Alterações microbianas e químicas de um gleissolo sob macaubeiras nativas em função da variação sazonal e espacial / Microbial and chamical changes in gleysol under native macauba palms by the spatial and seasonal variations

A macaúba (Acrocomia aculeata) é uma alternativa para a produção de biodiesel e, consorciada com pastagem, pode auxiliar na recuperação de áreas degradadas. O objetivo deste trabalho foi estudar as alterações nos atributos microbiológicos, na matéria orgânica e no N total do solo, em função da variação sazonal e espacial em um Gleissolo sob maciço de macaubeiras nativas, no Cerrado. O estudo observacional foi realizado na região de Planaltina de Goiás, na Fazenda Agropecuária Santa Fé. Foram selecionadas dez árvores em uma mata com macaubeiras nativas no bioma cerrado. A coleta de solo foi realizada na camada de 0 a 10 centímetros de profundidade, sob uma linha horizontal, imaginária, traçada a partir da base do caule das macaubeiras. As amostras de solo foram coletadas a 50, 150 e 250 centímetros de distância do caule da palmeira, durante o verão chuvoso (março de 2010) e inverno seco (julho 2010). Para a avaliação estatística das variáveis observadas, utilizou-se um modelo misto. As médias das variáveis observadas foram submetidas a testes para verificar se seguiam a distribuição normal, e a homogeneidade de variâncias. Em seguida, os dados foram submetidos ao teste F e as médias foram comparadas pelo teste t. Os atributos carbono microbiano (Cmic), respiração basal (RB), quociente metabólico (qCO2), a matéria orgânica do solo (MOS) e a relação C/N do solo são sensíveis à variação sazonal e espacial em mata de macaubeiras no Cerrado. O nitrogênio total (NT) foi sensível à variação espacial. A microbiota presente no solo sob macaubal se manteve mais equilibrada durante o período seco, apresentando maiores teores de carbono microbiano e quociente microbiano e menor quociente metabólico e relação C/N do solo.

Macauba palm (Acrocomia aculeata) is an alternative for biodiesel production and intercropped with pastures, can be used to recover degraded areas. The aim of this paper was to study the alterations of microbial and soil organic matter and total N, in function of sazonal and spatial variation of a Gleysol, under native macauba palms (Acrocomia aculeata). This observational study took place in Santa Fe Agropecuaria farm, in the region of Planaltina de Goias, State of Goias. Ten trees were selected from a native forest containing macauba palms. Soil samples were then taken at a depth of 0 - 10 cm from a horizontal imaginary line, drawn from the macauba`s palm trunk. Soil samples were taken from a 50, 150 and 250 cm distance from the trunk, during the wet summer (March, 2010) and the dry winter (July, 2010). The mixed model was used in order to evaluate the observational study. The observational means were submitted to testing to evaluate if their values followed a normal distribution and to test homogeneity of variance. Subsequently, data were submitted to the F-test and the means were compared using the t-test. The Cmic, RB, qCO2 and the MO and soil C/N have been found to be sensitive to seasonal and spatial variation in the native forest of macauba palms, in the Cerrado. The NT showed to be sensitive to spatial variation. The microbiota present in the soil under macauba palms was more efficient and maintained a higher equilibrium during the dry winter, presenting higher values of Cmic and Cmic:Corg, and lower values of qCO2 and soil C/N ratio.

Calidad bacteriológica de aguas en piscinas públicas y privadas de la ciudad de Cumaná, estado Sucre, Venezuela / Bacteriological quality of water of public and private pools of the city of Cumaná, Sucre state, Venezuela

Para evaluar la calidad bacteriológica de aguas de piscinas en la ciudad de Cumaná, estado Sucre, Venezuela, se recolectaron muestras de agua en 1 piscina pública y 4 privadas, codificadas de la A a la E; se tomaron 2 muestras semanales durante 2 meses, antes y después de la limpieza. Se determinó pH, temperatura y cloro residual; los aerobios mesófilos por contaje en placas, el Número Más Probable (NMP) para coliformes totales (CT) y fecales (CF) e identificación bacteriana por métodos convencionales. El pH osciló entre 6,8 y 7,3, la temperatura de 29 a 31ºC y el cloro residual de 0,3 a 0,5 mg/L. El contaje más elevado de bacterias mesófilas se obtuvo en B con 6x10 2 UFC/mL, y el más bajo en C con 3x10 2 UFC/mL. En relación al NMP, antes de la limpieza, el valor más alto se obtuvo en D con 2,8x10 3 CT/100 ml; E mostró el valor más alto de CF /100 ml. Después de la limpieza B mostró el valor más alto de CT ubicándose en 9,3mLx10 2 y los valores más alto de CF para D y E en 3x10 2 . Los valores de CF antes y después de la limpieza superan lo establecido por la normativa Venezolana (0 NMP/100mL). Estadísticamente, no se evidenciaron diferencias significativas entre las piscinas para CT y CF antes y después de la limpieza. Las bacterias Gramnegativas predominaron, en E (84,21%) y B (71,92%), Klebsiella pneumoniae, Escherichia coli y Pseudomonas aeruginosa. A presentó mayor número de aislados Grampositivos (44,44%), identificándose Staphylococcus epidermidis y Enterococcus faecalis. Estos resultados indican una constante contaminación bacteriana y riesgo sanitario.

To evaluate the bacteriological quality of water pools in the city of Cumaná, Sucre state, Venezuela, water samples were collected in 1 public and 4 private pools, coded A to E, respectively, 2 samples were taken weekly for 2 months before and after a pool cleaning process. We determined pH, temperature and residual chlorine, aerobic mesophilic for total plate count, the Most Probable Number (MPN) for total coliforms (TC) and fecal (FC) and bacterial identification by conventional methods. The pH in the samples ranged between 6.8 and 7.3, temperature of 29 to 31ºC and chlorine residual of 0.3 to 0.5 mg/L The highest count of aerobic mesophilic bacteria was obtained in B with 6x10 2 . CFU/mL. In relation to the MPN, before cleaning, the CT highest value was obtained in D with 2.8 x10 3 and CT/100mL, E showed the highest CF value with 6x10 2 CF/100mL. After cleaning, the results for B indicated the CT highest values, 9.3 x10 2 CT/100mL, and in D and E the results had the CF highest values, 3x10 2 CF/100 mL. CF values in the samples before and after cleaning exceed the standards established by Venezuela (0 NMP/100mL). Statistically, no significant differences were found between pools for CT and CF before and after cleaning. Gram-negative bacteria predominated, being more frequent in E (84.21%) and B (71.92%), mainly, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa. Sample A had more isolated Gram-positive (44.44%), identified as Staphylococcus epidermidis and Enterococcus faecalis. These results indicate a constant bacterial contamination and health risk.