Ref ID : 4648
Sudzuki Minoru and Shimoizum Jukichi; On the Fresh-Water Microfauna of the Antarctic Region II. Stability of Faunistic Composition of Antarctic Microorganisms. JARE Scientific Reports Special Issue 1:216-235, 1967
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The colonization of Antarctica by microorganisms has been analyzed during 1963-1966 by four ways of approach -faunological, sociological biogeographical, and experimental- using material mainly from Langhovde, Syowa Station, McMurdo Sound, and the Ongul Islands. The first three of these overlap to some extent, and the experimental approach may also provide some clues to this problem. Representative genera the strictly Antarctic microfauna are: Actinopoda: Actinophris. Rhizopoda: Amoeba, Chaos, Astramoeba, Euglypha, Corythion, Thecamoeba, Trinema, Microcorycia, Cryptodifflugia, Centropyxis, Difflugia, Arcella, Diplochlamis, Leptochlamys, Assulina, Vahlkampfia, Cochliopodium, Microgromia, Tracheleuglypha, Hyalosphenia, etc. Ciliata: Coloda, Homalogastra, Cyclidium, Trichopelma, Spathidium, Dileptus, Paradileptus, Opistotricha?, Holotricha, Pauroleptus, Pyxidium?, Vorticella?, Blepharisma, Nassula, Frontonia, Halteria, Strombilidium, etc. Rotatoria: Habrotrocha, Mniobia, Adineta, Rotaria, Pleuretra, Philodina, Macrotrachlea, Encentrum, Lepadella, Lecane, Monostyla, etc. Gastrotricha: Lepidoderma, Chaetonotus. Tardigrada: Hypsibius, Diphascon, Echiniscus, Paraechiniscus, Milnesium, Macrobiotus, Isohyposibius, Pseudechiniscus, etc. Without exception, these genera are regarded as "cosmopolitan" in distribution, frequently and abundantly encountered in both the xerophilous and hygrophilous biotopes of the regions of temperate climate, including Japan. And the occurrence-correlation of the above genera belongs to Sudzuki's types 1-3. One characteristic of the Antarctic community is found in the density of individuals rather than in the numbers of genera involved - in this respect, the Antarctic community is quite similar to the Hymalayan one occurring at altitudes above 5200 m. The experiment in which 0.094 ml of capillary moss-water from Tokyo was dropped into Antarctic Bryosystem and Chalikosystem revealed the following: 1) At least three types of species can be distinguished ecologically: a) easily adaptable; b) fairly adaptable; and c) slightly adaptable to the Antarctic condition. 2) To a) belong the majority of xerophilous, to b) hygrophilous and to c) some hydrophilous species. Now, we have arrived at a preliminary conclusion that Antarctic microfauna is relatively constant in composition, for all the transported species are, judging from our laboratory experiment, not always adapted to life in the Antarctic, and that only xerophilous and hygrophilous microorganisms can live in the Antarctic at present. Perhaps, some hydrophilous species found in the Antarctic today must have reached there in very recent times and have been adapting themselves to the Bryosystem of this region.