ORGANIC MATTER CONTENT, ORGANIC CARBON, NITROGEN, PHOSPHORUS AND PHEOPIGMENTS IN THE SEDIMENT OF SOME FRESHWATER LAKE ECOSYSTEMS ON THE COAST OF THE STATE OF ESPIRITO SANTO

Abstract

Vertical profiles (cores) of sediment were collected in 18 lagoons at the municipality of Linhares, lower Rio Doce region, in 1986. The sediment of the lakes Juparanã, Nova, Palmas, Palminhas, Durão, Aviso, Meio, Aguiar, Dentro e Sabiá, on the Formação Barreiras and the lakes Cacimba, Parda, Suruaca, Zacharias, Bonita e Machado at the quaternary deltaic plain was studied. Organic matter content, organic carbon, organic nitrogen, phosphate avaialable and pheopigments from the profiles were analysed and showed a wide variation amongst the lakes studied. The lakes of the quaternary plain often showed lower figures than those found for the lakes on the Formação Barreiras. Principal Component Analysis has been used in order to handle the data obtained through the analysis of the chemical components. This technique pointed out for different groups of lakes, grouped according to the content of the different sediment components. However, it did not allow a distinction of these groups in systems artificially eutrophicated and preserved from anthropic interference, which suggests that the knowledge about system dynamics is essential to data interpretation.