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Previous issue date: 2015-05-08 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Reservat?rios s?o ecossistemas artificiais, intermedi?rios entre rios e lagos,
apresentando caracter?sticas morfom?tricas e hidrol?gicas distintas que podem render muitos
benef?cios importantes para a sociedade. Entretanto, a utiliza??o dessa ?gua para abastecimento
humano, dessedenta??o de animais, lazer, produ??o agr?cola irrigada e desenvolvimento da
piscicultura, influenciam diretamente no aumento do aporte de nutrientes para os ambientes
aqu?ticos e, consequentemente, contribuem para a acelera??o da eutrofiza??o. Al?m disso,
modelos de mudan?as clim?ticas globais est?o prevendo a maior ocorr?ncia de eventos
extremos como chuvas intensas e seca severa, que criar? estresses hidrol?gicos em lagos. No
semi?rido nordestino j? se percebe a ocorr?ncia desses eventos, a seca dos anos de 2012, 2013 e
2014 foi a pior seca dos ?ltimos 60 anos, segundo a Ag?ncia Nacional de ?guas (ANA). Sendo
assim, o presente trabalho teve como objetivo avaliar a qualidade da ?gua de mananciais do
semi?rido tropical, identificando padr?es temporais em per?odos com eventos hidrol?gicos
extremos (chuva intensa e seca prolongada). Os resultados do estudo mostraram que os
reservat?rios Gargalheiras e Cruzeta apresentaram mudan?as significativas nas vari?veis
limnol?gicas entre os per?odos de chuva e de seca severa, com melhora no aspecto visual e na
maioria das vari?veis da qualidade da ?gua no per?odo chuvoso e maiores concentra??es de
nutrientes e elevados valores de condutividade el?trica no per?odo de seca severa, indicando
decaimento da sua qualidade. Entretanto, constataram-se comportamentos distintos entre os
reservat?rios no per?odo de seca severa. Enquanto Gargalheiras apresentou um comportamento
t?pico de reservat?rios da regi?o, com elevadas concentra??es de biomassa algal, indicando o
agravamento da eutrofiza??o, cruzeta demonstrou um colapso na biomassa total fitoplanctonica
evidenciado pela diminui??o das concentra??es de chla. Este fato se deu principalmente pela
baixa profundidade e proximidade com o sedimento ter facilitado a ressuspens?o de s?lidos
inorg?nicos e, consequentemente, ocasionar a caracter?stica t?rbida e limita??o por luz na
coluna d??gua. Al?m disso, os comportamentos distintos entre os reservat?rios estudados
indicam que as respostas destes ambientes frente ? problem?tica dos eventos extremos devem
levar em considera??o fatores como o clima da regi?o, tamanho e profundidade do reservat?rio,
al?m das caracter?sticas das suas bacias. / Reservoirs are artificial ecosystems, intermediate between rivers and lakes, with
diferent morphological and hydrological characteristics that can provide many important
benefits to society. However, the use of this water for human consumption, watering livestock,
leisure, irrigated agricultural production and pisciculture development, directly influence the
increase loading of nutrients to aquatic environments and contribute to acceleration of
eutrophication. Furthermore, global climate models are predicting a higher occurrence of
extreme events such as floods and severe droughts, which will create hydrological stresses in
lakes. In the semiarid northeast we can see the occurrence of these events, the drought of the
years 2012, 2013 and 2014 was the worst drought in 60 years, according to the National Water
Agency (ANA). Thus, this study aimed to evaluate the quality of the semiarid tropical water
sources, identifying temporal patterns in periods with extreme hydrological events (floods and
severe droughts). The study results showed that Gargalheiras and Cruzeta reservoirs presented
significative changes in the limnological variables between rain and severe drought periods,
with better appearance and in the most of the water quality variables in the rainy season and
higher nutrientes concentrations and high electrical conductivity values in severe season,
indicating decay of its quality. However, we found diferent behaviors between the reservoirs in
severe drought. While Gargalheiras showed a typical behavior of the region, with high
concentrations of algal biomass, indicating the worsening eutrophication, Cruzeta demonstrated
a colapse in the total phytoplankton biomass, evidenced by the decrease in chla concentrations.
This fact occurred because the low depth and proximity with the sediment facilited the inorganic
solids resuspension and, consequently, resulted in turbid water column and light by limitation.
In addition, the different behaviors between the reservoirs indicate that the responses of these
environments problems such as extreme events must take into account factors such the region
climate, size, depth of the reservoir and the basin characteristics.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/20028 |
| Date | 08 May 2015 |
| Creators | Figueiredo, Aline do Vale |
| Contributors | 71502076004, http://lattes.cnpq.br/2999389235108507, Sperling, Eduardo Von, 19893230659, http://lattes.cnpq.br/5558654308900981, Rocha, Odete, 86476947834, Mattos, Arthur, Becker, Vanessa |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA SANIT?RIA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| 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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