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Limnological characteristics of lake Amvrakia, a deep warm monomictic and sulphate lake in western Greece, are presented . A set of physical and chemical variables were monitored for one year cycle (October 1988-September 1989 . Phytoplankton community structure and biomass are given for the entire depth of the water column . The trophic status of the lake is compared to that of other temperate and tropical lakes . 207

SUMMARY: Sequences of LSU and SSU ribosomal RNA genes and phylogeny have not been widely investigated for the dinoflagellate Coolia monotis Meunier, and no information is available on the small and large rDNA subunits of Mediterranean strains. A strain isolated from the Thermaikos Gulf in northern Greece was identified as C. monotis-a new record for the Greek algal flora-using thecal morphology by light, epifluorescence and scanning electron microscopy. The small subunit and partial (D1/D2) large subunit sequences were analyzed and compared to other strains of C. monotis and dinoflagellates from various regions. Thecal architecture showed that the Greek strain of C. monotis was phenotypically similar, but not identical, to other strains reported in literature. The partial LSU sequence (700 bp) was found to vary by 113 bp positions (16%) from the C. monotis strain from New Zealand, whereas the SSU (1757 bp) had 15 bp differences (0.85%) from the strain from Norway. Phylogenetic tree construction showed that the Greek strain fell within the Coolia clade and had a close relationship with the families Ostreopsidaceae and Goniodomaceae of the order Gonyaulacales. Preliminary findings suggest the existence of different genotype strains of C. monotis with large intraspecific genetic variability and minimal morphological differentiation (similar phenotypes). Certain ecological and evolutionary implications of these findings are discussed.Keywords: Coolia monotis, Greece, microscopy, rDNA, taxonomy, phylogeny. RESUMEN: MORFOLOGÍA Y FILOGENIA DEL RDNA DE UNA SUBESPECIE MEDITERRÁNEA DE COOLIA MONOTIS (DINOPHYCEAE) DE GRECIA. -Las secuencias de los genes del RNA de las subunidades ribosomales grandes y pequeñas (LSU y SSU, respectivamente) y la filogenia del dinoflagelado Coolia monotis Meunier han sido poco investigadas, y no hay información disponible sobre los genes LSU y SSU de subespecies mediterráneas. Una subespecie aislada del golfo de Thermaikos en el norte de Grecia fue identificada como C. monotis -una nueva aportación a la flora algal griega-por medio de la morfología de la teca observada a través de microscopía óptica, de epifluorescia y electrónica. Las secuencias correspondientes a la subunidad pequeña y a la parte (D1/D2) de la subunidad grande fueron analizadas y comparadas a las de otras subespecies de C. monotis y otras especies de dinoflagelados de diversas regiones. La arquitectura de la teca mostró que la subespecie griega de C. monotis era fenotípicamente similar, pero no idéntica, a otras subespecies registradas en la literatura. Se encontró que la secuencia parcial de la LSU (700 pares de bases o bp) difería de la de C. monotis de Nueva Zelanda en las posiciones de 113 bp (16%), mientras que la SSU (1757 bp) se diferenciaba en 15 bp (0.85%) de la subespecie de Noruega. La construcción del árbol filogenetico demostró que la subespecie griega se situaba dentro de la rama de Coolia y presentaba una relación cercana con las familias Ostreopsidaceae y Goniodomaceae del orden Gonyaulacales. Resultados pre...

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There is continuous interest in many countries in maintaining and manipulating the rich ecological value of hypersaline ecosystems for aquaculture. The Megalon Embolon solar saltworks (northern Greece) were studied in sites of increasing salinity of 60-144 ppt to evaluate Dunaliella salina abundance and microalgal composition, in relation to physical and chemical parameters. Cluster and ordination analyses were performed based on the biotic and abiotic data matrices. Using fresh aliquots from 60 and 140 ppt salinity waters, phytoplankton performance was appraised with flask cultures in the laboratory by varying the inorganic PO 4 -P concentration at 23 • C and 30 • C. At the saltworks, among the most abundant microalgae identified were species of the genera Dunaliella, Chlamydomonas, Amphora, Navicula, and Nitzschia. Dunaliella salina populations were predominant comprising 5-22% of the total microalgal assemblages during spring, but only 0.3-1.0% during the summer, when grazing by Artemia parthenogenetica and Fabrea salina was intense. D. salina cell density in April-July was in the range of 0.4-12.5 × 10 6 L −1 with typical densities of 1.5-4.5 × 10 6 L −1 . Overall, microalgal densities were high in salinities of ≥100 ppt when inorganic-P concentrations were ≥0.20 mg L −1 within saltworks waters. Multivariate analysis of species abundance showed that algal growth responses were primarily related to variation in salinity and inorganic-P concentrations, but also to NO 3 -N concentration. In the laboratory, experiments indicated effective fertilization and denser microalgal growth under high inorganic PO 4 -P applications (4.0 and 8.0 mg L −1 ) at 60 ppt salinity and 23 • C. The lower PO 4 -P applications (0.6-2.0 mg L −1 ) were more effective at 60 ppt salinity and 30 • C. At 140 ppt salinity, microalgal growth response was less obvious at any of the corresponding phosphorus concentrations or temperatures. In both salinity experiments, Dunaliella salina bloomed easily and was predominant among the microalgae. Our observations indicate that Dunaliella salina populations and the overall rich microalgal profile of the saltworks, along with their performance in laboratory mono-and mixed cultures hold promise for mass cultivation within the M. Embolon saltworks basins.

