Intercalibration of the national classifications of ecological status for Eastern Continental lakes: Biological Quality Element: Phytoplankton

The European Water Framework Directive (WFD) requires the national classifications of good ecological status to be harmonised through an intercalibration exercise. In this exercise, significant differences in status classification among Member States are harmonized by comparing and, if necessary, adjusting the good status boundaries of the national assessment methods. Intercalibration is performed for rivers, lakes, coastal and transitional waters, focusing on selected types of water bodies (intercalibration types), anthropogenic pressures and Biological Quality Elements. Intercalibration exercises were carried out in Geographical Intercalibration Groups - larger geographical units including Member States with similar water body types - and followed the procedure described in the WFD Common Implementation Strategy Guidance document on the intercalibration process (European Commission, 2011). The Technical reports are organized in volumes according to the water category (rivers, lakes, coastal and transitional waters), Biological Quality Element and Geographical Intercalibration group. This volume addresses the intercalibration of the Eastern Continental Lake GIG Phytoplankton ecological assessment methods. Three countries (Bulgaria, Hungary, Romania) participated in the intercalibration exercise and harmonised their phytoplankton assessment systems. The results were approved by the WG ECOSTAT and included in the EC Decision on intercalibration (European Commission, 2018).JRC.D.2-Water and Marine Resource

Intercalibrating the national classifications of ecological status for very large rivers in Europe: Biological Quality Element: Phytoplankton

The European Water Framework Directive (WFD) requires the national classifications of good ecological status to be harmonised through an intercalibration exercise. In this exercise, significant differences in status classification among Member States are harmonized by comparing and, if necessary, adjusting the good status boundaries of the national assessment methods. Intercalibration is performed for rivers, lakes, coastal and transitional waters, focusing on selected types of water bodies (intercalibration types), anthropogenic pressures and Biological Quality Elements. Intercalibration exercises were carried out in Geographical Intercalibration Groups - larger geographical units including Member States with similar water body types - and followed the procedure described in the WFD Common Implementation Strategy Guidance document on the intercalibration process (European Commission, 2011). The Technical reports are organized in volumes according to the water category (rivers, lakes, coastal and transitional waters), Biological Quality Element and Geographical Intercalibration group. This volume addresses the intercalibration of the Very large river Phytoplankton ecological assessment methods. Thirteen countries (Austria, Belgium (Flanders), Bulgaria, Croatia, Czech Republic, Estonia, Germany, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia) participated in the intercalibration exercise and harmonised their benthic invertebrate assessment systems. The results were approved by the WG ECOSTAT and included in the EC Decision on intercalibration (European Commission, 2018). In addition, four countries (Italy, Finland, Norway, Sweden) provided justification for excluding Phytoplankton BQE assessment system.JRC.D.2-Water and Marine Resource

Karyotypic analysis of two algae species Scenedesmus incrassatulus Bohl and Scenedesmus antennatus Bréb (Chlorophyta, Chlorococcales).

The karyotypes (number, morphology and size of the chromosomes) of two algae species of Scenedesmus genus, S. incrassatulus and S. antennatus, were studied. The karyotype of S. incrassatulus (n=4) was asymmetric, characterized by two large metacentric, one large submetacentric and one small metacentric chromosomes. The karyotype assembly of S. antennatus (n=6) reveals two metacentrics and four submetacentrics. This karyotype was symmetric. The general chromosomal formulae of both species, as well as the total average metaphase length of their haploid set are presented. The results of chromosomal studies of other related species are compared and discussed. Data from the karyotypic analysis showed that S. incrassatulus, S. antennatus and S. obliquus are separate biological species from taxonomical point of view

Filamentous cyanoprokaryotes (Cyanoprokaryota/Cyanobacteria) in standing waters of Bulgaria: diversity and ecology

Cyanoprokaryotes are widespread organisms, which dominate in different water basins. In the present study, we have investigated the diversity of this group and related physicochemical parameters in 35 standing water basins in Bulgaria. We found 29 cyanoprokaryotic species, which belong to 13 genera from the orders Synechococcales, Spirulinales and Oscillatoriales. The frequency quotient of each species was calculated. Information about the distribution of the identified species and typology of the water basins is also provided

Zespoły fitoplanktonu i produkcja cyjanotoksyn w wybranych nizinnych jeziorach i zbiornikach Bułgarii

