Epilithic diatom communities - seasonal dynamics and ecological status assessment of selected rivers from the eastern and southeastern Serbia

Analizom zajednice silikatnih algi moņe se dobiti slika opńteg stanja, ekolońkog integriteta i kvaliteta vode odreĊenog vodenog ekosistema. U cilju implementacije Okvirne direktive o vodama, u Srbiji je doneta zakonska regulativa na osnovu koje je obavezna procena ekolońkog statusa povrńinskih voda na osnovu bentosne zajednice silikatnih algi. Predmet ove doktorske disertacije je floristiĉka studija epilitskih zajednica silikatnih algi, njihova sezonska dinamika i primena dijatomnih indeksa kao relevantnih parametara u proceni ekolońkog statusa odabranih reka istoĉne i jugoistoĉne Srbije. Algolońki i fiziĉko-hemijski uzorci su sakupljeni ńest puta u periodu od dvanaest meseci sa ńest lokaliteta duņ toka reke Vrle i reke Crnice, odnosno sa pet lokaliteta duņ toka reke Mlave i Radovanske reke. Pri izboru lokaliteta vodilo se raĉuna o poloņaju pastrmskog ribnjaka i njegovom uticaju kao potencijalnom izvoru zagaĊenja ovih reka. Tokom istraņivanog perioda identifikovano je ukupno 375 taksona epilitskih silikatnih algi u Vrli, Mlavi, Crnici i Radovanskoj reci. Pored ugroņenih taksona, identifikovani su i taksoni koji se smatraju retkim. Od ukupnog broja identifikovanih, 50 taksona je prvi put zabeleņeno u flori algi Srbije. Rod Decussata predstavlja novi rod za floru algi Srbije. CCA analiza uticaja ekolońkih parametara na distribuciju taksona epilitske zajednice silikatnih algi iz 4 istraņivane reke je pokazala da ribnjaci utiĉu na fiziĉko-hemijske osobine vode, a samim tim na sastav epilitske zajednice. Kao znaĉajni fiziĉko-hemijski faktori izdvojili su se NH4+, NH3 i EP. Na osnovu većine dijatomnih indeksa voda sve ĉetiri istraņivane reke je dobrog ekolońkog statusa (II klasa kvaliteta). Prema zakonskoj regulativi Srbije, na osnovu biolońkih (fitobentos) i fiziĉko-hemijskih elemenata, ekolońki status vode istraņivanog dela reke Vrle je dobar (II klasa), a reke Mlave umeren (III klasa). Konaĉan ekolońki status Crnice i Radovanske reke je procenjen kao slab (IV klasa)...By analyzing the benthic diatom community, a picture of the general condition, ecological integrity and water quality of a particular aquatic ecosystem can be obtained. In order to implement the Water Framework Directive, a legislation has been adopted in the Republic of Serbia that requires an assessment of the ecological status of surface waters based on the benthic diatoms. The aim of this PhD thesis was the floristic analysis of the epilithic diatom communities, their seasonal dynamics and the application of diatom indices as relevant parameters in the ecological status assessment of the selected rivers from the Eastern and Southeastern Serbia. Algological and physico-chemical samples were collected six times over a period of twelve months from six sites along the Vrla and Crnica rivers, and from five sites along the Mlava and Radovanska rivers. In selecting the sites taken into account the position of a trout ponds and its impact as a potential sources of pollution of the rivers. A total of 375 epilithic diatom taxa in Vrla, Mlavi, Crnica and Radovanova rivers were identified during the investigated period. Some endangered and rare taxa were identified. Of the total number of identified taxa, 50 taxa were new records for the Serbian algal flora. The genus Decussata, with the rare species D. hexagona, was recorded for the first time in Serbia. The CCA analysis of the impact of ecological parameters on the distribution of the diatom taxa from the investigated rivers has shown that the fish ponds affect the water physico-chemical properties and, consequently, the composition of the epilithic diatom communities. NH4+, NH3 and EP have been identified as important physical-chemical factors..

