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O que controla o crescimento do Fitopl?ncton em lagoas costeiras tropicais? um modelo para a lagoa de Extremoz (RN)

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Previous issue date: 2014-03-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The phytoplankton growth is dependent of several abiotic (nutrients, temperature)
and biotic (predation by zooplankton) variables. In this work, a mathematical model was
developed in Stella software to understand the planktonic dynamics of Extremoz
Lagoon (RN) and to simulate scenarios of different environmental conditions. Data were
collected monthly at two points of the lagoon. The state variables are phytoplankton and
zooplankton and forcing variables are nitrogen, phosphorus and temperature. The
results show that: a) the model are well coupled, especially when some constants
assume different values; b) simulated nutrient concentrations reduction decreases
phytoplankton biomass, but the increase of nutrients does not stimulate the growth; c)
changes in the temperature does not change the phytoplankton biomass; d) changes in
zooplankton biomass affect directly and reduces the phytoplankton, indicating a topdown control mechanism; e) changes in the nutrient concentration modified the biomass
of zooplankton suggesting a rapid flow of energy between nutrients, phytoplankton and
zooplankton and a ecosystem likely arranged in an inverted pyramid (higher
concentration of zooplankton than phytoplankton) / O crescimento fitoplanct?nico ? dependente de uma s?rie de vari?veis abi?ticas
(nutrientes, temperatura, luz) e bi?ticas (preda??o por zoopl?ncton e outros
fitoplanct?fagos, bact?rias que provocam lise celular no fitopl?ncton). Neste trabalho,
um modelo de compartimentos foi desenvolvido no software Stella para entender a
din?mica planct?nica da Lagoa de Extremoz (RN) e simular diferentes cen?rios de
altera??es em importantes vari?veis ambientais como fitopl?ncton e zoopl?ncton. As
medi??es foram realizadas mensalmente em dois pontos da lagoa. As vari?veis de
estado s?o fitopl?ncton e zoopl?ncton e as for?antes s?o nitrog?nio, f?sforo e
temperatura. Os resultados mostram que: a) o modelo se ajusta bem aos dados,
especialmente quando algumas constantes assumem diferentes valores; b) simula??es
de redu??es das concentra??es de nutrientes diminuem a biomassa fitoplanct?nica,
mas o aumento dos nutrientes n?o favorece o crescimento; c) altera??es na
temperatura n?o modificam a biomassa fitoplanct?nica; d) modifica??es na biomassa
de zoopl?ncton afetam diretamente e consideravelmente o fitopl?ncton, indicando um
mecanismo de controle top-down; e) altera??es nas concentra??es de nutrientes
modificam a biomassa do zoopl?ncton sugerindo um r?pido fluxo de energia entre
nutrientes, fito e zoopl?ncton e um prov?vel ecossistema arranjado em pir?mide
invertida (maior biomassa de zoopl?ncton do que fitopl?ncton)

Identiferoai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/16008
Date26 March 2014
CreatorsSilva, Andrievisk Gaudencio Pereira e
ContributorsCPF:13958013805, http://lattes.cnpq.br/6739463859587165, Rocha, Odete, CPF:86476948434, http://lattes.cnpq.br/7577441794992601, Guariento, Rafael Dettogni, CPF:10538128763, http://lattes.cnpq.br/1463776084744636, Becker, Vanessa, CPF:71502076004, http://lattes.cnpq.br/2999389235108507, Angelini, Ronaldo
PublisherUniversidade 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 SetsIBICT Brazilian ETDs
LanguagePortuguese
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis
Formatapplication/pdf
Sourcereponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN
Rightsinfo:eu-repo/semantics/openAccess

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