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Previous issue date: 2013-04-17 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The potentially toxic cyanobacterial blooms in water bodies are spread across the globe, resulting in the loss of water quality and adverse effects on human health. In arid and semiarid regions, the hydrologic regime characterized by an annual cycle of drought and rain, change the volume and the retention time of the reservoir. Such changes affect the limnological characteristics and causing changes in composition and biomass community of cyanobacteria. The reservoir Cruzeta (Zmax = 8.7 m) is a eutrophic water supply source located in the semiarid tropical (Northeast Brazil). Raised the hypothesis that the hydrological regime of semi-arid tropical is a determining factor in the availability of resources in eutrophic water sources, which influences the composition of dominant species of cyanobacteria. The aim of this study was to analyze the changes in biomass and species composition of cyanobacteria for two annual hydrological cycles and evaluate factors drivers. The study was divided into five distinct periods (dry 2010, rain 2011, dry 2011, rain 2012, dry 2012). The dominant group found in all periods was Cyanobacteria (99% of total biomass), which contributed to the low diversity. The filamentous species Cylindrospermopsis raciborskii was present at both points in almost every study. The colonial species Microcystis panniformis and Sphaerocavum brasiliensis dominated only in periods with lower volumes of water. The diatoms contribute more to the biomass during the period of severe drought. The point near the dam (P1) had phytoplankton biomass larger than the point near the tributary (P2). The dominant species of colonial cyanobacteria lasted until the overflow in P1, and P2 this dominance was until the first rains. The redundancy analysis indicated that physical factors such as light availability and water level were the main factors driving the seasonal succession of phytoplankton. The composition of phytoplankton in spring was alternated by species of filamentous cyanobacteria in conditions of poor stability of the water column, such as Cylindrospermopsis raciborskii, and colonial species under conditions of high stability of the water column, such as Microcystis panniformis and Sphaerocavum brasiliensis. The extremes of torrential rains and severe droughts, governed by the hydrological regime of the semi-arid region led to the availability of resources in the watershed, directing the spatial and temporal dynamics of phytoplankton in the reservoir Cruzeta / As flora??es de cianobact?rias potencialmente t?xicas est?o disseminadas em corpos aqu?ticos por todo o globo, resultando na perda da qualidade da ?gua e efeitos negativos para a sa?de humana. Em regi?es ?ridas e semi?ridas, o regime hidrol?gico, caracterizado por um ciclo anual de seca e chuva, altera o volume e o tempo de reten??o dos reservat?rios. Tais altera??es afetam as caracter?sticas limnol?gicas e, consequentemente, ocassiona mudan?as na composi??o e biomassa da comunidade de cianobact?rias. O reservat?rio Cruzeta (Zmax = 8,7 m) ? um manancial de abastecimento eutr?fico, localizado no semi?rido tropical (Nordeste, Brasil). Levantou-se a hip?tese de que o regime hidrol?gico do semi?rido tropical ? um fator determinante na disponibilidade de recursos em mananciais eutrofizados, o que influencia na composi??o e domin?ncia de esp?cies de cianobact?rias. O objetivo deste trabalho foi analisar as mudan?as na biomassa e na composi??o de esp?cies de cianobact?rias durante dois ciclos hidrol?gicos anuais e avaliar fatores direcionadores. O estudo foi dividido em 5 per?odos distintos (seca 2010, chuva 2011, seca 2011, chuva 2012, seca 2012). O grupo dominante encontrado em todos os per?odos foi de Cianobact?rias (99% da biomassa total), o que contribuiu para a baixa diversidade. A esp?cie filamentosa Cylindrospermopsis raciborskii esteve presente em ambos os pontos em quase todo o estudo. As esp?cies coloniais Microcystis panniformis e Sphaerocavum brasiliensis dominaram somente nos per?odos com menores volumes de ?gua. As diatom?ceas contribu?ram mais com a biomassa durante o per?odo de seca severa. O ponto pr?ximo a barragem (P1) apresentou biomassa fitoplant?nica maior que o ponto pr?ximo ao tribut?rio (P2). A domin?ncia das esp?cies coloniais de cianobact?rias se estendeu at? o extravazamento do reservat?rio no P1. No P2, esta domin?ncia ocorreu at? as primeiras chuvas. A an?lise de redund?ncia indicou que vari?veis f?sicas, tais como disponibilidade de luz e o volume de ?gua, foram os principais fatores de condu??o da sucess?o sazonal do fitopl?ncton. A composi??o do fitopl?ncton no manancial foi alternada por esp?cies de cianobact?rias filamentosas nas condi??es de pouca estabilidade da coluna d??gua, como a Cylindrospermopsis raciborskii, e por esp?cies coloniais nas condi??es de elevada estabilidade da coluna d??gua, como Microcystis panniformis e Sphaerocavum brasiliensis. Os eventos extremos de chuvas torrenciais e secas severas, regidos pelo regime hidrol?gico da regi?o do semi?rido determinaram a disponibilidade de recursos no manancial, direcionando a din?mica temporal e espacial do fitopl?ncton no reservat?rio Cruzeta
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/15999 |
| Date | 17 April 2013 |
| Creators | Medeiros, Luciana de Castro |
| Contributors | CPF:71502076004, http://lattes.cnpq.br/2999389235108507, Mattos, Arthur, CPF:07431937849, http://lattes.cnpq.br/6925820345407676, Santos, H?lio Rodrigues dos, CPF:75200252415, http://lattes.cnpq.br/9048384392428073, Soares, Maria Carolina Silva, CPF:03961522600, http://lattes.cnpq.br/2876963025435266, Becker, Vanessa |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-gradua??o em Engenharia Sanit?ria, UFRN, BR, Saneamento Ambiental; Meio Ambiente; Recursos H?dricos e Hidr?ulica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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