Jelena Krizmanić

New taxa of the genus Navicula (Bacillariophyceae) in the diatom flora of Serbia

The main objective of this paper is to report two benthic, epilithic diatom species from the Raška River. Samples were collected in April, June, August and November 2011 and March and May 2012 from 5 localities along the Raška River by scraping off the stone surface using a brush. Diatom frustules were first cleaned using the cold acid method, and then mounted on permanent slides. Descriptions (main valve measurements of the populations in the Raška River), ecology, distribution in Serbia and Europe, and appropriate photomicrographs of two species are presented. Navicula jakovljevicii Hustedt and Navicula catalanogermanica Lange-Bertalot & Hofmann are rarely found in Europe and these are new distributional records. These new taxa significantly contribute to diatom floristic diversity of the Raška River.

The application of benthic diatoms in water quality assessment (Mlava River, Serbia)

Abstract The main objective of this study was to assess the ecological status of the Mlava River based on epilithic diatoms and to test the use of diatom indices as a tool for estimating the quality of flowing waters in Serbia. Quantitative analysis showed that in April Achnanthidium minutissimum was dominant at each site, except at the fifth site, where Amphora pediculus was dominant. In July and September, Achnanthidium minutissimum, Achnanthidium pyrenaicum, Amphora pediculus, Denticula tenuis, Diatoma vulgaris, Gomphonema elegantissimum, Cocconeis pseudolineata and Cocconeis placentula var. lineata dominated. Detrended correspondence analysis (DCA) was used to detect the major patterns of variation in species composition. The first DCA axis summarizes the distribution of the diatom community, mainly through temperature, conductivity, oxygen and water hardness gradient. The second DCA axis was weakly correlated with few variables. Based on the average values of the pollution sensitivity index (IPS), commission for economical community metric (CEE) and biological diatom index (IBD), the water of the Mlava River belonged to water class I during all three seasons. Values of the diatom-based eutrophication/pollution index (EPI-D) indicated class II water quality. According to calculated trophic diatom index (TDI) values, water of the Mlava River was characterized by intermediate nutrient concentrations during three seasons. Principal components analysis was used to represent the correlation between diatom indices, and the highest correlation among the selected diatom indices is seen between EPI-D, IPS and IBD.

Driving factors affecting spatial and temporal variations in the structure of phytoplankton functional groups in a temperate reservoir

Abstract During the twenty-five years of existence, water quality has declined and severe blooms of cyanobacteria have occurred in the Grlište Reservoir. Changes in phytoplankton functional groups over time and along horizontal and vertical gradients were investigated in the course of a one-year study in this water-supply reservoir. We identified 19 dominant taxa, classified into 12 phytoplankton associations. The presence of the codons C, P, D and S1 differentiated the transitional from the lacustrine part of the reservoir. The nitrogen-fixing cyanobacteria Dolichospermum viguieri dominated the phytoplankton community in the epilimnion during August and September, when the reservoir showed P-limitation, but the bloom was not observed. The driving factors that accounted for the main variability in phytoplankton functional groups along the seasonal and vertical profile were identified using the direct gradient analysis (RDA). Our results revealed the importance of two bipolar factors. The first factor explained the variability in phytoplankton due to thermal stratification and physical mixing, each process affecting the algal community in contrasting ways. The second factor was interpreted as reduction vs. oxidation processes. Positive correlation between stratification and water pumping by a drinking water plant indicated that human activities were not severe enough to break down the thermal stability of the reservoir and to cause a cyanobacterial bloom.

