Acta Botanica 2-2015.indd ACTA BOT. CROAT. 74 (2), 2015 317 Acta Bot. Croat. 74 (2), 317–331, 2015 CODEN: ABCRA 25 ISSN 0365-0588 eISSN 1847-8476 DOI: 10.1515/botcro-2015-0022 Diatoms of the Dojkinci River (Stara Planina Nature Park, Serbia) JELENA KRIZMANIĆ1*, MARIJA ILIĆ2, DANIJELA VIDAKOVIĆ1, GORDANA SUBAKOV-SIMIĆ1, JELENA PETROVIĆ1, KATARINA CVETANOVIĆ3 1 University of Belgrade, Faculty of Biology, Institute of Botany and Botanical Garden »Jevremovac«, 43 Takovska, 11000 Belgrade, Serbia 2 University of Belgrade, Institute for Biological Research »Siniša Stanković«, 142 Bulevar despota Stefana, 11060 Belgrade, Serbia 3 University of Belgrade, Faculty of Chemistry, 12–16 Studentski trg, 11000 Belgrade, Serbia Abstract – Diatom samples were collected during July 2010 at 15 localities from different types of substrate (stone surfaces, sand, mud, fi lamentous algae and submerged mosses) from the Dojkinci River. During the research period, 124 taxa were determined within 43 genera. Among numerous common diatoms we recorded three taxa for the fi rst time in Serbia: Brachysira intermedia (Øst.) Lange-Bertalot, Chamaepinnularia mediocris (Krass.) Lange-Bertalot and Navicula tridentula Krass. Also, we observed 21 taxa which are rarely recorded taxa for Serbia. The most interesting was Diatomella balfouriana Grevill. that was previously known only from the River Tisa near Titel. In the studied material, it was identifi ed only in samples collected from the surface of boulders with mosses at the third locality. Their morphology, distribution and ecology are presented in this paper. Key words: Brachysira intermedia, Chamaepinnularia mediocris, Diatomella balfouri- ana, diatoms, distribution, Dojkinci River, Navicula tridentula. Introduction In lotic ecosystems, diatoms are considered to be the most diverse group of algae (ROUND et al. 1990). Regularly found diatom species in European freshwater habitats have well known ecological preferences (VAN DAM et al. 1994, COSTE et al. 2009). However, data about the distribution and ecology of diatom species that are rarely observed may be in- complete (e.g. WOJTAL 2001, 2004, SZABO et al. 2007, VAN DE VIJVER and LANGE-BERTALOT 2009, KELLY et al. 2009, ANDREJIĆ et al. 2012). As diatoms are very important indicators of * Corresponding author, e-mail: kjelena@bio.bg.ac.rs KRIZMANIĆ J., ILIĆ M., VIDAKOVIĆ D., SUBAKOV-SIMIĆ G., PETROVIĆ J., CVETANOVIĆ K. 318 ACTA BOT. CROAT. 74 (2), 2015 environmental changes and for the biological monitoring of lotic ecosystems (STEVENSON and PAN 1999, BERE and TUNDISI 2010), it is of great signifi cance to describe their preva- lence and ecology as well as possible. The mountain Stara planina (Balkan mountain) belongs to the system of Balkan moun- tains which ranges from Black Sea in the east to Vrška Čuka in the west (MARKOVIĆ 1980). It is one of the fl oristically and faunistically most diverse parts of Serbia and the entire Bal- kan Peninsula. The overall richness and diversity of species, as well as the presence of nu- merous endemic and relic forms point to a specifi c genesis thаt infl uenced the remarkable diversity of this mountain, which makes it distinct from other parts of the Balkans and Eu- rope from the biogeographical aspect. In 1997, at the suggestion of the Institute for Nature Conservation of Serbia, the Gov- ernment of the Republic of Serbia adopted the Regulation on the Protection of Stara Plani- na Nature Park which put Stara Planina under protection as a natural resource of great im- portance, and led to its being placed within the fi rst category of protection (MIJOVIĆ 2001). The total protected area of Stara Planina Nature Park is about 114.332 ha and it has a three- level system of protection (the fi rst degree of protection is applied to an area of 3.680 ha, or 3.23%; the second degree of protection applies to an area 20.159 ha, or 17.63%, and the third degree of protection to an area 90.493 ha, or 79.14%) (OFFICIAL GAZETTE RS, 2009). Stara Planina Nature Park is a protected natural resource nominated for the Program »Man and the Biosphere« (UNESCO-MAB) (IVANČEVIĆ et al. 2007). The Dojkinci River is formed by the merging of two streams: Belčin Dol and Tri klad- enca. It is about 25 km long and ends in its confl uence with the Jelovička River. This way the Visočica River is formed which belongs to the Black Sea basin. The substrate through the longest part of the Dojkinci River runs is red fi ne-grained sandstone, whose color comes from the large amount of Fe2O3 and is extremely rich in quartz sand (ANDJELKOVIĆ 1958), as opposed to most of rivers in Serbia, which have their beds made dominantly