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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 3056

Umezawa Shun-ichi and Matsuoka Kiyoshi; Effects of Hydrostatic Pressure on Survival of the Rotifer, Philodina roseola. Annotationes Zoologicae Japonenses 42(2):49-55, 1969

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When the surface-living rotifers are subjected to hydrostatic pressures, they are able to survive at pressure of 1600 atmospheres if released within a short time; they can tolerate well pressures of 1000 atmospheres and 100 atmospheres, for 30 minutes and 48 hours, respectively. The ability of the pressure tolerance depends not only on duration of compression, but also on temperature. The animals can tolerate well hydrostatic pressures if the temperature is nearly the same as that of their native environment. However, they are not shown to tolerate pressures if the temperature is lower than that of the normal environmental condition. Since, it has been known (Johnson, Eyring and Polissar, 1963) that pressure and temperature act antagonistically to one another, it may be presumed that the suppression of activities in the animal by pressure is not prevented by the action of decreasing temperature. A situation similar to that found at low temperatures is found at a temperature above that of the normal condition. The results obtained at high temperatures seem to be due to suppression of cell activities as a result of temperature effect upon the cell enzymes which are proteinaceous in nature. Mechanical injurious effects of hydrostatic pressure are scarcely found. This seems to be due to the high water permeability of the cuticle of the body surface.