Seasonal Algal Diversity and Environmental Parameters of Streams of Samur-Yalama National Park, Azerbaijan

Abstract

This study provides the first comprehensive assessment of freshwater algal diversity and ecological status in the streams of Samur-Yalama National Park, Azerbaijan—a region of high biodiversity but limited baseline data. Seasonal surveys in 2023 recorded 46 algal taxa, including 37 first regional records, across ten rivers spanning contrasting hydrochemical environments. Heterokontophyta dominated (69.6% of taxa), with epilithic and benthic habitats supporting the highest diversity. Simpson’s Dominance Index (0.120–0.131) and saprobic index (0.69–0.89) indicated high diversity and predominantly oligosaprobic to β-mesosaprobic conditions, reflecting mostly unpolluted, welloxygenated waters. Principal Component Analysis identified mineralization (sulfate, calcium, TDS) and nutrient gradients as key drivers of algal community structure. Sensitive diatoms such as Fragilaria capucina and Achnanthidium minutissimum dominated pristine sites, while tolerant taxa like Gomphonema parvulum and Nitzschia palea increased under moderate enrichment. These findings establish a regional reference for algal-based biomonitoring, highlight the vulnerability of semi-arid stream ecosystems to environmental change, and provide essential baseline data for conservation planning, future monitoring, and ecosystem management in the South Caucasus and comparable dryland regions.

Keywords

• Biodiversity
• Water quality
• Freshwater ecosystems
• Benthic algae
• Macro algae
• Phytoplankton

References

1. Abbasov, R., Karimov, R., & Jafarova, N. (2022). EcosYstem services in Azerbaijan: Value and losses. Springer. https://doi.org/10.1007/978-3-031-08770-7 google scholar
2. Abiyev, Y., Eker, R., Açıl, A., & Coskuner, K. A. (2025). Assessing fire susceptibility of threatened plant species in temperate forest ecosystem of Azerbaijan using Maxent method. Croatian Journal of Forest Engineering, 46(1), 141-154. https:// doi.org/10.5552/crojfe.2025.2456 google scholar
3. AfanasYev, D. F., Kamnev, A. N., Sushkova, E. G., & Steinhagen, S. (2016). The field guide to Ulva species found in the Black, Azov, Caspian Seas and eastern Baltic. Pero Publishing House. ISBN: 978-5-906883-16-2 google scholar
4. AfanasYev, D. F., Sushkova, E. G., & Kamnev, A. N. (2020). Marine and brackish species of Cladophoraceae and Aegagropila found in the Ponto-Caspian basin: The field guide. Pero Publishing House. https://repositorY.marine-research.ru/handle/ 299011/13575 google scholar
5. American Public Health Association (APHA). (2005). Standard methods for the examination of water and wastewater. American Public Health Association. google scholar
6. Ballah, M., Bhoyroo, V., & Neetoo, H. (2019). Assessment of the physico-chemical quality and extent of algal proliferation in water from an impounding reservoir prone to eutrophication. Journal of Ecology and Environment, 43, Article 5. https://doi.org/10.1186/s41610-018-0094-z google scholar
7. Barber, J., & Andersson, B. (1992). Too much of a good thing: Light can be bad for photosynthesis. Trends in Biochemical Sciences, 17(2), 61-66. https://doi.org/ 10.1016/0968-0004(92)90104-O google scholar
8. Barinova, S., & Kukhaleishvili, L. (2017). Diversity and ecology of algae and cyanobacteria in the Enguri River, Georgia. Elixir Bio Science. 104. 45934-45947). google scholar