One of the most evident consequences of eutrophication of waters is the progressive spreading of persistent cyanobacterial blooms. They are often accompanied by the production of cyanotoxins in concentrations, which are hazardous for human health. In this research, we analysed phytoplankton communities in four lowland water bodies, for the presence of cyanobacterial blooms and toxin production. The cyanobacterial biovolumes we found, determine three of the lowland water bodies: Onogur Reservoir (OR), Asparuhov Val Reservoir (AVR), and Srebarna Lake (SL) as “Alert Level 1” of potentially hazardous levels of cyanotoxins. Cyanobacterial biovolume exceeds the threshold value of 8 mm3 L-1 (recreational waters) in AVR and SL at the end of the summer period. In OR, we registered sustainable bloom of Microcystis spp. during the whole summer season, and extremely high average seasonal value of the total biovolume (146.5 mm3 L-1). Micro-cystins were reported in all four analysed water bodies, with the highest concentration in OR (6 µg L-1). Cylindrospermopsin was detected in AVR and OR, while saxitoxins were in AVR and SL. The concentrations of cyanotoxins do not exceed the guideline values in recreational waters. However, the increased biovolumes of cyanobacteria are a signal that in three of the analysed water bodies, monitoring is recommended at the levels of cyanotoxins during the summer period.Najbardziej widocznym efektem eutrofizacji wód są coraz obszerniejsze i dłużej utrzymujące się zakwity sinic. Często towarzyszy im produkcja cyjanotoksyn w stężeniach niebezpiecznych dla zdrowia człowieka. W niniejszej pracy analizowaliśmy zespoły fitoplanktonu w czterech nizinnych zbiornikach wodnych pod kątem występowania zakwitów sinicowych i produkcji toksyn. Na podstawie badań bioobjętości sinic określono stopień potencjalnego ryzyka związanego z produkcją niebezpiecznych stężeń cyjanotoksyn w dwóch zbiornikach Onogur (OR) i Asparuhov Val (AVR) oraz w jeziorze Srebarna (SL). Stopień ryzyka w tych akwenach określono na poziomie alarmowym 1 "Alert Level 1". Pod koniec okresu letniego w AVR i SL bioobjętość sinic przekroczyła wartość progową 8 mm3 L-1 (dla wód rekreacyjnych). W OR odnotowaliśmy stały zakwit Microcystis spp. przez cały sezon letni i wyjątkowo wysoką średnią sezonową wartość całkowitej bioobjętości (146,5 mm3 L-1). Mikrocystyny wykryto we wszystkich czterech badanych zbiornikach wodnych, przy czym najwyższe stężenie odnotowano w OR (6 µg L-1). Cylindrospermopsynę wykryto w AVR i OR, natomiast saksytoksyny - w AVR i SL. Stwierdzone stężenia cyjanotoksyn nie przekraczają wartości dopuszczalnych w wodach rekreacyjnych. Jednak zwiększone bioobjętości sinic wskazują, że w trzech z czterech analizowanych zbiorników wodnych należałoby monitorować poziom cyjanotoksyn w okresie letnim

Study on freshwater algal flora on the territory of the Bulgarka Nature Park

The study presents data on the diversity of freshwater algal flora on the territory of the Bulgarka Nature Park. One hundred ninety-four species, belonging to 11 divisions were identified. The conservation value of the identified species was assessed

What is known about Cyanoprokaryota and the algal blooms along the Bulgarian Black Sea coast: an overview

This article presents a summary of the research related to the taxonomic composition, algal blooms and toxic potential of representatives from Cyanoprokaryota (Cyanobacteria, Cyanophyta) in the coastal waters of the Bulgarian Black Sea area. Main strands of the algal research, including Cyanoprokaryota, are presented in a chronological order. The taxonomic composition of cyanoprokaryotic microorganisms, their importance as a part from the algal flora of the Bulgarian Black Sea coast and the main problems caused by this group organisms are discussed. This information could be used as a basis for future investigations related to the taxonomy, diversity, distribution and evaluation of the biological activity of cyanoprokaryotic species in the Black Sea and particularly in the Bulgarian coast area

Phytoplankton composition with an emphasis of Cyanobacteria and their toxins as an indicator for the ecological status of Lake Vaya (Bulgaria) – part of the Via Pontica migration route

