Their location is mainly dependent on currents and water clarity, as the plants require sunlight for photosynthesis .
Plankton is the basis of all aquatic food-chains.
The algae photosynthesize and are eaten by planktonic animals that fall prey to larger invertebrates, fishes, and even whales. Dead plankton sinks, and becomes food for detrital feeders. The Macmillan Encyclopedia 2001 4. photosynthesis A Dictionary of Food and Nutrition 5. All rights reserved.