9. Beardall, J., & Raven, J. A. (2016). Carbon acquisition by microalgae. In M. A. Borowitzka, J. Beardall, & J. A. Raven (Eds.), The physiology of microalgae (Developments in Applied Phycology, Vol. 6, pp. 89-100). Springer. https://doi.org/10.1007/978-3-319-24945-2_4 google scholar
10. Bellino, A., & Baldantoni, D. (2023). Biodiversity, Ecology and Distribution of Mediterranean Charophytes in Southern Italy. Plants (Basel, Switzerland), 12(19), 3434. https://doi.org/10.3390/plants12193434 google scholar
11. Blankenship, R. E. (2014). Molecular mechanisms of photosYnthesis (2nd ed.). WileY-Blackwell. ISBN 978-1-4051-8975-0 google scholar
12. Butterwick, C., HeaneY, S. I., & Talling, J. F. (2005). DiversitY in the influence of temperature on the growth rates of freshwater algae, and its ecological relevance. Freshwater Biology, 50(2), 291-300. https://doi.org/10.1111/j.1365-2427.2004.01317.x google scholar
13. Catalanotti, C., Yang, W., Posewitz, M. C., & Grossman, A. R. (2013). Fermentation metabolism and its evolution in algae. Frontiers in Plant Science, 4, 150. https://doi.org/10.3389/fpls.2013.00150 google scholar
14. Chen, J., Wang, S., Yan, Z., Zhao, X., Feng, M., Wang, J., & Zhou, Q. (2023). eDNA of zooplankton reveals the ecological communitY thresholds for keY environmental factors in the BaiYangdian Lake aquatic ecosYstem. Environmental Sciences Europe, 35(1), 91. https://doi.org/10.1186/s12302-023-00761-0 google scholar
15. Cottingham, K. L., Weathers, K. C., Ewing, H. A., Greer, M. L., & CareY, C. C. (2021). Predicting the effects of climate change on freshwater cYanobacterial blooms requires consideration of the complete cYanobacterial life cYcle. Journal of Plankton Research, 43(1), 10-19. https://doi.org/10.1093/plankt/fbaa059 google scholar
16. DubeY, D., Kumar, S., & Dutta, V. (2022). Algae and macrophytes as bioindicators of freshwater ecosystem. CRC Press. https://doi.org/10.1201/9781003220824-33 google scholar
17. Elser, J. J., Bracken, M. E., Cleland, E. E., Gruner, D. S., Harpole, W. S., Hillebrand, H., & Smith, J. E. (2009). Global analYsis of nitrogen and phosphorus limitation of primarY producers in freshwater, marine and terrestrial ecosYstems. Ecology Letters, 10(12), 1135-1142. https://doi.org/10.1111/j.1461-0248.2007.01113.x google scholar
18. Elser, J. J., Marzolf, E. R., & Goldman, C. R. (1990). Phosphorus and nitrogen limitation of phYtoplankton growth in the freshwaters of North America: A review and critique of experimental enrichments. Canadian Journal of Fisheries and Aquatic Sciences, 47(7), 1468-1477. https://doi.org/10.1139/f90-165 google scholar
19. Elser, J. J., Chrzanowski, T. H., Sterner, R. W., Schampel, J. H., & Foster, D. K. (1995). Elemental ratios and the uptake and release of nutrients bY phYtoplankton and bacteria in three lakes of the Canadian shield. Microbial ecology, 29(2), 145-162. https://doi.org/10.1007/BF00167161 google scholar
20. Falkowski, P. G., & Raven, J. A. (2007). Aquatic photosynthesis (2nd ed.). Princeton UniversitY Press. https://doi.org/10.1515/9781400849727 google scholar
21. Fanton, H., Affre, L., Franquet, E., et al. (2023). Heavy ionic pollution disrupts assemblages of algae, macroinvertebrates and riparian vegetation. Environmental Pollution, 331(Part 1), 121791. https://doi.org/10.1016/j.envpol. 2023.121791 google scholar
