Biodiversity of Soil Ciliates from Australia

Ciliates belong to the protists, which embrace the world of heterotrophic and autotrophic Protozoa or Infusionstierchen, that is, single-celled organisms of microscopic size (<1 mm), altogether about 250,000 named species, extant and fossil. Ciliates are that group of protists which have many hairs (cilia) on the body surface and in the mouth. The cilia serve for locomotion and food acquisition. About 10,000 named species belong to this taxon, which is, due to its unique nuclear apparatus (somatic macronucleus and generative micronucleus), usually considered as a distinct phylum. Many of them are excellent bioindicators for water and soil quality. The 10,000 species known, most from freshwater and the sea, are possibly only a small fraction of the real diversity; there is evidence that 80% of the ciliate diversity is still undescribed. Where are this many undescribed species? A considerable portion is contained in soil, where we discovered about 600 new (undescribed) species, and the statistical treatment of the data indicates that there are many more! The ciliates living in soil are poorly known, especially in Australia. Thus, we collected over 100 samples in various regions of Australia during the past 20 years. Most of them have been investigated and showed a great diversity of ciliates, including many undescribed species only few of which have been published. Thus, the research objectives and perspectives of the proposed project can be summarized as follows: to obtain reliable morphological and molecular information on soil ciliates from Australia by describing the species discovered in the samples mentioned above; to obtain reliable information on geographical distribution and endemism of soil ciliates by comparing the data with similar FWF-supported studies we did in Africa, the Neotropics, and the Holarctic; to educate young scientists in alpha-taxonomy (= description of species), a discipline threatened to become extinct in Europe and the USA, at least as concerns heterotrophic, free-living protists. The graduate students will be trained also in molecular methods in laboratories of colleagues specialized in this field. The results will be published as individual papers in peer-reviewed, open access journals and as a summary in a book, as we did with the Namibian and Neotropic soil ciliates. We have great experience in studying soil ciliates and our laboratory is in this respect unique worldwide. The project is planed for three years. The support needed amounts to about 340,000 Euro (~ 408,000 US Dollar), mainly to finance two graduate students and a technician.

In the early eighties, I planned to study Australian soil ciliates (hairy animalcules) to solve the question whether or not micro-organisms have cosmopolitan or restricted (endemic) distribution, i.e., occur only in certain areas. At this time, distribution was not a major question in the scientific community. However, this changed at the turn of the millennium when ecologists argued very strictly for a cosmopolitan distribution of single-celled organisms and small metazoans (consisting of many cells), such as rotifers. They argued that these organisms are so small (often <100 m) and numerous (hundreds or thousands individuals may occur in a gram of soil or water) that they become easily distributed globally by wind and weather. I opposed vehemently because the taxonomic literature showed rather many, usually large, flagship species that hardly can be overlooked even on superficial investigation, for instance, the 1 mm long, swamp living Neobursaridium gigas and the about 200 m long testate amoeba Nebela vas which is very common in litter and soil of the southern continents while absent in the northern realms though there are many similar habitats. With the present project, I could clarify the distribution problem because I studied four of the five main biogeographic realms (Holarctis, Africa, Neotropis, Antarctica) between 1990 and 2016 (see below).I collected 140 soil samples in Australia between 1987 and 2000 and studied their ciliate fauna with modern methods. The results are clear: Of the 450 species found, 120 were undescribed: they have subtle (subspecies) or distinct (new species and genera) differences to the species found in the biogeographic realms mentioned above. Some, possibly even many of these could be palaeoendemics which developed independently in Laurasia or Gondwana after the break on the Ur-continent Pangaea. In the meantime, several reviews show endemism in most groups of protists (e.g., diatoms, desmids, flagellates), in bacteria and microscopic fungi, and small metazoans, e.g., rotifers.Unfortunately, the planned monograph on Australian soil ciliates is still in work because I lost a year or so due to two heavy operations (subclavia aneurysm and an aneurysm fistula from a previous operation) during the project time, and the past six months I had a very painful problem with a vertebrate disc (three operations). Nonetheless, about 60% of the work, including all laboratory investigations, have been done and I am optimistic to finish the monograph until the end of the year 2018 because I am now in pension. About 60 species have been already published in individual papers and in our monographs on the Colpodea, the spathidiids and on the soil ciliates from Namibia (1459 pages) and Venezuela (912 pages).