Distribution of diatoms in spring in the Julian Alps (NW Slovenia)

DISTRIBUTION OF DIATOMS IN SPRINGS IN THE JULIAN ALPS (NW SLOVENIA) - In the Julian Alps (Slovenia), the diatom communities of 16 mountain springs were studied between May and October 1999. Four of them were sampled monthly for a more detailed investigation of seasonal changes in community structure. The sampling was performed by scraping of the rock surface. In all sampling stations, physical and chemical parameters were measured. The purpose of the work was qualitative assessment of the diatom communities. The diatom flora of these springs consisted of 60 diatom taxa and showed similarities with springs and headwater stream diatom communities from different geographic areas. Achnanthes minuttisima reached the highest relative abundance in most of the samples. Characteristic spring taxa (crenophiles) were present, but also included subdominant and rare taxa. Five different spring types were identified, with respect to diatom assemblages, using cluster analysis. Current velocity and periodical dryness in a spring appeared to be the dominant environmental factor affecting diatom distribution in selecting karst springs. In some springs, however, peculiar environmental factors (dim light, ionic strength) affected the structure of diatom assamblages. The Shannon-Wiener diversity index was the highest in permanent springs

Algae in the aerophytic habitat of Račiške ponikve cave (Slovenia)

In the cave entrance of Račiške ponikve, four selected sites with confluent algal growth and different sun irradiance levels were sampled for algological analysis. Altogether, 42 algal taxa were determined, with the highest proportion of cyanobacteria, 30 taxa (71%), followed by 8 taxa (19%) of Chlorophyta and 4 taxa (10%) of Chrysophyta. The favourable ratio of Oscillatoriales vs. Nostocales indicates that flora in Račiške ponikve cave is generally exposed to low photo flux. In the twilight zone of the cave, coccoid cyanobacteria prevailed. Moreover, at all sampling points algae characteristic of water and/or soil habitats were also identified besides typical aerophytic algae

Škodljiva cianobakterijska cvetenja v Sloveniji - Tipi cvetenj in proizvajalci mikrocistinov

Up to now, research on cyanobacteria and their biologically active substances has been directed principally towards their harmful effects on humans, and little has been done to elucidate their ecological role. In order to understand better the biological success of cyanobacterial blooms, and in order to be able to compare the results of different scientific investigations, we must find and agree on a definition of the phenomenon. We propose a definition of harmful cyanobacterial blooms based on the OECD boundary system of eutrophication with the addition of phycocyanin values. We have found a direct linkage between the trophic conditions in the water-bodies and the frequency of formation of cyanobacterial blooms. Specific toxic species and their strains have been studied intensively. However, in order to elucidate the mechanisms that enable cyanobacteria to overtake eutrophic water bodies we must change our approach. Cyanobacterial blooms should not be treated merely as different species or strains but as superorganisms. It is their intraspecific diversity that permits cyanobacteria to be successful in a variable water environment. Wehere focus attention on microcystin producers and microcystins as an adaptation to the limited light conditions, which arise in cyanobacterial blooms. The conclusions are illustrated with some data from surface water-bodies in Slovenia.Raziskave cianobakterij in biolosko aktivnih snovi, ki jih proizvajajo so bile do sedaj usmerjene predvsemna proucevanje skodljivih ucinkov na cloveka. Zelo malo je bilo storjenega v smeri preverjanja njihoveekoloske vloge. Za boljse razumevanje razvojnega uspeha cianobakterijskih cvetenj in da bi bili sploh sposobni primerjati rezultate razlicnih znanstvenih raziskav moramo najti najprej definicijo tega pojava. Predlagamo opredelitev skodljivih cianobakterijskih cvetov, ki temelji na OECD razmejitvenem sistemuevtrofikacije z dodanimi vrednostmi za fikocianine. Ugotovili smo neposredno zvezo med troficnim stanjem vodnih teles in pogostostjo pojavljanja cianobakterijskih cvetov. Stevilne toksicne cianobakterijske vrste in soje so ze podrobno proucevali. Vendar za boljse razumevanjemehanizmov, ki jim omogocajo prevlado v evtrofnih vodnih telesih, moramo spremeniti nas pristop. Cianobakterijske cvetove ne moremo obravnavati le kot zmesi razlicnih vrst in sojev, temvec kot superorganizme. Prav njihova intraspecificna raznovrstnost jim omogoca uspeh v spremenJjivem vodnem okolju. Naso pozomost bomo osredotocili na tiste cianobakterije, ki so sposobne proizvajati mikrocistine in na mikrocistine kot mozno prilagoditev naomejene svetlobne razmere,kakrsne nastopajo ob cvetenjih. Zakljucki smo podkreplili s podatki o vodnih telesih v Sloveniji