22. Flores-MoYa, A., Posudin, Y. I., Fernândez, J. A., Figueroa, F. L., & Kawai, H. (2002). Photomovement of the swarmers of the brown algae Scytosiphon lomentaria and Petalonia fascia: Effect of photon irradiance, spectral composition and UV dose. Journal of Photochemistry and Photobiology B: Biology, 66(2), 134140. https://doi.org/10.1016/S1011-1344(02)00233-6 google scholar
23. Fourtanier, E., & Kociolek, J. P. (2009). Catalogue of Diatom Names. California AcademY of Sciences. google scholar
24. Glibert P. M. (2020). Harmful algae at the complex nexus of eutrophication and climate change. Harmful algae, 91, 101583. https://doi.org/10.1016/j.hal.2019. 03.001 google scholar
25. Gollerbach, M. M., & PolYanskY, V. I. (1951). Freshwater algae and their study: Identifier of freshwater algae of the USSR (Vol. 2). California AcademY of Sciences. google scholar
26. Graham, L. E., Graham, J. M., & Wilcox, L. W. (2009). Algae (2nd ed.). Benjamin Cummings. google scholar
27. Hao, B., Wu, H., You, J., Xing, W., & Cai, Y. (2021). Biomass and physiological responses of green algae and diatoms to nutrient availability differ between the presence and absence of macrophytes. Ecological Indicators, 129, 107987. https://doi. org/10.1016/j.ecolind.2021.107987 google scholar
28. HeckY, R. E., Campbell, P., & Hendzel, L. L. (1993). The stoichiometry of carbon, nitrogen, and phosphorus in particulate matter of lakes and oceans. Limnology and Oceanography, 38(4), 709-724. https://doi.Org/10.4319/lo.1993.38.4.0709 google scholar
29. Jin, X., Zhang, Y., Li, Y., & Wang, Z. (2023). Suspended phosphorus pulses (TP ~0.05 mg L1 vs. SRP < 0.01 mg L') can sustain bloom events under low-flow conditions. Science of The Total Environment, 876, 162669. https://doi.org/10. 1016/j.scitotenv.2023.162669 google scholar
30. Khalil, S., Mahnashi, M. H., Hussain, M., Zafar, N., Waqar-Un-Nisa, Khan, F. S., Afzal, U., Shah, G. M., Niazi, U. M., Awais, M., & Irfan, M. (2021). Exploration and determination of algal role as bioindicator to evaluate water qualitY - probing fresh water algae. Saudi Journal of Biological Sciences, 28(10), 5728-5737. https://doi.org/10.1016/j.sjbs.2021.06.004 google scholar
31. Kirkwood, A.E. and Henley, W.J. (2006). Algal communıty dynamıcs and halotolerance ın a terrestrıal, hypersalıne envıronment. Journal of Phycology, 42: 537-547. https://doi.org/10.1111/j.1529-8817.2006.00227.x. google scholar
32. Kristiansen, J. (1996). Dispersal of freshwater algae — a review. Hydrobiologia 336, 151-157 (1996). https://doi.org/10.1007/BF00010829 google scholar
33. Lilisti, Z., Zamdial, Hartono, D., Brata, B., & Simarmata, M. (2021). The structure and composition of macrozoobenthos communitY in varYing water qualities in Kalibaru waters, Bengkulu, Indonesia. Biodiversitas, 22(1), 106-112. https://doi. org/10.13057/biodiv/d220115 google scholar
34. Lürling, M., Mello, M. M. E., van Oosterhout, F., de Senerpont Domis, L., & Marinho, M. M. (2018). Response of natural cYanobacteria and algae assemblages to a nutrient pulse and elevated temperature. Frontiers in Microbiology, 9, 1851. https://doi.org/10.3389/fmicb.2018.01851 google scholar
35. Magurran, A. E. (1988). Ecological diversity and its measurement. Princeton UniversitY Press. google scholar
