Filamentous green algae of the genus Zygnema are an essential part of hydro-terrestrial ecosystems. Despite several studies on their resistance to natural stresses, little is known about the composition of their assemblages and the changes they undergo over time. Two sites at altitudes above 2200 m a.s.l. in the Austrian Alps were selected for a 2-year observation period and sampled five times. Molecular phylogenetic analysis of the 152 isolated strains of Zygnema sp. was performed based on the rbcL and trnG sequences. Seven genotypes were found at these sites during the samplings, but their proportion varied throughout the seasons. The site with a more stable water regime also had a more stable representation of genotypes, in contrast to the site with fluctuating water availability. The mats formed resistant pre-akinetes at the end of the season with reduced photosynthetic activity. Contrary to expectations, the mats were not exposed to extremely cold temperatures in winter due to snow cover. Some genotypes have been previously observed at this site, indicating that the population composition is stable. This work highlights the importance of resistant pre-akinetes in surviving winter conditions, the ability of algae to re-establish mats, and the need to address the hidden diversity of the genus Zygnema.

Faculty of Science Department of Botany Charles University Benátská 2 128 00 Prague Czech Republic

Institute of Criminalistics Prague Strojnická 27 170 89 Prague Czech Republic

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Marchand PJ (2014) Life in the cold: an introduction to winter ecology (4th edition). University Press of New England

Starr G, Oberbauer SF (2003) Photosynthesis of arctic evergreens under snow: implications for tundra ecosystem carbon balance. Ecology 84(6):1415–1420. https://doi.org/10.1890/02-3154 DOI

Hawes I (1989) Filamentous green algae in freshwater streams on Signy Island. Antarctica Hydrobiologia 172(1):1–18. https://doi.org/10.1007/BF00031608 DOI

Pichrtová M, Holzinger A, Kulichová J, Ryšánek D, Šoljaková T, Trumhová K, Nemcova Y (2018) Molecular and morphological diversity of Zygnema and Zygnemopsis (Zygnematophyceae, Streptophyta) from Svalbard (High Arctic). Eur J Phycol 53(4):492–508. https://doi.org/10.1080/09670262.2018.1476920 PubMed DOI PMC

Pichrtová M, Hájek T, Elster J (2016) Annual development of mat-forming conjugating green algae Zygnema spp in hydro-terrestrial habitats in the Arctic. Polar Biol 39(9):1653–1662. https://doi.org/10.1007/s00300-016-1889-y DOI

Wehr J, Sheath RJ, Kociolek P (eds) (2015) Freshwater algae of north America

Gontcharov AA (2008) Phylogeny and classification of Zygnematophyceae (Streptophyta): current state of affairs. Fottea 8(2):87–104. https://doi.org/10.5507/fot.2008.004 DOI

Stancheva R, Sheath RG, Hall JD (2012) Systematics of the genus Zygnema (Zygnematophyceae, Charophyta) from Californian watersheds. J Phycol 48(2):409–422. https://doi.org/10.1111/j.1529-8817.2012.01127.x PubMed DOI

Poulíčková A, Žižka Z, Hašler P, Benada O (2007) Zygnematalean zygospores: morphological features and use in species identification. Folia Microbiol 52(2):135–145. https://doi.org/10.1007/BF02932152 DOI

One Thousand Plant Transcriptomes Initiative (2019) One thousand plant transcriptomes and the phylogenomics of green plants. Nature 574(7780):679–685. https://doi.org/10.1038/s41586-019-1693-2 DOI

Jiao C, Sørensen I, Sun X, Sun H, Behar H, Alseekh S, Philippe G, Palacio Lopez K, Sun L, Reed R, Jeon S, Kiyonami R, Zhang S, Fernie AR, Brumer H, Domozych DS, Fei Z, Rose JKC (2020) The Penium margaritaceum genome: hallmarks of the origins of land plants. Cell 181(5):1097-1111.e12. https://doi.org/10.1016/j.cell.2020.04.019 PubMed DOI

