Effects of surfactants on the ultrastructural organization of the phytoplankton, Chlamydomonas reinhardtii and Anabaena cylindrica

Abstract

Chlamydomonas reinhardtii and Anabaena cylindrica were used as model phytoplankton to show the ultrastructural changes in cell membranes and organelles exposed to the most common, commercial surfactants, the anionic sodium dodecyl sulphate and the cationic catamine, in a range of concentrations from 0.1 to 10.0 mg/l and an exposure range from 5 h to 7 days. It was found that cell structure was not affected significantly by short-time exposure (to 5 h) to low concentrations of the surfactants, but they caused an intensification of cell vacuolization compared to the control. The degree of change caused by the surfactants to the ultrastructure of cell organelles increased with the greater concentration of them. At higher surfactant concentrations (3.0 to 5.0 mg/l), marked cell vacuolization was observed and there were changes to membrane structure, especially to the plasma membrane but also to the chloroplast thylakoids. In addition, there were increases in the number and size of the mitochondria as well as morphological alterations to them. There was also a reduction in the nuclear chromatin condensation. At the highest surfactant concentrations (to 10 mg/ml), the cells had numerous degenerative changes, and death occurred to the majority of them. Thus, the results of the model system revealed the precise dependence of the degree of structural reorganisation of the cell organelles on the concentration of surfactant in the culture medium. The data on the state of the phytoplankton should be used for remotely monitoring the state of the microplanktonic organisms in water ecosystems.