In order to test the efficacy of the antibiotics bleocin™ (EMD Biosciences), paromomycin (MP Biomedicals), and the PPT-containing (200 g L-1) commercial herbicide Basta® (Bayer CropSciences) on D. salina CCAP 19/18, algal cells were grown in the presence of various concentrations of each selective agent (Table 3) using 100-ml stirrer flasks under the same conditions mentioned previously, with the exception of aeration. Each culture was inoculated with 10 ml of exponentially growing cells (1 x 105 cells ml-1) and the cell density was measured with a Zeiss Axiovert 100 inverted light microscope using a hemocytometer over a one week period. Additionally, cells were plated on agar to analyze viability on solid medium. Measurements were taken in duplicate and experiments were repeated two times.