Ciliated Protozoan communities in a fluvial ecosystem

The ciliated protozoan communities in the Llobregat River (Barcelona, Spain) were studied for one year. Samples were taken from 11 different stations. The physical-chemical factors of the water as well as the qualitative and quantitative nature of the ciliate populations were considered. 105 species of ciliates, grouped in 13 orders, were found.The species which constantly appeared at all 11 stations (although not every month) were Litonotus fasciola, Trithigmostoma cucullulus, Cyclidium glaucoma, Glaucoma scintillans, Vorticella microstoma, Oxytricha sp., Stylonychia mytilus, Aspidisca costata and Aspidisca lynceus. The index of diversity at the different stations, and the affinity between the most abundant species, were also determined.     

Microplankton dynamics in a perennially ice-covered Antarctic lake – Lake Hoare

1. Temporal and spatial variation in planktonic abundance, biomass and composition were determined in Lake Hoare (McMurdo Dry Valleys, Antarctica) over two summer seasons (1996–97 and 1997–98). 2. Phototrophic nanoflagellates (PNAN) dominated planktonic biomass, with a mean monthly biomass ranging between 27.3 and 40.4 μg C L^?1. The deep chlorophyll maximum was mainly composed of cryptophytes (>87% of total PNAN biomass) and varied in depth between 6 and 12 m. 3. Maximum bacterial concentration was 11.8 × 10⁵ cells mL^?1. Bacterial abundance showed relatively little temporal variation, with the exception of a drop in numbers that occurred in late November of both years studied. 4. Ciliates were the most successful heterotrophic protozoan group, with a mean monthly biomass (1.2–3.2 μg C L^?1) being typically at least double that of heterotrophic nanoflagellate (HNAN) biomass (0.1–0.7 μg C L^?1). 5. Microbial processes within this lake appear to be dominated by bottom up control. The relative importance of allochthonous inputs into the lake (from the ice‐cover and stream flow) and autochthonous recycling (by microzooplankton regeneration) are considered. 6. Results from a horizontal transect indicate that the permanence of the main sample hole may have enhanced planktonic biomass over a relatively small spatial scale.     

甘肃甘南高原沼泽湿地6种土壤纤毛虫记述

本文记述了在甘南高原沼泽湿地中鉴定到的6种土壤纤毛虫,这些种类分别为:野生假膜虫(Notohymena selvatica)、布若雷亚尼瓦拉虫(Wallackia bujoreani)、水藓宽口虫(Steinia sphagnicola)、埃托拟突口虫(Condylostomides etoschensis)、粘游仆虫(Euplotes muscicola)和斯坦赭虫(Blepharisma steini),其中,野生假膜虫、布若雷亚尼瓦拉虫和水藓宽口虫这3种为中国土壤纤毛虫新纪录种。     

In situ nutrient enrichment experiments with periphyton in agricultural streams

The abundance, composition and seasonal distribution of planktonic protozoans and physical and chemical variables such as temperature, dissolved oxygen content, pH, and chlorophyll a concentration were analyzed monthly from February 1985 to January 1986 in eutrophic Rio Grande Reservoir. Analyses were performed on water samples collected at the surface and bottom (0.5 m above the sediment) in three stations, and individual distribution profiles were constructed for the major species. Dominant protozoan taxa included Codonella cratera, Coleps amphacantus, Coleps hirtus, Halteria grandinella, Mesodinium pulex, Tintinnidium sp., Urotricha spp., Vorticella spp., and Difflugia sp.. The distribution of some species was probably related to temperature and dissolved oxygen content.     

