Structure of the periphytic algae community in natural substratum of the lagoon of the Federal University of Espírito Santo, Brazil

Abstract

The present study aimed at evaluating the structure of the periphytic algae community in Panicum rivulare Trin. and to relate it with some environmental variables of the lagoon of the Federal University od Espirito Santo, an artificial environment that receives domestic effluent in natura. The samplings had been carried monthly through one site sampling during eight months (October, 2001 to May, 2002). The community was evaluated through its main attributes: abundant and dominant species, frequency of occurrence, diversity, eveness, richness and population density. The determined environmental variables had been: salinity, electric conductivity, turbidity, transparency, depth, euphotic zone, pH, dissolved oxygen, water and air temperature and precipitation. The periphytic algae community was composed by 36 taxa, distributed in seven classes. The predominant class, qualitatively, was Chlorophyceae, followed of Cyanophyceae and Bacillariophyceae, being the less representative Oedogoniophyceae, Zygnemaphyceae, Euglenophyceae and Dinophyceae class. Chlorophyceae predominated quantitatively in the majority of the samplings and associated with the salinity, being Coelastrum microporum the only dominant species in the four first samplings. Water temperature and light had influenced the too much class, mainly Cyanophyceae and Bacillariophyceae. The results showed that the variation of the community structure was resulted of autogenic changes, reflected in the substitution of the species standard, throughout the studied period, in reply to the temporal variation of the environmental variable’s also influencing in the diversity and richness.

Key words: algae, macrophyte, temporal variation.