The first report on periphytic diatoms on artificial and natural substrate in the karstic spring Bunica, Bosnia and Herzegovina

This study presents investigations of the periphytic diatoms on artificial (glass slides) and natural substrates in the karstic, limnocrene spring of Bunica situated in the south of Bosnia and Herzegovina. Investigations were performed in summer 2010. Samples were collected every seven days for eight weeks. Physical and chemical characteristics of water, temperature, oxygen saturation, dissolved oxygen, electric conductivity and nutrients as well as flow velocity at sample site, were measured simultaneously with each sampling. Physical and chemical characteristics showed low temperature oscillations, good aeration and oligotrophic conditions. In general, greater diatom diversity was noted on natural substrate. A total of 104 diatom species were found on natural substrate and 82 on glass slides. The best represented genera on both types of substrate were Gomphonema and Navicula (each with eight species), Nitzschia (with six species), and Cocconeis (with five species). Achnanthidium exiguum, Achnanthidium minutissimum, Amphora pediculus, Cymbopleura amphicephala and Surirella minuta were recorded in all samples of natural substrate and Gomphonema minutum in artificial substrate samples

Effect of current velocity on diatom colonization on glass slides in unpolluted headwater creek

Abstract Background and Purpose: The goal of this study was to determine the effect of current velocity on diatom colonization rate during the first 30 days of artificial substrate (glass slides) exposure. Materials and Methods: From autumn 1990 to summer 1993 artificial substrates were submerged in an unpolluted mountain stream. The parallel oriented glass slides (against the surface) were placed 10 cm beneath thewater surface (protected from debris) and exposed to different current velocities (10–30 cm s–1, 40–60 cm s–1 and 80–100 cm s–1). The samples were collected seasonally. To define diatom colonization, a nonlinear regressive analysis of empirical data was performed. Results: A total of 71 diatom species were found. Species Cocconeis placentula, Surirella ovata, Gomphonema olivaceum, and Navicula gracilis were the most abundant, depending on different current velocity. Conclusions: The time needed for reaching the equilibrium progressively increased with the current velocity (F= 16.7; P< 0.01). In the summer and autumn, the time needed for the stabilization of diatom flora was longer than in spring and winter. Concerning species abundance, Cocconeis placentula, and Navicula gracilis were independent of the current velocity, while Surirella ovata was abundant at lower (≤30 cm s–1) and Gomphonema olivaceum at higher (≤60 cm s–1) current velocities

Dominantne vrste mrežnog fitoplanktona u Visovačkom jezeru, NP Krka

Species composition of the net-phytoplankton assemblage and seasonality of the dominant species were investigated in the travertine monomictic stratified riverine Lake Visovac in relation to the environmental variables. The one year investigation was based on monthly sampling from April 1995 to March 1996 at the two deepest vertical profiles, with a maximum depth of 25 m. Diatoms, especially Asterionella formosa Hass. dominated net-phytoplankton assemblages except in late summer and autumn when dinoflagellate species Ceratium hirundinella (O. F. Müller) Bergh became the dominate form. The effects of the short term dynamics of environmental factors on the algal growth in the barrage lenitic area of the calcareous river stressed several variables as important factors controlling annual net-phytoplankton distribution. Temperature was the variable that most affected species abundance, changes in dominance and species composition (Primer 5, BIO-ENV; http://www.primer-e.com/). CCA analysis performed on abundance dataset and environmental variables confirm the importance of temperature but also highlighted total phosphorus, conductivity and silica.Tijekom jednogodišnjeg razdoblja od travnja 1995. do ožujka 1996. istraživana je, u jednomjesečnim intervalima, vertikalna i sezonska distribucija mrežnog fitoplanktona u lenitičkom području Visovačkog jezera. Naglasak tijekom istraživanja bio je na sastav vrsta te povezanost dominantnih vrsta i okolišnih čimbenika. Najzastupljenija vrsta tijekom kasnog proljeća je dijatomeja Asterionella formosa Hass, dok ljeti i u jesen dominaciju preuzima dinoflagelat Ceratium hirundinella (O. F. Müller) Bergh. Od mjerenih ekoloških parametara, temperatura vode najznačajnije je utjecala na promjene u sastavu vrsta, njihovu zastupljenost i dominaciju (Primer 5, BIO-ENV). CCA analiza dobivena na osnovi zastupljenosti fitoplanktonskih stanica i praćenih ekoloških čimbenika potvrdila je znatan utjecaj temperature vode, kao i ukupnog fosfora, provodljivosti i silicija

