Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-27T13:44:02Z No. of bitstreams: 1 CarolineGabrielaBezerraDeMoura_TESE.pdf: 2231934 bytes, checksum: 890994db2e35bf07a5f1e900da0830e5 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-31T14:50:22Z (GMT) No. of bitstreams: 1 CarolineGabrielaBezerraDeMoura_TESE.pdf: 2231934 bytes, checksum: 890994db2e35bf07a5f1e900da0830e5 (MD5) / Made available in DSpace on 2017-01-31T14:50:22Z (GMT). No. of bitstreams: 1 CarolineGabrielaBezerraDeMoura_TESE.pdf: 2231934 bytes, checksum: 890994db2e35bf07a5f1e900da0830e5 (MD5) Previous issue date: 2015-12-14 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O objetivo desta tese ? compreender os fatores que influenciam o balan?o de carbono em reservat?rios do semi?rido do nordeste brasileiro e avaliar o efeito de peixes com diferentes h?bitos alimentares no balan?o de carbono destes ambientes. Os resultados desta tese nos mostraram que peixes com diferentes h?bitos alimentares podem influenciar o balan?o de carbono em reservat?rios (Cap?tulo I; Cap?tulo II; Capitulo III). Demonstramos atrav?s de experimentos de mesocosmos que peixes bent?voros (detrit?voros) aumentam a heterotrofia e emiss?o de CO2 para atmosfera, atrav?s da ressuspens?o de mat?ria org?nica e nutrientes presos ao sedimento, que estimulam as taxas de respira??o planct?nica e microbiana, assim como os processos de metanotrofia (Cap?tulo II). Por outro lado, peixes on?voros como a Til?pia do Nilo, favorecem a diminu??o da emiss?o de CO2 para a atmosfera, atrav?s do est?mulo da biomassa fitoplanct?nica ocasionado principalmente via cascata tr?fica pela diminui??o da biomassa de zoopl?ncton (Cap?tulo III). Al?m disso, reservat?rios que apresentam uma domin?ncia de s?lidos inorg?nicos em suspens?o pode indicar que o ambiente est? emitindo CO2 para a atmosfera. Em contrapartida, reservat?rios que apresentam uma domin?ncia de s?lidos org?nicos em suspens?o pode indicar que o ambiente esteja apreendendo CO2 da atmosfera (Cap?tulo I). Podemos concluir, que alguns fatores como a domin?ncia de s?lidos em suspens?o pode ser um indicativo da fun??o do ecossistema aqu?tico frente ao balan?o de carbono. Al?m disso, peixes com diferentes h?bitos alimentares podem influenciar o balan?o de carbono em reservat?rios. / The objective of this thesis is to understand the factors that influence the carbon balance in semi-arid reservoirs in northeastern Brazil and to evaluate the effect of the feeding characteristics in the carbon balance of these environments. The results of this thesis have shown that fish with different feeding characteristics can influence carbon balance in reservoirs (Chapter I, Chapter II, Chapter III). We have demonstrated through experiments mesocosms that benthivorous fish enhance heterotrophic and emission of CO2 to the atmosphere, through the suspension of organic matter and nutrients attached to sediment, which stimulate plankton and microbial respiration rates as well as methanotrophy processes (Chapter II). On the other hand, omnivorous fish like Nile Tilapia favor decrease CO2 emissions to the atmosphere by stimulating phytoplankton biomass mainly caused via trophic cascade by decrease in zooplankton biomass (Chapter III). In addition, reservoirs which have a predominance of inorganic suspended solids may indicate that the environment is emitting CO2 to the atmosphere. However, reservoirs have a dominance of organic suspended solids may indicate that the environment is uptake CO2 by the atmosphere (Chapter I). We can conclude, that some factors such as the dominance of suspended solids may be indicative of the of carbon balance function by aquatic ecosystem. In addition, fish with different feeding characteristics can influence the carbon balance in reservoirs.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-06T20:31:23Z No. of bitstreams: 1 FabianaOliveiraDeAraujoSilva_TESE.pdf: 783632 bytes, checksum: d5a28b9c131a2a8187ccb70b95821d14 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-08T17:34:29Z (GMT) No. of bitstreams: 1 FabianaOliveiraDeAraujoSilva_TESE.pdf: 783632 bytes, checksum: d5a28b9c131a2a8187ccb70b95821d14 (MD5) / Made available in DSpace on 2016-07-08T17:34:29Z (GMT). No. of bitstreams: 1 FabianaOliveiraDeAraujoSilva_TESE.pdf: 783632 bytes, checksum: d5a28b9c131a2a8187ccb70b95821d14 (MD5) Previous issue date: 2015-02-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / A eutrofiza??o ? a causa mais comum de deteriora??o da qualidade da ?gua no mundo. Este processo se d? pela entrada excessiva de nutrientes, nitrog?nio e f?sforo, nos