Algas perif赤ticas em dois ambientes do baixo rio Doce (lagoa Juparan e rio Pequeno 每 Linhares, Estado do Esp赤rito Santo, Brasil): varia o espacial e temporal = Periphytic algae in two environments of the lower Doce river (Juparan lagoon and Pequeno river 每 Linhares, Esp赤rito Santo State, Brazil): spatial and temporal variation

作者：Bruna Cavati; Valeria de Oliveira Fernandes

来源：Acta Scientiarum - Biological Sciences, 2008.

• algas perifiticas
• varia o espacial
• varia o temporal
• periphytic algae
• spatial variation
• temporal variation

A pesquisa objetivou avaliar a varia o espacial e temporal da comunidade de algas perif赤ticas em dois ambientes do baixo rio Doce: lagoa Juparan e rio Pequeno. Foram realizadas coletas trimestrais (agosto/04 a maio/05) em duas esta es amostrais, uma na lagoae outra no rio. Foram coletados pec赤olos de Eichhornia azurea (Sw.) Kunth. Os atributos da comunidade analisados foram: riqueza de t芍xons, freq邦那ncia de ocorr那ncia, densidade, abundancia e dominancia. Na lagoa Juparan , foram registrados 86 t芍xons 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 t芍xons 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 dom赤nio das formas filamentosas e unicelulares seguidas das coloniais. As classes Cyanophyceae e Bacillariophyceae foram mais representativas quantitativamente. N o houve varia o espacial. Pluviosidade, temperatura da 芍gua, condutividade el谷trica e transpar那ncia foram asvari芍veis que mais oscilaram conforme a esta o (seca ou chuvosa) e as que apresentaram maior n迆mero de correla es significativas com as vari芍veis biol車gicas, 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: Juparan 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