6 resultados para seasons of seeding
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
The biomonitoring technique for water quality in water bodies has been incorporated increasingly in management of the natural resources, using mainly indices of its aquatic community characteristics. In Brazil the first efforts to use this technique was restricted to the South and the Midwest region of this country. Located in the northeast region, this study was conducted at Rio Grande do Norte state and had as main objective the assessment of water quality in the Piranhas-Açu river using benthic macroinvertebrates community as biological indicators. Thus, were applied two biotic indices, the BMWP (Biological Monitoring Working Party score system) and the IBF (Family Biotic Index). According the requirements of these indices, two periods of sampling were determined as basic methodology, in dry seasons of 2006 and 2007. The sampling sites were around the municipalities of Açu, Ipanguaçu, Alto do Rodrigues and Pendências. Physical-chemical measurements; a protocol of rapid assessment of diversity of habitats, and determination of the degree of tolerance of each taxon to organic pollution were also performed. The most abundant organisms found in the river were tolerant with the prevalence of Chironomidae (Diptera) and Melanoides tuberculata. This results, together with those ones got in indices application, showed a considerable organic pollution in the four sample places and the reaches were classified as modified to impacted. According to the used indices, this study suggest that this river have significant alteration in the biotic community and water quality on the organic pollution, and this fact, occurs in the reach of the river further downstream, where were expected a good water quality. Considering these results, measures aiming the conservation of this water body are needed regarding as it is inserted into a fragile ecosystem with dry season phenomenon, and the water of this river has extremely importance for the local economy
Resumo:
The dams are limnic ecosystems of great importance for its multiple uses, among them, water supply for the public and to culture of artisanal fish are most relevant. The aim of the present study is to evaluate the physical-chemical characteristics and the phytoplankton community in two chosen sites (Point 1 littoral zone of point source; Point 2 pelagic zone of non-point source) of the Minister João Alves dam, which is also known as Boqueirão de Parelhas/RN. This represents the spatial distribution of the phytoplankton species in order to understand any possible alterations of the water quality and the phytoplankton composition in relation to the water quality originating from the impact of the tilapia, Oreochromis niloticus, culture. The study period also encompasses temporal variations exhibited in two seasons of an annual cycle, one during the dry season (Oct, Nov and Dec of 2008 and Jan of 2009), and the other rainy season (Mar, Apr, May and June of 2008) to extend the observation. The physicalchemical parameters, such as pH, temperature, electrical conductivity, concentration of dissolved oxygen were measured in situ and the values of the inorganic nutrients (nitrate, ammonium and orto-phosfato) and chlorophyll in the laboratory. The quali-quantitative analyses of the phytoplankton had been carried through sedimentation technique and the enumeration of the random of 400 cells, colonies and filaments counted using Sedgwick-Rafter counting chamber. The results of pH varied widely from the acidic to alkaline range with the minimum of 5.8 (± 0.8) and the maximum of 9.2 (± 0.7-0.8), at point 1 and 2. The dissolved oxygen content was higher in the rainy period than that in the dry period. The maximum electrical conductivity was of 1409 μScm-1 in point 1 and 431 minim of μScm-1, in point 2. There was a considerable alteration in the levels of inorganic nutrients such as nitrate-nitrogen, ammoniacal nitrogen and orthophosphate during the two cycles of study period. Phytoplankton assemblages presented a picture of alternate dominance among species Cyanobacteria, Bacillariophyceae and Chlorophyceae. The trophic state index diagnosed to the category of mesotrophic, which is based on the values of chlorophyll, total phosphorus and Secchi-disc measurements. The wind driven turbulence of the water column and the fresh inflow of water (flushing and dilution) during rainy season acted as constraint and did-not allow an exaggerated growth of the species of cyanobacteria. On the basis of the present we conclude that the culture of tilapias in cage-culture fails to produce pollution load that could compromise the quality of the water of the dam, probably be due to small dimension of the culture in relation to the size, volume of the water and the reservoir capacity support its own environment
