Diatom communities in freshwater springs with contrasting geology in the Apuseni Mountains
DOI:
https://doi.org/10.24193/subbbiol.2026.1.09Keywords:
Carpathian Mountains, carbonate substrate, metamorphic schist, diatom guildsAbstract
Freshwater springs are unique and fragile aquatic ecosystems characterized by a mosaic of microhabitats, hydrochemical properties influenced by geological substrate, and specialized biological communities. Springs from the Romanian Carpathian Mountains are poorly explored and the role of geological substrate in structuring diatom assemblages remains unclear. This study aims to characterize diatom communities and their dynamics in ten springs developed on contrasting geological substrates. Epibryon and epilithon samples were collected from at least three points of available microhabitats within the spring area. Standard methods were applied to obtain cleaned diatom material and the resulting assemblages were analyzed using multivariate ordination techniques, alongside ecological indicator values and functional guild structure. A total of 126 diatom taxa were identified and three of the investigated springs are reported here for the first time with respect to their diatom flora. Community composition differed significantly between the two contrasting groups of springs. Crystalline–metamorphic springs were associated with assemblages dominated by taxa typical of acidic and weakly mineralized waters, whereas carbonate springs supported communities characteristic of more alkaline conditions. Low-profile guilds dominated carbonate springs, whereas one crystalline–metamorphic spring showed a distinct high-profile-dominated structure. The results indicate that geological substrate shapes diatom community dynamics primarily through its control of physicochemical water properties. Indicator species analysis (IndVal) identified Pinnularia subcapitata W. Gregory as associated with crystalline–metamorphic springs, whereas Cocconeis euglypta Ehrenberg, Cocconeis placentula Ehrenberg and Meridion circulare C.Agardh were linked to carbonate-dominated springs. This study provides one of the first integrative multivariate assessments of crenic diatom communities in the Apuseni Mountains and highlights contrasting ecological patterns associated with different geological settings.
Article history: Received 13 March 2026; Revised 20 May 2026;
Accepted 20 May 2026; Available online 25 June 2026.
References
Aboal, M., Puig, M.A. & Prefasi, M. (1998). Diatom assemblages in springs in Castellón province, eastern Spain. Arch. Hydrobiol. Suppl. 125, 79–95.
Ahmadi Musaabad, L., Panahy Mirzahasanlou, J., Mahmoodlu, M.G. & Bahlakeh, A. (2019). Diatom flora in three springs of Golestan Province. J. Phycol. Res. 3(2), 432–442.
Angeli, N., Cantonati, M., Spitale, D., & Lange-Bertalot, H. (2010). A comparison between diatom assemblages in two groups of carbonate, low-altitude springs with different levels of anthropogenic disturbances. Fottea 10(1), 115-128. https://doi.org/10.5507/FOT.2010.006
Baker, L.-A., Biron, D.G., Millan, F., Voldoire, O., Breton, V., Allain, E., Wetzel, C.E., Ector, L. & Beauger, A. (2022). The substrate, a key factor or not, to explain the species diversity of diatom communities in mineral springs. Bot. Lett. https://doi.org/10.1080/23818107.2022.2028186
Beauger, A., Voldoire, O., Allain, E., Gosseaume, P., Blavignac, C., Baker, L.-A. & Wetzel, C.E. (2023). Biodiversity and environmental factors structuring diatom assemblages of mineral saline springs in the French Massif Central. Diversity 15, 283. https://doi.org/10.3390/d15020283
Bellinger, E.G. & Sigee, D.C. (2010). Freshwater algae: Identification and use as bioindicators. Wiley-Blackwell, Chichester, pp. 284.
