ИСТИНА

Marine Annelides make up about half of the benthic biomass living on the bottom of the world ocean. Most of the worms are active builders. They build tubes, constructions and labyrinth-like passage systems in the upper sediment layer, which form a system of microbiotopes, significantly change the macro and microstructure of the upper sediment layer, oxygen distribution, porosity and many other parameters that determine the possibility of colonization of the sediment layer by small animals, fungi and specific microflora. The fine structure of the tubes of sea worms was studied in representatives of more than 13 families and more than 25 species of annelids. In addition to the annelids, the structure of the tubes of several species of phoronids and the constructions of some marine amphipods were studied. The obtained data showed that the tubes of polychaetes differ in a number of ultrastructural characters. The thin structure of the tube allow us to determine the owner of the tube to the family, and in some cases to the genus or species level. The main characters of agglutinated tubes are the mutual orientation of the layers in the inner cylinder of the tube, as well as the details of the packing and fixing of sediment particles in its outer layer. The microstructure of the amphipod constructions differs significantly from that of annelid. An analysis of a number of fossil materials - remnants of tubes (supposedly belonging to marine annelids) showed that the microstructure characteristic of polychaete tubes is rarely preserved, since the grain of the rock replaces the material of the tube usually larger than the elements of the microstructure. At the same time, some types of especially characteristic tiubes could be identified in the fossil state. The study of the structure of the tubes in many cases will allow answering questions about the lifestyle of animals living in the midst of the ground and inaccessible for direct observation. This concerns questions about how animals increase the tube size (length and diameter of the tube) as they grow, whether animals are able to dissolve the walls of the tube. How animals build branching tubes. The ability of the worms to soften or dissolve the organic material of the tube allows us to ask in what degree, the tubes can protect their owners from predators.