Meroplankton

Sedimentary (attached) form of adult barnacle balyanus crayfish

Pelagic larva of the barnacle marine acorn ( Balanus improvisus )

Meroplankton ( Greek μέρο - part, πλανκτον - wandering) - a variety of plankton , which is a set of temporary pelagic larvae and eggs of coastal benthic multicellular invertebrates that develop in the pelagic of the Neritic zone above the shelf , for example, bottom mollusks , crustaceans , crustaceans ,. Pelagic eggs and fish larvae ( ichthyoplankton ), and sometimes some dinoflagellates and diatoms , also belong to meroplankton in a broad sense.

Meroplankton, that is, temporary plankton, is opposed to holoplankton , whose representatives spend the entire life cycle in the pelagic. Both of the above terms were proposed at the end of the 19th century by Johann Jakob Heckel ( German: Johann Jakob Heckel , 1790-1857), an Austrian botanist, zoologist and ichthyologist.

Pelagic larvae of benthic invertebrates are a very essential component of plankton in all non-rritic regions of the World Ocean , including the Arctic and Antarctic , where they temporarily participate in the life of cryopelagic communities associated with fast ice and pack ice. During intensive spawning of bottom species with pelagic development, the number of their larvae in neritic plankton is hundreds of thousands of individuals per 1 m³. Above some mussel and oyster banks, the number of such larvae sometimes exceeds 700,000 ind./m³ . At the maximum period, these larvae can make up a very significant part of the total zooplankton abundance and reach 80–95% ^{[1] [2]} .

The presence of the pelagic stage in the cycle of development of bottom organisms contributes to their more successful resettlement and nutrition. At least 70-80% of the species of benthos of the oceans have a pelagic stage of development. Their distribution is carried out both within the shelf and the outer shelf zone, and due to drift with the water masses of large ocean currents, for example, the Gulf Stream ^[1] . Meroplankton plays an important role in the nutrition of coastal fish and other aquatic organisms . After the end of the pelagic stage of development, representatives of multicellular invertebrates settle to the bottom or another substrate and then lead a free bottom or attached lifestyle. Pelagic larvae and juveniles of bottom fish also pass to the bottom lifestyle as they grow, and matured juveniles of most pelagic fish become an integral part of nekton .