Resumo:
This study aimed to evaluate the performance and profitability of Canindé goats kept under semi-intensive management in mix farming system. 84 animals were used, being 81 does e three bucks.. The means of fertility rate at parturition, prolificacy and percentages of pregnant, kid survival and reproductive rate were compared by Tukey test at significance level of 5.0%. The kid weights from birth to weaning were submitted to variance analysis considering sex and birth type and the means were compared by Tukey test at 5.0% of significance. The percentages of fertility rate by ultrassographic were 91.36 and parturition 74.84. The prolificacy was 1.53. Independently of sex the mortality rate of kids from birth to weaning was 12.3. The average weights of offspring were 2.11 and 1.92 kg and 6.74 and 6.84 kg for male and female offspring at birth and weaning, in this order. The average weights of kids, meaning PN, P28, P56, P63, in the first season of kidding were 2.11 ± 0.46 kg, 3.63 ± 1.04 kg, 5.96 ± 158 kg and 6.74 ± 1.79 kg. There was significant differences (P<0,05) only to birth weight of kids sons of buck 135. However, the fertility at parturition for first and second breeding seasons (BS) were 87.65 and 62.96, respectively (P<0.05). The prolificacy was 1.58 and 1.47 to first and second BS in this order. The percentages of offspring survival from birth to weaning, to first and second BS were 92.86 and 80.00, respectively. From the first BS the reproduction rate was 1.28 while in the second was 0.74. After weaning the duration of lactation was 104 days to first breeding parturition and 38 days in the second one. The total milk production was 853.50 kg. The kids weight gain was influenced by season of year, wet and dry and buck (P<0.05). Were concluded that the seasons of year when breeding season and parturition occur strongly affected the productive performance and profitability of production system
Resumo:
Intense precipitation events (IPE) have been causing great social and economic losses in the affected regions. In the Amazon, these events can have serious impacts, primarily for populations living on the margins of its countless rivers, because when water levels are elevated, floods and/or inundations are generally observed. Thus, the main objective of this research is to study IPE, through Extreme Value Theory (EVT), to estimate return periods of these events and identify regions of the Brazilian Amazon where IPE have the largest values. The study was performed using daily rainfall data of the hydrometeorological network managed by the National Water Agency (Agência Nacional de Água) and the Meteorological Data Bank for Education and Research (Banco de Dados Meteorológicos para Ensino e Pesquisa) of the National Institute of Meteorology (Instituto Nacional de Meteorologia), covering the period 1983-2012. First, homogeneous rainfall regions were determined through cluster analysis, using the hierarchical agglomerative Ward method. Then synthetic series to represent the homogeneous regions were created. Next EVT, was applied in these series, through Generalized Extreme Value (GEV) and the Generalized Pareto Distribution (GPD). The goodness of fit of these distributions were evaluated by the application of the Kolmogorov-Smirnov test, which compares the cumulated empirical distributions with the theoretical ones. Finally, the composition technique was used to characterize the prevailing atmospheric patterns for the occurrence of IPE. The results suggest that the Brazilian Amazon has six pluvial homogeneous regions. It is expected more severe IPE to occur in the south and in the Amazon coast. More intense rainfall events are expected during the rainy or transitions seasons of each sub-region, with total daily precipitation of 146.1, 143.1 and 109.4 mm (GEV) and 201.6, 209.5 and 152.4 mm (GPD), at least once year, in the south, in the coast and in the northwest of the Brazilian Amazon, respectively. For the south Amazonia, the composition analysis revealed that IPE are associated with the configuration and formation of the South Atlantic Convergence Zone. Along the coast, intense precipitation events are associated with mesoscale systems, such Squall Lines. In Northwest Amazonia IPE are apparently associated with the Intertropical Convergence Zone and/or local convection.
