Composition and abundance of the periphytic community and its relationship with some physicochemical variables in the Puente Roto stream in the municipality of Medio San Juan (Andagoya), Chocó, Colombia

Abstract

The periphyton is a community composed mainly of algae, bacteria, fungi, and invertebrates that plays a fundamental role in the dynamics of freshwater ecosystems and despite its importance, have been little studied in the aquatic systems of Chocó, for which it was studied the periphytic community, to determine its composition and its relationship with physical-chemical variables in the Puente Roto stream, Medio San Juan, Chocó, Colombia. Five samplings were carried out in three sampling stations. Samples of natural substrates (rocks, wood, and leaves) were collected, carefully scraping the surface of 10 cm2 with a spatula, this sample was taken to 50 ml with distilled water and fixed with 4% lugol. Some physicochemical variables (pH, water temperature and electrical conductivity) were measured. The periphytic community was composed of 2.397 individuals, grouped into five divisions, 8 classes, 19 orders, 26 families, 28 genera and 60 species. Chlorophyta, with 28 species, was the division with the highest specific richness and Bacillariophyta, with 1.706 individuals, was the one with the highest abundance. Bacillariophyceae, with 24 species and 1.706 individuals, was the best represented class in terms of species richness and abundance. Diversity presented its maximum at E3 (2.94 bits/ind). The physicochemical variables of the water did not show major variations, with electrical conductivity being the one with the greatest variation (16%). The applied canonical correspondence analysis showed that there is a high influence of the water temperature on the richness and abundance of the periphytic community.