The possible existence of endemism among microorganisms resulting from and preserved by geographic isolation is one of the most controversial topics in microbial ecology. We isolated 31 strains of "Spumella-like" flagellates from remote sampling sites from all continents, including Antarctica. These and another 23 isolates from a former study were characterized morphologically and by small-subunit rRNA gene sequence analysis and tested for the maximum temperature tolerance. Only a minority of the Spumella morpho-and phylotypes from the geographically isolated Antarctic continent follow the worldwide trend of a linear correlation between ambient (air) temperature during strain isolation and heat tolerance of the isolates. A high percentage of the Antarctic isolates, but none of the isolates from locations on all other continents, were obligate psychrophilic, although some of the latter were isolated at low ambient temperatures. The drastic deviation of Antarctic representatives of Spumella from the global trend of temperature adaptation of this morphospecies provides strong evidence for geographic transport restriction of a microorganism; i.e., Antarctic protistan communities are less influenced by transport of protists to and from the Antarctic continent than by local adaptation, a subtle form of endemism.One hot debate in microbial ecology deals with the geographic restriction of protistan taxa (8, 10-12, 22, 29). Some researchers believe that free-living protistan species are essentially ubiquitous and grow wherever suitable habitats exist. They assume that the microbial community found in any given habitat is a function of habitat properties only and not of historical factors, since there is an ubiquitous "seed bank." They further argue that geographic barriers to protists do not exist and consequently cannot contribute to evolutionary diversification (10,(12)(13)(14)(15).The basic assumption that microorganisms are easily dispersed across the physical and geographic barriers that halt the migrations of larger animals and plants (12) is, however, controversial and relies largely on the observed ubiquity of morphospecies. It has been challenged by other researchers, who believe that protists have a biogeography that has been shaped by geographic barriers (8, 30). The discussion has initiated much recent research into the existence of endemic species (10,16,28,38). However, even the definition of a species is controversial, and the low resolution of the morphospecies concept for protists appears to be an obstacle to the settling of the debate (32).Fortunately, increasing evidence for phylogenetic and ecophysiological differentiation below the morphospecies level (4,21,22,26,29,38) can theoretically be used to solve the question of possible endemism among protists. If there were no geographic barriers to protists, correlations between the habitat temperature, as a factor selecting certain strains from the seed bank, and the temperature tolerance of these strains should be independent of the geographic location. ...

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Eukaryotic microorganisms (protists) are a very important component of microbial communities inhabiting groundwater aquifers. This is not unexpected when one considers that many protists feed heterotrophically, by means of either phagotrophy (bacterivory) or osmotrophy. Protistan numbers are usually low (< 10(2) per g dw of aquifer material) in pristine, uncontaminated aquifers but may increase by several orders of magnitude in aquifers subject to organic pollution. Small flagellates (typically 2-3(5) microns in size in situ) are by far the dominant protists in aquifers, although amoebae and occasionally ciliates may also be present in much lower numbers. Although a wealth of new taxonomic information is waiting to be brought to light, interest in the identity of aquifer protists is not exclusively academic. If verified, the following hypotheses may prove to be important towards our understanding of the functioning of microbial communities in aquifers: (1) Differences in swimming behavior between species of flagellates lead to feeding heterogeneity and niche differentiation, implying that bacterivorous flagellates graze on different subsets of the bacterial community, and therefore play different roles in controlling bacterial densities. (2) Bacterivorous flagellates grazing on bacteria capable of degrading organic compounds have an indirect effect on the overall rates of biodegradation.

Comments are made on some existing classification systems of the Cryptophyceae. A new system is also proposed. This allows for the existence of three orders, four families, seven pigmented genera and two colourless oneS. Formal diagnoses are given of the Cryptophyceae classis emendata, Pyrenomonadales ord.nov., Pyrenomonadaceae fam.nov. And Cryptomonadales ord.nov. A new name is proposed, Goniomonadales stat.et nom.nov. Most diagnoses or descriptions of taxa above the generic level are based on only one character. This could make the system capable of accommodating new genera with little difficulty.

Nomenclature, far from being a dry dusty subject, is today more relevant than ever before. Researchers into genomics are discovering again the need for systems of nomenclature-names are what we use to communicate about organisms, and by extension the rest of their biology. Here, we briefly outline the history of the published international codes of nomenclature, tracing them from the time of Linnaeus in the eighteenth century to the present day. We then outline some of what we feel are the major challenges that face the codes in the twenty-first century; focusing primarily on publication, priority, typification and the role of science in the naming of organisms. We conclude that the codes are essential for taxonomists in the pursuance of their science, and that the democratic nature of decision-making in the regulation of the rules of nomenclature, though sometimes perceived as a potential weakness, is in fact one of its great strengths.