The first record of the genus Decussata (Patrick) Lange-Bertalot (Bacillariophyta) in Serbia – description, distribution and ecology of the rare species D. hexagona (Torka) Lange-Bertalot

The aim of this paper is to present the distribution of Decussata hexagona, a new species in diatom flora of Serbia. Seventy-two diatom samples were collected from six localities along the Vrla and Rasina Rivers during 2011 and 2012. Decussata hexagona was recorded with single specimens or low relative abundance (0.3%) from epilithic communities in seven samples from the Vrla River and in one sample from the Rasina River. It was recorded in unusual epilithic habitats of running neutral to low-alkaline waters with low ion content

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

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 fi fth 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

Prilog poznavanju distribucije roda Navicula na teritoriji Srbije

Rod Navicula 1822. godine je opisao Bory de St. Vincent obuhvativši birafidne izopolarne taksone vretenastog oblika. Vrste roda Navicula karakterišu poprečne pruge izgrađene od jednog niza pora (lineola), filiformna rafa i dva krupna hromatofora. Prema podacima iz Algaebase (Guiry i Guiry 2018) rod Navicula obuhvata 1264 taksona. Tokom 2011. i 2012. godine sakupljeni su epilitski uzorci silikatnih algi iz sedam reka Srbije (Rasina, Rača, Raška, Studenica, Mlava, Vrla i Radovanska reka). Rezultati su pokazali da je rod Navicula jedan od najzastupljenijih u istraživanim rekama. Od ukupnog broja identifikovanih taksona zabeleženo je 15 novih za floru silikatnih algi Srbije. Svi ovi taksoni preferiraju karbonatne, oligo- do eutrofne vode, sa pH većom od 7 i umerenom koncentracijom elektrolita. Nijedan od ovih taksona nije zabeležen sa značajnom brojnošću, ali je njihovo prisustvo važano sa aspekta biodiverziteta. N. moskalii se izdvaja kao retko zabeležen takson u Evropi (Cantontati i sar. 2017). Rezultati naših istraživanja šire njen areal, kao i opseg dimenzija valve, pružajući nove detalje o autekološkim karakteristikama taksona. Ovi rezultati ukazuju na neophodnost detaljnijih i intenzivnijih istraživanja u cilju proširenja znanja o silikatnim algama Srbije.Kladovo, Srbija, 25–30.09.2018. [www.serbiosoc.org.rs

Interesting Navicula Bory de Saint-Vincent species from Serbia

The genus Navicula was originally described in 1822 by Bory de St. Vincent. The concept of Navicula has changed from extremely heterogeneous collective genus to a narrowly defined, apparently homogeneous genus. The group Navicula sensu stricto involves 250-300 species and the great majority of them live in fresh, inland waters, and few inhabit brackish waters (Lange-Bertalot 2001). Knowledge about diatom biodiversity increase as a result of a more detail morphometric analysis of the frustula by light (LM) and scanning electron microscopy (SEM). Navicula splendicula was described by Van Landingham (1975). According to Lange-Bertalot (2001) it is known to inhabit southern and central Europe, with certainty. Distribution of N. splendicula from 2001 till today become wider, but in published papers SEM micrographs, as well as the dimensions of frustula, were not given and specified. LM and SEM observation of species from Serbia (Rasina and Vrla rivers) showed a variation from literature data regarding dimensions of frustula and variability of the ultrastructure of the central raphe ends. The poster illustrates all differentiating characters with brief notes on the ecology of the N. splendicula from two rivers in Serbia.10th Central European Diatom Meeting (10th CEDM), 20 – 23 April, 2016, Budapes

Epiphytic and epilithic diatom communities along the Raška River – implications for the water quality

We compared epiphytic and epilithic diatom communities in the Raška River, and their use in river biomonitoring. The material was collected in April, June, August and November 2011, and March 2012 from 5 localities along the Raška River. The result showed high variation of the diatom species composition between this two micro-habitats. The most abundant genera were Navicula, Gomphonema and Nitzschia, but with higher diversity in epiphytic diatom community. During first season, Achnanthidium minutissimum and Gomphonema tergestinum were dominant taxa in epilithic, while A. minutissimum and Diatoma vulgaris in epiphytic diatom community. Epilithic diatoms are the favoured community for monitoring water quality. However, at any river, diatom species are located on various substrates at the same sampling site. For diatom diversity assessment it is necessary to investigate all micro-habitats. Our results point to a difference in values of TDI diatom index between macrophytes and stone samples. Is it necessary to investigate all micro-habitats, or is the type of substratum independent for water quality monitoring?6th Balkan Botanical Congress, Rijeka, September 14-18, 201

