Comunidades zooplanctônicas como bioindicadoras da qualidade da água de quatro reservatórios da região semi-árida do Rio Grande do Norte

The response of zooplankton assemblages to variations in the water quality of four man-made lakes, caused by eutrophication and siltation, was investigated by means of canonical correspondence analysis. Monte Carlo simulations using the CCA eingenvalues as test statistics revealed that changes in zooplankton species composition along the environmental gradients of trophic state and abiogenic turbidity were highly significant. The species Brachionus calyciflorus, Thermocyclops sp. and Argyrodiaptomus sp. were good indicators of eutrophic conditions while the species Brachionus dolabratus, Keratella tropica and Hexarthra sp. were good indicators of high turbidity due to suspended sediments. The rotifer genus Brachionus was the most species-rich taxon, comprising five species which were associated with different environmental conditions. Therefore, we tested whether this genus alone could potentially be a better biological indicator of these environmental gradients than the entire zooplankton assemblages or any other random set of five species. The ordination results show that the five Brachionus species alone did not explain better the observed pattern of environmental variation than most random sets of five species. Therefore, this genus could not be selected as a target taxon for more intensive environmental monitoring as has been previously suggested by Attayde and Bozelli (1998). Overall, our results show that changes in the water quality of man-made lakes in a tropical semi-arid region have significant effects on the structure of zooplankton assemblages that can potentially affect the functioning of these ecosystems

Avaliação de indicadores de impactos ambientais no perímetro irrigado Cruzeta-Região semi-árida do RN

Environmental impacts are defined as the processes of social and ecological changes caused by nuisance ambient. In agriculture are diverse, and the intensive use of land and inappropriate agricultural practices causes negative effect on the environment besides affecting crop productivity and quality of life of man. So this study was objective to analyze parameters indicators of environmental impacts in the Cruzeta the Discrict Irrigation. During the period July 2007 to March 2008 samples were collected in lot 01 and 02 of the irrigation district. The monitoring was conducted in four sampling points, three (3) located in the irrigation channels and 1 (one) located in a cacimbão. Were monitored pH, CE, STD, SS, NO3-, OD, DT, PST, RAS, CT, Ca+2, Mg+2, Na+ and K+ and heavy metals. Analysis was performed, soil fertility, determining the infiltration rate, moisture content of soil and flow measurement. The results showed that the parameters considered most effective in evaluating the indicators of environmental impacts were: Suspended solid, turbidity, dissolved oxygen and Coliform termotelerantes. The concentrations of nitrate were below the limit established by CONAMA (2005). High levels of STD were found in the point P4. The risk of salinity in cacimbão Lot 02, the water was classified as Class II, or medium risk of salinity in the remaining points was classified as Class I. The iron and aluminum were found high concentrations in four sampling points independent of the dry or rainy. On the ground, found high levels of phosphorus in both samples collected in the batch 01, as the lot 02. The pH levels found in samples of soil, the soil can be classified as neutral and moderate alkalinity. The high infiltration rate obtained in the tests performed in lots 01 and 02 indicated the high permeability of soil at these points

Qualidade de água como tema para a socialização do conhecimento científico em região semi-árida brasileira

During the dry and rainy periods, in the Piranhas-Assu river hydrographic basin, variations in bacterioplankton and trophic state indexes were studied in the lotic and lentic environments. The means of total bacterial density wavered in the order of 107 organisms. mL-1 and they were higher in the rainy period. Cocci bacteria were numerically predominant in all sampling points, influencing the total abundance of bacterioplankton. Total bacterial biomass varied from 659 to 1997,3 µgC.L-1 due to the high values of filaments cellular volume. Total phosphorus amounted 108 µg.L-1 and it had a positive correlation with chlorophyll a (r = 0,94; p < 0,05) during dry period, when these variables presented higher concentrations. There wasn t a high spatial variation. The low transparency of water and the phosphorus and chlorophyll concentrations indicated eutrophic or hipereutrophic levels in studied points of reservoir. These variables, associated with high density and biomass values found, alert to the necessity of a constant monitoring of the semi-arid aquatic ecosystems, where the quality of water is affected by dry occurrence

Usos e qualidade da água em região semi-árida do nordeste brasileiro: percepção ambiental de professores e alunos

Density and biomass of bacterioplankton in parts of the Marechal Dutra reservoir were studied in periods of dry and rainy season. The averages of the total bacterial densities oscillated in the order of 107 organisms/ mL of sample. The cocci cells were numerically predominant, influencing considerably the total abundance of the bacterioplankton. The total bacterial biomass, was considered raised and varied from 2.431,82 to 2.739,01 μgC.L-1, in function of the high values of biovolume of the filaments forms, and showed no marked spacial fluctuation. These high values of density and biomass alert for the necessity of a frequent monitoring of aquatic ecosystems of semi-arid region, where the quality of the water is affected by the occurrence of extensive dry periods, influencing considerably the quality of life of its population

Sustentabilidade ambiental do cultivo intensivo de Tilápias (Oreochromis niloticus) em tanques-rede e a capacidade de suporte de quatro reservatórios em uma região semi-árida tropical