Three new records for diatoms from the Nišava River and its tributary, the Jerma River (Southern Serbia)

The main objective of this paper is to report three benthic diatom species from the Nišava and Jerma Rivers, which prove to be new findings in the context of the Serbian diatom flora. These are also new distributional records for all three species. Monthly samples (from stones, sediments and macrophytes) were collected from May 2008 to May 2009. Diatom frustules were cleaned using chemical agents, and mounted on permanent slides. Descriptions (main valve measurement of the populations in the Nišava and Jerma Rivers), ecology, distribution in Serbia and Europe, and appropriate photomicrographs of three species are presented. Navicula novaesiberica Lange-Bertalot and Neidiomorpha binodiformis (Krammer) Lange-Bertalot & Cantonati are rarely found in Europe, while Parlibellus protracta (Grunow) Witkowski is more common. Navicula novaesiberica and Neidiomorpha binodiformis were found at higher water temperatures in comparison to temperatures reported in the existing literature. These new taxa significantly contribute to diatom floristic richness of the Nišava and Jerma Rivers in Serbia.

A Checklist of Desmids (Conjugatophyceae, Chlorophyta) of Serbia. III. Genus Staurastrum

Abstract The first data about the distribution of desmids in Serbia derive from the year 1883 and from that time up to the end of 2010 there were identified 646 different taxa. The species-rich genus Staurastrum is represented with 116 taxa which is about 18% of the total number of desmids in Serbia. Taxa of the genus Staurastrum occur in a large variety of habitats in Serbia, but the greatest diversity was recorded in high mountain peat bogs. In Serbia till now, a large number of taxa of the genus Staurastrum (40.5%) has been found only on one locality (exceptionally rare taxa). In contrast, the species S.alternans, S. gracile, S. orbiculare, S. paradoxum, S. polymorphum and S. tetracerum belong to the most common species in Serbia. In this paper a review is presented of the main taxonomic and ecological characteristics of taxa of the genus Staurastrum, recorded from Serbia.

Contribution to the improvement of diatom-based assessments of the ecological status of large rivers – The Sava River Case Study

The Sava River Basin is a major drainage basin of southeastern Europe, significantly influenced by anthropogenic activities. Our study was focused on diatom communities as an indicator of the ecological status of running waters. We investigated over 937km of the Sava River at 19 sampling sites. Benthic diatom communities and 17 diatom indices were analyzed along with a large set of environmental parameters. CCA revealed that the most important elements along the spatial gradient were As and Si. Our results show that the species Navicula recens (Lange-Bert.) Lange-Bertalot and Eolimna minima (Grunow) Lange-Bertalot are very abundant at downstream localities where the highest concentrations of As were measured. The number of motile diatoms increased along the nutrient gradient, i.e. with Si availability. Correlations between diatom indices and selected environmental factors showed that temperature, As, Si and Fe are in significant negative correlation with most diatom indices. Analysis revealed the influence of As and metals in water on diatoms, although their concentrations did not exceed environmental standards. While our findings do not confirm that diatom indices reveal the intensity of pressures solely caused by nutrient and/or organic pollutants, they suggest that in moderately polluted large rivers benthic diatoms are good bioindicators of multiple pressures, and that diatom indices could serve as indicators of the level of overall degradation of an ecosystem.

Additional information on the distribution and ecology of the recently described diatom species Geissleria gereckei

Abstract The main objective of this paper is to report new information about the distribution and ecology of a recently described diatom species, Geissleria gereckei. The opportunity for updating the information on the distribution and ecology of the species was provided by the finding of well-developed G. gereckei populations on the lithic material and bryophytes in the Raška and Mlava rivers (Serbia). For several years after the first description, G. gereckei has been known only from the type locality and from another spring in the Dolomiti Bellunesi National Park (the south-eastern Alps). After accurate LM and SEM observations, we provide evidence for the occurrence of the species also in the two above-mentioned rivers in Serbia, as well as in the south-western and south-eastern Alps. After an extensive literature search, it appears that the species is known with certainty only from these sites. Our observations and details from the literature suggest that the species is able to occupy a much broader ecological niche than the very-specific one observed at the time of discovery. The two main determinants for the species’ occurrence appear to be the carbonate nature of the catchments or aquifers, and the ability of the species to be competitive in habitats or microhabitats exposed to seasonal desiccation.

