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6 • "PROTIST—2016
belonging to Spirotrichs. Maximum number of oxytrichids were found in Rithala sewage site though ciliate diversity was less. Maximum ciliate diversity was found in ANDC whereas ciliate diversity was less in Karnal. Colpodids were present in all the sites examined but most abundant in sewage site. Variation in soil ciliate diversity can be correlated with soil quality of studied habitats.
SOIL PROTIST BACTERIA CONSUMPTION IS CENTRAL TO NUTRIENT CYCLING Adl S.M.
University ofSaskatchewan sina.adl@usask.ca
Protists are the most abundant consumers of bacteria in soils. Their diversity covers most lineages making them the most diversity group of organisms in soils. Communities assemble along abiotic microgradients, such as pO2, pCO2, pH, temperature, etc. Species of protist bacterivores are not homologous or interchangeable. Species in functional groups have differing ecological preferences, occupying distinct niches. There are significant measurable species specific differences regarding prey ingestion rates and prey preferences. It has been well recognised in both soil and aquatic ecology that ignoring inter-species variability in behaviour and consumption rates is problematic. The top-down grazing pressure on bacteria was calculated for a variety of species representing a variety of feeding types, from functional response curves. We calculated threshold prey levels that sustained growth and initial rate slopes for ingestion rates, to compare competitive ability at low food conditions. Together with maximum growth rates and maximum ingestion rates inter-specific competitiveness and niche preferences could be distinguished. Data will be presented for several well established cercozoa cultures, amoebae cultures, ciliates, and other protists. This information helps to improve our calculations of global bacteria biomass turnover rates in soils. It also helps to understand how soils can support dozens of bacterivorous species in each gram of soil, in a seemingly similar habitat.
BIODIVERSITY STUDIES IN LORICATE PROTISTS: THE CASE OF TINTINNIDS (ALVE-OLATA, CILIOPHORA, SPIROTRICHA) Agatha S.1, Santoferrara L.F.2
1 - Dept. of Ecology and Evolution, University of Salzburg, Salzburg, Austria
2 - Dept. Marine Sciences, University of Connecticut, Groton, Connecticut, USA sabine.agatha@sbg.ac.at
Species identification is crucial in biodiversity research (ecology, taxonomy, barcoding etc.). In tintinnids, taxonomy and classification are almost exclusively based on features of their vase-shaped loricae (houses). The lorica-based species circumscriptions are, however, problematic as loricae might show a considerable intraspecific variability and interspecific similarity and might be influenced by the cell cycle and physico-chemical factors. To overcome the difficulties with deviating species limitations suggested by "lumpers" or "splitters" in revisionary treatises, it is recommend to "go back to the roots", i.e., to use exclusively the original descriptions or authoritative redescriptions for identification. Additionally, good documentation of the identified loricae by means of illustrations and morphometric data is advisable. Depending on the aim of the tintinnid study, further procedures are proposed to generate at high rates long-lasting high-quality species re-/ descriptions and/or DNA barcodes, which are essential for reliable phylogenetic analyses and thus for the establishment of a natural tintinnid classification. These suggestions represent a compromise between data quality and work effort and can most easily be followed by collaborations of molecular biologists and morphologic taxonomists. Financially supported by FWF project P28790.
MICROBIAL EUKARYOTES IN OILSANDS-ASSOCIATED ENVIRONMENTS OF NORTHERN ALBERTA
Aguilar M.1, Richardson E.1, Paoli L.2, Nesbo C.3, Foght J.3, Dunfield P.F.4, Dacks J.B.15
1 - Department of Cell Biology, University of Alberta. Edmonton, Canada
2 - Département de Biologie, Ecole normale supérieure, Paris, France
3 - Department of Biological Sciences, University of Alberta, Edmonton, Canada
4 - Department of Biological Sciences, University of Calgary, Calgary, Canada
5 - Department of Life Sciences, Natural History Museum, London, UK
dacks@ualberta.ca
The oil sands in Northern Alberta are the second largest bitumen deposit in the world, and comparable in magnitude to world's reserves of conventional petroleum. They have global significance as energy reservoirs. However, some aspects of their exploitation are also cause for environmental concern. Fluid wastes from bitumen extraction are retained in enormous tailings 'ponds' under a policy of no release to the environment. The estimated surface area of tailings ponds in Alberta ranges from 77-176
Protistology ■ 7
km2. Thus, since their commissioning approximately five decades ago, the ponds have accumulated anoxic, brackish, hydrocarbon and heavy metal containing sediments overlain by a thinner layer of process-affected water that may be oxic near the surface. Microbial processes are anticipated to play a major role in remediation of these environments, and, although the prokaryotic communities are increasingly well-characterized, little is known about the microbial eukaryotes present in the oxic and anoxic environments. We have recently reported the first NGS-based exploration of protists in tailings ponds. We found that, despite the anoxic and hydrocarbon-enriched nature of the environment, the tailings ponds harbour complex communities of microbial eukaryotes indicating that these organisms should be taken into account when studying the microbiology of the oil sands.
