BIOLOGY 151 Lecture Notes - Aerenchyma, Groundwater Recharge, Ecosystem Services
Document Summary
Although they are not as strongly mobile as fish, many phytoplankton are capable of considerable diurnal vertical movement. Some important phytoplankton groups, like dinoflagellates (including the red tides but also many benign species), have flagella to power their motion. Others, such as diatoms, some of the most abundant algae in the ocean, use oil droplets that can be varied in size. They move upwards to take advantage of the light during the day, but their activities deplete the nutrients near the surface. This is possible because many of the phytoplankton have generation times of about one day, whereas zooplankton have generation times of several days or a few weeks. Consequently, a single volume of water generates a far greater total gross production of phytoplankton biomass per year than it generates of total gross zooplankton. Flowing-water ecosystems have little phytoplankton and depend on detritus from the land for much of their energy.
