PAŽOUTOVÁ, M., ŠKALOUD, P. & NEMJOVÁ, K.: Phylogenetic position of Ooplanctella planoconvexa gen. et comb. nova and Echinocoleum elegans (Oocystaceae, Trebouxiophyceae, Chlorophyta). - Fottea 10(1): 75-82, 2010
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SZABÓ-TAYLOR, K.É., KISS, K.T, LOGARES, R., EILER, A., ÁCS, É., TOTH, B. & BERTILSSON, S. : Composition and dynamics of microeukaryote communities in the River Danube. - Fottea 10(1): 99–113, 2010
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ANGELI, N., CANTONATI, M., SPITALE, D. & LANGE–BERTALOT, H.: A comparison between diatom assemblages in two groups of carbonate, low-altitude springs with different levels of anthropogenic disturbances. - Fottea 10(1): 115–128, 2010
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RADEA, C., LOUVROU, I., PANTAZIDOU, A. & ECONOMOU-AMILLI, A.: Photosynthetic microorganisms as epibionts and euendoliths on biotic substrates in a thermal spring with ferric-iron deposits. - Fottea 10(1): 129–140, 2010
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The present work summarizes the current diversity, distribution and autecology of desmids found within the Czech Republic; the focus is on the occurrence and autecology of rare taxa. Data are based on the author’s extensive sampling from 2003–2009, during work for both his master’s degree, and currently, his Ph.D. dissertation. Over 1 400 samples were collected, from various types of wetland habitats ranging from eutrophic fishponds, diverse bogs and fens, to ephemeral pools and various aerophytic habitats. Altogether, 526 taxa of desmids (401 species) belonging to 27 genera were found, 80 of them newly described in the Czech Republic. In the present work, 169 rare or otherwise noteworthy taxa, belonging to the following genera: Mesotaenium (1), Netrium (1), Roya (2), Tortitaenia (1), Gonatozygon (2), Closterium (14), Haplotaenium (2), Pleurotaenium (3), Docidium (1), Actinotaenium (6), Euastrum (9), Micrasterias (7), Cosmarium (78), Xanthidium (7), Staurodesmus (4), Staurastrum (25), Cosmocladium (2), Sphaerozosma (2), Hyalotheca (1) and Desmidium (1) are depicted by line drawings and briefly discussed with regard to their ecology, taxonomy or distribution within the Czech Republic or Central Europe. In addition, SEM images are provided for 45 taxa, and, finally, a comprehensive table is included with indicative notations concerning all taxa found.
The coccoid green algae Coenochloris planoconvexa and Echinocoleum elegans are assigned to different families (Radiococcaceae and Oocystaceae, respectively), but display similar ray–like mucilaginous envelopes. Molecular analysis of the 18S rRNA gene of C. planoconvexa CAUP H 5502 and E. elegans SAG 37.93 revealed that they both belong to Oocystaceae. However, the two strains were not a part of a monophyletic cluster. Furthermore, their morphology differed, namely in the shape of their mucilaginous envelopes, and in their ability to form four–celled units in a broadened sporangial wall. Because the name Coenochloris cannot be used for members of Oocystaceae, a new genus Ooplanctella, with the type species O. planoconvexa comb. nova, is proposed.
Petalonema alatum is an interesting cyanobacterial species of subaerial calcareous habitats in gorges of the National Park Slovenský raj, Slovakia. Observation of different morphological forms in natural and culture materials is demonstrated and discussed. Cultures of P. alatum differed from natural populations mainly in the width of the filament apex, massiveness of mucilage sheaths, and degree of heteropolarity. This means that these features are more likely controlled by environmental variables. Other characteristics (heteropolarity, false branching, sheath structure) were found to be stable and consequently can have taxonomical importance.
A total of 18 species of silica–scaled chrysophytes (Chrysophyceae: one species each in Chrysosphaerella, Spiniferomonas, and Paraphysomonas; Synurophyceae: 11 Mallomonas spp. and four Synura spp.) was recorded from river samples collected in Edo State, Benin, Nigeria, from both dry and rainy seasons in 2003. Identifications were based on transmission electron microscopy. Five are new records for Nigeria, including four being newly reported for Africa. Two further species could not be identified.