Epipelonske dijatomeje u Šerićkoj bari (sjeveroistočna Bosna i Hercegovina)

Epipelic diatom communities were studied in the Šerićka bara marsh in northeast Bosnia and Herzegovina throughout 2009. During spring and summer a total of 57 species was found at 6 sampling points. The highest number of species was noted for genera Gomphonema (8) and Nitzschia (5). The most abundant species were Melosira varians C.Agardh, Gyrosigma acuminatum (Kützing) Rabenhorst, Lemnicola hungarica (Grunow) F.E.Round & P.W.Basson, Navicula cryptocephala Kützing, Cocconeis placentula var. placentula Ehrenberg, Hippodonta capitata (Ehrenberg) Lange-Bertalot, Metzeltin & Witkowski, Fallacia pygmaea (Kützing) A.J.Stickle & D.G.Mann, Anomoeoneis sphaerophora E.Pfi tzer, Craticula cuspidata (Kutzing) D.G.Mann, Cyclotella meneghiniana (Kutzing) D.G.Mann and Tryblionella hungarica (Grunow) Frenguelli. The spatial variation of the epipelic community was higher in summer as summarized by PCO analysis. Values of the Shannon-Wiener Diversity Index ranged from 2.47 to 2.96, while the Rott Trophic Index ranged from 2.7 to 3.4. Most of the species were eutraphentic (61%) and alkaliphilous (60%), indicating the eutrophic and polytrophic status of this wetland.U radu su istraživane epipelonske zajednice dijatomeja tijekom 2009. godine u Šerićkoj bari u sjeveroistočnoj Bosni i Hercegovini. Determinirano je 57 vrsta na 6 lokaliteta u proljetnoj i ljetnoj sezoni uzorkovanja. Rodovi najbrojnij i vrstama su Gomphonema (8) i Nitzschia (5), a dominantne vrste bile su Melosira varians C.Agardh, Gyrosigma acuminatum (Kützing) Rabenhorst, Lemnicola hungarica (Grunow) F.E.Round & P.W.Basson, Navicula cryptocephala Kützing, Cocconeis placentula var. placentula Ehrenberg, Hippodonta capitata (Ehrenberg) Lange-Bertalot, Metzeltin & Witkowski, Fallacia pygmaea (Kützing) A.J.Stickle & D.G.Mann, Anomoeoneis sphaerophora E.Pfizer, Craticula cuspidata (Kutzing) D.G.Mann, Cyclotella meneghiniana Kutzing i Tryblionella hungarica (Grunow) Frenguelli. Struktura epipelonske zajednice bila je prostorno raznolikija u ljetnoj u odnosu na proljetnu sezonu uzorkovanja. Shannon-Wienerov indeks raznolikosti iznosio je od 2,47 do 2,96, dok se trofički indeks prema Rott-u kretao u rasponu od 2,7 do 3,4. Najveći broj vrsta pripadao je kategoriji alkalifi lnih (60%) i eutrofnih (61%) pokazatelja i upućuje na eutrofni i politrofni status močvare

TALOŽENJE SEDRE U KRŠKOM POTOKU KAO INDIKATOR KVALITETE VODE (PARK PRIRODE PAPUK, HRVATSKA)

