Paulo José Duarte-Neto

Infield greenhouse gas emissions from sugarcane soils in Brazil: effects from synthetic and organic fertilizer application and crop trash accumulation

Bioethanol from sugarcane is becoming an increasingly important alternative energy source worldwide as it is considered to be both economically and environmentally sustainable. Besides being produced from a tropical perennial grass with high photosynthetic efficiency, sugarcane ethanol is commonly associated with low N fertilizer use because sugarcane from Brazil, the worlds largest sugarcane producer, has a low N demand. In recent years, several models have predicted that the use of sugarcane ethanol in replacement to fossil fuel could lead to high greenhouse gas (GHG) emission savings. However, empirical data that can be used to validate model predictions and estimates from indirect methodologies are scarce, especially with regard to emissions associated with different fertilization methods and agricultural management practices commonly used in sugarcane agriculture in Brazil. In this study, we provide in situ data on emissions of three GHG (CO2, N2O, and CH4) from sugarcane soils in Brazil and assess how they vary with fertilization methods and management practices. We measured emissions during the two main phases of the sugarcane crop cycle (plant and ratoon cane), which include different fertilization methods and field conditions. Our results show that N2O and CO2 emissions in plant cane varied significantly depending on the fertilization method and that waste products from ethanol production used as organic fertilizers with mineral fertilizer, as it is the common practice in Brazil, increase emission rates significantly. Cumulatively, the highest emissions were observed for ratoon cane treated with vinasse (liquid waste from ethanol production) especially as the amount of crop trash on the soil surface increased. Emissions of CO2 and N2O were 6.9 kg ha−1 yr−1 and 7.5 kg ha−1 yr−1, respectively, totaling about 3000 kg in CO2 equivalent ha−1 yr−1.

Frozen chicken for wild fish: nutritional transition in the Brazilian Amazon region determined by carbon and nitrogen stable isotope ratios in fingernails.

Amazonian populations are experiencing dietary changes characteristic of the nutrition transition. However, the degree of change appears to vary between urban and rural settings. To investigate this process, we determined carbon and nitrogen stable isotope ratios in fingernails and dietary intake of Amazonian populations living along a rural to urban continuum along the Solimões River in Brazil.

Stocks of carbon and nitrogen and partitioning between above- and belowground pools in the Brazilian coastal Atlantic Forest elevation range

We estimated carbon and nitrogen stocks in aboveground biomass (AGB) and belowground biomass (BGB) along an elevation range in forest sites located on the steep slopes of the Serra do Mar on the north coast of the State of São Paulo, southeast Brazil. In elevations of 100 m (lowland), 400 m (submontane), and 1000 m (montane) four 1-ha plots were established, and above- (live and dead) and belowground (live and dead) biomass were determined. Carbon and nitrogen concentrations in each compartment were determined and used to convert biomass into carbon and nitrogen stocks. The carbon aboveground stock (CAGB) varied along the elevation range from approximately 110 to 150 Mg·ha−1, and nitrogen aboveground stock (NAGB), varied from approximately 1.0 to 1.9 Mg·ha−1. The carbon belowground stock (CBGB) and the nitrogen belowground stock (NBGB) were significantly higher than the AGB and varied along the elevation range from approximately 200–300 Mg·ha−1, and from 14 to 20 Mg·ha−1, respectively. Finally, the total carbon stock (CTOTAL) varied from approximately 320 to 460 Mg·ha−1, and the nitrogen total stock (NTOTAL) from approximately 15 to 22 Mg·ha−1. Most of the carbon and nitrogen stocks were found belowground and not aboveground as normally found in lowland tropical forests. The above- and belowground stocks, and consequently, the total stocks of carbon and nitrogen increased significantly with elevation. As the soil and air temperature also decreased significantly with elevation, we found a significantly inverse relationship between carbon and nitrogen stocks and temperature. Using this inverse relationship, we made a first approach estimate that an increase of 1°C in soil temperature would decrease the carbon and nitrogen stocks in approximately 17 Mg·ha−1 and 1 Mg·ha−1 of carbon and nitrogen, respectively.

