(A) P. parvum (CCAP 946/6) cell observed by SEM (background digitally removed). Note the presence of two long flagella and the shorter central haptonema. (B) Three P. parvum cells observed by optical microscopy using a Leica DM6000 fitted with a 100× objective. Cells show the golden colour typically associated with blooms of the organism. (C) Scales of P. parvum observed by transmission electron microscopy (TEM). Scale bar represents 100 nm.