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The diatoms are one of the most important groups of organisms for biomonitoring studies. In Turkey, most previous applications of diatoms to water quality monitoring have focused on the pennate diatoms, with almost no attention given to the centric forms. The paper presents the centric diatoms in some river catchments in Central Anatolia (Konya closed catchment and Kızılırmak) and Western Anatolia (Marmara, Sakarya, Susurluk, Akarçay, Küçük Menderes, and Meriç-Ergene in the Marmara and Aegean regions). The survey of these catchments is based on samples collected between 2009 and 2013 from 33 different locations, including some springs from Türkmen Mountain and Domaniç forest, as well as small streams and big rivers of the Anatolian Peninsula. Altogether 30 taxa were found, of which 14 are new records for the freshwater diatom flora of Turkey.

Centric diatom taxa in the Cyclotella ocellata and C. comensis complexes show high morphological variability and often apparently continuous morphological transitions. In this study, we investigated natural assemblages of the C. ocellata/C. comensis complex from Hungarian and Croatian lakes and from Turkish streams using morphological and molecular methods. The studied assemblages contained cells with morphologies resembling C. ocellata as well as other, closely related, species: C. comensis, C. pseudocomensis, C. costei, and C. trichnoidea. The goal of our paper was to assess whether the observed morphological differences were due to intraspecific variability or suggest the existence of several, putatively distinct species.Ten morphometric characters were measured, which, either individually, or in pairs, did not differentiate the nominal taxa in our assemblages. However, multivariate discriminant analysis has revealed a group including C. ocellata and C. trichonidea morphologies could be separated from another containing C. comensis, C. pseudocomensis and C. costei.A nuclear (18S rDNA) and a chloroplast (rbcL) gene were amplified and partially sequenced from environmental DNA or from isolated cells. The sequences showed little variability among the assemblages and nominal species. Although general congruence of molecular and morphometric separation supports the species level separation of C. ocellata/trichonidea from the probably conspecific C. comensis/pseudocomensis/costei, sequence divergences between the groups are in the same range as within them, so that a conspecificity of all four taxa cannot be unequivocally excluded.

One of the key actions identified by the Water Framework Directive (WFD; 2000/60/EC) is to develop ecological assessment tools and carry out a European intercalibration (IC) exercise. The aim of the Intercalibration is to ensure that the values assigned by each Member State to the good ecological class boundaries are consistent with the Directive’s generic description of these boundaries and comparable to the boundaries proposed by other MS. In total, 83 lake assessment methods were submitted for the 2nd phase of the WFD intercalibration (2008-2012) and 62 intercalibrated and included in the EC Decision on Intercalibration (EC 2013). The intercalibration was carried out in the 13 Lake Geographical Intercalibration Groups according to the ecoregion and biological quality element. In this report we describe how the intercalibration exercise has been carried out in the cross-GIG Lake Phytobenthos group., JRC.H.1-Water Resources

WOS: 000301990400025, A compilation/discussion of data published on diatoms in aquatic systems from Turkey is provided based on data ordered according to type of study, type of water body, and river basins within the conterminous Turkish territory. The majority of phycological studies in Turkey focus on phytoplankton seasonal changes in lakes and reservoirs located in lowlands, while only a few studies related to high mountain lakes and lotic systems have been published. Palaeolimnological work is also restricted to some basins, while others have been completely neglected from this perspective. Several studies performed during last decade focus on the application of diatoms to water quality monitoring, a topic that is rapidly gaining popularity among local scientists. The main shortcoming in all the studies is the pervasive use of publications based on European material as identification sources, which may have resulted in force-fitting of Turkish taxa into European-based concepts, thus giving a skewed impression of diversity and an imprecise estimation of the ecological requirements of the different taxa. Additionally, because of current research practices, chiefly by native researchers, the vast majority of publications only contain reports of the most common taxa. Even for these common diatoms, there is a severe lack of supporting information in the form of descriptions, argumentation or illustrations, which makes the elaboration of a catalogue a difficult if not impossible task. The aim of this manuscript is to provide a background for further investigations; it includes an identification of neglected geographical and research areas.

