One metric used to indicate a physiological response in algal cultures is pigment concentration. Typically the photosynthetic pigment chlorophyll a is used to indicate the health of a growing culture or as a measure of productivity in a population. I am extracting and measuring carotenoid production in Nannochloropsis salina to determine the relationship between culture management and physiological status. 96 well plates make the measurement of numerous samples a breeze. A standard curve can be created with Beta-Carotene.