Resumo:
The biomonitoring technique for water quality in water bodies has been incorporated increasingly in management of the natural resources, using mainly indices of its aquatic community characteristics. In Brazil the first efforts to use this technique was restricted to the South and the Midwest region of this country. Located in the northeast region, this study was conducted at Rio Grande do Norte state and had as main objective the assessment of water quality in the Piranhas-Açu river using benthic macroinvertebrates community as biological indicators. Thus, were applied two biotic indices, the BMWP (Biological Monitoring Working Party score system) and the IBF (Family Biotic Index). According the requirements of these indices, two periods of sampling were determined as basic methodology, in dry seasons of 2006 and 2007. The sampling sites were around the municipalities of Açu, Ipanguaçu, Alto do Rodrigues and Pendências. Physical-chemical measurements; a protocol of rapid assessment of diversity of habitats, and determination of the degree of tolerance of each taxon to organic pollution were also performed. The most abundant organisms found in the river were tolerant with the prevalence of Chironomidae (Diptera) and Melanoides tuberculata. This results, together with those ones got in indices application, showed a considerable organic pollution in the four sample places and the reaches were classified as modified to impacted. According to the used indices, this study suggest that this river have significant alteration in the biotic community and water quality on the organic pollution, and this fact, occurs in the reach of the river further downstream, where were expected a good water quality. Considering these results, measures aiming the conservation of this water body are needed regarding as it is inserted into a fragile ecosystem with dry season phenomenon, and the water of this river has extremely importance for the local economy
Resumo:
The dams are limnic ecosystems of great importance for its multiple uses, among them, water supply for the public and to culture of artisanal fish are most relevant. The aim of the present study is to evaluate the physical-chemical characteristics and the phytoplankton community in two chosen sites (Point 1 littoral zone of point source; Point 2 pelagic zone of non-point source) of the Minister João Alves dam, which is also known as Boqueirão de Parelhas/RN. This represents the spatial distribution of the phytoplankton species in order to understand any possible alterations of the water quality and the phytoplankton composition in relation to the water quality originating from the impact of the tilapia, Oreochromis niloticus, culture. The study period also encompasses temporal variations exhibited in two seasons of an annual cycle, one during the dry season (Oct, Nov and Dec of 2008 and Jan of 2009), and the other rainy season (Mar, Apr, May and June of 2008) to extend the observation. The physicalchemical parameters, such as pH, temperature, electrical conductivity, concentration of dissolved oxygen were measured in situ and the values of the inorganic nutrients (nitrate, ammonium and orto-phosfato) and chlorophyll in the laboratory. The quali-quantitative analyses of the phytoplankton had been carried through sedimentation technique and the enumeration of the random of 400 cells, colonies and filaments counted using Sedgwick-Rafter counting chamber. The results of pH varied widely from the acidic to alkaline range with the minimum of 5.8 (± 0.8) and the maximum of 9.2 (± 0.7-0.8), at point 1 and 2. The dissolved oxygen content was higher in the rainy period than that in the dry period. The maximum electrical conductivity was of 1409 μScm-1 in point 1 and 431 minim of μScm-1, in point 2. There was a considerable alteration in the levels of inorganic nutrients such as nitrate-nitrogen, ammoniacal nitrogen and orthophosphate during the two cycles of study period. Phytoplankton assemblages presented a picture of alternate dominance among species Cyanobacteria, Bacillariophyceae and Chlorophyceae. The trophic state index diagnosed to the category of mesotrophic, which is based on the values of chlorophyll, total phosphorus and Secchi-disc measurements. The wind driven turbulence of the water column and the fresh inflow of water (flushing and dilution) during rainy season acted as constraint and did-not allow an exaggerated growth of the species of cyanobacteria. On the basis of the present we conclude that the culture of tilapias in cage-culture fails to produce pollution load that could compromise the quality of the water of the dam, probably be due to small dimension of the culture in relation to the size, volume of the water and the reservoir capacity support its own environment