of carbonate (MARKOVIĆ 1980). These siliceous, low-conductivity mountain habitats are currently being shown to host benthic diatom communities of high species richness (CANTONATI and LANGE- BERTALOT 2011, CANTONATI et al. 2011, LIU et al. 2011). The morphology, distribution and ecology of algal fl ora of Stara planina is poorly known (SIMIĆ 1995, 1996, 2002), especially for diatoms from Dojkinci River (OBUŠKOVIĆ 1993, OBUŠKOVIĆ et al. 1994). In this paper, we present the results of a fl oristic study of the diatoms of the Dojkinci River (Stara planina, Serbia). Among numerous common diatoms three new taxa for Serbia were identifi ed, as well as 21 taxa that are rarely recorded in Serbia. Materials and methods During July of 2010 the material which is used in the present study was collected from 15 localities along the Dojkinci River. From the gravel surface and boulders epilithic sam- ples were scraped by scalpel blade and brush. Epipsamic samples were collected from the surface of sand and mud substrates, while the epiphyton was taken from mosses Plagiom- nium sp. and Philonotis sp. and liverwort Marchantia polymorpha Line subsp. polymorpha. Samples were immediately fi xed with formaldehyde to a fi nal concentration of 4%. In order to remove organic matter, fi eld samples were treated with concentrated acid (H2SO4) and DIATOMS OF THE DOJKINCI RIVER IN SERBIA ACTA BOT. CROAT. 74 (2), 2015 319 KMnO4, and then washed several times with distilled water in a laboratory. Afterwards the material was airdried on cover glasses and mounted in Naphrax®. Permanent slides, pre- pared material and aliquots of the samples were deposited in the diatom collection of the University of Belgrade, Faculty of Biology. Light microscope observations and micro- graphs were made using a Zeiss AxioImagerM.1 microscope with DIC optics and AxioVi- sion4.8 software. Conductivity, oxygen, pH and water temperature were measured with a Lovibond Multimeter WTW 340i at each sampling site. Ammonium ions, nitrates, phos- phates, alkalinity and total hardness were measured using a Lovibond MultiDirect Photom- eter. Terminology of valve morphology is based according BARBER and HAWORTH (1981) and ROUND et al. (1990). The abundance was estimated by counting 400 valves of each taxa present on a slide. Sampling sites along with levels of protection in Stara Planina Nature Park are present- ed on the map (Fig. 1). Fig. 1. Sampling sites along the Dojkinci River with levels of protection in Stara Planina Nature Park. Results A total of 125 diatom taxa (Tab. 1) belonging to 43 genera were determined in material from the Dojkinci River. The genus with the highest number of species was Eunotia Ehren- berg with 18 taxa. Eunotia paludosa was the dominant taxon with an abundance of as much KRIZMANIĆ J., ILIĆ M., VIDAKOVIĆ D., SUBAKOV-SIMIĆ G., PETROVIĆ J., CVETANOVIĆ K. 320 ACTA BOT. CROAT. 74 (2), 2015 Tab. 1. Diatom species list from Dojkinci River. Achnanthes coarctat a (Brébisson) Grunow Frustulia saxonica Rabenhorst Achnanthidium exile (Kützing) Heiberg Frustulia vulgaris (Thwaites) De Toni Achnanthidium lineare W. Smith Geissleria decussis (Østrup) Lange-Bertalot & Metzeltin Achnanthidium microcephalum Kützing Gomphonema acuminatum Ehrenberg Achnanthidium minutissimum (Kützing) Czarnecki Gomphonema exilissimum (Grunow) Lange- Bertalot & E. Reichardt Amphora sp. Gomphonema gracile Ehrenberg Aulacoseira sp. Gomphonema micropus Kützing Aulacoseira granulata (Ehrenberg) Simonsen Gomphonema parvulius (L.-B. & Reichardt) Lange-Bertalot & Reichardt Brachysira brebissonii R. Ross Gomphonema parvulum (Kützing) Kützing Brachysira intermedia (Østrup) Lange-Bertalot Gomphonema pumilum (Grunow) E. Reichardt & Lange-Bertalot Caloneis silicula (Ehrenberg) Cleve Hantzschia amphioxys (Ehrenberg) Grunow Chamaepinnularia mediocris (Krasske) Lange-Bertalot & Krammer Humidophila contenta (Grunow) Lowe et al. Cocconeis pediculus Ehrenberg Humidophila ingeae (Van de Vijver) Lowe et al. Cocconeis placentula Ehrenberg Humidophila perpusilla (Grunow) Lowe et al. Cocconeis placentula var. lineata (Ehrenberg) van Heurck Luticola mutica (Kützing) D.G. Mann Cocconeis placentula var. pseudolineata Geitler Melosira varians C. Agardh Cymatopleura solea (Brébisson) W. Smith Meridion circulare (Greville) C. Agardh Cymbella compacta Østrup Navicula sp. Cymbella parva (W. Smith) Kirchner Navicula angusta Grunow Cymbella perparva Krammer Navicula cryptocephala Kützing Cymbopleura anglica (Lagerstedt) Krammer Navicula cryptotenella Lange-Bertalot Cymbopleura naviculiformis (Auerswald ex Heiberg) Krammer Navicula exilis Kützing Diatoma ehrenbergii Kützing