Beracko, P., Sochuliaková, L., Cíbik, J. & Lánczos, T. (2022). Drivers predicting biodiversity and community assembly of benthic diatoms in a karst spring environment. Diatom Res. 37, 181–197. https://doi.org/10.1080/0269249X.2022.2100486
Blanco, S., Viso, R., Borrego-Ramos, M., López-Flores, R., Mota-Echeandía, D., Tierra, M. & Castañeda, C. (2025). The ecology of benthic diatom assemblages in saline wetlands of the Ebro Basin, NE Spain. Microb. Ecol. 88, 16. https://doi.org/10.1007/s00248-025-02514-3
Cantonati, M. (1998). Diatom communities of springs in the Southern Alps. Diatom Res. 13(2), 201-220. https://doi.org/10.1080/0269249X.1998.9705449
Cantonati, M., & Pipp, E. (2000). Longitudinal and seasonal differentiation of epilithic diatom communities in the uppermost sections of two mountain spring-fed streams. Verh. - Int. Ver. Theor. Angew. Limnol. 27 (3), 1591–1595. https://doi.org/10.1080/03680770.1998.11901507
Cantonati, M., Gerecke, R., & Bertuzzi, E. (2006). Springs of the Alps–sensitive ecosystems to environmental change: from biodiversity assessments to long-term studies. Hydrobiologia 562(1), 59-96. https://doi.org/10.1007/s10750-005-1806-9
Cantonati M., Rott E., Pfister P. & Bertuzzi E. (2007). Benthic algae in springs: biodiversity and sampling methods. In: Cantonati M., Bertuzzi E. & Spitale D. (eds), The spring habitat: biota and sampling methods. Ed. Museo Tridentino di Scienze Naturali, Trento: 77-112 (Monografi e del Museo Tridentino di Scienze Naturali, 4).
Cantonati, M. & Spitale, D. (2009). The role of environmental variables in structuring epiphytic and epilithic diatom assemblages in springs and streams of the Dolomiti Bellunesi National Park (south-eastern Alps). Fundam. Appl. Limnol. 174, 117–133. https://doi.org/10.1127/1863-9135/2009/0174-0117
Cantonati, M., Füreder, L., Gerecke, R., Jüttner, I. & Cox, E.J. (2012a). Crenic habitats, hotspots for freshwater biodiversity conservation: Toward an understanding of their ecology. Freshw. Sci. 31, 463–480. https://doi.org/10.1899/11-111.1
Cantonati, M., Angeli, N., Bertuzzi, E., Spitale, D., & Lange-Bertalot, H. (2012b). Diatoms in springs of the Alps: spring types, environmental determinants, and substratum. Freshw. Sci. 31(2), 499-524. https://doi.org/10.1899/11-065.1
Cantonati, M., Bilous, O., Spitale, D., Angeli, N., Segadelli, S., Bernabè, D., Lichtenwöhrer, K., Gerecke, R. and Saber, A.A. (2022). Diatoms from the spring ecosystems selected for the long-term monitoring of climate-change effects in the Berchtesgaden National Park (Germany). Water, 14(3), 381. https://doi.org/10.3390/w14030381
De Cáceres, M., & Legendre, P. (2009). Associations between species and groups of sites: Indices and statistical inference. Ecology, 90(12), 3566–3574. https://doi.org/10.1890/08-1823.1
De Cáceres, M. (2023). indicspecies: Relationship between species and groups of sites (R package version 1.7.14). https://cran.r-project.org/package=indicspecies
Fernández-Martínez, M., Barquín, J., Bonada, N., Cantonati, M., Churro, C., Corbera, J. & Romero, E. (2024). Mediterranean springs: Keystone ecosystems and biodiversity refugia threatened by global change. Glob. Change Biol. 30, e16997. https://doi.org/10.1111/gcb.16997
Ford, D.C. & Williams, P.W. (2007). Karst hydrogeology and geomorphology. John Wiley & Sons, Chichester, pp. 562.
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(2), 355-368. https://doi.org/10.5507/fot.2009.035
Geological Institute of Romania (revised 2018). Geology, INSPIRE Annex II, scale 1:200,000 [WMS service]. Geological Institute of Romania, Bucharest [Accessed 01 March 2026] https://inspire-geoportal.ec.europa.eu
Hájková, P., Bojková, J., Franková, M., Opravilová, V., Hájek, M., Kintrová, K. & Horsák, M. (2011). Disentangling the effects of water chemistry and substratum structure on moss-dwelling unicellular and multicellular micro-organisms in spring fens. J. Limnol. 70, 54–60. https://doi.org/10.4081/jlimnol.2011.s1.54
Hammer, Ø., Harper, D.A.T., & Ryan, P.D. (2001). PAST: Paleontological Statistics software package for education and data analysis. Palaeontol. Electron. 4(1): 9. https://doi.org/10.1016/j.ecohyd.2020.07.007
Kelly, M.G., Cazaubon, A., Coring, E., Dell'Uomo, A., Ector, L., Goldsmith, B., Guasch, H., Hürlimann, J., Jarlman, A., Kawecka, B., Kwandrans, J. (1998). Recommendations for the routine sampling of diatoms for water quality assessments in Europe. J. Appl. Phycol., 10(2), 215-224. https://doi.org/10.1023/A:1008033201227
Krammer, K., Lange-Bertalot, H. (1986). Bacillariophyceae, 1. Teil: Naviculaceae, In: Ettl H, Gerloff, J., Heynig, H., Mollenhauer, D. (eds), Süßwasserflora von Mitteleuropa 2/1. Ed. Gustav Fischer Verlag, Stuttgart & New York, pp. 876.