Abstract:The present paper deals with biocommunities of cave Leontari, Attica (Greece) focusing on its lithophytic cyanobacteria, and the associated microfauna. The cave is of archaeological importance, not touristically exploited, naturally lighted through the entrance; it consists of one chamber with poor stalactite and stalagmite limestone decoration. During a survey in three campaigns, samples of cyanobacteria and soil invertebrates were collected from four sites (I-IV) along a light(PAR)-temperature-humidity gradient. Light microscopic observations of natural and cultured material have shown that epilithic and endolithic cyanobacteria were almost the exclusive component of cave photosynthetic microflora. Twenty two taxa were identified including the taxonomically interesting morphotypes Chroococcus spelaeus, Asterocapsa sp. and Chlorogloea sp. Arthropods were found as dominant soil invertebrates represented by nine taxa.

Caves have generally been found to host phototrophic micro-organisms from various taxonomic groups, with cyanobacteria comprising an important group that have adapted to these stable and highly specific environments. A polyphasic study based on aspects of classical morphology and molecular data revealed two new monospecific genera from fresh material of Greek and Spanish caves. Both taxa are characterized by obligatory true branching (T-type, V-type and false branching), the presence of heterocysts, and reproduction by hormocysts and akinetes. They shared some similarities in their morphological characteristics as revealed by light, scanning electron and transmission electron microscopy, but phylogenetic analysis based on 16S rRNA gene sequences showed that the two phylotypes were different (89.8 % similarity); this represents an example of shared morphology in genetically different strains of cave-adapted species. Phenotypic and genetic traits strongly support classification of the phylotypes as independent taxa in the order Stigonematales (the most differentiated and complicated group of cyanobacteria), family Loriellaceae Geitl 1925. Hence, the names Iphinoe spelaeobios Lamprinou and Pantazidou gen. nov., sp. nov. and Loriellopsis cavernicola Herná ndez-Mariné and Canals gen. nov., sp. nov. are proposed.Caves represent a stable ecosystem where light controlling the growth of photosynthetic organisms is the limiting factor (Hernández-Mariné & Canals, 1994;Asencio & Aboal, 1996). However, a variety of microhabitats for autotrophic growth is created when adequate natural light reaches the inner part of the caves or when artificial lights are installed.There have been many studies concerning the photosynthetic microflora of these unique environments worldwide (Borzi, 1917;Chu, 1952;Chu et al., 1991;Friedmann, 1955Friedmann, , 1964 Şerbãnescu & Decu, 1962;Claus, 1962Claus, , 1964Hajdu, 1966;Golubić, 1967;Skuja, 1970;Bourrelly & Dupuy, 1973;Dobat, 1977;Leclerc et al., 1983;Abdelahad, 1989;Sant'Anna et al., 1991;Aboal et al., 1994;Asencio & Aboal, 1996, 2000 Ariño et al., 1997;Vinogradova et al., 1998;Dor & Dor, 1999; Hernández-Mariné et al., 2001; Roldán et al., 2004;Pantazidou & Roussomoustakaki, 2005;Lamprinou et al., 2009; Roldán & Hernández-Mariné, 2009). Despite the fact that Greece has more than 8000 karstic caves, since limestone is the dominant rock over the land area, studies on cave microflora are scarce (Anagnostidis et al., 1982; IliopoulouGeorgoudaki et al., 1993;Pantazidou, 1996Pantazidou, , 1997Pantazidou & Roussomoustakaki, 2005;Lamprinou et al., 2009). A similar situation is observed in Spain, even though several caves are known, mainly in the Mediterranean area (GraciaAlonso, 1974;Asencio & Aboal, 1996, 2000 Beltrán & Asencio, 2009; Hernández-Mariné et al., 2001; Roldán et al., 2004; Roldán & Hernández-Mariné, 2009).Abbreviations: LM, light microscopy; PAR, photosynthetically active radiation; RH, relative humidity; SEM, scanning electron microscopy; TEM, transmission electron microscopy.The ...

Abstract:al., Engene et al., 2013). These interesting and biochemically active compounds possess biological activity covering a wide range of antibacterial (Mundt et al