Navicula gregaria Donkin Diatoma ehrenbergii f. capitulata (Grunow) Lange-Bertalot Navicula lanceolata Ehrenberg Diatoma hyemalis (Roth) Heiberg Navicula recens (Lange-Bertalot) Lange-Bertalot Diatoma mesodon (Ehrenberg) Kützing Navicula reichardtiana Lange-Bertalot Diatoma moniliformis (Kützing) D.M. Williams Navicula tridentula Krasske Diatomella balfouriana Greville Navicula tripunctata (O. F. Müller) Bory de Saint-Vincent Diploneis sp. Neidium sp. Encyonema lunatum (W. Smith) Van Heurck Neidium subampliatum (Grunow) Flower Encyonema silesiacum (Bleisch) D.G. Mann Nitzschia sp. Encyonema ventricosum (C. Agardh) Grunow Nitzschia acicularis (Kützing) W. Smith Encyonopsis falaisensis (Grunow) Krammer Nitzschia alpina Hustedt DIATOMS OF THE DOJKINCI RIVER IN SERBIA ACTA BOT. CROAT. 74 (2), 2015 321 Encyonopsis microcephala (Grunow) Krammer Nitzschia fonticola (Grunow) Grunow Epithemia adnata (Kützing) Brébisson Nitzschia linearis W. Smith Eunotia sp. Nitzschia palea (Kützing) W. Smith Eunotia bilunaris (Ehrenberg) Schaarschmidt Nitzschia recta Hantzsch ex Rabenhorst Eunotia boreoalpina Lange-Bertalot & Nörpel-Schempp Orthoseira sp. Eunotia circumborealis Lange-Bertalot & Norpel Pinnularia sp. Eunotia diodon Ehrenberg Pinnularia acoricola Hustedt Eunotia exigua (Brébisson ex Kützing) Rabenhorst Pinnularia borealis Ehrenberg Eunotia fallax A. Cleve Pinnularia borealis var. rectangularis Carlson Eunotia fl exuosa (Brébisson ex Kützing) Kützing Pinnularia microstauron var. nonfasciata Krammer Eunotia groenlandica (Grunow) Nörpel- Schempp & Lange-Bertalot Pinnularia subcapitata var. subrostrata Krammer Eunotia minor (Kützing) Grunow Pinnularia viridiformis Krammer Eunotia nymanniana Grunow Placoneis sp. Eunotia paludosa Grunow Planothidium sp. Eunotia paratridentula Lange-Bertalot & Kulikovskiy Planothidium frequentissimum (Lange-Bertalot) Lange-Bertalot Eunotia praerupta Ehrenberg Planothidium lanceolatum (Brébisson ex Kützing) Bukhtiyarova Eunotia rhomboidea Hustedt Psammothidium sp Eunotia subherkiniensis Lange-Bertalot Psammothidium subatomoides (Hustedt) L. Bukhtiyarova & Round Eunotia tetraodon Ehrenberg Reimeria sinuata (Gregory) Kociolek & Stoermer Eunotia trinacria Krasske Rhoicosphenia abbreviata (C. Agardh) Lange- Bertalot Eunotia valida Hustedt Stauroneis anceps Ehrenberg Fallacia subhamulata (Grunow) D. G. Mann Stauroneis gracilis Ehrenberg Fragilaria arcus (Ehrenberg) Cleve Stauroneis smithii Grunow Fragilaria biceps (Kützing) Lange-Bertalot Staurosirella pinnata (Ehrenberg) D. M. Williams & Round Fragilaria capucina Desmazières Surirella brebissonii var. kuetzingii Krammer & Lange-Bertalot Fragilaria capucina var. gracilis (Oestrup) Hustedt Surirella linearis W. Smith Fragilaria ulna (Nitzsch) Lange-Bertalot Surirella minuta Brébisson Fragilaria vaucheriae (Kützing) J. B. Petersen Tabellaria fl occulosa (Roth) Kützing Fragilariforma virescens (Ralfs) D. M. Williams & Round Tetracyclus rupestris (Braun) Grunow Frustulia crassinervia (Brébisson) Lange- Bertalot & Krammer KRIZMANIĆ J., ILIĆ M., VIDAKOVIĆ D., SUBAKOV-SIMIĆ G., PETROVIĆ J., CVETANOVIĆ K. 322 ACTA BOT. CROAT. 74 (2), 2015 as 80% and was found on all types of substrates. Subdominant taxon was Achnanthidium minutissimum with the abundance of 9.28–42.13%. Of these identifi ed taxa, three were new records to Serbia: Brachysira intermedia, Chamaepinnularia mediocris and Navicula tri- dentula. They were rarely distributed with very low abundance in samples. Twenty one rarely observed taxa were: Achnanthes coarctata (Brébisson) Grunow, Achnanthidium exile (Kützing) Heiberg, Brachysira brebissonii R. Ross (Pl. 2, Figs. 13–18), Humidophila ingeae (Van de Vijver) Lowe et al. (Pl. 1, Figs. 18–24), H. perpusilla (Grunow) Lowe et al. (Pl 1, Plate 1. Light microscope micrographs. Eunotia tetraodon (Figs. 1–3); E. fl exuosa (Fig. 4); E. diodon (Fig. 5); E. subherkiniensis (Fig. 6); E. rhomboidea (Fig. 7); E. exigua (Figs. 8–13); Psam- mothidium subatomoides (Figs. 14–17); Humidophila ingeae (Figs. 18–24); H. perpusilla (Figs. 25–26); Tetracyclus rupestris (Figs. 27–30). Scale bar = 10 μm. DIATOMS OF THE DOJKINCI RIVER IN SERBIA ACTA BOT. CROAT. 