Intensive production of tilápias, in cages or net tanks, has been proposed as an alternative to increase fish production, that would generate income and offer animal protein in different tropical and subtropical countries. However, this system of production enriches the aquatic environment with nutrients, principally nitrogen and phosphor derived from the dejections of the metabolism of food and eventual food surpluses consumed by the fishes; the alimentation of the fishes in this production modality is dependent on fish food. The emission of these nutritions in levels above the limit that the system is capable metabolize can provoke a phenomenon called eutrofization, putting in risk the quality of water for public and for fish production activities. In this context the work had as a goal to evaluate the trófico state of the four reservoirs for intensive production of tilapias in net-tanks, in other words, he maximum fish production that the reservoirs are able to hold, keeping the desired quantity of nutrient concentrations in water for public use. The results of the four ecosystems in the Boqueirão de Parelhas reservoir showed that it s possible to have an intensive production of tilapias in net tanks, in this environment the annual average concentration of phosphor, was below the considered critical limits to deflagrate the process of eutrofization in semi-arid regions. The carrying capacity of the Boqueirão de Parelhas reservoir depends on the conversion of the feeding facts and phosphor content in the food but it should vary between 100 and 300 tons per year over a variation in the conversion feeding factor of 1,7 to 2,0:1 and a variation in the P in the food of 0,7 to 0,9%

Ecologia da polinização de Ipomoea asarifolia (Ders.) Roem. & Schult. (Convolvulaceae) na região semi-árida de Pernambuco

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Convergencias y divergencias en la integración sudamericana

Incluye Bibliografía

Entrelíneas, franja costera de San Cristóbal - La Laja

Intervención en San Cristóbal, Las Palmas de Gran Canaria, Gran Canaria.Viviendas y espacio libre.Curso 2011-2012 TUTORA: Elisenda Monzón Peñate. Cotutor Estructuras: Benito García-Maciá Cotutor Instalaciones: Pablo Hernández Ortega. Cotutor Construcción: Ricardo Santana Rodríguez

Entrelíneas, franja costera de San Cristóbal - La Laja

Rehabilitación de una manzana del barrio de San Cristóbal y construcción de viviendas colectivas + equipamiento

Entrelíneas: franja costera de San Cristóbal, La Laja, Las Palmas de Gran Canaria

[ES]Los accesos y conexiones con San Cristóbal son limitados y presentan un serio problema para los habitantes del barrio. Los dos pasos subterráneos que conectan con la zona superior se encuentran en mal estado, son inseguros e insalubres. Bajo este pretexto surge la idea de generar una paso "equipado" donde se sucedan actividades y aporte al espacio mayor funcionalidad. Si a ello se añade el echo de que la conexión coexiste con el espacio residual que genera la salida rodada del barrio, se nos presenta la oportunidad de dotar al lugar y devolver, en cierto forma, el "espacio raptado" por la autovía. Por tanto, y en vista de que San Cristóbal solo dispone de pequeños equipamientos locales dispersos, se propone la creación de un espacio capaz de albergar todas aquellas actividades que los usuarios demanden. Un espacio flexible que a su vez se individualiza mediante "pabellones" que estan al servicio del ciudadano, puesto que la intención es que el propio usuario decida qué necesita y cuándo, con el objetivo de que el espacio pueda estar en funcionamiento las 24 horas del día. A su vez, se destaca la intervención generada en el espacio libre que se ubica en las inmediaciones del edificio La Granja, ya que ahora pasa a ser un espacio verde capaz de ser usado por los habitantes del barrio, configurándose así una conexión entre la playa, el paseo, el equipamiento y el espacio verde.

Entrelíneas: franja costera de San Cristóbal, La Laja

[ES]El barrio de San Cristóbal se caracteriza por una situación estratégica dentro de la ciudad de Las Palmas de Gran Canaria. Su condición de lugar aislado, que a su vez se incluye dentro del sistema urbano, su proximidad a espacios dotacionales relevantes, su inevitable relación con el mar, etc., hacen del barrio un lugar ideal para vivir, en donde coexisten conceptos como lo local y lo urbano, lugar de trabajo y lugar de bienestar o la relación con la ciudad y la naturaleza. El objetivo de la propuesta es fomentar el uso de la calle, entendiéndola como espacio de encuentro y de relación que forma parte de lo residencial, de la vivienda, y que crea espacios ambiguos en donde no es fácil diferenciar entre lo público y lo privado, lo individual y lo colectivo, el interior y el exterior. La reactivación de esta zona del barrio se realiza mediante la introducción de usos comunitarios en planta baja, que permitan una mayor interacción entre el vacío y lo edificado y la creación de un nuevo espacio de encuentro elevado que permita dotar a todas las viviendas de las características de extensión existentes en las que se encuentran a nivel de calle. Se trata de una intervención que, a pesar de volcarse hacia el interior, trata de no perder la referencia del exterior, del mar.

Entrelíneas franja costera de San Cristóbal