Permeability of riparian forest strips in agricultural, small subtropical watersheds in south-eastern Brazil

If riparian buffer zones are ineffective in preventing C4 plant carbon from upland areas reaching the stream sediment, the composition of stream fauna can be significantly altered. The permeability of riparian forest strips in agricultural, small subtropical watersheds in south-eastern Brazil was measured in nine watersheds categorised according to the predominant land cover of the legally required 30-m buffer riparian zone. Four watersheds with well preserved riparian forest along the 30-m buffer zone were designated as FOREST watersheds; three watersheds, with a predominance of C4 grasses from sugarcane to pasture, mixed with preserved riparian forests, were designated MIXED watersheds; and two watersheds were termed PASTURE-SUGAR because their entire 30-m buffer zone was covered by C4 plants. Stable carbon (δ13C) isotopes were used as tracers of upland C4 carbon in sediments, suspended particulate organic carbon, terrestrial and aquatic invertebrates and two species of neotropical fish. Although the intact 30-m buffer zone of riparian forests did not entirely prevent the input of C4 to the river environment and food web, there was a significant increase in C4 carbon in those watersheds where the buffer zone was not covered by riparian forests. These findings emphasise the importance of riparian forests in mitigating disturbance in streams and support efforts to preserve such riparian corridors.

A critical appraisal of marginal increment analysis for assessing temporal periodicity in band formation among tropical sharks

Marginal increment ratio (MIR) analyses were conducted as part of age and growth studies on three coastal/semi-oceanic species, the smalltail shark, Carcharhinus porosus, daggernose shark, Isogomphodon oxyrhynchus and the night shark C. signatus, and two ubiquitous oceanic species, blue shark, Prionace glauca, and whitetip shark, C. longimanus, collected in equatorial areas off Brazil with the aim of establishing the interspecific temporal nature of vertebral band formation. Monthly variations in marginal bands were analyzed using mean MIR on the entire sample as the standard method for all species. Reasons for the inconclusive results regarding these species are critically appraised with respect to three main sources of bias that are associated with marginal increment analysis (MIA). Bias due to insufficient sample sizes may have hampered the analysis for I. oxyrhynchus and C. longimanus due to movements from shallow waters to seamounts for the former species and to extensive migrations for the latter. Bias due to data collection over too long a period is thought to have influenced monthly mean MIR for C. porosus and P. glauca. For the latter, individuals from different age groups lay down rings at different times, making band deposition inconsistent between individuals. Finally, bias due to births occurring over too long a period was the prevalent cause for confounding MIR values among I. oxyrhynchus and C. signatus species, whose birth period lasts several months and leads to different ages within the same cohort. Other approaches used for MIA in C. signatus and P.␣glauca led to distinct times of band formation by age-groups when compared to MIR applied on the entire sample. For the daggernose shark, delays in events related to the reproductive cycle from one year to the next were also found to confound MIR. Requirements for the use of MIR implying a band width that displays a sinusoidal cycle when temporally plotted (month or season) were not fulfilled for any of these species. The method has been of little utility for detecting the periodicity of band deposition among sharks from the tropics. This emphasizes the need for supplying information on the temporal periodicity of pair deposition based on other methods.

Age and growth estimation of bigeye tuna, Thunnus obesus (Teleostei: Scombridae) in the southwestern Atlantic

The purpose of the current study was to supply the first information on age and growth for Thunnus obesus caught in the equatorial south-western Atlantic using dorsal spines, an approach that has been successfully employed for ageing tuna species. The study was conducted using a multi-model inference based on information theory for back-calculated and observed length-at-age data. Uncertainty associated with the parameter estimation was verified and results were compared to other accounts on the species, considering both the statistical and methodological contexts. Samples were collected in Natal city (Rio Grande do Norte State, Brazil) from February 1999 to January 2000, of tuna vessels and from surveys, aimed at providing information on the Brazilian Exclusive Economic Zone (EEZ) in the area around Sao Pedro and Sao Paulo Archipelago. Validation using marginal increment indicated that one ring is deposited per year. Mean length-at-age ranged of 54.3 to 177.5 cm (fork length) for ages 1 to 9 years. Von Bertalanffy, Richards, and Gompertz models were considered suitable for the bigeye tuna. Hence, the model-averaged asymptotic length ¯L∞ was estimated. The averaged model generated in the present study by back-calculation was considered appropriate for describing the growth of T. obesus.

Land cover changes and greenhouse gas emissions in two different soil covers in the Brazilian Caatinga

