Freshwater Cyanobacterial blooms and Cyanotoxin production in Serbia in the past 25 years

Since 1980 cyanobacterial blooms occurred in a large number of reservoirs lakes and water flows (rivers and channels) in Serbia. Among 83 water ecosystems examined, 58 were found in blooming condition almost every year during last 2 decades. All natural lakes, accumulations, rivers and canals in Vojvodina province (agricultural part) proved to be sites with frequent cyanobacterial proliferation. During the summer 2005-spring 2006 microcystin-LR survey in Vojvodina, the toxin was permanently present in all examined ecosystems and the highest value of 362.68 μgL-1 was detected in Ludoš Lake. The part of Central Serbia is very problematic for ground water supply. For that reason more than 20 reservoirs serve as drinking water suppliers. Significant and persistent cyanobacterial blooms have been recognized in 9 of them. Samples for cyanotoxin analyses were taken during and after blooms in Ćelije Reservoir and in drinking water in Kruševac town 2 days later. Concentration of microcystin-LR was 650 μgL-1 in the reservoir while the tap water contained 2.5μgL-1

Biofilm forming cyanobacteria, algae and fungi on two historic monuments in Belgrade, Serbia

Biofilm on the sandstone substrata of the bridge 'Brankov most' and on the granite substrata of the 'Monument of the Unknown Hero' contains a complex consortia of cyanobacteria, algae, and fungi. Coccoid and filamentous cyanobacteria, green algae and diatoms make up the photosynthetic part of the biofilm while hyphal fragments, chlamydospores, fruiting bodies and spores take part as fungal components. These structures make a dense layer by intertwining and overlapping the stone surface. Five cyanobacterial, 11 algal and 23 fungal taxa were found. The interaction of the biofilm's constituents results in the bioweathering of the stone substrata through mechanical penetration, acid corrosion and the production of secondary mycogenic biominerals.

Rediscovery of Chara canescens Loiseleur in Serbia

Chara canescens is the only charophyte performing parthenogenetic reproduction. Although most recently found populations consist solely of parthenogenetically reproducing females, bisexual populations exist as well, making the species a unique example of the sympatric occurrence of both reproductive modes. In Serbia, C. canescens was found only once for certain, near Prokuplje in 2005. The purpose of the present study is to report a reliable new finding of C. canescens in Serbia, in a stable parthenogenetic female population. Sampling was conducted on 7 July 2018 from the Plava Banja pond near the city of Kikinda. Results of water analyses revealed high concentrations of almost all measured parameters, but especially high levels of salinity and alkalinity markers. Very high concentrations of sulphates and chlorides in the Plava Banja pond pointed to extreme ion anomalies. On the basis of the concentration of nutrients in it, the Plava Banja pond can be characterised as a eutrophic water body. Chara specimens collected from this pond were identified as C. canescens, and only females in the reproductive phase were detected. The environmental features of this habitat are typical in relation to preferences of the given species for light and salinity (ion concentration). This record is of great importance because C. canescens has been declared to be probably extinct in the wild in Serbia

Rod Haslea i novi taksoni silikatnih algi za floru Srbije u alkalnim slanim staništima Vojvodine

Alkalna slana staništa predstavljaju jedinstvena staništa koja su specifična za centralnu Evropu i nalaze se na listi prioritetnih staništa Evropske Direktive o staništima (Directive Habitats 1992). Ono što ova staništa izdvaja od drugih sličnih slanih voda je dominacija jona Na+, HCO3– and CO32–. U Srbiji ona su retka, ugrožena, mozaično raspoređena i najzastupljenija na teritoriji Vojvodine. Povišen salinitet i promenljiv vodni režim tokom godine su glavni faktori koji uslovljavaju pojavu jedinstvenog biljnog i životinjskog sveta. Algološki uzorci su sakupljani u periodu od 2003. godine do danas. Istraživanje je obuhvatilo 10 lokaliteta, koji predstavljaju različite tipove alkalnih slanih staništa: kanalizovane slatine, zabarene slane livade, slane bare i mineralne bare. Uzorci obuhvataju različite zajednice silikatnih algi: plankton, bentos i epifite. Utvrđeno je prisustvo 22 taksona silikatnih algi po prvi put zabeleženih na teritoriji Srbije, a među njima prvi put i rod Haslea Simonsen sa dve vrste: H. duerrenbergiana i H. spicula. Identifikovani taksoni su karakteristični za brakične vode, kao i različite tipove kopnenih voda sa povišenim do veoma povišenim sadržajem elektrolita. Dosadašnja istraživanja silikatnih algi alkalnih slanih staništa Vojvodine su sporadična (Vidaković i sar. 2018). Ovakav tip istraživanja je neophodan kako bi što bolje sagledali diverzitet silikatnih algi u cilju očuvanja ovih jedinstvenih staništa koja su pod intezivnim i konstantnim antropogenim uticajem.Kladovo, Srbija, 25–30.09.2018. [www.serbiosoc.org.rs