Harmful cyanobacterial blooms in Slovenia - Bloom types and microcystin producers

Up to now, research on cyanobacteria and their biologically active substances has been directed principally towards their harmful effects on humans, and little has been done to elucidate their ecological role. In order to understand better the biological success of cyanobacterial blooms, and in order to be able to compare the results of different scientific investigations, we must find and agree on a definition of the phenomenon. We propose a definition of harmful cyanobacterial blooms based on the OECD boundary system of eutrophication with the addition of phycocyanin values. We have found a direct linkage between the trophic conditions in the water-bodies and the frequency of formation of cyanobacterial blooms. Specific toxic species and their strains have been studied intensively. However, in order to elucidate the mechanisms that enable cyanobacteria to overtake eutrophic water bodies we must change our approach. Cyanobacterial blooms should not be treated merely as different species or strains but as superorganisms. It is their intraspecific diversity that permits cyanobacteria to be successful in a variable water environment. Wehere focus attention on microcystin producers and microcystins as an adaptation to the limited light conditions, which arise in cyanobacterial blooms. The conclusions are illustrated with some data from surface water-bodies in Slovenia

In memoriam: Mihael Bricelj (1946–2016)

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Typology of lakes in Slovenia

A typology of natural lakes in Slovenia with the surface area of >50 ha was prepared according to the Water Framework Directive. Lake Bled and Lake Bohinj were taken into consideration only. Both systems proposed by the Water Framework Directive (Directive 2000/60/EC) for the preparation of the lake typology were tested. Using the system A, the satisfactory differentiation for the description of biological reference conditions could not be established. The system B was chosen based on the obligatory descriptors that include altitude, latitude, longitude, depth, geology and size. An additional descriptor, which concerns bioregional affiliation, was also chosen (sensu Urbanič, 2006a), which includes two obligatory descriptors, altitude and geology. These two descriptors are not specifically mentioned in the description of lake types

Razširjenost kremenastih alg v izvirih na območju Julijskih Alp (SZ Slovenija)