Survival of protozoa in cooling tower biocides

Protozoa from cooling towers may serve as hosts for legionellae, but such protozoa have not been examined with respect to effects of cooling tower biocides. In this study, two ciliate species,Tetrahymena sp andColpoda sp, and two amoebae species,Vannella miroides andAcanthamoeba hatchetti, were isolated from a cooling tower and tested for survival in the presence of four cooling tower biocides. The protozoa were exposed for 24 h to a thiocarbamate compound, an isothiazolone compound, quaternary ammonium compounds (QAC), and tributyltin neodecanoate with quarternary ammonium compounds (TBT/QAC). After exposure, cells were examined for viability. The highest concentration of each biocide in which cells could survive was compared to the manufacturers' recommended maintenance dosage (MRMD) of the biocides.Tetrahymena andColpoda survived concentrations within the range of the MRMD of thiocarbamate and QAC.Vannella andAcanthamoeba survived concentrations within the MRMD of thiocarbamate, isothiazolone, and QAC.Colpoda cysts andAcanthamoebae cysts remained viable after exposure to concentrations much greater than the MRMD of thiocarbamate, isothiazolone, and QAC. None of the protozoa in any stage could survive the MRMD of TBT/QAC. These results show that protozoa indigenous to cooling towers may survive the recommended concentration of certain biocides, and this information may be important in devising procedures for eradicating hosts for legionellae.     

Temporal plankton dynamics in an oligotrophic maritime Antarctic lake

• 1 The population density, diversity and productivity of the microbial plankton in an oligotrophic maritime Antarctic lake were studied for a 15‐month period between December 1994 and February 1996.
• 2 In the lake, concentrations of nutrients and dissolved organic carbon were uniformly low, temperature varied over a small annual range of 0.1–3 °C, and the surface was ice‐covered except during a period of approximately 6 weeks in summer.
• 3 The total of 57 morphotypes of protozoa observed during the study is a higher taxonomic diversity than previously reported from continental Antarctic lakes, but lower than that found in more eutrophic maritime Antarctic lakes. Likewise, planktonic abundance and productivity were lower than has been reported in other lakes on Signy Island, but generally higher than those of lakes on the Antarctic continent.
• 4 There were marked seasonal and interannual variations in planktonic population density.
• 5 Chlorophyll a concentrations ranged from undetectable to 4.2 µg L^‐1 and the greatest rate of primary productivity measured was 4.5 mg C m^‐3 h^‐1. The phytoplankton was dominated by small chlorophytes and chrysophytes, with phototrophic nanoflagellate abundance ranging from 1.1 × 10³ to 1.2 × 10⁷ L^‐1.
• 6 Bacterial densities of 3.6 × 10⁸ to 1.9 × 10¹⁰ L^‐1 were recorded and bacterial productivity reached a peak of 0.36 µg C L^‐1 h^‐1. Numbers of heterotrophic nanoflagellates between 5.0 × 10⁴ and 1.8 × 10⁷ L^‐1, and of ciliates from undetectable to 1.1 × 10⁴ L^‐1 were observed. Naked amoebae were usually rare, but occasionally reached peaks of up to 1.5 × 10³ L^‐1.

     

Notes on the soil ciliate biota (Protozoa, Ciliophora) from the Shimba Hills in Kenya (Africa): diversity and description of three new genera and ten new species

A very diverse ciliate community was found in nine soil samples from the Shimba Hills Nature Reserve in Kenya, equatorial Africa. The ciliates, respectively, their resting cysts, were re-activated from air-dried samples using the non-flooded Petri dish method. Species were determined from life and by silver impregnation. 34 (27%) of the 125 taxa identified had not yet been described in 1985, when the samples were collected and investigated. The richest samples, each containing 59 species, were those from a deciduous primary forest and a young secondary pine forest. The most remarkable species discovered in the Shimba Hills were Krassniggia auxiliaris, Bresslauides terricola, Gigantothrix herzogi, and Afrothrix darbyshirei. They are flagships with a very distinct morphology and easy to recognise due to their extraordinarily large body size. Krassniggia auxiliaris occurs also in Australia and probably has a restricted Gondwanan distribution, like some other ciliates. Bresslauides terricola was later found in soils from all main biogeographical regions, except for Antarctica. Gigantothrix herzogi and Afrothrix darbyshirei are still unique to the Shimba Hills. The following taxa are described in detail: Sikorops woronowiczae nov. gen., nov. spec., Arcuospathidium multinucleatum nov. spec., Dileptus similis Foissner, 1995, Plagiocampa bitricha nov. spec., Drepanomonas exigua exigua Penard, 1922, D. exigua bidentata nov. sspec., Parafurgasonia protectissima (Penard, 1922) nov. comb., P. terricola nov. spec., Brachyosoma brachypoda mucosa nov. sspec., Gigantothrix herzogi nov. gen., nov. spec., Afrothrix darbyshirei nov. gen., nov. spec., Oxytricha africana nov. spec., and O. elegans nov. spec.     