The Caatinga biome covers an area of 844,453km(2) and has enormous endemic biodiversity, with unique characteristics that make it an exclusive Brazilian biome. It falls within the earths tropical zone and is one of the several important ecoregions of Brazil. This biome undergoes natural lengthy periods of drought that cause losses in crop and livestock productivity, having a severe impact on the population. Due to the vulnerability of this ecosystem to climate change, livestock has emerged as the main livelihood of the rural population, being the precursor of the replacement of native vegetation by grazing areas. This study aimed to measure GHG emissions from two different soil covers: native forest (Caatinga) and pasture in the municipality of São João, Pernambuco State, in the years 2013 and 2014. GHG measurements were taken by using static chamber techniques in both soil covers. According to a previous search, so far, this is the first study measuring GHG emissions using the static chamber in the Caatinga biome. N2O emissions ranged from -1.0 to 4.2mgm(-2)d(-1) and -1.22 to 3.4mgm(-2)d(-1) in the pasture and Caatinga, respectively, and they did not significantly differ from each other. Emissions were significantly higher during dry seasons. Carbon dioxide ranged from -1.1 to 14.1 and 1.2 to 15.8gm(-2)d(-1) in the pasture and Caatinga, respectively. CO2 emissions were higher in the Caatinga in 2013, and they were significantly influenced by soil temperature, showing an inverse relation. Methane emission ranged from 6.6 to 6.8 and -6.0 to 4.8mgm(-2)d(-1) in the pasture and Caatinga, respectively, and was significantly higher only in the Caatinga in the rainy season of 2014. Soil gas fluxes seemed to be influenced by climatic and edaphic conditions as well as by soil cover in the Caatinga biome.

Uso das redes neurais artificiais na aplicação de metodologia para alocação de recursos da saúde

OBJECTIVE To describe the construction of a factor of allocation of financial resources, based on the populations health needs. METHODS Quantitative study with data collected from public databases referring to the state of Pernambuco, Northeastern Brazil, between 2000 and 2010. Variables which reflected epidemiological, demographic, socio-economic and educational processes were selected in order to create a factor of allocation which highlighted the health needs of the population. The data sources were: SUS (Brazilian Unified Health System) Department of Computer Science, Atlas of Human Development in Brazil, IBGE (Brazilian Institute of Geography and Statistics), Information System on Public Health Budgets, National Treasury and data from the Pernambuco Health Secretariat between 2000 and 2010. Pearsons coefficient was used to assess linear correlation and the factor of allocation was calculated using analysis by artificial neural networks. The quartiles of the municipalities were defined according to their health needs. RESULTS The distribution shown here highlights that all the coastal region, a good part of the Mata Norte and Mata Sul regions and the Agreste Setentrional and Agreste Central regions are in Quartile 1, that which has the largest number of municipalities. The Agreste Meridional region had municipalities in all of the quartiles. In the Pajeú/Moxotó region, many of the municipalities were in Quartile 1. Similar distribution was verified in the Sertão Central region. In the Araripe region, the majority of the municipalities were in Quartiles 3 or 4 and the São Francisco region was divided between Quartiles 1, 2 and 3. CONCLUSIONS The factor of allocation grouped together municipalities of Pernambuco according to variables related to public health needs and separated those with extreme needs, requiring greater financial support, from those with lesser needs.OBJETIVO: Descrever a construcao de fator de alocacao de recursos financeiros com base na necessidade em saude da populacao. METODOS: Estudo quantitativo, com dados coletados em bases de dominio publico, referentes ao estado de Pernambuco nos anos entre 2000 e 2010. Foram selecionadas variaveis que refletissem os indicadores epidemiologicos, demograficos, socioeconomicos e educacionais para compor um fator de alocacao que apontasse as necessidades de saude da populacao. As fontes pesquisadas foram: Departamento de Informatica do Sistema Unico de Saude, Atlas do Desenvolvimento Humano no Brasil, Instituto Brasileiro de Geografia e Estatistica, Sistema de Informacoes sobre Orcamentos Publicos em Saude, Tesouro Nacional e dados da Secretaria Estadual de Saude de Pernambuco de 2000 a 2010, de acordo com a disponibilidade da informacao mais recente. Foi realizada a correlacao linear de Pearson e, para o calculo do fator de alocacao, a analise pelas Redes Neurais Artificiais. Os quartis dos municipios foram definidos segundo as necessidades em saude. RESULTADOS: A distribuicao apresentada aponta a Regiao Litorânea e boa parte da Regiao da Mata Norte e Sul e do Agreste Setentrional e Central situados no Quartil 1, este com o maior numero de municipios. O Agreste Meridional teve municipios em todos os quartis. Na Regiao do Pajeu/Moxoto, grande parte dos municipios esteve no Quartil 1. Semelhante distribuicao foi verificada no Sertao Central. No Araripe, a maioria dos municipios esteve nos Quartis 3 ou 4 e a Regiao do Sao Francisco ficou dividida entre os Quartis 1, 2 e 3. CONCLUSOES: O fator de alocacao agregou os municipios pernambucanos, por agrupar variaveis que sao relacionadas com as necessidades em saude da populacao, e separou os que possuem extremas necessidades de maior aporte financeiro daqueles que precisam com menor intensidade.