Karstic lake ecosystems are specific and have great ecological significance. They provide unique habitats to numerous organisms, macroinvertebrates as well as planktonic organisms, the latter representing the reasons why it is important to understand how those complex and diverse ecosystems function. Dinoflagellates are an important part of phytoplankton community as they sometimes contribute significantly to the total phytoplankton biomass. Results in this paper were obtained during phytoplankton ecology research with the objective to document armored dinoflagellate species. The taxonomic interest for dinoflagellates started during project of comparative studies on centric diatoms and dinoflagellates of Hungarian and Croatian large rivers, reservoirs and lakes and continued with project of taxonomical comparative studies on dinoflagellates species on the same area. During the projects, phytoplankton samples collected in period from 1995 to 2006 on 21 localities in Croatia were reviewed. Preliminary results of first project were presented on Croatian Biological Congress in 2006 as first annotated check list of 20 free-living armored dinoflagellates of the Croatian freshwater systems. A main goal of the paper was to present detailed taxonomic morphological features of armored dinoflagellate taxa assigned to the genera Ceratium, Peridinum and Peridiniopsis in Croatian freshwater karstic systems. Taxonomical observations and general morphological structures are based on SEM and light micrographs. Results present data from scanning electron microscopy, sketchy drawings of main distinguishing features and species-specific ecological preferences and/or tolerance in karstic systems. Also, taxonomical issues of problematic species, such as Peridinium umbonatum/incospicuum group, are shortly discussed.

WOS: 000296070300017, Water is one of the most essential factors for civilization, and also among the most important items in the new world order due to its unrenewable feature. In this regard, developed countries have continually been monitoring and classifying their water. For this reason, a number of EU countries have developed a national water quality system, considering characteristic structure of their own rivers and have used this type of indices for revealing the current stituation of their water quality level. While water quality monitoring was first determined according to physical and chemical parameters, biological factors such as algae, especially diatoms, benthic macroinvertebrates and fish have recently been used for this purpose. Investigation of benthic diatoms is recommended by the Water Framework Directives (WFD) and European Parliament 2000 directive, 2000/60/EC. They are considered key organisms in ecological quality analyses of water courses and have been applied for more than a decade in several countries of Europe (Austria, Switzerland, Germany, Belgium, France, Poland, Finland, Luxemburg, United Kingdom, Spain, Portugal, Italy). Water quality monitoring, based on diatom indices, is a new topic for Turkey especially after the 2000s, and it is getting more and more important each clay. The aim of this study, was to form a database for future studies based on diatoms in Turkey.

Epilithon and epiphyton samples collected from Lake Balaton (Hungary) in 2006 and 2007 contained, as dominant, specimens similar to those described in 1902 by Pantocsek as Fragilaria hungarica. Since Pantocsek had previously used the name F. hungarica in 1892 for a fossil taxon from Deménd (Slovakia), the Lake Balaton specimens required a new name. Additionally, information collected during this study, using light (LM) and scanning electron microscopy (SEM), supports the transfer of the specimens from Lake Balaton to the genus Staurosira Ehrenberg. The nomenclatural consequences from Pantocsek's dual use of the name F. hungarica, are solved herein by the proposal of the new name Staurosira grigorszkyi nom. nov.

The population of an unknown naviculoid diatom from karstic, polymictic Lake Vrana in Croatia was identified as Navicula hedinii Hustedt, a species that was described in 1922 from a small lake in eastern Turkestan. The occurrence of Navicula hedinii in samples collected for the study of the relationship between phytoplankton and environmental variables in a lake, allowed a detailed study of the morphological features of this diatom species using light microscopy (LM), scanning (SEM) and transmission electron microscopy (TEM). Type material collected by Sven Hedin and kept at the Friedrich Hustedt Diatom Collection in Bremerhaven was also examined using light and scanning electron microscopy. These results, the possible conspecificity with the Croatian species and the implication for the correct taxonomical position of this species are discussed. Based on the ultrastructure of this species, it can no longer be included within the taxonomical concept of Navicula s.s. Bory. Due to the large similarity species Navicula pseudocrassirostris Hustedt certainly stands very near to Navicula hedinii and it is used in the comparison. Following a comparative morphological analysis of species with genera bearing similar characters (Adlafia, Veigaludwigia, Kobayasiella, Cavinula, Stenoneis, Climaconeis, Berkeleya, Sellaphora, Cosmioneis), a new genus, Envekadea Van de Vijver, Gligora, Kralj & Cocquyt gen. nov. is proposed. The genus name Envekadea is derived from the NVKD (Nederlands-Vlaamse Kring van Diatomisten), the association of the Dutchspeaking diatomists. The name was chosen to underline its relationship with Adlafia, a genus named after the Association of the French-speaking diatomists (ADLaF)

Bu araştırmada, Temmuz 2003-Ocak 2004 tarihleri arasında alınan örneklerde analiz edilen Düden Şelalesi (Antalya) bentik diyatomeleri, taramalı elektron mikroskopta incelenmiş ve mikrografları alınmıştır.