Antioxidative and bifidogenic properties of baker’s yeast β-D-glucan

Poster presented at XLIX Savetovanje Srpskog hemijskog društva, (13-14. maj 2011., Kragujevac)Abstract: [https://cer.ihtm.bg.ac.rs/handle/123456789/5058

Antioxidative and bifidogenic properties of baker’s yeast β-D-glucan

Ćelijski zid pekarskog kvasca je glavni izvor nesvarljivog polisaharida beta-D-glukana Beta-D-glukan je fiziološki aktivno jedinjenje (opšte poznato kao modulator biološkog odgovora), koji aktivira imuni odgovor domaćina protiv bakterijske, virusne, gljivične i parazitske infekcije, kao i neoplazija. Cilj našeg istraživanja je ispitivanje bifidogenog i antioksidativnog potencijala (1->3),(1->6)-beta-D-glukana izolovanog iz pekarskog kvasca, kao novog prebiotskog dodatka infant formulama. Ukupan broj bifidobakterija nakon 48 h inkubacije u infant formuli sa dodatkom 0,1% (m /V) beta-D-glukana (čistoće 99,54%) bio je značajno viši u odnosu na zrelo majčino mleko, infant formulu sa dodatkom inulina ili infant formulu bez prebiotika, kao referentne supstrate. Promene broja bifidobakterija pra ene su promenama suve biomase, ukupnih bakterijski generisanih kiselina i pH. beta-D-glukan najveće čistoće nema antioksidativnu aktivnost, dok prečišćeni ekstrakti glukana (93,15%, 75,54% i 49,30%) uklanjaju hidroksil radikale. Na osnovu bifidogenog efekta možemo da zaključimo da je beta-D-glukan iz kvasca dobar kandidat kao novi prebiotik za dopunu infant formula.The cell wall of baker’s yeast is a major source of nondigestible polysaccharide beta-glucan ((1->3),(1->6)-beta-D-glucan). Baker’s yeast beta-glucan is a physiologically active compound (generally named “biological response modifier”) and is a broad-spectrum enhancer of host defense against bacterial, viral, fungal and parasitic infections, as well as neoplasia. The aim of our study was to investigate the bifidogenic and antioxidative potential of (1->3),(1->6)-beta-D-glucan isolated from the baker’s yeast (Saccharomyces cerevisiae) in relation to digestibility and purity, as a new infant formula prebiotic supplement. The total number of bifidobacteria after 48 h of incubation in the substrate composed of infant formula supplemented with 0.1 % (m/v) beta-D-glucan (purity 99.54 %) was significantly higher than in mature breast milk, infant formula supplemented with inuline or infant formula without added prebiotic, which were used as reference substrates. Changes in the number of bifidobacteria were followed by the changes in dry biomass, total bacteria-generated organic acids and pH. In contrast, the purest beta-D-glucan did not show any antioxidative activity, while partially purified glucan extracts (93.15%, 75.54% and 49.30%) scavenged hydroxyl radicals. Regarding to digestibility and bifidogenic efficacy Saccharomyces cerevisiae beta-D-glucan could be a candidate as a new infant formula prebiotic supplement.Poster: [https://cer.ihtm.bg.ac.rs/handle/123456789/5059

Expansion of invasive diatom species Didymosphenia geminata (Lyngb.) M.Schmidt and Diadesmis confervacea (Grun.) Hustedt in the waters of Serbia

For the first time in Serbia, the presence of Didymosphenia geminata was recorded in lakes of the Šar Planina mountain (Urošević, 1994). Subsequently, it was observed in the rivers Danube, Tisa, Sava. Detailed range of D. geminata spreading in the waters of Serbia was given by Subakov-Simić et al. (2006). Throughout monitiring rivers and channels in Serbia we recorded expand of this species in norther part of Serbia, Vojvodina, in the channel Novi Sad-Savino Selo. Diadesmis confervacea is diatom with a mainly tropical distribution. Majority of the findings in Europe originate from quiescent waters of botanical gardens and it is common in power plant discharges (Coste and Ector, 2000). They suggest it is invasive species that may spread further if global warming persists. While monitoring rivers and channels of Serbia from 2002 till 2013 we noticed the rapid expansion of distribution of D. confervacea. It occupied new habitats and nowadays can be found in the rivers Jegrička and Zasavica, as well in the channals Bački Petrovac-Karavukovo, Bečej-Bogojevo and Kikindski kanal in Vojvodina.6th Balkan Botanical Congress, Rijeka, September 14-18, 201