Krammer, K., Lange-Bertalot, H. (1988). Bacillariophyceae, 2. Teil: Bacillariaceae, Epithemiaceae, Surirellaceae, In: Ettl, H., Gerloff, J., Heynig, H., Mollenhauer, D. (eds), Süßwasserflora von Mitteleuropa 2/2. Ed. Gustav Fischer Verlag, Stuttgart & New York, pp. 596.
Krammer, K., Lange-Bertalot, H. (1991a). Bacillariophyceae, 3. Teil: Centrales, Fragilariaceae, Eunotiaceae, In: In: Ettl, H., Gerloff, J., Heynig, H., Mollenhauer, D. (eds), Süßwasserflora von Mitteleuropa 2/3. Ed. Gustav Fischer Verlag, Stuttgart, Jena, pp. 598.
Krammer, K., Lange-Bertalot, H. (1991b). Bacillariophyceae, 4. Teil: Achnanthaceae. Kritische Ergänzungen zu Navicula (Lineolatae) und Gomphonema, In: Ettl, H., Gärtner, G., Gerloff, J., Heynig, H., Mollenhauer, D. (eds), Süßwasserflora von Mitteleuropa 2/4. Ed. Gustav Fischer Verlag, Stuttgart & New York, pp. 437.
Lai, G. G., Padedda, B. M., Wetzel, C. E., Lugliè, A., Sechi, N., & Ector, L. (2016). Epilithic diatom assemblages and environmental quality of the Su Gologone karst spring (centraleastern Sardinia, Italy). Acta Bot. Croat. 75(1), 129-143.
Lai, G.G., Burato, S., Padedda, B.M., Zorza, R., Pizzul, E., Delgado, C. & Cantonati, M. (2019). Diatom biodiversity in karst springs of Mediterranean geographic areas with contrasting characteristics: Islands vs mainland. Water 11, 2602. https://doi.org/10.3390/w11122602
Lai, G.G., Padedda, B.M., Ector, L., Wetzel, C.E., Lugliè, A. & Cantonati, M. (2020). Mediterranean karst springs: Diatom biodiversity hotspots under the pressure of hydrological fluctuation and nutrient enrichment. Plant Biosyst. 154, 673–684. https://doi.org/10.1080/11263504.2019.1674402
Lecointe, C., Coste, M. & Prygiel, J. (1993). “Omnidia”: Software for taxonomy, calculation of diatom indices and inventories management. Hydrobiologia 269, 509–513. https://doi.org/10.1007/BF00028048
Letáková, M., Fránková, M. & Poulíčková, A. (2018). Ecology and applications of freshwater epiphytic diatoms. Cryptogamie Algol. 39, 3-22. https://doi.org/10.7872/crya/v39.iss1.2018.3
Lowe, R.L., Kociolek, J.P., Johansen, J.R., Van de Vijver, B., Lange-Bertalot, H. & Kopalová, K. (2014). Humidophila gen. nov., a new genus for a group of diatoms (Bacillariophyta) formerly within the genus Diadesmis: species from Hawai‘i, including one new species. Diatom Res. 29, 351-360. https://doi.org/10.1080/0269249X.2014.889039
Malviya, S., Scalco, E., Audic, S., Vincent, F., Veluchamy, A., Poulain, J. & Bowler, C. (2016). Insights into global diatom distribution and diversity in the world’s ocean. Proc. Natl. Acad. Sci. U.S.A. 113, E1516–E1525. https://doi.org/10.1073/pnas.1509523113
Micle, M., Şuteu, A. M., Momeu, L., Coman, P., Battes, K. P., & Cîmpean, M. (2018). Seasonal dynamics of biota from several springs located in the Apuseni Mountains, Romania. Sci. Stud. Res. Biol. 27(2).