74 (2), 2015 323 Figs. 25–26), Diatomella balfouriana Greville (Pl. 2, Figs. 21–30), Eunotia diodon Ehren- berg (Pl. 1, Fig. 5), E. exigua (Brébisson ex Kützing) Rabenhorst (Pl. 1, Figs. 8–13), E. fl exuosa (Brébisson ex Kützing) Kützing (Pl. 1, Fig. 4), E. praerupta Ehrenberg, E. rhom- boidea Hustedt (Pl. 1, Fig. 7), E. subherkiniensis Lange-Bertalot (Pl. 1, Fig. 6), E. tetra- odon Ehrenberg (Pl. 1, Figs. 1–3), Fallacia subhamulata (Grunow) D.G. Mann, Frustulia crassinervia (Brébisson) Lange-Bertalot & Krammer (Pl. 2, Fig. 1–4), F. saxonica Raben- horst, Navicula angusta Grunow (Pl. 2, Fig. 5–6), Nitzschia alpina Hustedt (Pl. 2, Fig. 8), Plate 2. Light microscope micrographs. Frustulia crassinervia (Figs. 1–4); Navicula angusta (Figs. 5–6); Navicula tridentula (Fig. 7); Nitzschia alpina (Fig. 8); Brachysira intermedia (Figs. 9–12); B. brebissonii (Figs. 13–18); Chamaepinnularia mediocris (Figs. 19–20); Diatomella balfouriana (Figs. 21–30). Scale bar = 10 μm. KRIZMANIĆ J., ILIĆ M., VIDAKOVIĆ D., SUBAKOV-SIMIĆ G., PETROVIĆ J., CVETANOVIĆ K. 324 ACTA BOT. CROAT. 74 (2), 2015 Pinnularia acoricola Hustedt, Psammothidium subatomoides (Hustedt) L. Bukhtiyarova & Round (Pl. 1, Figs. 14–17) and Tetracyclus rupestris (Braun) Grunow (Pl. 1, Figs. 27–30). The most interesting was Diatomella balfouriana. The paper presents the description and distribution of four species and their ecology. Main valve measurements of the populations in the Dojkinci River are shown in Tab. 2, and chemical analyses of the water in Tab. 3. Description of the three new taxa for Serbian diatom fl ora and one rarely observed taxon Brachysira intermedia (Østrup) Lange-Bertalot in LANGE-BERTALOT and MOSER (1994) (Pl. 2, Figs. 9–12) Description: Valves are lanceolate, gradually narrowed and at the ends almost pointed, length 22.13–27.3 μm, breadth 5.18–6.26 μm. The axial area is narrow linear near the api- ces, small and rhombic at the central area. The raphe is fi liform. The striae are parallel, at the ends sometimes parallel to slightly convergent, 26–27 in 10 μm. Ecology: Water temperature range from 6.4 °C to 12.5 °C, pH varied from 5.46 to 6.5 and concentrations of other nutrients were low. Distribution (Serbia): along the upper course of the Dojkinci River (locality 1–5), on the surface of boulders, mud and on the mosses, with low abundance (0.23–0.61%), at the alti- tude from 1442.5 to 1723.5 m a.s.l. Tab. 2. Main valve measurements of the four species in the Dojkinci River. Taxon Length (μm) Width (μm) Striae in 10 μm Brachysira intermedia 22.13–27.3 5.18–6.26 26–27 Chamaepinnularia mediocris 10.26–12.74 2.81–3.02 17–20 Navicula tridentila 15 4.1 Diatomella balfouriana 13.6–23.86 4.97–5.83 19–20 Tab. 3. Physico-chemical parameters of the water during sampling period. Variable Values Water temperature (°С) 6.4–12.5 Altitude (m) 924–1723.5 Conductivity (μS cm–1) 213–302 pH 5.46–6.5 Hardness (mg L–1) 25–67 Total alkalinity (mg L–1) 0.1 Alkalinity P (mg L–1) 0.1 NO3-N (μg L–1) 0.635 PO4-P (μg L–1) 1.45 DIATOMS OF THE DOJKINCI RIVER IN SERBIA ACTA BOT. CROAT. 74 (2), 2015 325 Chamaepinnularia mediocris (Krasske) Lange-Bertalot and Krammer in LANGE-BERTALOT and METZELTIN (1996) (Pl. 2, Figs. 19–20) Description: Valves are linear to broadly oval, with rounded apices and a gibbous mid- dle, length 10.26–12.74 μm, breath 2.81–3.02 μm. The axial area is narrow near the apices, becoming wider near the central area. The central area is a transverse fascia. The raphe is fi liform and slightly arched. The striae are parallel, 17–20 in 10 μm. Ecology: Water temperature 12.5 °C, pH 6.5 and concentrations of other nutrients were low. Distribution (Serbia): in the upper course of the Dojkinci River at only one locality (4) with very low abundance (0.12%), on surface of mud, at the altitude 1432 m a.s.l. Navicula tridentula Krasske (1923) (Pl. 2, Fig. 7) Description: Valve is linear, triundulate, with capitate ends, length 15 μm, breath 4.1 μm. The axial area is very narrow, linear, central area is variables size, often diffi cult to see. The raphe is fi liform. Ecology: Water temperature 12.5 °C, pH 6.5 and concentrations of other nutrients were low. Distribution (Serbia): in the lower course of the Dojkinci River at locality 11, only one specimen, on surface of sand at the altitude of 1015.5 m a.s.l. Diatomella balfouriana Greville (1855) (Pl. 2, Figs. 21–30) Description: Valves are linear with rounded apices, lenght 13.6–23.86 μm, breath 4.97– 5.83 μm.The axial area is wide. The raphe is fi liform, with dilated external proximal raphe ends that terminate relatively distant from one another. The striae are short and parallel to radiate, 19–20 in 10 μm. The general character of this species is a septum which is present on each valvocopula. The septum extends the entire length of the valve and has three large openings, the largest in the center and two smaller at the ends. Ecology: Water temperature 12.5 °C, pH 6.5 and concentrations of other nutrients were low. Distribution (Serbia): in the upper course of the Dojkinci River at only one locality (3) with an abundance of 23.78%, on surface of boulders with