Bu araştırmada, Ağustos 1998-Nisan 1999 tarihleri arasında alınan örneklerde analiz edilen, Değirmendere (Zigana-Trabzon) Irmağı bentik diyatomeleri, taramalı elektron mikroskopta incelenmiş ve mikrografları alınmıştır.

Phytoplankton in the naturally eutrophicated and periodically anoxic salt Lake Rogoznica was investigated in the period from April 2004 to March 2005. The research provided first data on composition and abundance, as well as temporal and spatial distribution of nanophytoplankton. The lake is karstic and stratified, with regard to temperature, salinity, density, oxygen and hydrogen sulphide concentration. The layer above the halocline (above 6-7 m) is unstable, while the layer below has low oxygen saturation and high sulphur concentration. The nanophytoplankton cell counts were obtained with phase contrast 40 x objective using the inverted microscope Zeiss Axiovert 200. Extreme ecological conditions resulted in low species diversity with high abundance. Nanophytoplankton maximum abundance alternated with microphytoplankton maximum, not following the succession typical for temperate climate conditions. The community was composed of the following recognizable higher taxa: diatoms, dinoflagellates, coccolithophorides, cryptophytes and green flagellates. Pennate diatoms dominated the community in summer and late autumn with maximum abundance in the halocline layer. Centric diatoms were present throughout the year in the whole water column, with maximum development in winter. Under the scanning electron microscope (HITACHI S-2600-N) we were able to distinguish the centric genera such as Thalassiosira, Podosira and Hyalodiscus. Within pennate diatoms we determined Brachysira aponina and Thalassionema nitzschioides.

Dinoflagelati s 21 lokaliteta na području Republike Hrvatske istraživani su u razdoblju od 1995. do 2006. godine. Uzorci fitoplanktona za kvalitativne i kvantitativne analize uzimani su u krškim, baražnim jezerima, akumulacijama, rijekama, povremeno plavljenim područjima i malim stajačicama (lokve, bare). Provedena istraživanja po prvi puta daju sustavan popis slobodno živućih oklopljenih (tekatnih) vrsta dinoflagelata slatkovodnih ekosustava Hrvatske. Sustavni popis dinoflagelata za istraživano područje Hrvatske uključuje 20 vrsta (izuzevši podvrste, varijetete i forme) koje pripadaju rodovima: Ceratium, Peridinium i Peridiniopsis. Za istraživane lokalitete na području Hrvatske po prvi puta su zabilježeni nalazi 12 vrsta i to sedam novih vrsta roda Peridiniopsis /Peridiniopsis borgei Lemmermann, Peridiniopsis cunningtonii Lemmermann, Peridiniopsis elpatiewskyi (Ostenfeld) Bourrelly, Peridiniopsis kevei Grigorszky et Vasas, Peridiniopsis penardiforme (Linderman) Bourrelly, Peridiniopsis penardii (Lemmermann) Bourrelly, Peridiniopsis polonicum (Woloszyńska) Bourrelly/ i pet vrsta roda Peridinium /Peridinium lomnickii, Woloszyńska, Peridinium palatinum Lauterborn, Peridinium gatunense Nygaard, Peridinium umbonatum Stein, Peridinium volzii Lemmermann/. Rezultati istraživanja daju uz taksonomiju, temeljenu na fotodokumentaciji SEM i svjetlosnoj mikroskopiji, uvid u prostornu i sezonsku distribuciju te utjecaj fizičko-kemijskih čimbenika na ekologiju pojedinih vrsta.

The genus Entomoneis Ehrenberg includes pennate diatoms with structurally complex frustules, characterized by bilobate raphe-bearing keel elevated from the valve body, the morphologically variable junction lines and numerous girdle bands. Entomoneis species are mostly epipelic, found in brackish or marine sediments, with few freshwater representatives. The systematics of the genus is still underexplored, as there are 45 recorded taxa of which only 18 are taxonomically accepted. Up to date, there are only three Entomoneis species recorded in the Adriatic Sea: Entomoneis alata (Ehrenberg) Ehrenberg, Entomoneis paludosa (W. Smith) Reimer and Entomoneis pulchra (Bailey) Reimer. Here we propose a new diatom species belonging to the genus Entomoneis isolated during BIOTA (Bio-tracing Adriatic water masses) expedition conducted in February/March 2015 in the southeastern Adriatic Sea. The enigmatic taxon was found in the water samples in low abundances (up to 200 cells/L), and three monoclonal strains were established from plankton net samples. The description and the proposed taxonomic affiliation are based on both morphological observations (LM, SEM, TEM) and molecular analyses from cultivated strains. In addition to characteristic Entomoneis features such as panduriform cells often torsioned along the apical axis and raphe with simple/straight endings positioned on the sigmoid keel, we found several peculiar morphological characters for the newly proposed species: (1) cells are very small, being 11-22 μm long and 3-7 μm wide, (2) frustules are very lightly silicified with very delicate appearance and without striae or fibulae visible in LM, (3) striae structure appears smooth in SEM, but TEM observations reveal two parallel rows of marginal rectangular perforations, (4) valvocopulae are perforated by teardrop shaped areolae and (5) junction lines are straight to slightly arcuate. According to our initial phylogenetic results, NJ tree based on rbcL gene sequence data places our isolates as a distinct subgroup in the Entomoneis clade negating close phylogenetic relation to any other recognized Entomoneis species. However, further analyses will give us the exact position of the adriatic species within the Entomoneis genus and a clearer picture of its relationship with other canal- raphe-bearing diatom genera.

