Sea water looks clear but through a microscope you can
see that it is teeming with millions of tiny plants and creatures. They are
called plankton and are drifting forms of organic life found at various depths.
Plant Plankton
Plant plankton, called phytoplankton, are microscopic algae which float in mid-water and live in the
surface layers of the open ocean. They make their own food and oxygen. They need
sunlight to do this so they live near the surface of the ocean where there is
light. This process is called photosynthesis.
Animal Plankton
Animal plankton, called zooplankton or krill, consists of tiny animals—some of which are the young of
ocean animals such as starfish, jellyfish, barnacles and fish. They feed on
phytoplankton. All life in the sea depends on plankton. Small fish and
crustaceans eat this plankton in order to survive and grow. They, in turn, are
eaten by bigger fish. At the end of this food chain, people eat nutritious seafood.
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