Distribution of invasive species Actinocyclus normanii (Hemidiscaceae, Bacillariophyta) in Serbia

In Serbia Actinocyclus normanii was registered in several rivers and canals. In 1997, it was found as planktonic species in the Tisza River and in benthic samples (in mud) in the Veliki Bački Canal. In 2002, it was found as planktonic species in the Danube–Tisza–Danube Canal (Kajtasovo) and the Ponjavica River (Brestovac and Omoljica). Four years later, in 2006, the species was found in plankton, benthos and epiphytic samples in the Ponjavica River (Omoljica). A. normanii is a cosmopolite, alkalibiontic and halophytic species. It occurs in waters with moderate to high conductivity and it is indicator of eutrophied, polluted waters. Its spread could be explained by eutrophication of surface waters

Mineral waters of Serbia and development of phototrophic microbial communities near points of emergence and on wellheads

Phototropic microorganisms in thermal mats had not attracted enough attention in Serbia in the past. The research presented in this paper is the first to address biofilms at selected occurrences of mineral water in Serbia (Bogatić, Metković and Belotić in the Mačva District as well as Radaljska Banja, Lukovska Banja and Vranjska Banja) (in Serbian, banja denotes a spa town). The study period is from 2014 to 2016. The temperatures of the studied occurrences are in the 30–93.9 °C range and the chemical composition corresponds to the HCO3 − – Na++K+ and SO4 2−, HCO3 − – Na++K+ types of mineral water. One of the objectives was to examine the condition of wellheads (incrustation, biofouling and corrosion), focusing on the presence of phototrophic microorganisms whose metabolites may lead to changes in mineral water quality, yield and chemistry. Analysis by light and scanning electron microscopy provides insight into the diversity of phototrophic microorganisms that populate biofilms near the points of emergence and on wellhead. The research reveals the presence of representatives of three groups of phototrophic microorganisms: Cyanobacteria, Chlorophyta and Bacillariophyta. Cyanobacteria were the most numerous, dominated by the order Oscillatoriales with ten recorded genera, of which Leptolynbgya and Phormidium feature the largest numbers of species. The order Chroococcales are the second most numerous, with seven recorded genera, of which Gloeocapsa and Synechocystisare the most noteworthy. The largest numbers of representative taxa were noted at Radaljska Banja and Vranjska Banja, where mineral waters originate from Encrustalithostratigraphic units of igneous origin, followed by mineral water occurrences in karst aquifers (Bogatić and Belotić) and an intergranular aquifer (Metković). The smallest number of identified phototrophic microorganisms is noted at Lukovska Banja, where the origin is associated with a fractured aquifer formed in sedimentary and metamorphic rocks, with occasional diabase interbeds. Although many representative taxa are found on only one of the studied localities, such as Synechococcus bigranulatus and Pseudanabaena thermalis, those of the genera Leptolyngbya, Phormidium and Cosmarium laeve, as well as genera of the phylum Bacillariophyta, occur at several sampling sites. Principal component analysis (PCA) was used to show the relationship between documented cyanobacterial and algal taxa and environmental parameters.  Key words: Serbia, mineral waters, phototrophic microorganisms, biofilm.  Mineralne vode v Srbiji in razvoj fototrofnih mikrobnih združb na mestih izvirov in na ustjih vrtin Fototrofni mikroorganizmi v oblogah termalnih izvirov v Srbiji v preteklosti niso bili deležni posebne pozornosti. V članku predstavljena raziskava je prva, ki obravnava biofilme na izbranih mestih izvirov mineralnih vod v Srbiji (Bogatić, Metković in Belotić v Mačvi ter Radaljska Banja, Lukovska Banja in Vranjska Banja) (v srbskem jeziku je banja izraz za toplice). Preučevanje je potekalo med letoma 2014 in 2016. Temperature obravnavanih voda se gibljejo med 30 in 93,9 °C, glede na kemijsko sestavo pa jih uvrščamo v HCO3 − – Na++ K+ in SO4 2−, HCO3 − – Na++K+ tipe mineralne vode. Eden od ciljev raziskave je bil proučevati razmere na ustjih vrtin (inkrustacija, obrast in korozija) in se še posebej posvetiti navzočnosti fototrofnih mikroorganizmov, katerih metaboliti lahko spremenijo kakovost, izdatnost in kemizem mineralnih vod. Z analizo slik s svetlobnim in vrstičnim elektronskim mikroskopom lahko podrobneje spoznamo raznolikost fototrofnih organizmov, ki sestavljajo biofilme na mestih izvirov in na ustjih vrtin. Raziskava je pokazala obstoj predstavnikov treh skupin fototrofnih mikroorganizmov: cianobakterij ter predstavnikov debel Chlorophyta in Bacillariophyta. Cianobakterije so bile najbolj številčne, prevladovali so osebki reda Oscillatoriales z desetimi ugotovljenimi rodovi, od katerih je bilo največje število vrst iz rodov Leptolynbgya in Phormidium. Red Chroococcales je bil s sedmimi zabeleženimi rodovi drugi najbolj številčen, prevladovala sta Gloeocapsa in Synechocystis. Največreprezentativnih taksonov je bilo v Radaljski Banji in Vranjski Banji, kjer mineralne vode izvirajo iz litostratigrafskih enot vulkanskega izvora, sledijo mineralne vode iz kraškega (Bogatić in Belotić) in medzrnskega vodonosnika (Metković). Najmanjfototrofnih organizmov je bilo v vzorcu iz Lukovske Banje, kjer vode izvirajo iz razpoklinskih vodonosnikov v sedimentnih in metamorfnih kamninah z vmesnimi lečami diabaza. Čeprav soštevilne reprezentativne taksone našli le na eni od proučevanih lokacij, kot na primer Synechococcus bigranulatus in Pseudanabaena thermalis, se tisti iz rodu Leptolyngbya, Phormidium in Cosmarium laeve in predstavniki več rodov, ki pripadajo deblu Bacillariophyta, pojavljajo na več vzorčnih mestih. Za ugotavljanje odvisnosti med taksoni cianobakterij in alg ter okoljskimi parametri so uporabili analizo glavnih komponent.Ključne besede: Srbija, mineralne vode, fototrofni mikroorganizmi, biofilm.

