Academic Journals Database
Disseminating quality controlled scientific knowledge

Algas perifíticas em dois ambientes do baixo rio Doce (lagoa Juparanã e rio Pequeno – Linhares, Estado do Espírito Santo, Brasil): variação espacial e temporal = Periphytic algae in two environments of the lower Doce river (Juparanã lagoon and Pequeno river – Linhares, Espírito Santo State, Brazil): spatial and temporal variation

ADD TO MY LIST
 
Author(s): Bruna Cavati | Valéria de Oliveira Fernandes

Journal: Acta Scientiarum : Biological Sciences
ISSN 1679-9283

Volume: 30;
Issue: 4;
Start page: 439;
Date: 2008;
Original page

Keywords: algas perifíticas | variação espacial | variação temporal | periphytic algae | spatial variation | temporal variation

ABSTRACT
A pesquisa objetivou avaliar a variação espacial e temporal da comunidade de algas perifíticas em dois ambientes do baixo rio Doce: lagoa Juparanã e rio Pequeno. Foram realizadas coletas trimestrais (agosto/04 a maio/05) em duas estações amostrais, uma na lagoae outra no rio. Foram coletados pecíolos de Eichhornia azurea (Sw.) Kunth. Os atributos da comunidade analisados foram: riqueza de táxons, freqüência de ocorrência, densidade, abundância e dominância. Na lagoa Juparanã, foram registrados 86 táxons e a densidadevariou de 20.592 ind cm-2 (mai/05) a 88.712 ind. cm-2 (nov/04). No rio Pequeno, foram registrados 83 táxons e a densidade variou de 16.049 ind. cm-2 (fev/05) a 71.663 ind. cm-2 (ago/04). Em ambos os ambientes, as classes predominantes qualitativamente foramCyanophyceae, Bacillariophyceae e Zygnemaphyceae, havendo domínio das formas filamentosas e unicelulares seguidas das coloniais. As classes Cyanophyceae e Bacillariophyceae foram mais representativas quantitativamente. Não houve variação espacial. Pluviosidade, temperatura da água, condutividade elétrica e transparência foram asvariáveis que mais oscilaram conforme a estação (seca ou chuvosa) e as que apresentaram maior número de correlações significativas com as variáveis biológicas, evidenciando heterogeneidade temporal.This research aimed to evaluate the spatial and temporal variation of the periphytic algae community within two environments of the lower Doce River: Juparanã Lagoon and Pequeno River. Samplings were carried out every three months from August 2004 to May 2005 at both sites. Natural substrata of Eichhornia azurea (Sw.) Kunth petioles were collected from the sites. The community was analyzed according to species richness, frequency of occurrence, density of organisms, abundance and dominancy. Eighty-six taxa were recorded in the lagoon,and the density of organisms varied from 20,595 ind. cm-2 (May/05) to 88,712 ind. cm-2 (Nov/04). Eighty-three taxa were recorded in the river, and the density of organisms varied from 16,049 ind cm-2 (Feb/05) to 71,663 ind. cm-2 (Aug/04). At both sites, the classes thatpredominated qualitatively were Cyanophyceae, Bacillariophyceae and Zygnemaphyceae, in which filamentous and unicellular forms dominated, followed by colonial forms. Quantitatively, the most representative classes were Cyanophyceae and Bacillariophyceae. A spatial variation was not observed. Precipitation, water temperature, electric conductivity and transparency were the variables that most oscillated according to seasonal variation (dry or rainy season). They alsopresented a greater number of significant correlations with the biological variables, showing evidence of temporal heterogeneity.
Affiliate Program      Why do you need a reservation system?