The life cycle of phytoplankton is very short. In one phrase they’re grown in a bloom or not, then they photosynthesize, take carbon out of the atmosphere and then they die. However their life cycle is much more detailed. Like plants, they grow. Blooms are started by a place in the ocean or lake that has lots of nutrients. These nutrients cause the phytoplankton to reproduce really quickly. Phytoplankton reproduces also without a bloom, but not as rapidly. Immediately after the bloom they commence their carbon eating cycle and begin photosynthesizing. When they are over used or over heated they simply die and sink to the bottom of the ocean or the lake. But not for all the phytoplankton, lots get eaten by zooplankton, but there are still plenty left to clean the air. The others will live as long until they don’t have sufficient conditions. Over time phytoplankton skeletons will form sedimentary rock; this is how the great white cliffs of Dover were formed.