First report and distribution of invasive species Actinocyclus normanii f. subsalsa Hustedt in Serbia

Actinocyclus normanii f. subsalsa is considered native marine or brackish water species (Baltic Sea, Caspian Sea). The species has spread into common freshwaters, throughout the world, and was considered as invasive or potentially invasive species (Kaštovský et al. 2010, Kipp et al. 2012). Phytoplankton, phytobenthos and epilithic samples were used for this study. In laboratory the field samples were treated with standard method with cold acid by Krammer and Lange-Bertalot (1986). Permanent slides were mounted in Naphrax. In Serbia, Actinocyclus normanii f. subsalsa, was registered in several rivers and canals. In 1997 was found as planktonic species in the Tisza River and in benthic samples (in mud) in the Veliki Bački Canal. In 2002 was found as planktonic species in the Danube–Tisza–Danube Canal (Kajtasovo) and the Ponjavica River (Brestovac and Omoljica). Four years later, in 2006, the species was found in plankton, benthos and epiphytic samples in the Ponjavica River (Omoljica). Actinocyclus normanii f. subsalsa is a cosmopolite, alkalibiontic (pH range from 8.0 – 8.83) and halophytic species. It occurs in waters with high conductivity (348 – 918 µS/cm) and it is indicator of eutrophied, polluted waters. Its spread is probably explained by eutrophication of surface waters. The presence of many diatom taxa could give evidence of a wide scale of the environmental possibilities for their development within the studied area. Identification of invasive algae species in water bodies is possible through the long-term floristic studies and continuous biomonitoring of surface waters. Therefore, we continue to monitoring the occurrence of invasive taxa in the waters of Serbia.11th International Conference „Advances in research on the flora and vegetation of the Carpato-Pannonian region”, Budapest, 12–14 February 201

The effects of biocides on the growth of aerophytic green algae (Chlorella sp.) isolated from a cave environment