mosses, at the altitude 1503.5 m a.s.l.; Tisa River at Titel (SZABADOS 1966). Discussion The main purpose of the study was to collect records on diatom assemblages from the Dojkinci River, which has a bottom substrate (red sandstone) unusual when compared with the substrates of other rivers in Serbia. In many mountainous areas of the word the highest elevations are reached on siliceous crystalline mountain ranges. These sites are often pristine, relatively remote, and included in nature preserves because of their value for biodiversity conservation, recreation, and as storages of good-quality water (CANTONATI and LANGE-BERTALOT 2011). Stara Planina Na- ture Park has similar characteristics and very rich valuable fl ora and fauna with an impor- tant role in biodiversity conservation in Serbia, as well as, in the Balkan Peninsula. KRIZMANIĆ J., ILIĆ M., VIDAKOVIĆ D., SUBAKOV-SIMIĆ G., PETROVIĆ J., CVETANOVIĆ K. 326 ACTA BOT. CROAT. 74 (2), 2015 The diatom fl ora of Dojkinci River was mainly formed by acidophilic, limno-terrestial, moss-inhabiting, widely distributed species. The large development of acidophilic species is related to siliceous riverbed rocks of the Dojkinci River. The dominant diatom genus in the Dojkinci River was Eunotia, with 18 taxa. According to LANGE-BERTALOT et al. (2011) the genus Eunotia is mainly restricted to freshwater oligotrophic and oligosaprobic habi- tats, which enables it to play an important role as indicator in water monitoring (ALLES et al. 1991, KWANDRANS 2007). Physico-chemical conditions of the Dojkinci River are suitable for dominance of different Eunotia species. According to PAVLOV and LEVKOV (2013) and WOJTAL et al. (1999) E. paludosa was established as dominant taxon in the samples taken from the mud substrates and from mosses. Achnanthidium minutissimum is one of the most frequently occurring diatoms in fresh- water benthic samples globally (PATRICK and REIMER 1966; KRAMMER and LANGE-BERTALOT 1991; POTAPOVA and HAMILTON 2007; HOFMANN et al. 2013). This species has been reported from different type of waters, alkaline and acidic, oligotrophic and hypertrophic (VAN DAM et al. 1994; POTAPOVA and HAMILTON 2007). A Brachysira intermedia is widespread in waters of mountain regions on silica surfaces with low electrolyte content and in oligo- to dystrophic waters. According to LANGE-BERTA- LOT and MOSER (1994) and HOFMMAN et al. (2013), valve length is 25–33 μm, valve breadth 5–6.5 μm, striae 26–30 in 10 μm. Valve measurements in our samples were similar to those in the literature. Chamaepinnularia mediocris can be found in oligo- to dystrophic freshwaters of moun- tain regions (springs, streams and lakes) on silica substrates. According to VAN DAM et al. (1994), C. mediocris is an acidophilic species, mainly occurring at pH < 7. HOFMMAN et al. (2013) state that this species prefers moderately acidic waters. Our results showed that the water of the Dojkinci River is moderately acidic (pH was 6.5) at the site at which this alga was recorded. C. mediocris mainly occurs on wet and moist or temporarily dry places. FRÁNKOVÁ et al. (2009) found C. mediocris in Sphagnum fens, as did KAPETANOVIĆ et al. (2011). Also, BUCZKÓ and WOJTAL (2005) and VAN DE VIJVER and BEYENS (1997) found this species on different type of mosses. In our sample C. mediocris was found on a mud sub- strate, at an altitude of 1432 m a.s.l., which is higher than that shown by KAPETANOVIĆ et al. (2011) (at an altitude 930 m a.s.l.). Researches of BUCZKÓ and WOJTAL (2005) noted C. me- diocris along with Eunotia exigua which is complementary with our fi ndings. Morphologi- cal data show that the valve is 9–16 μm long, 2–3 μm wide and has 20–30 striae in 10 μm (HOFMMAN et al. 2013). According to VESELA and JOHANSEN (2009), valve length is 10–12 μm, valve breadth 2.7 μm, striae 18–21 in 10 μm. Valve measurements in our samples were similar those in literatures. Chamaepinnularia mediocris is known from: Strømness Bay area, South Georgia, Ant- arctica (VANDEVIJVER and BEYENS 1997); Laurentian Great Lakes (STOERMER et al. 1999); Hungary (BUCZKÓ and WOJTAL 2005, BUCZKÓ 2006); Great Smoky Mountains National Park, USA (JOHANSEN et al. 2007); Penza oblast, European Russia (KULIKOVSKII 2008); Elbs- andsteingebirge region, Czech Republic (VESELA and JOHANSEN 2009); Western Carpathian spring fens, between the Czech Republic and Slovakia (FRÁNKOVÁ et al. 2009); Mt. Zvijez- da near Sarajevo, Bosnia and Herzegovina (KAPETANOVIĆ et al. 2011); lakes in the Azores archipelago, Portugal (PEREIRA et al. 2014). DIATOMS OF THE DOJKINCI RIVER IN SERBIA ACTA BOT. CROAT. 