Becker B, Feng X, Yin Y, Holzinger A (2020) Desiccation tolerance in streptophyte algae and the algae to land plant transition: evolution of LEA and MIP protein families within the Viridiplantae. J Exp Bot 71(11):3270–3278. https://doi.org/10.1093/jxb/eraa105 PubMed DOI PMC

Holzinger A, Pichrtová M (2016) Abiotic stress tolerance in charophyte green algae: new challenges for omics techniques. Front Plant Sci 7:678. https://doi.org/10.3389/fpls.2016.00678 PubMed DOI PMC

Pichrtová M, Kulichová J, Holzinger A (2014) Nitrogen limitation and slow drying induce desiccation tolerance in conjugating green algae (Zygnematophyceae, Streptophyta) from polar habitats. PLoS ONE 9(11):e113137. https://doi.org/10.1371/journal.pone.0113137 PubMed DOI PMC

Fuller C (2013) Examining morphological and physiological changes in Zygnema irregulare during a desiccation and recovery period. Dissertation, California State University San Marcos

Pichrtová M, Arc E, Stöggl W, Kranner I, Hájek T, Hackl H, Holzinger A (2016) Formation of lipid bodies and changes in fatty acid composition upon pre-akinete formation in Arctic and Antarctic Zygnema (Zygnematophyceae, Streptophyta) strains. FEMS Microbiol Ecol 92(7):fiw096. https://doi.org/10.1093/femsec/fiw096

Kaplan F, Lewis LA, Herburger K, Holzinger A (2013) Osmotic stress in Arctic and Antarctic strains of the green alga Zygnema (Zygnematales, Streptophyta): effects on photosynthesis and ultrastructure. Micron 44(1):317–330. https://doi.org/10.1016/j.micron.2012.08.004 PubMed DOI PMC

Pichrtová M, Hájek T, Elster J (2014) Osmotic stress and recovery in field populations of Zygnema sp (Zygnematophyceae, Streptophyta) on Svalbard (High Arctic) subjected to natural desiccation. FEMS Microbiol Ecol 89(2):270–280. https://doi.org/10.1111/1574-6941.12288 PubMed DOI

Remias D, Holzinger A, Aigner S, Lütz C (2012) Ecophysiology and ultrastructure of Ancylonema nordenskiöldii (Zygnematales, Streptophyta), causing brown ice on glaciers in Svalbard (high arctic). Polar Biol 35(6):899–908. https://doi.org/10.1007/s00300-011-1135-6 DOI

Remias D, Schwaiger S, Aigner S, Leya T, Stuppner H, Lütz C (2012) Characterization of an UV- and VIS-absorbing, purpurogallin-derived secondary pigment new to algae and highly abundant in Mesotaenium berggrenii (Zygnematophyceae, Chlorophyta), an extremophyte living on glaciers. FEMS Microbiol Ecol 79(3):638–648. https://doi.org/10.1111/j.1574-6941.2011.01245.x PubMed DOI

Aigner S, Remias D, Karsten U, Holzinger A (2013) Unusual phenolic compounds contribute to ecophysiological performance in the purple-colored green alga Zygogonium ericetorum (Zygnematophyceae, Streptophyta) from a high-alpine habitat. J Phycol 49(4):648–660. https://doi.org/10.1111/jpy.12075 PubMed DOI PMC

Trumhová K, Holzinger A, Obwegeser S, Neuner G, Pichrtová M (2019) The conjugating green alga Zygnema sp (Zygnematophyceae) from the Arctic shows high frost tolerance in mature cells (pre-akinetes). Protoplasma 256(6):1681–1694. https://doi.org/10.1007/s00709-019-01404-z PubMed DOI PMC

Morris GJ, McGrath JJ (1981) Intracellular ice nucleation and gas bubble formation in Spirogyra. Cryo Lett 2:341–352

Hawes I (1990) Effects of freezing and thawing on a species of Zygnema (Chlorophyta) from the Antarctic. Phycologia 29(3):326–331. https://doi.org/10.2216/i0031-8884-29-3-326.1 DOI

