Selenium accumulation in unicellular photosynthetic algae Chlamydomonas reinhardtii and Thalassiosira weissflogii grown in Se-contaminated media

The objective of this study was to investigate the accumulation of Se (IV) and Se (VI) and their effect on the growth of two unicellular photosynthetic algae, Chlamydomonas reinhardtii and Thalassiosira weissflogii. For this purpose, a cell growth rate experiment was conducted, in nutrient media spiked with several non-lethal levels of Se salts of both oxidation states, and the growth curves were constructed spectrophotometrically for all the conditions under examination. Cells were also grown in larger volumes in all conditions and the selenium contents of individual Chlamydomonas reinhardtii and Thalassiosira weissflogii cells were quantitated through the use of conventional ICP-MS and SC ICP-MS. Comparisons are being made between cell suspensions grown in different selenium salts in the two organisms. Our data show that the cell growth rates depend on the Se species (IV or VI) in the growth media. Similar observations were made with the Inductively Coupled Plasma – Mass Spectrometrry analysis regarding the accumulation of the different Se species in the cells.