36. Muxtarova, Ş. C., & Muradova, A. B. (2021). Xaçmaz va Şabran rayonlarında Yerlaşan kontinental sututarlarında Yayılan diatom Yosunların elektron mikroskopik üsullarla öYranilmasi [Electron microscopic study of diatom algae distributed in continental wetlands located in Khachmaz and Shabran regions]. Azerbaijan Journal of Botany, 2, 50-57. google scholar
37. Muniz, I. P. (1990). Freshwater acidification: Its effects on species and communities of freshwater microbes, plants and animals. Proceedings of the Royal Society of Edinburgh Section B: Biological Sciences, 97, 227-254. https://doi.org/10.1017/ S0269727000005364 google scholar
38. Naselli-Flores, L., & Padisâk, J. (2023). EcosYstem services provided By marine and freshwater phYtoplankton. Hydrobiologia, 850, 2691-2706. https://doi.org/10. 1007/s10750-022-04795-Y google scholar
39. NeplYukhina, A. A., Saifutdinov, R. A., Paskhina, A. A., & Korobushkin, D. I. (2022). Diatom diversity, distribution and ecology in Mediterranean ecosYstems of Abrau Peninsula, north-western Caucasus. Biodiversity data journal, 10, e89405. https://doi.org/10.3897/BDJ.10.e89405 google scholar
40. Nong, X., Guan, X., Chen, L., et al. (2024). Identifying environmental impacts on planktonic algal proliferation and associated risks: A five-Year observation study in Danjiangkou Reservoir, China. Scientific Reports, 14, Article 21568. https://doi.org/10.1038/s41598-024-70408-4 google scholar
41. Nunes, P., Roland, F., Amado, A. M., Resende, N. da S., & Cardoso, S. J. (2022). Responses of phYtoplanktonic chlorophyll-a composition to inorganic turbiditY caused by mine tailings. Frontiers in Environmental Science, 9, Article 605838. https:// doi.org/10.3389/fenvs.2021.605838 google scholar
42. Nuriyeva, M. A. (2019). Diversity and taxonomic structure of CYanoprokarYota in the Azerbaijani sector of the Caspian Sea. Plant & Fungal Research, 2(2), 2-10. google scholar
43. Odum, E. P., & Barrett, G. W. (2005). Fundamentals of ecologY (5th ed.). Thomson Brooks/Cole. google scholar
44. Oemke, M.P., Burton, T.M. (1986). Diatom colonization dynamics in a lotic system. Hydrobiologia 139, 153. https://doi.org/10.1007/BF00028099) google scholar
45. Paerl, H. W., & Huisman, J. (2009). Climate change: A catalYst for global expansion of harmful cyanobacterial blooms. Environmental Microbiology Reports, 1(1), 2737. https://doi.org/10.1111/j.1758-2229.2008.00004.x google scholar
46. Paerl, H. W., & Otten, T. G. (2013). Harmful cYanobacterial blooms: Causes, consequences, and controls. Microbial Ecology, 65(4), 995-1010. https://doi. org/10.1007/s00248-012-0159-Y google scholar
47. Paerl, H. W., Hall, N. S., & Calandrino, E. S. (2011). Controlling harmful cyanobacterial blooms in a world experiencing anthropogenic- and climatic-induced change. Science of the Total Environment, 409(10), 1739-1745. https://doi.org/10.1016/j. scitotenv.2010.12.001 google scholar
48. Persoone, G., & De Pauw, N. (1979). SYstems of biological indicators for water qualitY assessment (pp. 39-75). ECSC, EEC, EAEC Luxembourg. google scholar
49. Reinl, K. L., Harris, T. D., North, R. L., Almela, P., Berger, S. A., Bizic, M., Burnet, S. H., Grossart, H.-P., Ibelings, B. W., Jakobsson, E., Knoll, L. B., Lafrancois, B. M., McElarney, Y., Morales-Williams, A. M., Obertegger, U., Ogashawara, I., Paule-Mercado, M. C., Peierls, B. L., Rusak, J. A., ... Yokota, K. (2023). Blooms also like it cold. Limnology and Oceanography Letters, 8(6), 546-564. https://doi.org/10. 1002/lol2.10316 google scholar