Holzinger A, Albert A, Aigner S, Uhl J, Schmitt-Kopplin P, Trumhová K, Pichrtová M (2018) Arctic, Antarctic, and temperate green algae Zygnema spp under UV-B stress: vegetative cells perform better than pre-akinetes. Protoplasma 255(4):1239–1252. https://doi.org/10.1007/s00709-018-1225-1 PubMed DOI PMC

Permann C, Pierangelini M, Remias D, Lewis LA, Holzinger A (2022) Photophysiological investigations of the temperature stress responses of Zygnema spp (Zygnematophyceae) from subpolar and polar habitats. Phycologia, accepted.

Busch A, Hess S (2021) Sunscreen mucilage: a photoprotective adaptation found in terrestrial green algae (Zygnematophyceae). Eur J Phycol 57(1):107–124. https://doi.org/10.1080/09670262.2021.1898677 DOI

Hawes I (1988) The seasonal dynamics of Spirogyra in a shallow, maritime Antarctic lake. Polar Biol 8(6):429–437. https://doi.org/10.1007/BF00264719 DOI

Simons J, van Beem AP (1990) Spirogyra species and accompanying algae from pools and ditches in the Netherlands. Aquat Bot 37(3):247–269. https://doi.org/10.1016/0304-3770(90)90073-T DOI

Sheath RG, Burkholder JM (1985) Characteristics of softwater streams in Rhode Island II Composition and seasonal dynamics of macroalgal communities. Hydrobiologia 128(2):109–118. https://doi.org/10.1007/BF00008730 DOI

Cambra J, Aboal M (1992) Filamentous green algae of Spain distribution and ecology. Limnetica 8(1):213–220. https://doi.org/10.23818/limn.08.21 DOI

Cattaneo A, Kalff J (1978) Seasonal changes in the epiphyte community of natural and artificial macrophytes in Lake Memphremagog(Que. & Vt.). Hydrobiologia 60(2):135–144. https://doi.org/10.1007/BF00163179 DOI

Arc E, Pichrtová M, Kranner I, Holzinger A (2020) Pre-akinete formation in Zygnema sp From polar habitats is associated with metabolite re-arrangement. J Exp Bot 71(11):3314–3322. https://doi.org/10.1093/jxb/eraa123 PubMed DOI PMC

Davey MC (1991) The seasonal periodicity of algae on Antarctic fellfield soils. Ecography 14(2):112–120. https://doi.org/10.1111/j.1600-0587.1991.tb00641.x DOI

Pichrtová M, Remias D, Lewis LA, Holzinger A (2013) Changes in phenolic compounds and cellular ultrastructure of Arctic and Antarctic strains of Zygnema (Zygnematophyceae, Streptophyta) after exposure to experimentally enhanced UV to PAR ratio. Microb Ecol 65(1):68–83. https://doi.org/10.1007/s00248-012-0096-9 PubMed DOI

Novis PM (2004) New records of Spirogyra and Zygnema (Charophyceae, Chlorophyta) in New Zealand. N Z J Bot 42(1):139–152. https://doi.org/10.1080/0028825X.2004.9512895 DOI

Climate Kühtai by Climate-Data.org (n.d.). Accessed Mar 24, 2022. https://en.climate-data.org

Ryšánek D, Hrčková K, Škaloud P (2015) Global ubiquity and local endemism of free-living terrestrial protists: phylogeographic assessment of the streptophyte alga Klebsormidium. Environ Microbiol 17(3):689–698. https://doi.org/10.1111/1462-2920.12501 PubMed DOI

McCourt RM, Karol KG, Bell J, Helm-Bychowski KM, Grajewska A, Wojciechowski MF, Hoshaw RW (2000) Phylogeny of the conjugating green algae (Zygnematophyceae) based on rbcL sequences. J Phycol 758:747–758 DOI