Lampenflora communities of bacteria, cyanobacteria, algae, mosses and lichens colonize illuminated show-caves as a consequence of disturbances to the caves’ ecological equilibrium. These communities have unesthetic impacts and can cause the biodeterioration of limestone. A 15% hydrogen peroxide solution was proposed for use as an ecological agent for the safe removal of these microorganisms. This study tested the effects of three different biocides (hydrogen peroxide, a commercial solution containing salicylic acid and a product containing chlorine dioxide as the active component), on the growth of green algae (Chlorella sp.), which are frequently encountered in lampenflora communities. Chlorella sp. was treated with the biocides under laboratory condition, and chlorophyll a (Chl a) concentrations were measured 1 h, 3 days, 7 days and 10 days after treatment. The change in Chl a concentration was compared to the untreated control group at each time point. All three biocides prevented the growth of green algae and the product containing chlorine dioxide appeared to be the most effective growth inhibitor. Hydrogen peroxide is known to suppress lampenflora growth in caves, and further studies on other biocides remain necessary to identify a solution that is both ecologically safe and economically feasible

Water quality assessment of Vrutci reserovir tributaries based on diatom indices

Silikatne alge su važna grupa akvatičnih organizama osetljivih na promene u svojoj životnoj sredini. Međutim, njihova praktična upotreba kao bioindikatora je relativno nova u Srbiji. U ovom istraživanju sakupljeni su epilitski uzorci iz 14 pritoka akumulacije Vrutci u toku septembra i oktobra 2014. godine. Identifikovano je ukupno 84 taksona silikatnih algi. Najveće populacije u okviru epilitske zajednice silikatnih algi u većini pritoka grade Cocconeis placentula var. lineata i Achnanthidium minutissimum var. minutissimum. Rezultati izračunavanja dijatomnih indeksa, uz pomoć softverskog paketa OMNIDIA, ukazuju da je ekološki status vode većine ispitivanih pritoka odličan do dobar. Samo rezultati dijatomnih indeksa za pritoke Simića potok, Konjski potok, Bioštanska Banja i neimenovanu pritoku 13 pokazuju prisustvo umerene antropogene eutrofikacije.Faculty of Agriculture, Belgrade-Zemun, Serbia, June, 10 – 12. 2015

Mineral waters of Serbia and development of phototrophic microbial communities near points of emergence and on wellheads

Phototropic microorganisms in thermal mats had not attracted enough attention in Serbia in the past. The research presented in this paper is the first to address biofilms at selected occurrences of mineral water in Serbia (Bogatic, Metkovic and Belotic in the Macva District as well as Radaljska Banja, Lukovska Banja and Vranjska Banja) (in Serbian, banja denotes a spa town). The study period is from 2014 to 2016. The temperatures of the studied occurrences are in the 30-93.9 degrees C range and the chemical composition corresponds to the HCO3- -Na++ K+ and SO42-, HCO3--Na++ K+ types of mineral water. One of the objectives was to examine the condition of wellheads (incrustation, biofouling and corrosion), focusing on the presence of phototrophic microorganisms whose metabolites may lead to changes in mineral water quality, yield and chemistry. Analysis by light and scanning electron microscopy provides insight into the diversity of phototrophic microorganisms that populate biofilms near the points of emergence and on wellhead. The research reveals the presence of representatives of three groups of phototrophic microorganisms: Cyanobacteria, Chlorophyta and Bacillariophyta. Cyanobacteria were the most numerous, dominated by the order Oscillatoriales with ten recorded genera, of which Leptolynbgya and Phormidium feature the largest numbers of species. The order Chroococcales are the second most numerous, with seven recorded genera, of which Gloeocapsa and Synechocystisare the most noteworthy. The largest numbers of representative taxa were noted at Radaljska Banja and Vranjska Banja, where mineral waters originate from lithostratigraphic units of igneous origin, followed by mineral water occurrences in karst aquifers (Bogatic and Belotic) and an intergranular aquifer (Metkovic). The smallest number of identified phototrophic microorganisms is noted at Lukovska Banja, where the origin is associated with a fractured aquifer formed in sedimentary and metamorphic rocks, with occasional diabase interbeds. Although many representative taxa are found on only one of the studied localities, such as Synechococcus bigranulatus and Pseudanabaena thermalis, those of the genera Leptolyngbya, Phormidium and Cosmarium laeve, as well as genera of the phylum Bacillariophyta, occur at several sampling sites. Principal component analysis (PCA) was used to show the relationship between documented cyanobacterial and algal taxa and environmental parameters