Tufa deposition and accompanying periphyton community were studied on artificial substrates, in karst Jankovac Stream (Papuk Nature Park, Croatia). Influence of environmental parameters on protozoans and metazoans in periphyton were assessed in two microhabitats, differed in flow velocity (fast 1.28 0.61 m s-1, medium 0.56 0.50 m s-1), and across different exposure period (one and two months). Measured environmental parameters indicated oligotrophic water condition. Samples collected in fast flow velocity reached significantly higher tufa deposition (0.26 0.04 mg cm-2 d-1) contrary to those in medium flow velocity (0.09 0.01 mg cm-2 d-1). Results of our study suggested that tufa deposition increased with temperature, flow velocity, amount of organic matter and algal biomass. In total, 26 taxa were identified on artificial substrate, among them 16 ciliate and 5 rotifer taxa. Most taxa recorded low abundance in periphyton, < 10 ind cm-2. Just few taxa achieved higher maximum abundances, i.e., ciliates: Chilodonella cucullulus (28 ind cm-2), Vorticella similis (68 ind cm-2) and rotifers: bdelloids (55 ind cm-2) and Dicranophorus forcipatus (64 ind cm-2). Periphyton community achieved statistically significant higher abundance in fast than in medium flow velocity microhabitats, with increasing effect through the longer exposure. We presume that oligotrophic conditions in karst running water facilitate tufa deposition. In this study we revealed microscopic freshwater organisms, often neglected in investigation, but very important in food webs as link to gastropods, crustaceans, insect larvae, juvenile and adult fish.Taloženje sedre i naseljavanje perifitonske zajednice istraživani su na umjetnim podlogama, u krškom potoku Jankovac (Park prirode Papuk, Hrvatska). Razmatran je utjecaj okolišnih čimbenika na zajednicu protozoa i metazoa u perifitonu, u dva mikrostaništa, koja su se razlikovala s obzirom na brzinu strujanja vode (brza struja vode 1,28 0,61 m s-1, srednja struja vode 0,56 0,50 m s-1) i vremensku ekspoziciju (jedan ili dva mjeseca). Mjereni okolišni čimbenici ukazuju na oligotrofiju sustava. Uzorci u brzoj struji vode postigli su veće vrijednosti taloženja sedre (0,26 0,04 mg cm-2 d-1) za razliku od uzoraka u srednjoj struji vode (0,09 0,01 mg cm-2 d-1). Rezultati ovog istraživanja ukazuju da su na taloženje sedre pozitivno utjecali temperatura, brzina strujanja vode, količina organske tvari i biomasa algi. Ukupno je determinirano 26 svojti u perifitonu na umjetnim podlogama, 16 svojti pripadalo je trepetljikašima, a 5 kolnjacima. Većina svojti bila je prisutna s malom abundancijom, < 10 jed. cm-2. Samo je nekoliko svojti postiglo veću abundanciju, na primjer, trepetljikaši: Chilodonella cucullulus (28 jed. cm-2), Vorticella similis (68 jed. cm-2) I kolnjaci: bdeloidni (55 jed. cm-2) i Dicranophorus forcipatus (64 jed. cm-2). Perifitonska zajednica postigla je statistički značajno veću abundanciju u mikrostaništu s brzom u odnosu na mikrostanište sa srednjom brzinom strujanja vode, a abundancija se također povećavala s vremenom ekspozicije. Pretpostavljmo da oligotrofni uvjeti u krškim vodama pogoduju taloženju sedre. U ovom istraživanju prikazani su mikroskopski slatkovodni organizmi, koji su često zanemareni u istraživanjima, ali su vrlo važni u hranidbenim lancima, kao poveznica prema puževima, rakovima, ličinkama kukaca, ličinačkim i adultnim stadijima riba

Algal assemblages in springs of different lithologies (ophiolites vs. limestone) of the Konjuh Mountain (Bosnia and Herzegovina) - Online supplement