Neustupa J, Škaloud P, Št’astný J (2010) The molecular phylogenetic and geometric morphometric evaluation of Micrasterias crux-melitensis/M. radians species complex. J Phycol 46(4):703–714. https://doi.org/10.1111/j.1529-8817.2010.00863.x DOI

Hepperle D (2004) SeqAssem. A sequence analysis tool, contig assembler and trace data visualisation tool for molecular sequences. http://www.sequentix.de/software_seqassem.php . Accessed 05 June 2020

Stecher G, Tamura K, Kumar S (2020) Molecular evolutionary genetics analysis (MEGA) for macOS. Mol Biol Evol for Mac 37(4):1237–1239. https://doi.org/10.1093/molbev/msz312 DOI

Posada D (2008) JModelTest: phylogenetic model averaging. Mol Biol Evol 25(7):1253–1256. https://doi.org/10.1093/molbev/msn083 PubMed DOI

Ronquist F, Huelsenbeck JP (2003) MrBayes 3: Bayesian phylogenetic inference under mixed models. Bioinformatics 19(12):1572–1574. https://doi.org/10.1093/bioinformatics/btg180 PubMed DOI

Zwickl DJ (2006) Genetic algorithm approaches for the phylogenetic analysis of large biological sequence datasets under the maximum likelihood criterion. Ph.D. dissertation. The University of Texas at Austin

Rambaut A (2009) FigTree. Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, Tree figure drawing tool

Webb WL, Newton M, Starr D (1974) Carbon dioxide exchange of Alnus rubra. Oecologia 17:281–291. https://doi.org/10.1007/BF00345747 PubMed DOI

Hammer O, Harper DAT, Ryan PD (2001) PAST: paleontological statistics software package for education and data analysis. Palaeontol Electron 4:1–9

Feng X, Holzinger A, Permann C, Anderson D, Yin Y (2021) Characterization of two Zygnema strains (Zygnema circumcarinatum SAG 698–1a and SAG 698–1b) and a rapid method to estimate nuclear genome size of Zygnematophycean green algae. Front Plant Sci 12:1–15. https://doi.org/10.3389/fpls.2021.610381 DOI

Chen C, Barfuss MH, Pröschold T, Schagerl M (2012) Hidden genetic diversity in the green alga Spirogyra (Zygnematophyceae, Streptophyta). BMC Evol Biol 12:77. https://doi.org/10.1186/1471-2148-12-77 PubMed DOI PMC

Stancheva R, Hall JD, Mccourt RM, Sheath RG (2013) Identity and phylogenetic placement of Spirogyra species (Zygnematophyceae, Charophyta) from California streams and elsewhere. J Phycol 49(3):588–607. https://doi.org/10.1111/jpy.12070 PubMed DOI

Nemjová K, Neustupa J, St astny J, Skaloud P, Vesela J (2011) Species concept and morphological differentiation of strains traditionally assigned to Micrasterias truncata. Phycol Res 59(3):208–220. https://doi.org/10.1111/j.1440-1835.2011.00619.x DOI

Vanormelingen P, Chepurnov VA, Mann DG, Sabbe K, Vyverman W (2008) Genetic divergence and reproductive barriers among morphologically heterogeneous sympatric clones of Eunotia bilunaris sensu lato (Bacillariophyta). Protist 159(1):73–90. https://doi.org/10.1016/j.protis.2007.08.004 PubMed DOI

Connell JH (1978) Diversity in tropical rain forests and coral reefs. Science 199(4335):1302–1310. https://doi.org/10.1126/science.199.4335.1302 PubMed DOI

Grime JP (1973) Competitive exclusion in herbaceous vegetation. Nature 242(5396):344–347. https://doi.org/10.1038/242344a0 DOI

Moniz MBJ, Rindi F, Novis PM, Broady PA, Guiry MD (2012) Molecular phylogeny of Antarctic Prasiola (Prasiolales, Trebouxiophyceae) reveals extensive cryptic diversity. J Phycol 48:940–955. https://doi.org/10.1111/j.1529-8817.2012.01172.x PubMed DOI