corpos aqu?ticos causando flora??es de algas e cianobact?rias. Em lagos rasos esses efeitos s?o mais complicados devido a uma maior intera??o do corpo aqu?tico com o entorno, com o ar e o sedimento. Existem v?rias t?cnicas de restaura??o de lagos eutrofizados, com uma vasta gama de resultados bem sucedidos, mas no Brasil h? apenas um ?nico caso de restaura??o bem sucedida: o lago Parano? em Bras?lia. A regi?o semi?rida brasileira possui milhares de lagos artificiais, regionalmente chamados de a?udes, em sua maioria rasos e eutr?ficos. A eutrofiza??o desses corpos aqu?ticos ? documentada e o fitopl?ncton desses ambientes ? frequentemente dominado por cianobact?rias potencialmente t?xicas. O principal objetivo desta tese de doutorado ? testar diferentes t?cnicas de restaura??o da qualidade da ?gua que possam ser facilmente aplicadas em lagos rasos do semi?rido brasileiro. Resultados de um experimento em laborat?rio sugerem que a aplica??o de argila adsorvente de f?sforo associada a um coagulante ? base de alum?nio ? uma t?cnica efetiva na remo??o do f?sforo reativo sol?vel e na diminui??o da taxa de crescimento da Cylindrospermopsis raciborskii, cianobact?ria potencialmente t?xica que domina nos reservat?rios do semi?rido brasileiro, mas que esse efeito ? dependente da biomassa no momento da aplica??o da t?cnica. Os resultados de um experimento de campo realizado em mesocosmos num lago raso eutrofizado demonstraram que a aplica??o de coagulante ? base de alumn?nio em conjunto com a da remo??o de peixes bent?voros ? mais eficiente na remo??o de f?sforo total e clorofila-a da coluna de ?gua do que a aplica??o isolada de apenas uma dessas t?cnicas. Por fim, testes de laborat?rio demostraram que o coagulante ? base de alum?nio apresentou um bom desempenho em remover turbidez e f?sforo total em testes de bancada com ?gua de seis reservat?rios do semi?rido, sendo a efici?ncia reduzida com o aumento da biomassa de clorofila e pH. Os resultados deste estudo mostram que ? poss?vel melhorar a qualidade da ?gua de reservat?rios eutrofizados no semi?rido brasileiro atrav?s do controle da carga interna de nutrientes seja pela precipita??o e inativa??o do f?sforo no sedimento, como tamb?m pela inibi??o da libera??o do f?sforo no sedimento por peixes bioturbadores, e que os resultados s?o aditivos quando as t?cnicas s?o aplicadas em conjunto. / Eutrophication is the most common cause of water quality degradation in the world. This process occurs by excessive nutrients inputs, nitrogen and phosphorus, to the aquatic systems resulting in algal and cyanobacterial blooms. In shallow lakes these effects are pronounced due to the higher interaction of the lake with watershed, air and sediment. There are innumerous restoration techniques of eutrophied lakes with a range of successful results but there is only one case of successful lake restoration in Brazil: Parano? Lake in Bras?lia city. The Brazilian semiarid region has many artificial lakes, named a?udes, which are mostly eutrophic and shallow lakes. The eutrophication in these lakes is reported and the phytoplankton community is dominated by potentially toxic cyanobacteria species, mainly Cylindrospermopsis raciborskii. The aim of this thesis is to test techniques for water quality management which can be easily applied in Brazilian semiarid lakes. Results from a laboratory experiment suggest that the addition of a phosphorus sorbent clay associated with an aluminium based coagulant is an effective technique in removing soluble reactive phosphorus and reducing C. raciborskii growth rate ? cyanobacteria potentially toxic dominant in reservoirs of Brazilian semiarid ? but this effect is dependent on the biomass in the application moment. Results from a field experiment in mesocosm in a eutrophied lake showed that the addition of aluminium based coagulant and removal of benthivorous fish is more efficient in removing total phosphorus and chlorophyll-a from water column than the isolated application of one of the techniques. Lastly, laboratory tests showed that aluminium based coagulant exhibited good performance in removing turbidity and total phosphorus from water of six reservoirs but the efficiency was reduced by algal biomass and pH. The results of this study showed that the improvement in water quality of eutrophied reservoirs in semiarid region is possible through internal loading control by phosphorus precipitation and inactivation in sediments or inhibition of phosphorus release by benthivorous fishes, and also that these results show are additives in water quality improvement.