The sea world is surprising and various. In it meet as the huge animals reaching in length several dozen meters and which weight is hundreds of tons, and absolutely tiny organisms. Some of them actively pave to themselves the way through thickness of waters, others quietly swim on a current. They are also called plankton.
What floats in the thickness of water
Plankton that in translation from Greek means "wandering" - it is set of the marine organisms swimming in the waters and not capable to resist currents. Most of members of this set are absolutely tiny plants and animal – diatomic and some other species of seaweed, bacteria, protozoa, Crustacea, coelenterates and mollusks, eggs and larvae of fishes, larvae of invertebrates. However quite large objects – huge seaweed, huge jellyfishes and even some fishes, for example, fish moon which weight reaches two tone, but which at the same time prefers not to move also occur among passively floating, using the muscular efforts, and to soar in the thickness of waters or on a surface. Before such large representatives of flora and fauna carried in separate category – macroplankton.
Plankton has huge value for sea inhabitants as serves as food to the majority of animal species, directly or through links of a food chain.
Classification
There are several classifications of the organisms which are a part of plankton. Scientists divide its inhabitants depending on specific accessory. So, there is phytoplankton, zooplankton and ikhtioplankton. Phytoplankton is meant as that part of freely floating organisms which is capable to photosynthesis implementation. Those are diatomic seaweed, dinoflagellyata and other monocelled seaweed and also cyanobacteria. Excessive reproduction of phytoplankton causes such phenomenon as water blossoming. Zooplankton represents set incapable to resist to a current of animals. Here carry heterotrophic protests, small Crustacea. The main part of a diet of zooplankton is made by phytoplankton and also the smaller fellows. Allocate a special kind of zooplankton – ikhtioplankton. Carry caviar to it and larvae of fishes and also the fishes swimming only at will of a current. Depending on a way of life plankton is divided on goloplankton and meroplankton. Representatives of the first class carry out all the life, soaring in thicknesses of waters. Those organisms for which the similar way of life is only the intermediate stage belong to a meroplankton. Those are larvae and a roe of fish and multicellular invertebrates and also representatives of some seaweed. In process of growth meroplankton or settles on a bottom and begins to lead a benthonic life, or starts active swimming.