Figure 3: A) During the stationary phase, cells increased the release of coccoliths into the medium. In some cases, especially in the case of E. huxleyi RCC1216, aggregates of coccoliths and cells occurred frequently. The single populations (aggregates, single cells with coccoliths, naked cells) which are visible under the microscope, can be assigned clearly in the FACS scatter plot. Population heterogeneity is also obvious in the red autofluorescence histograms. B) Direct correlation of FLR and chlorophyll content obtained by photometrical analysis of the extracts is only practicable when cultures are homogeneous. The AFLR correlation can also be applied for highly heterogeneous culture broths.