74 (2), 2015 327 Navicula tridentula has cosmopolitan widespread, sporadically at typical habitat, such as springhead of stream, peat bogs, swamp. KRAMMER and LANGE-BERTALOT (1986) state that the species prefers fresh water with low concentrations of electrolytes. According to VAN DAM et al. (1994), N. tridentula is an alcalophilic species, mainly occurring at pH < 7, in wet and moist or temporarily dry places. In the Dojkinci River N. tridentula was found at one locality at pH 6.5, on a sandy surface. In Thailand (LEELAHAKRIENGKRA 2013) the spe- cies was recorded at an altitude 478–489 m a.s.l., but in Dojkinci River the same species was recorded on higher altitude (1015.5 m a.s.l.). Valve measurements of the population from the Dojkinci River had similar values, as well as, values according to KRAMMER and LANGE-BERTALOT (1986): valve length 11–19 μm, breadth 3.5–4 μm, striae are not visible on LM. Navicula tridentula is known from: north western United States (BAHLS 2009); western Carpathian spring fens, between the Czech Republic and Slovakia (FRÁNKOVÁ 2009); Chi- ang Dao District, Thailand (LEELAHAKRIENGKRA 2013). New species for diatom fl ora of Serbia recorded at localities of the Dojkinci River were found with very low abundances, although they were on substratum typical for them. A cosmopolitan species, Diatomella balfouriana is widespread from the Arctic to Ant- arctica. It is characteristic for oligo- to dystrophic boreo-alpine mountain freshwaters, with low conductivity and nutrient poor (KRAMMER and LANGE-BERTALOT 1986). However, D. balfouriana was recorded in temporary pools of brackish water, as well as in moist soil near the ocean round Antarctica (VAN DE VIJVER et al. 2012). Until now, there is only one pub- lished record about D. balfouriana for Serbia, in the Tisa River (plain river in northern part of Serbia, pH mainly occurring about 7) (SZABADOS 1966). This can be considered poorly reliable information, because there are no microphotographs which can confi rm the fi nding. In addition, the type of substrate (mud at the bottom of the river) and pH are not typical of D. balfouriana. Our fi ndings are complementary with literature data: oligo- to dystrophic freshwater, low-conductivity and nutrient-poor, boreo-alpine mountain habitats. KRAMMER and LANGE-BERTALOT (1986) states that the valve is 12–52 μm long, 6–8 μm wide and 18– 21 striae in 10 μm. According to KOCIOLEK (2011), valve length is 12–40 μm, breadth is 3.5–6 μm and there are 18–22 striae in 10 μm. Valve measurements of the population from the Dojkinci River had values similar to those given by KOCIOLEK (2011), but the breadths of the valves reported here are smaller than those given by KRAMMER and LANGE-BERTALOT (1986). Acknowledgments Financial support was provided by the Ministry of Education and Science of the Repub- lic of Serbia (Project No. TR 037009). References ALLES, E., NÖRPEL-SCHEMPP, M., LANGE-BERTALOT, H., 1991: Zur Systematik und Ökologie charakteristischer Eunotia-Arten (Bacillariophyceae) in elektrolytarmen Bachberläu- fen. Nova Hedwigia 53, 171–213. KRIZMANIĆ J., ILIĆ M., VIDAKOVIĆ D., SUBAKOV-SIMIĆ G., PETROVIĆ J., CVETANOVIĆ K. 328 ACTA BOT. CROAT. 74 (2), 2015 ANDREJIĆ, J., KRIZMANIĆ, J., CVIJAN, M., 2012: Three new records for diatoms from the Nišava River and its tributary, the Jerma River (Southern Serbia). Oceanological and Hydrobiological Studies 41, 17–23. ANĐELKOVIĆ, M., 1958: Geological composition and tectonics of the south-western slope of the Stara planina Mountain (in Serbian). Srpska Kraljevska akademija, Posebna izdanja, Prirodnjački i matematički spisi 24, 1–48. BAHLS, L. L., 2009: A checklist of diatoms from inland waters of the northwestern United States. Proceedings of the Academy of Natural Sciences of Philadelphia 158, 1–35. BARBER, H. G., HAWORTH, E. Y., 1981: Aguide to the morphology of the diatom frustule. Freshwater Biological Association. Ambleside, Cumbria. BERE, T., TUNDISI, J. G., 2010: Biological monitoring of lotic ecosystems: the role of dia- toms. Brazilian Journal of Biology 70, 493–502. BUCZKÓ, K., 2006: Bryophytic diatoms from Hungary. Proceedings of the 18th International Diatom Symposium, 2–7 September 2004, Miedzyzdroje, Poland, 1–15. BUCZKÓ, K., WOJTAL, A., 2005: Moss inhabiting siliceous algae from Hungarian peat bogs. Studia Botanica Hungarica 36, 21–42. CANTONATI, M., LANGE-BERTALOT, H., 2011: Diatom monitors of close-to-pristine, very-low alkalinity habitats: three new Eunotia species from springs in Nature Parks of the south- eastern Alps Journal of Limnology 70, 209–221. CANTONATI, M., LANGE-BERTALOT, H., DECET, F., GABRIELI, J., 2011: Diatoms in very-shallow pools of the