Global soil ciliate (Protozoa, Ciliophora) diversity: a probability-based approach using large sample collections from Africa, Australia and Antarctica

Large sample collections from Africa (92 samples), Australia (157) and Antarctica (90) were investigated for soil ciliates using the non-flooded Petri dish method, which re-activates the ciliates' resting cysts from air-dried samples. Species were determined from life and by silver impregnation. The African samples were the richest, containing 507 species (240 undescribed,=47%), followed by the Australian (361 species, 154=43% undescribed) and the Antarctic (95 species, 14=15% undescribed) samples. The percentage of new species/sample was consistently low, viz. 4–8% on average, indicating that new species were considerably undersampled relative to described ones, very probably due to methodological shortcomings, i.e. usually only cysts of the more euryoecious species could be reactivated. Thus, a probability theory-based statistical approach was applied to the data sets to compensate for the underestimated number of undescribed species. This procedure indicated that, depending on the region, 70–80% of the soil ciliates are still unknown and global soil ciliate diversity amounts to at least 1330–2000 species. Several indicators, especially the constant rate at which new species have been found during a 20-year period of intensive research, suggest that this estimate is conservative. This revised version was published online in August 2006 with corrections to the Cover Date.     

Spatio-temporal Patterns of Protozoan Communities in a Meso-eutrophic Reservoir (Esch-sur-Sûre,Luxembourg)

The spatio-temporal distribution of the heterotrophic nanoflagellates (HNF) and ciliates was monitored in the reservoir of Esch-sur-Sûre during the year 1999. Three main periods of protozoan development were observed, in early April, early May, and in July. On the basis of the seasonal dynamics, it appeared that the early spring development of protozoa was probably not controlled by resources or predators. The second protozoan development was progressively controlled by the increase of metazooplankton density that led to the clear water phase characterised by very low protozoan densities and biomasses. A summer development of protozoa was possible thanks to the development of bacteria and moderate metazooplankton densities due to the appearance of non-edible algae. Prorodontida, Halteriida and Strombidiida were the dominant ciliates in the upper part of the water column. A development of Tintinnida was moreover observed in spring whereas Philasterida and Sessilida developed in winter and summer. Ciliates occupied the entire water column in spring and were concentrated in the epilimnion and the metalimnion during the summer period where they fed on bacteria and algae.     

Distribution of the entodiniomorphid ciliate Troglocorys cava Tokiwa, Modrý, Ito, Pomajbíková, Petrželková, & Imai, , (Entodiniomorphida: Blepharocorythidae) in wild and captive chimpanzees

Trophozoites of Troglocorys cava were detected in all but one of the wild chimpanzee populations from Rubondo Island (Tanzania), with a prevalence ranging between 20% and 78%. However, the ciliate was absent in all captive groups. Prevalence appeared to increase with the number of sequential samples taken from a particular individual and reached 95.5% in wild individuals sampled at least 4 times.     

Refinements of and commentary on the silver staining techniques of Fernández-Galiano

The original ammoniacal silver carbonate staining technique and subsequent modification developed by Fernández-Galiano are useful for investigating ciliate protozoan systematics and/or ciliate cortical structure and morphogenesis. The technique is complicated, however, by both uncertainties arising from the need to count drops of reagents and subjective control of the staining intensity. I have resolved these complications by defining volumes of reagents rather than using drops and by defining a range of staining times. I also comment on various steps of the techniques. My techniques are simplified and refined to produce consistent, high quality staining results.