Natural Earth (2024). Free vector and raster map data [Accessed 01 March 2026] https://www.naturalearthdata.com/
Nicolosi Gelis, M. M., Sathicq, M. B., Jupke, J., & Cochero, J. (2022). DiaThor: R package for computing diatom metrics and biotic indices. Ecological Modelling, 465, 109859. https://doi.org/10.1016/j.ecolmodel.2021.109859
Oksanen, J., Simpson, G. L., Blanchet, F. G., Kindt, R., Legendre, P., Minchin, P. R., O’Hara, R. B., Solymos, P., Stevens, M. H. H., Szoecs, E., & Wagner, H. (2024). vegan: Community ecology package (R package version 2.6-6). https://cran.r-project.org/package=vegan
Orășeanu, I. (2016). Hidrogeologia carstului din Muntii Apuseni. 1st Ed. Belvedere, Oradea, pp. 289. ISBN 978-606-94188-0-2
Orășeanu, I. (2020). Hidrogeologia carstului din Munții Apuseni. 2nd Ed. Belvedere, Oradea, pp. 349. ISBN 978-606-94188-9-5.
Pebesma, E. (2018). Simple features for R: Standardized support for spatial vector data. The R Journal, 10(1), 439–446. https://doi.org/10.32614/RJ-2018-009
Pouličková, A., Hájková, P., Křenková, P. & Hájek, M. (2004). Distribution of diatoms and bryophytes on linear transects through spring fens. Nova Hedwigia 78, 411–424. https://doi.org/10.1127/0029-5035/2004/0078-0411
Pouličková, A., Hájek, M. & Rybníček, K. (eds.) (2005). Ecology and palaeoecology of spring fens of the West Carpathians. Palacký University Press, Olomouc, pp. 210.
Rimet, F., & Bouchez, A. (2012). Life-forms, cell-sizes and ecological guilds of diatoms in European rivers. Knowl manag Aquat Ec, (406), 01. https://doi.org/10.1051/kmae/2012018
Soininen, J. (2007). Environmental and spatial control of freshwater diatoms—A review. Diatom Res. 22, 473-490. https://doi.org/10.1080/0269249X.2007.9705724
Șuteu, A.-M., Momeu, L., & Pușcaș, M. (2025). The diatom communities from Apuseni Mountains: A first approach on crenic diatom flora. Stud. Univ. Babes-Bolyai Biol., 70(2), 163–195. https://doi.org/10.24193/subbbiol.2025.2.10
Taxböck, L., Linder, H.P. & Cantonati, M. (2017). To what extent are Swiss springs refugial habitats for sensitive and endangered diatom taxa? Water 9, 967. https://doi.org/10.3390/w9120967
Van Dam, H., Mertens, A., & Sinkeldam, J. (1994). A coded checklist and ecological indicator values of freshwater diatoms from the Netherlands. Neth. J. Aquat. Ecol. 28(1), 117-133. https://doi.org/10.1007/BF02334251
Vanormelingen, P., Verleyen, E. & Vyverman, W. (2008). The diversity and distribution of diatoms: From cosmopolitanism to narrow endemism. Biodivers. Conserv. 17, 393–405. https://doi.org/10.1007/s10531-007-9253-4
Wickham, H. (2016). ggplot2: Elegant graphics for data analysis. Springer, Cham, pp. 260. https://doi.org/10.1007/978-3-319-24277-4
Wojtal, A.Z. & Sobczyk, Ł. (2006). Composition and structure of epilithic diatom assemblages on stones of different size in a small calcareous stream (S Poland). Algol. Stud. 119, 105-124. https://doi.org/10.1127/1864-1318/2006/0119-0105
Wojtal, A. Z., & Sobczyk, Ł. (2012). The influence of substrates and physicochemical factors on the composition of diatom assemblages in karst springs and their applicability in water-quality assessment. Hydrobiologia 695(1), 97-108. https://doi.org/10.1016/j.ecolind.2011.07.002
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