Site of Community Importance Danta di Cadore Mires (southeastern Alps), and the potential contribution of these habitats to diatom biodiversity conservation. Nova Hedwigia 93, 475–507. COSTE, M., BOUTRY, S., TISON-ROSEBERY, J., DELMAS, F., 2009: Improvements of the Biologi- cal Diatom Index (BDI): Description and effi ciency of the new version (BDI-2006). Ecological Indicators 9, 621–650. FRÁNKOVÁ, M., 2009: Ecology and taxonomy of diatoms of Western Carpathian spring fens. PhD Thesis, Faculty of Science Masaryk University, Brno. FRÁNKOVÁ, M., BOJKOVÁ, J., POULÍČKOVÁ, A., HÁJEK, M., 2009: The structure and species richness of the diatom assemblages of the Western Carpathian spring fens along the gradient of mineral richness. Fottea 9, 355–368. GREVILLE, R. K., 1855: Report on a collection of Diatomaceae made in the district of Brae- mar by Professor Balfour and Mr. George Lawson. Annals and Magazine of Natural History 15, 252–261. HOFMANN, G., WERUM, M., LANGE-BERTALOT, H., 2013: Diatomeen im Süßwasser-Benthos von Mitteleuropa. Koeltz Scientifi c Books, Königstein. JOHANSEN, J. R., LOWE, R. L., CARTY, S., FUČIKOVÁ, K., OLSEN, C. E., FITZPATRICK, M. H., RESS, J. A., FUREY, P. C., 2007: New algal species records for Great Smoky Mountains Na- tional Park, with an annotated check list of all reported algal taxa for the park. South- eastern Naturalist 6, 99–134. KAPETANOVIĆ, T., JAHN, R., REDŽIĆ, S., CARIĆ, M., 2011: Diatoms in a poor fen of Bijambare protected landscape, Bosnia & Herzegovina. Nova Hedwigia 93, 125–151. DIATOMS OF THE DOJKINCI RIVER IN SERBIA ACTA BOT. CROAT. 74 (2), 2015 329 KELLY, M., BENNION, H., BURGESS, A., ELLIS, J., JUGGINS, S., GUTHRIE, R., JAMIESON, J., ADRI- AENSSENS, V., YALLOP, M., 2009: Uncertainty in ecological status assessments of lakes and rivers using diatoms. Hydrobiologia 633, 5–15. KOCIOLEK, P., 2011: Diatomella balfouriana. In: Diatoms of the United States. Retrieved May 28, 2013 from http://westerndiatoms.colorado.edu/taxa/species/diatomella_balfouriana. KRAMMER, K., LANGE-BERTALOT, H., 1986: Bacillariophyceae. 1. Teil: Naviculaceae. In: ETTL, H., GERLOFF, J., HEYNIG, H., MOLLENHAUER, D. (eds.), Süßwasserfl ora von Mitteleuropa 2/1, 1–876. G. Fischer Verlag, Jena. KRAMMER, K., LANGE-BERTALOT, H., 1991: Bacillariophyceae. 4. Teil: Achnanthaceae. Kri- tische Ergänzungen zu Navicula (Lineolatae) und Gomphonema. In: ETTL, H., GARTNER, G., GERLOFF, J., HEYNIG, H., MOLLENHAUER, D. (eds.), Süßwasserfl ora von Mitteleuropa 2/4, 437. G. Fischer Verlag, Stuttgart & New York. KRASSKE, G., 1923: Die Diatomeen des Casseler Beckens und seiner Randegebirge einigen wichtigen Funden aus niederhessen. Botanisches Archiv 3, 198. KULIKOVSKII, M. S., 2008: The species composition and distribution of diatoms in Sphagnum bogs of European Russia: ecosystems of the Volga Upland. Inland Water Biology 1, 347–355. KWANDRANS, J., 2007: Diversity and ecology of benthic diatom communities in relation to acidity, acifi cation and recovery of lakes and rivers. Diatom Monographs 9. IVANČEVIĆ, B., SAVIĆ, S., SABOVLJEVIĆ, M., NIKETIĆ, M., TOMOVIĆ, G., ZLATKOVIĆ, B., RAN ĐE- LO VIĆ, V., LAKUŠIĆ, D., ĆETKOVIĆ, A., PAVIĆEVIĆ, D., KRPO-ĆETKOVIĆ, J., CRNOBRNJA-ISA I- LOVIĆ, J., PUZOVIĆ, S., PAUNOVIĆ, M., 2007: Checklist of the species at mountan Stara Planina in Serbia. In: LAKUŠIĆ, D., ĆETKOVIĆ, A. (eds.), Biodiversity of the Stara planina Mountain in Serbia: results of the Project: »Trans-boundary cooperation through the management of shared natural resources–Promotion of networks and exchanges in the countries of South-Eastern Europe« (in Serbian), 150–151. Regional Environmental Center of Central and East Europe, Offi ce in Serbia, Belgrade. LANGE-BERTALOT, H., MOSER, G., 1994: Brachysira – Monographie der Gattung. Bibliothe- ca Diatomologica 29. J. Cramer, Berlin–Stuttgart. LANGE-BERTALOT, H., METZELTIN, D., 1996: Indicators of oligotrophy. 800 Taxa representa- tive of three ecologically distinct lake types, carbonate buffered-oligodystrophic-weak- ly buffered soft water. In: LANGE-BERTALOT, H. (ed.), Iconographia Diatomologica. An- notated Diatom Monographs. Vol. 2. Ecology, Diversity, Taxonomy, 1–390. Koeltz Scientifi c Books, Königstein. LANGE-BERTALOT, H., BAK, M., WITKOWSKI, A., TAGLIAVENTI, N., 2011: Eunotia and some related genera. Diatoms of Europe 6. Koeltz Scientifi c Books, Königstein. LEELAHAKRIENGKRA, P., 2013: Diversity of freshwater benthos in the ecotourism area at Chi- ang Dao District in Chiang Mai Province, Thailand. Biodiversity Journal 4, 399–406. LIU, Y., WANG, Q., FU, CH., 2011: Taxonomy and distribution of diatoms in the genus Euno- tia from the Da’erbin Lake and Surrounding Bogs in the Great Xing’an Mountains, China. Nova Hedwigia 92, 205–232. MARKOVIĆ, J., 1980: Regional geography of SFR Yugoslavia (in Serbian). GRO »Nikola Nikolić«, Kragujevac. KRIZMANIĆ J., ILIĆ M., VIDAKOVIĆ D., SUBAKOV-SIMIĆ G., PETROVIĆ J., CVETANOVIĆ K. 330 ACTA BOT. CROAT. 