NOVEL PICOPLANKTONIC GROUPS FROM LAKE BAIKAL REVEALED BY MASSIVE SEQUENCING
Annenkova N.V.1, Logares R.2
1 - Limnological Institute SB RAS, Russia
2 - Institute of Marine Sciences, CSIC, Spain tasha.annenkova@gmail.com
Compared to the ocean, freshwater systems offer multiple ecological niches in terms of oxygen and DOC concentrations, light accessibility, temperature variability. However, we are still limited by the data of freshwater microbes biodiversity. Studies are highly biased because correspond mainly to Europe and North America. In particular, studies of Northern Asian protists are very limited, though this region extends on about 8000 km in length and has a big impact on microorganisms' migrations. Lake Baikal is the oldest and deepest lake in the world, being located in Northern Asia. It is cold, oxygen rich, and has one ofthe world richest endemic freshwater biotas, belonging both to very ancient lineages and to recent immigrants. Our goal was to explore small planktonic protists populating the lake. The genetic diversity (V4 region ofthe 18S rDNA) of planktonic microeukaryotes (< 8 ^m fraction) was analyzed in 48 samples using the Illumina MiSeq platform. We determined 1,461 protist OTUs, with 9.6% of them having less than 90% similarity with sequences from SILVA database. We suggest that they belong to endemic Baikal protists. We analyzed the phylogenetic relationships ofgroups such as MAST, Telonemiidae, Perkinsiidae, Chitridiomycota which were not previously described in Lake Baikal. Interestingly, we found Amoebophrya-like 18S rDNA in Baikal, even though Syndiniales were not reported from freshwaters. Overall, the most diverse
group was stramenopiles. This study contributes to improve our understanding of the diversity of protist communities living in ancient lakes as well as to comprehend better intra-lake evolutionary diversification processes. Supported by project of RAS # 0345-2014-0003
MODELLING THE LOCAL-TO-GLOBAL DIVERSITY FOR MICROBES AND MULTICELLULARS: COULD WE ESTIMATE THE NEAR-IMPONDERABLE? Azovsky A.I.
Lomonosov Moscow State University, Moscow, Russia aiazovsky@mail.ru
In the current discussion around either "protist diversity is different" or not, the ratios oflocal:global diversity and relative endemicity are often treated as arguments. This approach has, however, been flawed by the fact that actual global diversity of protists is still largely unknown, especially for the rare species. I use simple models to simulate distribution of species on the 400-cell lattice. Three models have been considered:
1) "Everything is everywhere" (equal probability for a particular species to occur at every cell);
2) "Environmental selection" (a species can occupy only a fixed portion of randomly distributed "suitable localities"); and
3) "Endemicity" (most of species are restricted in its potential distribution to a few regions).
To parameterize the models, several world-wide datasets on ciliates, flagellates and harpacticoid copepods were used. The local:regional and re-gional:global diversity ratios and percentage of endemics were estimated by simulating the equal-effort sampling across the lattice, with varying the full number of species ("actual diversity") and number of samplings per cell ("sampling effort"). All parameters, predicted by every model, strongly depended on the sampling effort but were only slightly, if ever, influenced by the observed:actual global diversity ratio. The predictions of the first two models were generally close to each other, but differed noticeably from those of the third one. These results indicate that the above-mentioned parameters are heavily influenced by undersampling. Nevertheless, they can serve as informative characteristics in comparative biodiversity studies, even ifthe true number of species can hardly be estimated overall.
GLOBAL DIVERSITY AND DISTRIBUTION OF MARINE BENTHIC HETEROTROPHIC FLAGELLATES
Azovsky A.I.1, Tikhonenkov D.V.23
