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Abstract: Cyanobacteria are adaptable and dominant organisms that exist in many harsh and extreme environments due to their great ecological tolerance. They produce various secondary metabolites, including cyanotoxins. While cyanobacteria are well studied in surface waters and some aerial habitats, numerous other habitats and niches remain underexplored. We collected 61 samples of: (i) biofilms from springs, (ii) aerial microbial mats from buildings and subaerial mats from caves, and (iii) water from borehole wells, caves, alkaline, saline, sulphidic, thermal, and iron springs, rivers, seas, and melted cave ice from five countries (Croatia, Georgia, Italy, Serbia, and Slovenia). We used (q)PCR to detect cyanobacteria (phycocyanin intergenic spacer—PC-IGS and cyanobacteria-specific 16S rRNA gene) and cyanotoxin genes (microcystins—mcyE, saxitoxins—sxtA, cylindrospermopsins—cyrJ), as well as amplicon sequencing and morphological observations for taxonomic identification. Cyanobacteria were detected in samples from caves, a saline spring, and an alkaline spring. While mcyE or sxtA genes were not observed in any sample, cyrJ results showed the presence of a potential cylindrospermopsin producer in a biofilm from a sulphidic spring in Slovenia. This study contributes to our understanding of cyanobacteria occurrence in diverse habitats, including rare and extreme ones, and provides relevant methodological considerations for future research in such environments.
Keywords: extreme environments, cylindrospermopsin, sulphidic springs, caves, qPCR, PC-IGS
Published in DiRROS: 01.09.2026; Views: 91; Downloads: 76
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Abstract: V poročilu so predstavljeni rezultati ekološke raziskave Prvega (Jezero pod Vršacem), Petega in Šestega (Dvojno jezero) Triglavskega jezera v dolini Sedmerih Triglavskih jezer. Prvo jezero je najbolj severno ležeče jezero v dolini, ki ima dva stalna pritoka iz dveh potočkov ter je bilo pred letom 1994 tudi poleti popolnoma ali delno prekrito z ledom, snegom in plundro. Po letu 1994 je jezero poleti večinoma brez snega in ledu. Dvojno Triglavsko jezero je bilo od leta 1991 naseljeno z ribami, kar je korenito spremenilo lastnosti obeh jezer, obenem sta jezera tudi pod vplivom planinske koče pri Triglavskih jezerih, ki se nahaja med Močivcem in Petim jezerom. Med letom 2020 in 2023 je, v okviru projekta Vrh Julijcev (Izboljšanje stanja vrst in habitatnih tipov Triglavskem narodnem parku), katerega vodilni partner je JZ Triglavski Nacionalni Park, potekal intenziven izlov rib in druge aktivnosti, kot je odstranjevanje makrofitov. Raziskavo v takšni obliki in obsegu smo izvedli prvič jeseni 2023, nato pa jo ponovili v septembru leta 2024 in 2025. Na terenu smo izmerili fizikalne, kemijske in izbrane biološke parametre jezer, odvzeli vzorce za kemijske analize vode, vzorce zooplanktona, fitoplanktona, fitobentosa (perifitona) ter bentoških nevretenčarjev, popisali prisotnost makrofitov in dvoživk ter rezultate primerjali s preteklimi podatki, pogledali dolgoročne trende in ovrednotili ekološko stanje vseh treh jezer. Raziskava v letu 2025 je nadaljevanje večletnega spremljanja stanja jezer, povzetega v poročilih pripravljenih s strani Nacionalnega Inštituta za biologijo za Triglavski nacionalni park od leta 2019 do leta 2024, hkrati pa tudi nadaljevanje raziskav, ki so se pričele v letu 1989 pod vodstvom biologov z Oddelka za biologijo Univerze Edvarda Kardelja in Inštituta za biologijo ter nadaljevale v 90. letih prejšnjega stoletja in prvem in drugem desetletju tega stoletja pod vodstvom prof. dr. Antona Branclja z Nacionalnega inštituta za biologijo. Prvo jezero je glede na izmerjene parametre v primerjavi z leti 2023 in 2024 ostalo v podobnem stanju z manjšimi odstopanji. Koncentracija klorofila a na gladini se je v Prvem jezeru po enem letu povišala, prav tako tudi koncentracija skupnega dušika na gladini, medtem ko je koncentracija skupnega dušika na dnu malenkost upadla, v primerjavi z letom 2023 pa so vrednosti še vedno nižje. Glede na leti 2023 in 2024 se je koncentracija skupnega fosforja znižala. Dodatne analize izvirov, ki se stekata v jezero so pokazale višje vrednoti nitratov v vzorcih iz izvirov kot v jezeru. Dno jezera tudi letos preraščajo nitaste zelene alge in lasastolistna vodna zlatica. V Petem jezeru se je kemijsko stanje v primerjavi z lanskim letom precej poslabšalo. Nasičenost s kisikom je po štirih letih ponovno padla pod 100% (dno), v primerjavi z leti 2023 in 2024 pa so analize pokazale tudi povišanje koncentracije klorofila a ter skupnega dušika. Presenetljivo pa je, da smo pri Šestem jezeru zaznali pozitivne spremembe, analize klorofila a so pokazale rekordno nizke vrednosti, prav tako analiza skupnega fosforja ter dušika, katerih koncentracija v Šestem jezeru z leti ves čas upada. Dno Dvojnega jezera še vedno povsem preraščajo nitaste zelene alge. Glede na vse zaznane spremembe se predlaga nadaljnje spremljanje stanja.