The biodiversity of algal communities and environmental conditions were investigated in the springs of Mt. Konjuh. The assemblages of 20 springs emerging from different lithologies (limestones and ophiolites, respectively) comprised 234 algal taxa. Diatoms and cyanobacteria were the most species-rich groups. The most common alkaliphilic, circumneutral, and eutraphentic diatoms were represented by the genera Gomphonema, Nitzschia, Navicula, Cymbella, and Achnanthidium, and by the cyanobacterial genus Phormidium. Hierarchical clustering and SIMPROF analysis based on relative algal abundance clustered springs into six groups, separating them mainly according to spring type and lithology. Indicator species for groups and springs on different lithological substrata were singled out, revealing 33 taxa with preferences for ophiolites, and 20 taxa with preferences for carbonates. The values of the Shannon-Wiener diversity index were moderately high per spring location, and similar for the two groups of springs on different lithologies. A higher similarity in species composition was noted between springs on ophiolites and limestones than between springs on ophiolites and other types of siliceous substrata. The present study suggests that algal assemblages in springs emerging from ophiolites, even those made up by a preponderance of silicates, should be analyzed separately from those related to springs on other siliceous substrata. The results obtained showed that most of the springs studied are affected by anthropogenic impacts and morphological alterations leading to the dominance of highly ompetitive meso- and eutraphentic algal species, thus emphasizing the importance of further investigation and conservation of these habitats

Microbial mats as shelter microhabitat for amphipods in an intermittent karstic spring

Microbial mats represent complex communities where cyanobacteria and diatoms as key organisms provide shelter for diverse assemblages of aquatic invertebrates, like the small stygophilous amphipod Synurella ambulans. Studies addressing such communities in the karst springs have rarely examined springheads, and have ignored intermittent springs. During high flow conditions the stygophilic crustaceans are flushed to the surface of a temporary stream Krčić where microbial mats prevent their drift and enables their successful retreat into underground in the periods of drought. The objective of this study was to characterize the microbial mat community of the Krčić Spring as a shelter for S. ambulans during strong current and high water level. Representative samples for diatom and cyanobacterial species identification and composition, as well as the fresh mat material for potential animal activity and cyanobacterial phylogenetic analysis were collected. The most dominant diatom was Achnanthidium minutissimum, whilst Fragilaria capucina, Meridion circulare, Navicula cryptocephala and Nitzschia palea had abundance greater than 0.5%. Morphological observations of cyanobacteria revealed that Phormidium favosum was the most dominant, with Hydrocoleum muscicola as a subdominant. Cyanobacterial phylogenetic relationship revealed two distinct clusters: (i) &quot;Phormidium cluster&quot;, confirming morphological observations in both winter and spring samples, and (ii) &quot;Wilmottia cluster&quot;, a first report for Croatia and found exclusively in the winter sample. Laboratory observations revealed a small stygophilic amphipod S. ambulans, hiding and feeding inside the pockets of fresh microbial mat. The intermittent Krčić Spring as a predator-free and competitor-free ecosystem provides a spatiotemporal conformity between microbial mat and stygophilous amphipod

Submerged macrophytes as a habitat for zooplankton development in two reservoirs of a flow-through system (Papuk Nature Park, Croatia)

In order to determine the influence of lentic habitats and macrophyte stands on the plankton development and seston flux, an investigation of zooplankton was carried out in the karst Jankovac flow-through system (Papuk Nature Park, Croatia). The system was characterized by low abundance (1–116 ind.L−1) and high diversity of identified zooplankton. Eighty-six taxa were recorded, comprising 57 rotifers, 15 cladocerans, 8 copepods and 6 members of other groups of organisms. The spatial oscillations of environmental parameters and biocoenosis assemblage revealed statistically significant differences between lotic and lentic habitats, as well as between vegetated and non-vegetated stations. These differences mainly respond to higher concentration of food resources and zooplankton/zooseston abundance and biomass in lentic, especially vegetated, habitats. This is also proved by results of principal component analysis (PCA), which suggested that the main drivers of development of the planktonic community were the food resources and the avoidance of flow velocity. Accordingly, shoreline areas with submerged macrophyte stands of Hippuris vulgaris L. were the most productive parts, represented by highest zooplankton abundance, biomass and biodiversity. Flow velocity significantly affected crustaceans assemblage, so that higher abundances of the larger cladocerans and copepods were achieved in vegetated stations with low flow velocity, while rotifers showed to be rheotolerance organisms. On the other hand, the longitudinal discontinuum of the stream channel by two man-made reservoirs could offer new habitats to enrich seston with organic particles and bioseston. The results of our study pronounce the need for further monitoring of this hydrosystem, especially considering biodiversity and microhabitats conservation