Benthic diatoms of the Vrla River (Serbia) and their application in the water ecological status assessment

Abstract Epilithic diatoms from the Vrla River (Serbia) have been used to assess the ecological status of water. A total of 227 diatom taxa belonging to 50 genera were identified in the Vrla River during six research seasons with 13 dominant species recorded. Gomphonema (30 species), Navicula (28) and Nitzschia (26) were the most species-rich genera, followed by Pinnularia (12) and Encyonema (11). One taxa was recorded as new to Serbia – Geissleria acceptata. CCA grouped the diatom taxa into three main groups. The first group included taxa found at most of the sampling sites, the second group involved diatom taxa significantly positively correlated with the oxygen, while the third group showed positive correlation with temperature. RDA showed that some diatom taxa, including: Cocconeis placentula var. placentula, C. placentula var. lineata, C. pseudolineata and Mayamaea atomus var. permitis, are significantly positively correlated with temperature, while others, for example Achnanthidium minutissimum, Hannaea arcus, Nitzschia pura are mostly correlated with total phosphorus, alkalinity and water hardness. The ecological status of the Vrla River ranged from moderate, good to high. It was shown that according to the diatom indices, the ecological status of water downstream and upstream of a trout fish pond was slightly different.

Uncertainty of using habitat fidelity in biomonitoring based on benthic diatoms - the Raška River case study

Epilithic diatoms are frequently recommended for river biomonitoring, while much less emphasis is placed on epiphytic communities. This study considers use of epiphytic and epilithic diatom communities from the Raška River in biomonitoring. A total of 212 diatom taxa were recorded in both communities. Dominant diatoms were Achnanthidium minutissimum (Kützing) Czarnecki, A. affine (Grunow) Czarnecki, A. subatomus (Hustedt) Lange-Bertalot, Amphora pediculus (Kützing) Grunow, Diatoma vulgaris Bory, Gomphonema tergestinum (Grunow) Fricke, Cocconeis placentula var. lineata (Ehrenberg) Van Heurck, Melosira varians Agardh and Navicula tripunctata (Müller) Bory. Redundancy analysis (RDA) was used to detect the relationships between diatoms, some environmental factors and sampling sites. Diatoms of the epiphytic community showed a clearly grouping in relation to the sampling sites as compared with diatoms of the epilithic community. Species common to both communities showed a similar correlation with some environmental variables (BOD, pH, NH4+, TP, NO3− and conductivity), with three exceptions (Diatoma vulgaris, Cymbella compacta, and Encyonema silesiacum). Pearson’s correlation coefficient showed correlation between selected environmental variables and diatom indices calculated using OMNIDIA 6.2 software (TDI, IPS, CEE, GENRE, TID, SID, SHE and IDSE/5). Diatoms of the epiphytic community are more clearly clustered in relation to the sampling sites as compared with diatoms of the epilithic community. According to our results there is still “place” in biomonitoring for epiphytic community. The present study highlights the necessity of sampling both epiphytic and epilithic communities because substrate specificity could play important role in biomonitoring.

Structure and succession of periphyton in an urban reservoir: artificial substrate specificity

Abstract Substrate specificity of the periphyton community is usually underestimated in both periphyton ecology and biomonitoring studies, thus different kinds of both natural and artificial substrates (of organic and inorganic origin) are employed. Periphyton colonization and successional trajectories are particularly debatable processes when different kinds of substrates are considered. In our field experiment, we deployed four kinds of artificial substrates (two inorganic ones – glass and ceramic, and two organic ones – willow and yew wooden tiles) for the development of periphyton in an urban reservoir referred to as Lake Savsko (Belgrade, Serbia). We comparatively investigated the structure, colonization process, diversity and successional trajectories of periphyton. We also assessed the relationship between the dynamics of algae growth forms (ecological groups) on different substrates and selected abiotic limnological factors. Our objective was to determine whether the type of substrate affects periphyton characteristics at various levels and whether an artificial substrate potentially affects the bioindication capacity of ecological groups. We concluded that all substrates behave similarly at the level of structure and colonization phases, but when considering diversity and successional trajectories, the substrate specificity was demonstrated. Our results suggest that communities developed on inert substrates (glass and ceramic) could provide more realistic insight into complex environmental changes.