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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 645

Norbert Wilbert and David Kahan; Ciliates of Solar Lake on the Red Sea Shore. Arch.Protistenk 124:70-95, 1981

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Solar Lake, about 20 km south of Elat, is a mesothermal, monomictic lake heated heliothermally. Its turnover occurs in the summer months, during July and August. During the rest of the year the lake is layered. The epilimnion is about 1 m thick, the metalimnion lying at a depth of 90-120 cm. The hypolimnion is anaerobic and can be heated to a maximum of 56.6 degrees C. The water is 4 to 6 m deep, depending on the season. During the stagnation period in the spring of 1978 qualitative measurements were made of the ciliate fauna in the lake. Samples were taken from the pelagic and benthic regions, from the shore to the middle of the lake. No ciliates were found in the entire pelagic region. All the 16 species found in the benthic region were in the zone of layered algal mats (Zone IV) and in the "pinacle algal mat" (Zone III) (Krumbein and Cohen 1974). These two zones extend to the lower boundary of the epilimnion. In the algal mats of the deeper Zones II and I no ciliates were found. This result is apparently due to the high water temperatures prevailing at these depths and to the anaerobic conditions, for adequate food (algae and bacteria) is present. Stephanopogon apogon, Uronema nigricans, Uronema filificum, Parauronema virginianum, Pseudocohnilembus marinus, Halteria grandinella, Euplotes rariseta and Uronychia transfuga are bacteriophagous; the algal-eaters include Frontonia marina, Condylostoma reichi n. spec., Condylostoma patulum, Tachysoma spec. and Holosticha diademata. Enchelyodon trepida and Litonotus lamella are predators on other ciliates. One ecological characteristic shared by the species found is their high salinity tolerance. L. lamella, U. nigricans, H. grandinella and H. diademata are known to live in fresh water and in the ocean, and the main range of the other species covers a great variety of marine biotopes. The infraciliature of all the ciliates was studied with AgNO3 (by the method of Chatton-Lwoff) or protargol (Wilbert). Condylostoma reichi is new to science. New species and genus characteristics of Uronychia transfuga are described, on the basis of infraciliature and morphogenetic stages.