The microphytoplankton in Lake Visovačko jezero was studied during one year period, on base of monthly sampling data covering period from April 1995 to March 1996. Changes in species composition and seasonality of the dominant species were investigated in relation to the environmental variables. Diatoms dominated the phytoplankton assemblage of the lenitic barrage area of karstic River Krka. The master species in Lake Visovačko jezero was Asterionella formosa Hass. The dinoflagellates (Ceratium hirundinella (O. F. Müller) Bergh) were generally the second most representative group in terms of abundance, where their annual development has been shifted to the late summer and autumn period. In the Lake Visovačko jezero, under mesotrophic conditions Reynolds groups B and C are present, with exception of late summer and autumn assemblages which were characterized by association of large dinoflagellate species known as Group LM. The effects of the short term dynamics of environmental factors on the algal growth in barrage lenitic area of calcareous river stressed several variables as important factors controlling annual microphytoplankton distribution. The temperature was the most valuable variable affecting the species abundance, changes in dominance and species composition (Primer 5, BIO-ENV). CCA analysis performed on abundance dataset and environmental variables confirm the importance of temperature but also highlighted total phosphorus, conductivity and silica.

The present paper is a revision of diatoms and dinoflagellates contributions to the algal assemblages in Croatian waterbodies concerning the spices number and diversity. The aim is to define diatoms and dinoflagellates flora in several freshwater and some brackish habitats in Mediterranean and continental part of Croatia. Study contains data sets of several investigations held at Krka River, Zrmanja River, Drava River and Plitvice Lakes. Analyses were based on relevant studies and available data during last decade. In the term of species number diatoms dominated mostly the assemblages same planktonic, periphyitic and benthic, in Croatian rivers, their barrage lakes, reservoirs and estuary. Since taxonomy is rapidly developing discipline, instead of conclusion, in the paper, several future objective are defined: (i) future taxonomical investigations of centric diatom species and dinoflagellates (ii) definition of annual development of species concerning species environmental requirements, and (iii) in the term of taxonomy, comparisons of similar and species sharing the same names, and concerning ecology, comparison of assemblages, with similar in neighboring countries.

The small karstic Zrmanja River (69 km long) discharges into central-eastern Adriatic Sea. High oxygen saturation and water transparency, as well as low nutrient concentrations indicated the oligotrophic character of the river. We present taxonomic composition and vertical distribution of diatoms attached on artificial substrate (Plexiglas) in the lower reach of the Zrmanja River, in July 2000. Thirty attached diatoms were determined on Plexiglas plates distributed throughout the 2.5 deep water column. The most frequent (>78 %) and abundant (>10^5 cells cm-2) diatoms were Achnanthes and Fragilaria species. The highest abundances (4.4 x 10^5 cells cm-2) were found at the depth of 0.5 m, while number of taxa increased with depth.

Net phytoplankton and periphyton from artificial substrate (plexy slides) were investigated on a vertical profile of travertine barrage lotic area of the River Krka, located in karstic region of the NW Dinarid Mountains (Croatia). Net phytoplankton samples were collected monthly during a year, at six depths. Periphyton samples were carried out after 30, 60, and 90 days of exposition during summer period at three depths. Plexy slides were placed parallel and perpendicular to the current velocity. The physical and chemical parameters were measured simultaneously. Seasonal distribution of net phytoplankton abundance showed two peaks, in June and March. The highest abundance was observed at depths of 5 and 10 meters. In periphyton community the highest cells density was observed after 60 days of exposition on horizontally placed surface, in epilimnion. During the research period 42 and 88 species were identified in phytoplankton and periphyton community, respectively. Main abundance constitution corresponded to the diatoms, in phytoplankton same as in periphyton. The canonical correspondence analysis (CCA) of the full data set indicated some separation of the data in ordination space based on seasons for plankton and days of exposition for periphyton. First three axes for plankton data explained 17.0 % and for periphyton data explained 25.9 % of the species variance. The most influential parameters associated with the first axis were: temperature, total phosphorus and dissolved oxygen for plankton, and total phosphorus, orthophosphates and conductivity for periphyton. Parameters that correlated with the second axis were nitrites and nitrates for plankton, and temperature and total nitrogen for periphyton.

