Haematococcus algae. Differential interference contrast light micrograph of Haematococcus pluvialis algae. This green alga exists in either a resting (cyst) phase or a vegetative stage. This alga contains the pigment astaxanthin (red), an antioxidant and important ingredient in cosmetics. H. pluvialis is commonly found in temperate areas worldwide. Magnification: x345 when printed at 10 centimetres across.