle of solar radiation. In addition, low wind speed contributes to SST rising by inhibiting vertical mixing. In the second mechanism, fCO2 decreases are associated to SSS decreases caused by heavy rainfall.

The crossbreeding of two or more breeds from the Bos taurus and Bos indicus species is an alternative for obtaining high-quality meat from animals adapted to tropical climates. Quality and sensory attributes of beef, mainly its tenderness and flavour, are very important with regard to the consumer’s point of view. This study aimed to evaluate the physico-chemical and sensory characteristics of crossbred young bulls and heifers, the offspring of Angus or Limousin bulls and 1/2 Angus + 1/2 Nellore or 1/2 Simental + 1/2 Nellore cows that were finished on feedlot or pasture. Meat quality traits (pH, colour, cooking loss, water holding capacity and shear force) and sensory parameters (characteristic beef aroma/flavour intensity, strange aroma/flavour intensity, tenderness and juiciness descriptive attributes, flavour, texture (tenderness) and overall acceptance) were evaluated. The genetic group had an effect on the beef pH, but it was not as relevant as the effect of the combination between the production system and the sex or genetic group, which affected many of the quality and sensory traits.

To reduce uncertainty regarding the contribution of continental shelf areas in low latitude regions to the air-sea CO2 exchange, more data are required to understand the carbon turnover in these regions and cover gaps in coverage. For the first time, inorganic carbon and alkalinity were measured along a cross-shelf transect off the coast of Maranhão (North Brazil) in 9 cruises spawning from April 2013 to September 2014. On the last 4 transects, dissolved organic matter and nutrients were also measured. The highest inorganic and organic carbon concentrations are observed close to land. As a result of low productivity and significant remineralization, heterotrophy dominates along the transect throughout the year. Although the temporal variability is significantly reduced at the offshore station with carbon concentrations decreasing seaward, the fugacity of CO2 (fCO2) at this station remains significantly higher, especially during the wet season, than the open ocean values measured routinely by a merchant ship further west. Overall, the continental shelf is a weak source of CO2 to the atmosphere throughout the year with an annual mean flux of 1.81±0.84 mmol m−2 d−1. The highest magnitudes of fCO2 are observed during the wet season when the winds are the weakest. As a result, the CO2 flux does not show a clear seasonal pattern. Further offshore, fCO2 is significantly lower than on the continental shelf. However, the oceanic CO2 flux, with an annual mean of 2.32±1.09 mmol m−2 d−1, is not statistically different from the CO2 flux at the continental shelf because the wind is stronger in the open ocean.

From the mid twentieth century onwards, the developed and many developing countries experienced rapid changes in their agricultural activity. This was characterized by intensification, supported by mechanization and the use of synthetic fertilizers, chemicals for pest control, together with concentration and specialization, which resulted in enterprises of larger scale focusing on specific products motivated principally by a global market of commodities.

Land-use change (LUC) in Brazil has important implications on global climate change, ecosystem services and biodiversity, and agricultural expansion plays a critical role in this process. Concerns over these issues have led to the need for estimating the magnitude and impacts associated with that, which are increasingly reported in the environmental assessment of products. Currently, there is an extensive debate on which methods are more appropriate for estimating LUC and related emissions and regionalized estimates are lacking for Brazil, which is a world leader in agricultural production (e.g. food, fibres and bioenergy). We developed a method for estimating scenarios of past 20-year LUC and derived CO₂ emission rates associated with 64 crops, pasture and forestry in Brazil as whole and in each of its 27 states, based on time-series statistics and in accordance with most used carbon-footprinting standards. The scenarios adopted provide a range between minimum and maximum rates of CO₂ emissions from LUC according to different possibilities of land-use transitions, which can have large impacts in the results. Specificities of Brazil, like multiple cropping and highly heterogeneous carbon stocks, are also addressed. The highest CO₂emission rates are observed in the Amazon biome states and crops with the highest rates are those that have undergone expansion in this region. Some states and crops showing large agricultural areas have low emissions associated, especially in southern and eastern Brazil. Native carbon stocks and time of agricultural expansion are the most decisive factors to the patterns of emissions. Some implications on LUC estimation methods and standards and on agri-environmental policies are discussed.