Keywords: visokogorska jezera, ekološko stanje, trofični indeks, kemični in biološki parametri, Dolina Sedmerih Triglavskih jezer, kemijska analiza vode, zooplankton
Published in DiRROS: 09.07.2026; Views: 265; Downloads: 2

Abstract: Functional genomics offers a powerful, unbiased approach to elucidating the molecular mechanisms underlying the toxicity of environmental pollutants. In this study, we applied genome-wide screening in Chlamydomonas reinhardtii to investigate two classical herbicides: paraquat and diuron. Our screen successfully uncovered critical nuclear-encoded pathways that govern susceptibility. For both herbicides, we identified genes regulating the assembly and maintenance of the photosynthetic machinery, highlighting the central role of nuclear control over these chloroplast-localized targets. Beyond these target-related factors, we discovered novel nontarget-site resistance mechanisms. For paraquat, we identified intracellular trafficking as the central determinant of toxicity, experimentally characterizing a P5B ATPase transporter and a fatty acid elongation pathway whose disruption, we propose, converges on the same endomembrane delivery route through sphingolipid depletion. In contrast, our screening data suggest that diuron tolerance may be associated with a metabolic strategy focused on energy conservation, where the inactivation of specific NADPH-consuming enzymes could preserve reducing power for essential antioxidant defense. Collectively, these findings demonstrate that functional genomics can reveal novel, complex modes of action even for well-characterized chemicals, providing the mechanistic resolution required to advance modern ecotoxicological risk assessments.
Keywords: paraquat, diuron
Published in DiRROS: 09.06.2026; Views: 319; Downloads: 341
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Abstract: DNA metabarcoding of benthic diatoms has been successfully applied for biomonitoring at the national scale and can now be considered technically ready for routine application. However, protocols and methods still vary between and within countries, limiting their transferability and the comparability of results. In order to overcome this, routine use of DNA metabarcoding for diatom biomonitoring requires knowledge of the sources of variability introduced by the different steps of the procedure. Here, we examine how elements of routine procedures contribute to variability between European laboratories. A set of four experiments were performed focusing on DNA extraction and PCR amplification steps to evaluate their reproducibility between different laboratories and the variability introduced by different protocols currently applied by the scientific community. Under the guidance of a reference laboratory, 17 participants from 14 countries performed DNA extraction and PCR amplification in parallel, using the same fixed protocol and their own choice of protocol. Experiments were performed by each participant on a set of standardised DNA and biofilm samples (river, lake and mock community) to investigate potential systematic and random errors. Our results revealed the successful transferability of a protocol amongst labs and a highly similar and consistent ecological assessment outcome obtained regardless of the protocols used by each participant. We propose an “all for one but prove them all” strategy, suggesting that distinct protocols can be used within the scientific community, as long as their consistency is be proven by following minimum standard requirements.
Keywords: cross-laboratory experiment, DNA-based approach, ecological status assessment, intercalibration, standardisation, environmental science, biomonitoring, DNA metabarcoding, benthic diatoms
Published in DiRROS: 17.01.2025; Views: 1053; Downloads: 895
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Abstract: Vodna telesa, kot sta Tivolski ribnik in Koseški bajer, so pomembni elementi mest. Kot antropogeni tvorbi sta pomembna tako z vidika naravne kot tudi kulturne dediščine. Raziskave so pokazale, da predstavljajo ribniki v spremenjeni krajini, kjer so vodotoki večinoma regulirani in naravni obrežni pasovi okrnjeni ali celo odstranjeni, habitate in zatočišča za različne ptice in žuželke. To je posebej pomembno v mestih, kjer je biotska pestrost zaradi človekovih posegov močno zmanjšana. Z vidika ekosistemskih storitev imajo ribniki pomembno socialno vlogo, saj njihova okolica predstavlja mesto za sprostitev, sama vodna telesa pa lahko služijo tudi v izobraževalne namene. Njihova vloga je tudi podporna, saj uravnavajo okoljske razmere (blažijo temperaturna nihanja in povečujejo vlažnost zraka) na območju. Zaradi intezivnih bioloških procesov se različne snovi, ki prihajajo v ribnike s spiranjem in pritoki, tam razgradijo ali spremenijo. Vse vloge pa so povezane z celovitostjo življenjske združbe in uravnoteženostjo procesov v ribnikih, saj je znano, da je lahko ekološki potencial siromašnih evtrofnih sistemov močno zmanjšan. Za oceno učinkov v letu 2011 izvedene sanacije ribnika Tivoli ter ovrednotenje stanja Koseškega bajerja smo v letih 2012 in 2013 v skladu s projektno nalogo Preiskave kakovosti vode ribnika Tivoli in Koseškega bajerja opravili preiskave obeh ribnikov. Izvedli smo vzorčenje fitoplanktona, bentoških nevretenčarjev, fitobentosa in makrofitov ter opravili meritve in vzorčenje vode za fizikalno-kemijske analize. V končnem poročilu so zbrani rezultati analiz, ocenjeno je stanje obeh vodnih teles ter predlagani ukrepi za izboljšanje stanja. Ker metodologija za izdelavo ocene ekološkega potenciala še ni pripravljena, smo vodni telesi uvrstili v trofične kategorije. Izjema je le vrednotenje na osnovi bentoških nevretenčarjev.
Keywords: ekologija sladkih voda
Published in DiRROS: 16.09.2024; Views: 1375; Downloads: 1699
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