In the Julian Alps (Slovenia), the diatom communities of 16 mountain springs were studied between May and October 1999. Four of them were sampled monthly for a more detailed investigation of seasonal changes in community structure. The sampling was performed by scraping of the rock surface. In all sampling stations, physical and chemical parameters were measured. The purpose of the work was qualitative assessment of the diatom communities. The diatom flora of these springs consisted of 60 diatom taxa and showed similarities with springs and headwater stream diatom communities from different geographic areas. Achnanthes minuttisima reached the highest relative abundance in most of the samples. Characteristic spring taxa (crenophiles) were present, but also included subdominant and rare taxa. Five different spring types were identified, with respect to diatom assemblages, using cluster analysis. Current velocity and periodical dryness in a spring appeared to be the dominant environmental factor affecting diatom distribution in selecting karst springs. In some springs, however, peculiar environmental factors (dim light, ionic strength) affected the structure of diatom assamblages. The Shannon-Wiener diversity index was the highest in permanent springs.Od maja do oktobra 1999 smo v dvomesečnih presledkih vzorčili kremenaste alge v 16 kraških izvirih na območju Julijskih Alp (Slovenija). Za raziskave sezonskih sprememb v združbi kremenastih alg smo v štirih izvirih vzorčili enkrat mesečno. Za vzorčenje smo uporabili metodo strganja alg s površine kamnov. Na vseh vzorčnih mestih smo izmerili tudi fizikalne in kemijske parametre. Glavni namen naloge je bila kvalitativna ocena združb kremenastih alg. V izvirih smo skupno določili 60 vrst. V združbah kremenastih alg so se pokazale nekatere podobnosti z izviri in potoki na različnih geografskih območjih. V večini vzorcev je najvišjo relativno pogostost dosegla vrsta Achnanthes minutissima. Pojavljale so se tudi vrste, značilne za izvire (krenofilne), skupaj z redkimi in ogroženimi vrstami. S klastersko analizo, ki je temeljila na združbah kremenastih alg, smo določili pet skupin izvirov. Hitrost vodnega toka in občasne presahnitve izvira sta dejavnika, ki sta najbolj vplivala na razvoj združbe kremenastih alg v izbranih izvirih. V nekaterih izvirih sta na združbo kremenastih alg vplivali tudi zasenčenost izvira ter trdota vode. Shannon-Wienerjev diverzitetni indeks je bil najvišji v stalnih izvirih

Lampenflora Algae and Methods of Growth Control

Karst caves are unique natural features and habitats where specialized organisms live. Some caves are also important as cultural heritage sites. In recent decades, many caves have experienced intensified tourist visits. To attract visitors, artificial illumination was installed that changed conditions in the caves. As a result,communities of organisms called lampenflora develop in close and remote proximity to lights. These phototrophic organisms are inappropriate from an aesthetic point of view and cause the degradation of colonized substrata, which is a particular problem in caves with prehistoric art. Key factors that allow lampenflora to grow are light and moisture. Illuminated spots in caves can be quickly colonized by algae, some of which have broad tolerances for different substrata. Several phototrophs can survive in caves even at photon flux densities lower than the photosynthetic compensation point. In this paper, the pros and cons of physical, chemical, and biological methods to control phototrophic growth are reviewed and discussed. Experiences in show caves can be helpful in controlling undesirable algal growth in other environments

Alge v aerofitskem habitatu jame Račiške ponikve (Slovenija)

In the cave entrance of Račiške ponikve, four selected sites with confluent algal growth and different sun irradiance levels were sampled for algological analysis. Altogether, 42 algal taxa were determined, with the highest proportion of cyanobacteria, 30 taxa (71%), followed by 8 taxa (19%) of Chlorophyta and 4 taxa (10%) of Chrysophyta. The favourable ratio of Oscillatoriales vs. Nostocales indicates that flora in Račiške ponikve cave is generally exposed to low photo flux. In the twilight zone of the cave, coccoid cyanobacteria prevailed. Moreover, at all sampling points algae characteristic of water and/or soil habitats were also identified besides typical aerophytic algae.Za algološko vrstno sestavo smo v jamskem vhodu Račiških ponikev opravili vzorčenje na štirih izbranih mestih s konfluentno obrastjo alg in različno izpostavljenostjo sončni osvetlitvi. Skupaj smo identificirali 42 taksonov alg, z največjim deležem cianobakterij, 30 taksonov (71%), ki so jim sledili predstavniki Chlorophyta z 8 taksoni (19%) in s 4 taksoni (10%) Chrysophyta. Višji delež Oscillatoriales v primerjavi s predstavniki Nostocales nakazuje, da je flora v jamskem vhodu Račiških ponikev izpostavljena pretežno šibkim intenzitetam svetlobe. V jami v pasu somraka prevladujejo kokoidne cianobakterije. Na vseh vzorčnih mestih smo poleg alg, ki so značilne aerofitske, identificirali tudi alge, ki navadno uspevajo v vodnih in terestičnih habitatih