Vertical Distribution of Bacteria in Various Lakes of East Java, Indonesia

Abstract

Ecosystems are composed of a large number of diverse organisms that make up very complex interactions. Several studies have proven the influence of abiotic factors on the distribution of bacteria in the environment. Bacteria play an important role in biogeochemical cycles and support the productivity of ecosystems. The important role of bacteria in the environment causes the need for research on the vertical distribution of bacteria. The purpose of this research was to determine the vertical distribution of bacteria in some lakes in eastern Java. The samples were taken from 3 lakes in East Java namely, Ranu Grati, Ranu Regulo, and Ranu Pane. The bacterial samples were taken at 5 stations in each lake. The samples, vertically taken from 4 points, the upper, middle and lower surface according to the depth of the Secchi disc and the bottom of the lake, were isolated and identified. It was found 14 species of bacteria from Ranu Pane, 24 species of bacteria from Ranu Regulo, and 36 species of bacteria from Ranu Grati. The most dominant and abundant bacteria in Ranu Pane, Ranu Regulo, and Ranu Grati were coded with A, B, G3 respectively. The bacteria in all the lakes were spread over all stations and were vertically scattered at all points. The abiotic factors measured have a positive effect on the vertical distribution of bacteria.