Wikipedy.com                                                                                           Online encyclopedia

   Home     Add article      About

 INDEX

Plankton facts

Plankton is the great mass of floating and drifting animals and plants found in the sea and fresh water. Most of them are so small that they can be seen only with a microscope. They are suspended in the water much like the dust particles we can sometimes see in a beam of light.  Below you can see some plankton facts

The planktonic plants are extremely important to the life of the sea, because they are responsible for making nearly all the food material in the sea. They do this by the process called photosynthesis (see Photosynthesis interesting facts). The tiny animals of the marine plankton graze on the plants. They in turn are preyed on by larger animals (such as herring) which are in their turn eaten by larger fish (such as cod). In fact, some of the sea's largest creatures - some whales and sharks - eat only plankton.

Planktonic plants live only in the upper levels of the water because they must have sunlight to carry on photosynthesis. Not enough light penetrates below about 150 feet in most parts of the sea for photosynthesis. Planktonic animals may, however, swim down several hundred feet during daylight, but then float to the surface again at night.

Some more plankton facts: the plants of the marine plankton are called phytoplankton; the animals, zooplankton. All phytoplankton come from the large group of plants called algae. The main types are diatoms, which range in size from 1/2,500 to 1/250 of an inch. They are single-celled, and each consists of an irregular sac of protoplasm (living jelly) surrounded by a delicate, transparent box or shell.

Diatoms occur in a great variety of beautiful shapes, often with fine spines. The zooplankton consists of members of many animal groups, including protozoans (single-celled animals), jellyfish, worms and snails.

But the largest groups are crustaceans, particularly the type known as copepods, or oar-footed creatures. These all spend their entire life as plankton. Other sea animals, such as fish, crabs, barnacles, starfish and many mollusks, are planktonic only as eggs or when young. They then settle on the sea-bed, or join the members of the nekton (the active swimming group).

Wikipedy.com ^@ - Online Encyclopedia