The centric diatom Cyclotella striata is a common planktonic species in temperate estuaries as well as in the eastern coastal Adriatic Sea. We determined seasonal appearance of the species in the eastern Adriatic Zrmanja River estuary in the period from June 1998 - February 2001. The estuary is highly stratified (salt wedge), with sharp halocline. The depth of the halocline is determined by the Zrmanja river inflow. In summer salinity was high due to low river inflow. The highest inflow (avg 65 m3 s-1) and lowest salinity was registered in the period December - April. Annual temperature varies from 6.7 - 26.55 º ; ; C (avg 16.39 º ; ; C), and the salinity from 0 - 38 psu (avg 18.97 psu). Concentration of nutrients was low and transparency high, implying the oligotrophy of the estuary. In the Zrmanja Estuary microphytoplankton was mostly composed of diatoms (avg 1.9 x 105 cellsL-1), while dinoflagelates (avg 103 cellsL-1) and cocolithophorids (1.2 x 102 cellsL-1) were less abundant. Diatom Cyclotella striata was abundant species in spring (March - May), providing maximum of 2 x 106 cellsL-1. It appeared mostly in short chains of cells with valve diametar of about 8µ ; ; m and pervalval axis length of about 5 µ ; ; m. Cyclotella striata is marine diatom, but prefers decreased salinity. It could be mostly detected in the salinity range between 13 and 30 psu, with maximum development within the range of 13 to 17 psu. It was most abundant in and below the halocline. Due to such termohaline preferences C. striata was mostly distributed in the middle reach of the Zrmanja Estuary (in the area of stations N1 and Z1). In the upper reach of the estuary, average abundance was much lower. Cyclotella striata preferred temperatures from10 - 17 ˚ C. Outer stations were characterized by more stabile ecological conditions and more constant appearance of C. striata.

The abundance of phytoplankton, thermohaline conditions and concentration of nutrients were determined in the highly stratified Zrmanja Estuary, eastern Adriatic coast, Croatia, in the period from June 1998 to October 2000.

Periphyton assemblages (algal biofilms) can be important factor for majority of production in shallow, unshaded, coastal aquatic habitats. The karstic river Zrmanja (69 km) discharges into the eastern–central Adriatic Sea, and forms shallow, highly stratified estuary. The distribution of attached diatoms on artificial substrates and those in plankton was analyzed in the upper reach of the estuary in July 2000. The sharp halocline was detected in the 1–1.5 m layer. The brackish layer above the halocline (14 PSU), and marine layer (30-34 PSU) bellow the halocline was detected. Thermic conditions (19 to 24 şC) were characterized by subsurface temperature maximum in the halocline. The extremely low concentrations of nutrients (orthophosphates 0.02-0.06 mmol L-1, nitrates 5.3-7.6 mmol L-1), and high oxygen saturation (80-90%) indicated oligothrophic character of the estuary. The euphotic layer extended to the bottom (4 m deep). The maximum abundance of penatae diatoms (9.6 x 107 cells cm–2) was registered after 16 days of colonization in the upper reach of the estuary. The similar abundance was found after 28 days of colonization. The attached penatae diatom Cocconeis scutellum reached the abundance of 105 cells cm-2 after 16 days, while 3.8 x 105 cells cm-2 after 28 days of colonization, in the brackish layer. The local anthropogenic input of nutrients resulted in the 11% and 15% greater abundance of total attached pennatae diatoms, and C. scutellum, respectively. In plankton, C. scutellum was mostly distributed in the 1-3 m layer (400-6400 cells L-1). The outflowing current above the halocline detached cells from the substrate and transported them down the estuary. The population successively sank and accumulated around the halocline, died in the layer of strong gradient of salinity and continued to sink to the bottom. Due to transport by currents, suspended C. scutellum cells were 30% more abundant at the 6 km downstream station. The population was not detectable in the middle reach of the estuary where salinity increased to 34.51 PSU.