Limnology: physico-chemical parameters and phytoplankton composition

Abstract

A characterization of freshwater ecosystems can be made using many different factors (e.g. salinity, pH, eutrophication, colour, geomorphology, aquatic macrophytes, fauna). In 1950, Sioli presented a useful classification for the water types of Amazonia (primarily based on colour), a classification that is probably applicable to the whole of the Neotropics. He distinguishes clear water, white water and black water. Clear water has a very low content of nutrients, humic acids and sediment particles. White water carries an extensive load of sediments, colouring the water white to light-brown. White water is richer in nutrients than clear or black water. Black water is coloured tea brown due to dissolved humic acids. The presence of humic acids decreases the pH. The water is poor in nutrients, and the turbidity is low.