Use of artificial neural networks in applying methodology for allocating health resources

OBJECTIVE To describe the construction of a factor of allocation of financial resources, based on the populations health needs. METHODS Quantitative study with data collected from public databases referring to the state of Pernambuco, Northeastern Brazil, between 2000 and 2010. Variables which reflected epidemiological, demographic, socio-economic and educational processes were selected in order to create a factor of allocation which highlighted the health needs of the population. The data sources were: SUS (Brazilian Unified Health System) Department of Computer Science, Atlas of Human Development in Brazil, IBGE (Brazilian Institute of Geography and Statistics), Information System on Public Health Budgets, National Treasury and data from the Pernambuco Health Secretariat between 2000 and 2010. Pearsons coefficient was used to assess linear correlation and the factor of allocation was calculated using analysis by artificial neural networks. The quartiles of the municipalities were defined according to their health needs. RESULTS The distribution shown here highlights that all the coastal region, a good part of the Mata Norte and Mata Sul regions and the Agreste Setentrional and Agreste Central regions are in Quartile 1, that which has the largest number of municipalities. The Agreste Meridional region had municipalities in all of the quartiles. In the Pajeú/Moxotó region, many of the municipalities were in Quartile 1. Similar distribution was verified in the Sertão Central region. In the Araripe region, the majority of the municipalities were in Quartiles 3 or 4 and the São Francisco region was divided between Quartiles 1, 2 and 3. CONCLUSIONS The factor of allocation grouped together municipalities of Pernambuco according to variables related to public health needs and separated those with extreme needs, requiring greater financial support, from those with lesser needs.OBJETIVO: Descrever a construcao de fator de alocacao de recursos financeiros com base na necessidade em saude da populacao. METODOS: Estudo quantitativo, com dados coletados em bases de dominio publico, referentes ao estado de Pernambuco nos anos entre 2000 e 2010. Foram selecionadas variaveis que refletissem os indicadores epidemiologicos, demograficos, socioeconomicos e educacionais para compor um fator de alocacao que apontasse as necessidades de saude da populacao. As fontes pesquisadas foram: Departamento de Informatica do Sistema Unico de Saude, Atlas do Desenvolvimento Humano no Brasil, Instituto Brasileiro de Geografia e Estatistica, Sistema de Informacoes sobre Orcamentos Publicos em Saude, Tesouro Nacional e dados da Secretaria Estadual de Saude de Pernambuco de 2000 a 2010, de acordo com a disponibilidade da informacao mais recente. Foi realizada a correlacao linear de Pearson e, para o calculo do fator de alocacao, a analise pelas Redes Neurais Artificiais. Os quartis dos municipios foram definidos segundo as necessidades em saude. RESULTADOS: A distribuicao apresentada aponta a Regiao Litorânea e boa parte da Regiao da Mata Norte e Sul e do Agreste Setentrional e Central situados no Quartil 1, este com o maior numero de municipios. O Agreste Meridional teve municipios em todos os quartis. Na Regiao do Pajeu/Moxoto, grande parte dos municipios esteve no Quartil 1. Semelhante distribuicao foi verificada no Sertao Central. No Araripe, a maioria dos municipios esteve nos Quartis 3 ou 4 e a Regiao do Sao Francisco ficou dividida entre os Quartis 1, 2 e 3. CONCLUSOES: O fator de alocacao agregou os municipios pernambucanos, por agrupar variaveis que sao relacionadas com as necessidades em saude da populacao, e separou os que possuem extremas necessidades de maior aporte financeiro daqueles que precisam com menor intensidade.

Comparison of microbial processing of Brachiaria brizantha, a C4 invasive species and a rainforest species in tropical streams of the Atlantic Forest of south-eastern Brazil

The breakdown of allochthonous organic matter is considered to be the main source of energy and nutrients for the majority of first-order streams. Thus, land-use change and riparian vegetation, such as deforestation and conversion of native forest to pasture lands, will lead to unwanted changes of the structure and function of aquatic ecosystems due to the disturbance of organic-matter supply. The C4 grasses, extensively used as forage in tropical regions, are poorly studied as important sources of allochthonous material because they are usually considered as a poor source of nutrients. Because the effects of land-use change on ecosystem functions are not fully known, we aimed to evaluate how such changes in riparian vegetation can affect nutrient cycling by means of measuring the decomposition rate of an abundant native C3 species and an exotic C4 grass species in first-order streams of the Atlantic Forest. Our results showed that C4 detritus decomposed faster than did C3 detritus, despite its lower nutrient concentration. This was likely to be due to the lower lignin concentration of the C4 species than the native C3 species. Lignin also influenced nutrient-loss dynamics of the C3 species, because it can interact with other cellular constituents and prevent the decomposition of most labile compounds. Our results supported the observation that the replacement of riparian vegetation alters breakdown rates and nutrient distributions, which may disrupt aquatic food webs.