The diversity of microeukaryote communities inhabiting rivers is still poorly known. Here, we have analyzed the periphytic and planktonic microeukaryote communities present in one section of the River Danube by two different methods: 18S rRNA–based terminal restriction fragment length polymorphism with fragment sequencing and microscopical analysis of the phytoplankton and periphyton. Both data sets were then related to environmental variables. Molecular fingerprinting revealed diverse communities with fluctuating composition, with the majority of sequences affiliated to the groups Bacillariophyta, Synurophyceae and Chlorophyceae. This was in accordance with microscopical data. The total number of detected T–RFs during the study period was 145, with more than half of the T–RFs being restricted to either plankton or periphyton. This suggests that the likely different natural selection regimes experienced by microeukaryotes in these two environments may promote the presence of different lineages in each of them. Significant correlations were found between phytoplankton chlorophyll–a content, phosphorus content, temperature, and the T–RFLP pattern of the planktonic microeukaryotic community, suggesting that the former environmental factors are especially important in structuring the planktonic microeukaryote communities in the River Danube. These data, together with earlier studies suggest that molecular methods are an invaluable addition in pursuit of the better understanding of the diversity and fluctuation of freshwater microeukaryotic communities.
ANGELI, N., CANTONATI, M., SPITALE, D. & LANGE–BERTALOT, H.: A comparison between diatom assemblages in two groups of carbonate, low-altitude springs with different levels of anthropogenic disturbances.
Since several decades diatoms are increasingly used for the assessment of the trophic status of different freshwater ecosystems. However, spring habitats have been only marginally considered concerning this topic. The purpose of this research was to compare the diatom assemblages of two groups of carbonate, low–altitude springs, affected by different levels of anthropogenic disturbances. Between 2005 and 2008, diatoms were sampled in 57 low–altitude, carbonate springs, keeping separate the main microhabitats (stones and bryophytes), and assessing an extensive number of morphological, physical, and chemical variables. Two datasets were considered for the present paper: the first (CESSPA, N = 25) includes carbonate springs located within the River Adige catchment, the second (CRENODAT selected springs, N = 32) includes springs located not exclusively within the same basin, and very similar to the previous ones as regards lithological substratum, altitude range, shading. Trophic and saprobity indices, together with multivariate techniques, were used to assess differences between the diatom assemblages in the two datasets. Indices revealed higher trophic and saprobic levels for the CESSPA springs than for the other group (CRENODAT). Values of the Shannon–Wiener diversity index were similar for the two groups while the average richness was slightly higher in nature–near springs (CRENODAT); higher percentages of endangered or rare taxa (Red List) were found only in the nature–near springs. The main impacts affecting the
CESSPA springs were found to be both anthropogenic disturbances, such us water abstraction and spring–bed modification, and higher nitrate values. The importance of the fine tuning of diatom–based bioassessment methods in spring habitats is stressed.
Rust–coloured shells of the aquatic gastropod Ventrosia ventrosa, a new record for eastern Greece, indicating presence of iron (EDAX analysis) were studied for detection of iron–encrusted photosynthetic epibionts in a Greek brackish–water thermal spring (38 °C). Microscopic analyses (LM, SEM) revealed the presence of a biofilm consisted of mostly facultative micro–epibionts, i.e. a) 5 periphytic taxa of coccal and filamentous cyanobacteria, including a taxonomically and ecologically interesting morphospecies, Xenococcus cf. pyriformis, dominated exclusively on the shell surface, and b) pennate diatoms with higher species richness (18 periphytic taxa of the genera Amphora, Brachysira, Cymbella, Diatoma, Encyonema, Navicula, Nitzschia, Pleurosigma, Synedra, Ulnaria; 5 taxa as new records for Greece), most of them emerging only after acid treatment of whole gastropod shells. The abundant diatoms thriving directly or nearby the iron–coatings (Cocconeis placentula var. euglypta and Achnanthes brevipes sensu lato) exhibited different modes of attachment (‘adnate’ and ‘pendunculate’, respectively). Two euendolithic cyanobacteria (Hyella sp. and Leptolyngbya terebrans; the former with special taxonomic interest) were also found perforating the delicate gastropod shells, with no distinct differentiation in the extent of infestation between live and dead gastropod shells. Moreover, the possible impact of these encrusted photosynthetic assemblages on V. ventrosa was investigated; statistical analysis showed that a) there is no ‘drag effect’, induced by the epibionts, influencing the gastropod growth (i.e. shell length), b) shell size enlargement provides a favourable space and promotes the intense fouling by both micro–epibionts and macro–epibionts (egg–capsules), and c) the detachment prevention of egg–capsules is attributed to the biofilm development.
The morphology of Makinoella tosaensis Okada 1949, a chlorococcalean coenobial alga described from Japan and since then observed only in Korea, has been studied under the LM from field material and in laboratory cultures. Its collection from a small fountain in the campus park of the Slovak Academy of Sciences in Bratislava, Slovakia, is the first record outside East Asia. The morphology of coenobia and cells in this material is in agreement with published data of the species.