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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 1205

J.H. Tietjen, J.J. Lee, J. Rullman, A. Greengart, and J. Trompeter; Gonobiotics culture and physiological ecology of the marine nematode Rhabditis marina Bastian. Culture and Ecology of a Marine Nematode :535-543, 1971

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The marine nematode Rhabditis marina Bastian has been isolated in gonotobiotic culture from collections of Zostera marina made in North Sea Habor, Southampton, New York. A strain of R. marina has been maintained with three species of bacteria (Pseudomonas sp., Flavobacterium marinum, and Micrococcus sp.) for over 120 generations. A monoxenic strain with Pseudomonas sp. has been maintained for over 25 generations. The life cycle is completed in 5 days under "normal" laboratory growth conditions. Reproduction occurs over a wide (0-80 0/00) salinity range (the highest salinity tested) and a wide (10-38 degrees C) temperature range; optimum growth occurs at 45-55 0/00 and 25-30 degrees C. Normal development is oviparous, but ovoviviparous development is seen in older females. Transfer feeding and synxenic culture experiments have shown that R. marina has rather specific nutritional requirements, which seem to be completely satisfied by a relatively restricted group of microorganisms. Selected species of bacteria comprise the normal diet of this organism. Microscopic observations of intact algae in the digestive tract of the worms and failure of [32]P to transfer to the worm from the ingested algae indicate that the worms are not able to digest all ingested potential food organisms. The geographical distribution of the species in relation to its physiological ecology is discussed.