Ryšánek D, Holzinger A, Škaloud P (2016) Influence of substrate and pH on the diversity of the aeroterrestrial alga Klebsormidium (Klebsormidiales, Streptophyta): a potentially important factor for sympatric speciation. Phycologia 55(4):347–358. https://doi.org/10.2216/15-110.1 PubMed DOI PMC

Hainz R, Wöber C, Schagerl M (2009) The relationship between Spirogyra (Zygnematophyceae, Streptophyta) filament type groups and environmental conditions in Central Europe. Aquat Bot 91(3):173–180. https://doi.org/10.1016/j.aquabot.2009.05.004 DOI

Vitova M, Bisova K, Kawano S, Zachleder V (2015) Accumulation of energy reserves in algae: from cell cycles to biotechnological applications. Biotechnol Adv 33:1204–1218. https://doi.org/10.1016/j.biotechadv.2015.04.012 PubMed DOI

McLean RJ, Pessoney GF (1971) Formation and resistance of akinetes of Zygnema. In: Parker BC, Brown RM Jr (eds) Contributions in phycology. Allen, Lawrence KS, 145–152

Herburger K, Lewis LA, Holzinger A (2015) Photosynthetic efficiency, desiccation tolerance and ultrastructure in two phylogenetically distinct strains of alpine Zygnema sp (Zygnematophyceae, Streptophyta) role of pre-akinete formation. Protoplasma 252(2):571–589. https://doi.org/10.1007/s00709-014-0703-3 PubMed DOI

Steiner P, Buchner O, Andosch A, Holzinger A, Lütz-Meindl U, Neuner G (2021) Winter survival of the unicellular green alga Micrasterias denticulata: insights from field monitoring and simulation experiments. Protoplasma 258:1335–1346. https://doi.org/10.1007/s00709-021-01682-6 PubMed DOI PMC

Nagao M, Matsui K, Uemura M (2008) Klebsormidium flaccidum, a charophycean green alga, exhibits cold acclimation that is closely associated with compatible solute accumulation and ultrastructural changes. Plant Cell Environ 31(6):872–885. https://doi.org/10.1111/j.1365-3040.2008.01804.x PubMed DOI

Steiner P, Obwegeser S, Wanner G, Buchner O, Lütz-Meindl U, Holzinger A (2020) Cell wall reinforcements accompany chilling and freezing stress in the Streptophyte green alga Klebsormidium crenulatum. Front Plant Sci 11:1–14. https://doi.org/10.3389/fpls.2020.00873 DOI

Jimel M, Kvíderová J, Elster J (2021) Annual cycle of mat-forming filamentous alga Tribonema cf minus (Stramenopiles, Xanthophyceae) in hydro-terrestrial habitats in the high arctic revealed by multiparameter fluorescent staining. J Phycol 57(3):780–796. https://doi.org/10.1111/jpy.13109 PubMed DOI

Hejduková E, Elster J, Nedbalová L (2020) Annual cycle of freshwater diatoms in the high arctic revealed by multiparameter fluorescent staining. Microb Ecol 80(3):559–572. https://doi.org/10.1007/s00248-020-01521-w PubMed DOI

Morgan-Kiss RM, Priscu JC, Pocock T, Gudynaite-Savitch L, Huner NPA (2006) Adaptation and acclimation of photosynthetic microorganisms to permanently cold environments. Microbiol Mol Biol Rev 70(1):222–252. https://doi.org/10.1128/MMBR.70.1.222-252.2006 PubMed DOI PMC

Karsten U, Holzinger A (2012) Light, temperature, and desiccation effects on photosynthetic activity, and drought-induced ultrastructural changes in the green alga Klebsormidium dissectum (Streptophyta) from a high alpine soil crust. Microb Ecol 63(1):51–63. https://doi.org/10.1007/s00248-011-9924-6 PubMed DOI

Davey MC (1989) The effects of freezing and desiccation on photosynthesis and survival of terrestrial Antarctic algae and cyanobacteria. Polar Biol 10(1):29–36. https://doi.org/10.1007/BF00238287 DOI