Sludge worm

Description

Tubifex tubifex, also called the sludge worm, "Boogie Worm", or sewage worm, is a species of tubificid segmented worm which inhabits the sediments of lakes and rivers on several continents. Tubifex probably includes several species, but distinguishing between them is difficult because the reproductive organs, commonly used in species identification, are resorbed after mating, and because the external characteristics of the worm vary with changes in salinity. These worms ingest sediments, selectively digest bacteria, and absorb molecules through their body walls. Micro-plastic ingestion by Tubifex worms acts as a significant risk for trophic transfer and biomagnification of microplastics up the aquatic food chain. The worms can survive with little oxygen by waving hemoglobin-rich tail ends to exploit all available oxygen, and can exchange carbon dioxide and oxygen through their thin skins, in a manner similar to frogs. They can also survive in areas heavily polluted with organic matter that almost no other species can endure. By forming a protective cyst and lowering its metabolic rate, T. tubifex can survive drought and food shortage. Encystment may also function in the dispersal of the worm. They usually inhabit the bottom sediments of lakes, rivers, and occasionally sewer lines and outlets. Tubifex is a cosmopolitan genus of tubificid annelids that inhabits the sediments of lakes, rivers and occasionally sewer lines. At least 13 species of Tubifex have been identified, with the exact number not certain, as the species are not easily distinguishable from each other. Tubifex worms are hermaphroditic: each individual has both male (testes) and female (ovaries) organs in the same animals. These minute reproductive organs are attached to the ventral side of the body wall in the celomic cavity. In mature specimens, the reproductive organs are clearly found on the ventral side of the body. Although the Tubifex worms are hermaphrodites, the male and female organs become mature at different times; thus self-fertilization is avoided, and cross-fertilization is encouraged. Two mature Tubifex worms undergo copulation by joining ventral and anterior surfaces together with their anterior ends pointing opposite directions. Thus, the spermathecal opening of each worm is nearer to the male apertures of another worm.