Made available in DSpace on 2014-12-17T14:02:00Z (GMT). No. of bitstreams: 1 PatriciaLSCL.pdf: 1934431 bytes, checksum: cb552f8c167ecea1cf7b85c22d8a6a10 (MD5) Previous issue date: 2010-03-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / It is important to evaluate the quality of water for proper management of these resources, since the increase of environmental degradation and the multiple use of water resources are decreasing the quality of water consumed by living beings. The objective of this study was to characterize the phytoplankton community and its variations during periods of dray and rain in Jiqui Lake located in Parnamirim, RN. It was also aimed to analyze the physical and chemical factors of this environment, in order to contribute to the knowledge of water quality used for human consumption. The collection of water samples were carried out in September 2008 to August 2009. The collection of the phytoplankton community was carried out in four sampling sites (surface, bottom, margin of the lake without macrophytes and site dominated by macrophytes). Phytoplankton was collected using plankton net of 20?m. The analysis of nutrients and identification of phytoplankton were performed in the laboratory. The results indicate that concentration of chlorophyll a was high in the bottom with mean value of 1.07 ?gL-1 (SD ? 1.61). During the study period there was a dominance of the following species: Euglena gracilis, Trachelomonas sp, Cyclotellas sp, Gomphonema apuncto, Navicula cuspidata var. cuspidata, Navicula sp, Rhopalodia gibba. There was homogeneity between limnological values in the four study sites, with significant difference between the periods of drought and rain. The Jiqui Lake is considered oligotrophic due to its low concentrations of chlorophyll a, high transparency and low levels of nutrients. The values of BOD and chlorophyll a concentration remained below the permitted standards existing for freshwaters in Brazil, thus the water from Lake Jiqui is of good quality, suitable for human consumption. / O aumento da degrada??o ambiental e o uso m?ltiplo dos recursos h?dricos v?m diminuindo a qualidade da ?gua consumida pelos seres vivos, por isso ? importante a sua avalia??o para o adequado gerenciamento desses recursos. Este estudo teve como objetivo caracterizar a comunidade fitoplanct?nica juntamente com a sua varia??o durante os per?odos de estiagem e de chuva da Lagoa do Jiqui, localizada em Parnamirim, RN, al?m de analisar os fatores f?sico-qu?micos desses ambientes aqu?ticos, a fim de contribuir para o conhecimento da qualidade de ?gua desse manancial utilizada para o abastecimento humano. As coletas das amostras de ?gua foram realizadas de setembro de 2008 a agosto de 2009. A coleta da comunidade fitoplanct?nica foi realizada em quatro s?tios de amostragem (superf?cie, fundo, banco da macr?fitas e na margem da lagoa sem macr?fitas). O fitopl?ncton foi coletado utilizando-se uma rede de pl?ncton de 20?m. Em laborat?rio, foram realizadas as an?lises dos nutrientes e a identifica??o da comunidade fitoplanct?nica. Os resultados indicam que a concentra??o da clorofila a foi elevada no fundo com valor m?dia de 1,07 ?gL-1 (DP? 1,61). Durante o per?odo de estudo ocorreu uma domin?ncia das esp?cies Euglena gracilis, Trachelomonas sp, Cyclotellas sp, Gomphonema apuncto, Navicula cuspidata var. cuspidata, Navicula sp, Rhopalodia gibba. Houve homogeneidade entre os valores limnol?gicos nos quatro s?tios estudados, com diferen?a significativa entre os per?odos de estiagem e de chuva. A Lagoa do Jiqui ? oligotr?fica, uma vez que apresenta baixas concentra??es de clorofila a, alta transpar?ncia e baixos valores de nutrientes. Os valores da DBO e concentra??o da clorofila a se mantiveram abaixo do permitido pelos padr?es existentes para ?guas doces no Brasil, assim conferindo as ?guas da Lagoa do Jiqui de boa qualidade, adequada para o consumo humano.