UDC 553.7:579(497.11) Vladimir Šaraba, Slađana Popović, Olivera Krunić, Gordana Subakov Simić, Željko Kljajić, Milojko Lazić: 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 HCO 3 − -Na + +K + and SO 4 2− , HCO 3 − -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 , HCO 3 − -Na + +K + tipe mineralne vode. Eden od ciljev raziskave je bil proučevati razmere na ustjih vrtin (inkru stacija, 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

Cyanobacteria are ancient organisms that are capable of colonizing different habitats in various climatic zones due to their plasticity and rapid accommodation. They are a widely studied group of microorganisms due to the presence of many potentially toxic and invasive species. The aim of this research was a diversity exploration of the freshwater Cyanobacteria in the Zasavica River, which is part of the Special Nature Reserve ?Zasavica? in Serbia. Organisms were sampled once a month at two study sites during one year. Phytoplankton and metaphyton analysis showed the presence of 50 freshwater cyanobacterial taxa, of which 12 are new taxa for Serbia. Three invasive and potentially toxic species (Cylindrospermopsis raciborskii, Sphaerospermopsis aphanizomenoides and Raphidiopsis mediterranea) were recorded only in metaphyton in April at one site. It can be expected that, if conditions change, this species can migrate and form phytoplankton blooms. [Projekat Ministarstva nauke Republike Srbije, br. ON 176020]

Detailed studies of the Chrysophyceae class of algae have not been undertaken in Serbia thus far. The golden algae usually occur during the winter and spring months. Chrysophyceae of the Zasavica River in Serbia were studied at two localities from December 2012 to Jun 2013. In our research, 26 taxa were recorded and the genus with the highest diversity was Mallomonas (15 species). The most abundant species during the whole study period were Synura uvella, Dinobryon divergens and Dinobryon sociale. At the beginning of summer, Chrysophyceae disappeared from the phytoplankton community. [Projekat Ministarstva nauke Republike Srbije, br. 176020 i br. III 43004]

Sinanodonta woodiana (Lea, 1834), Chinese pond mussel (Bivalvia: Unionoida: Unionidae) is one of the most invasive aquatic macroinvertebrate species found in Europe. We report the Chinese pond mussel for the first time in Montenegro, in August 2012, in Lake Sasko (Adriatic part of the Central Mediterranean subarea). One specimen of the Chinese pond mussel was observed in a habitat with a predominantly silt-clay substrate. The main pathway of species introduction was evaluated to be via fish stocking.