74 (2), 2015 MIJOVIĆ, D., 2001: The review measure and perspective of protection of Stara planina Mt. (in Serbian). Protection of Nature 52 (2), 153–158. OBUŠKOVIĆ, LJ., 1993: Algological and saprobiological analyses of some waters in the river basin of the Visočica and the Temštica. Proceedings 3rd Meeting of the Flora of South- eastern Serbia, Leskovac-Pirot, 1–14. OBUŠKOVIĆ, LJ., MASLIĆ, M., CAKIĆ, P., JAKOVČEV, D., 1994: Hydoecological investigations of some waters of Mt. Stara planina. Proceedings23rd Annual Conference of the Serbian Water Pollution Control Society »Water 1994«, Igalo, 188–192. OFFICIAL GAZETTE OF THE REPUBLIC OF SERBIA, 2009: Regulation on the Protection of Na- ture Park »Stara Planina« 23/2009, (in Serbian), 1–3, Uredba o zaštiti parka prirode »Stara planina«. PATRICK, R., REIMER, C. W., 1966: The Diatoms of the United States exclusive of Alaska and Hawaii. Academy of Natural Sciences of Philadelphia Monographs. 13 (I), 688. PAVLOV, A., LEVKOV, Z., 2013: Diversity and distribution of taxa in the genus Eunotia Eh- renberg (Bacillariophyta) in Macedonia. Phytotaxa 86, 1–117. PEREIRA, C. L., RAPOSEIRO, P. M., COSTA, A. C., BAO, R., GIRALT, S., GONÇALVES, V., 2014: Bio geography and lake morphometry drive diatom and chironomid assemblages’ com- position in lacustrine surface sediments of oceanic islands. Hydrobiologia 730, 93–112. POTAPOVA, M., HAMILTON, P. B., 2007: Morphological and ecological variation within the Achnanthidium minutissimum (Bacillariophyceae) species complex. Journal of Phycol- ogy 43, 561–575. ROUND, F. E., CRAWFORD, R. M., MANN, D. G., 1990: The Diatoms: biology and morphology of the genera. Cambridge University Press, Cambridge. SIMIĆ, S., 1995: Benthic algal communities of the Trgoviški Timok River (in Serbian). Mas- ter thesis. University of Belgrade, Faculty of Biology. SIMIĆ, S., 1996: Algae from the Trgoviški Timok River (Serbia, Yugoslavia) (in Serbian). Glasnik Instituta za botaniku i botaničke bašte Univerziteta u Beogradu XXX, 107–118. SIMIĆ, S., 2002: Distribution of blue-green algae (Cyanophyta) in streams of Mt. Stara Planina Serbia. Archives of Biological Science 54, 141–148. STEVENSON, R. J., PAN, Y., 1999: Assessing environmental conditions in rivers and streams with diatoms. In: STOERMER, E. F., SMOL, J. P. (eds.), The Diatoms: applicationsfor the environmental and earth sciences, 11–40. Cambridge University Press, Cambridge. STOERMER, E. F., KREIS, R. G. JR., ANDRESEN, N. A., 1999: Checklist of Diatoms from the Laurentian Great Lakes. II. Journal of Great Lakes Research 25, 515–566. SZABADOS, M., 1966: Data to the knowledge of the microorganisma of the Jugoslav reaches of Tisza and the »Danube-Tisza canal«. Tiscia II, 3–11. SZABO, K., KISS, K., TOTH, B., METZELTIN, D., ACS, E., 2007: Navicula novaesiberica Lange- Bertalot; a new record of the species from the Danube River in Hungary. Diatom Re- search 22, 497–502. VAN DAM, H., MERTENS, A., SINKELDAU, J., 1994: A coded checklist and ecological indicator values of freshwater diatoms from The Netherlands. Netherlands Journal of Aquatic Ecology 28, 117–133. DIATOMS OF THE DOJKINCI RIVER IN SERBIA ACTA BOT. CROAT. 74 (2), 2015 331 VAN DE VIJVER, B., BEYENS, L., 1997: The epiphytic diatom fl ora from mosses of Strømness Bay area. Polar Biology 17, 492–501. VAN DE VIJVER, B., ECTOR, L., COX, E. J., 2012: Ultrastructure of Diatomella balfouriana with a discussion of septum-like structures in diatom genera. Diatom Research 27, 213– 221. VAN DE VIJVER, B., LANGE-BERTALOT, H., 2009: New and interesting Navicula taxa from western and northern Europe. Diatom Research 24, 415–429. VESELA, J., JOHANSEN, J., 2009: The diatom fl ora of ephemeral headwater streams in the Elb- sandsteingebirge region of the Czech Republic. Diatom Research 24, 443–477. WOJTAL, Z. A., WITKOWSKI, A., METZELTIN, D., 1999: The diatom fl ora of the »Bor na Czer- wonem« raised peat–bog in the Nowy Targ Basin (Southern Poland). Fragmenta Floris- tica et Geobotanica 44, 167–192. WOJTAL, Z. A., 2001: New or rare species of the genera Achnanthidium and Psammothid- ium (Bacillariophyceae) in the diatom fl ora of Poland. Polish Botanical Journal 49, 215–220. WOJTAL, Z. A., 2004: New locality of Diadesmis tabellariaeformis (Krasske) Lange-Bertalot et Wojtal (Bacillariophyceae) in Europe. Algological Studies Supplement 112, 89–94.