As producers of biomass, cyanobacteria are a major part of the phytoplankton in a large number of water basins. Due to the cyanobacterial blooms and cyanotoxins produced, these organisms are recognized as a threat and ecological risk for water bodies. Released cyanotoxins may cause death of many organisms including birds and fish. Vaya Lake is the largest natural lake in Bulgaria. It is located on the Via Pontica migration route of birds between Europe and Africa. Since 2003, the lake has been declared as a "Wetland of international importance” under the Ramsar Convention. According to the literature data from 2002-2006, the Lake is defined as highly eutrophied due to strong anthropogenic pressure, but regular monitoring of the cyanobacterial blooms and presence of cyanotoxins after this period is missing. Taking into account the importance of this unique, protected ecosystem, our aim was to make a complete ecological assessment of the present state of Lake Vaya by using the phytoplankton, with an emphasis on cyanobacterial blooms and the presence of cyanotoxins. As results of the study, we 1) characterized the phytoplankton composition qualitatively and quantitatively; 2) evaluated the ecological status of the western and eastern part of the Lake; 3) identified the potential producers of cyanotoxins; 4) observed cyanobacterial blooms and discussed the influence of macrophytes on their spread; 5) measured the concentrations of the cyanotoxins MCs, CYL and STXs in water samples from both parts of the Lake. Our results indicated the need for continued observation of cyanobacterial composition, blooming and the presence of cyanotoxins in Lake Vaya

Polyphasic characterisation of Microcoleus autumnalis (Gomont, 1892) Strunecky, Komárek & J.R.Johansen, 2013 (Oscillatoriales, Cyanobacteria) using a metabolomic approach as a complementary tool

As a result of the continuous revision of cyanobacterial taxonomy, Phormidium autumnale (Agardh) Trevisan ex Gomont, 1892 has been transferred to the genus Microcoleus as Microcoleus autumnalis (Gomont, 1892) Strunecky, Komárek & J.R.Johansen, 2013. This transfer was based on a single strain and literature data. In the present study, we revise the taxonomic position of Microcoleus autumnalis by applying the classical approach of polyphasic taxonomy and additionally using metabolomics. Cyanobacterial strains identified as Phormidium autumnale and Microcoleus vaginatus (type species of the genus Microcoleus) were used for comparative analyses. In addition, the taxonomic relationship between the species Phormidium autumnale and Phormidium uncinatum was determined on the basis of polyphasic characteristics. Monitoring of the morphological variability of Phormidium autumnale and Microcoleus vaginatus strains showed a difference in the morphology concerning the ends of the trichomes, the shape of the apical cells, as well as the presence/absence of the calyptra and its shape. The performed TEM analysis of the thylakoid arrangement of the studied strains showed parietal arrangement of the thylakoids in the representatives of genus Phormidium and fascicular arrangement in genus Microcoleus. Molecular genetic analyses, based on 16S rDNA, revealed grouping of the investigated P. autumnale strains in a separate clade. This clade is far from the subtree, which is very clearly formed by the representatives of the type species of genus Microcoleus, namely M. vaginatus. The metabolomic analysis involving P. autumnale and M. vaginatus strains identified 39 compounds that could be used as potential biochemical markers to distinguish the two cyanobacterial species. Based on the data obtained, we suggest changing of the current status of Microcoleus autumnalis by restoring its previous appurtenance to the genus Phormidium under the name Phormidium autumnale (Agardh) Trevisan ex Gomont, 1892 and distinguishing this species from genus Microcoleus

Phytoplankton composition with an emphasis of Cyanobacteria and their toxins as an indicator for the ecological status of Lake Vaya (Bulgaria) – part of the Via Pontica migration route

As producers of biomass, cyanobacteria are a major part of the phytoplankton in a large number of water basins. Due to the cyanobacterial blooms and cyanotoxins produced, these organisms are recognized as a threat and ecological risk for water bodies. Released cyanotoxins may cause death of many organisms including birds and fish. Vaya Lake is the largest natural lake in Bulgaria. It is located on the Via Pontica migration route of birds between Europe and Africa. Since 2003, the lake has been declared as a "Wetland of international importance” under the Ramsar Convention. According to the literature data from 2002-2006, the Lake is defined as highly eutrophied due to strong anthropogenic pressure, but regular monitoring of the cyanobacterial blooms and presence of cyanotoxins after this period is missing. Taking into account the importance of this unique, protected ecosystem, our aim was to make a complete ecological assessment of the present state of Lake Vaya by using the phytoplankton, with an emphasis on cyanobacterial blooms and the presence of cyanotoxins. As results of the study, we 1) characterized the phytoplankton composition qualitatively and quantitatively; 2) evaluated the ecological status of the western and eastern part of the Lake; 3) identified the potential producers of cyanotoxins; 4) observed cyanobacterial blooms and discussed the influence of macrophytes on their spread; 5) measured the concentrations of the cyanotoxins MCs, CYL and STXs in water samples from both parts of the Lake. Our results indicated the need for continued observation of cyanobacterial composition, blooming and the presence of cyanotoxins in Lake Vaya