50. Romanov, R. E., Zhakova, L. V., Efremov, A. N., KonechnaYa, G. Y., Boldina, O. N., Afanasyev, D. F., Akatova, T. V., & Melnikov, D. G. (2025). The CharophYtes (Characeae, Charophyceae) of the Caucasus. Plants, 14(12), Article 1788. https:// doi.org/10.3390/plants14121788 google scholar
51. Sânchez, M., Perez, G., Izaguirre, I., & Pizarro, H. (2013). Influence of underwater light climate on periphYton and phYtoplankton communities in shallow lakes from the Pampa Plain (Argentina) with contrasting steadY states. Journal of Limnology, 72(1), 62-78. https://doi.org/10.4081/jlimnol.2013.e6 google scholar
52. Schmid, A. M. M. (1994). Aspects of morphogenesis and function of diatom cell walls with implications for taxonomY. Protoplasma, 181, 43-60. google scholar
53. Seckbach, J., & Kociolek, P. (2011). The diatom world. Springer. google scholar
54. Smith, V. H. (1983). Low nitrogen to phosphorus ratios favor dominance bY blue-green algae in lake phYtoplankton. Science, 221(4611), 669-671. https://doi.org/ 10.1126/science.221.4611.669 google scholar
55. Stancheva, R., & Sheath, R. G. (2016). Benthic soft-bodied algae as bioindicators of stream water quality. Knowledge and Management of Aquatic Ecosystems, 417, Article 15. https://doi.org/10.1051/kmae/2016002 google scholar
56. Stenger-Kovâcs, C., Beres, V. B., Buczkö, K., Tapolczai, K., Padisâk, J., Selmeczg G. B., & LengYel, E. (2023). Diatom community response to inland water salinization: a review. Hydrobiologia, 850(20), 4627-4663. https://doi.org/10.1007/s10750-023-05167-w google scholar
57. Tasnim, N., Karmakar, D., Hasan, R., et al. (2023). Effect of light intensitY and pH on cell density assessed bY spectrophotometry for the unicellular algae Chlorella vulgaris. American Journal of Plant Sciences, 14, 472-481. https://doi.org/10. 4236/ajps.2023.144031 google scholar
58. U.S. Environmental Protection Agency. (2019). National recommended water qualitY criteria—Aquatic life criteria table (EPA-822-R-19-001). https://www.epa. gov/wqc/national-recommended-water-quality-criteria-aquatic-life-criteria-table google scholar
59. Van der Werff, A. (1999). A new method of concentrating and cleaning diatoms and other organisms. Verhandlungen des Internationalen Vereins für Limnologie, 12, 276-277. google scholar
60. Volkova, E. A., Zimens, E. G., & VishnYakov, V. S. (2020). New taxonomic records of Zygnemataceae (Charophyta) from the Lake Baikal region. Limnology and Freshwater Biology, 6, 1090-1100. google scholar
61. Vuorio, K., Jarvinen, M., & Kotamaki, N. (2020). Phosphorus thresholds for bloom-forming cyanobacterial taxa in boreal lakes. Hydrobiologia, 847, 4389-4400. https://doi.org/10.1007/s10750-019-04161-5 google scholar
62. Wehr, J. D., Sheath, R. G., & Kociolek, J. P. (2015). Freshwater algae of North America: Ecology and classification (2nd ed.). Academic Press. google scholar
63. Williams, D. M. (1985). MorphologY, taxonomY and inter-relationships of the ribbed araphid diatoms from the genera Diatoma and Meridion (Diatomaceae: BacillariophYta). Bibliotheca Diatomologica, 8, 1-228. google scholar
64. Zahradkova, S., & Soldan, T. (2008). Saprobic system. In S. E. Jorgensen & B. D. Fath (Eds.), Encyclopedia of Ecology (pp. 3242-3343). Elsevier BV. google scholar
65. Zepernick, B. N., Gann, E. R., Martin, R. M., Pound, H. L., Krausfeldt, L. E., Chaffin, J. D., & Wilhelm, S. W. (2021). Elevated pH conditions associated with Microcystis spp. blooms decrease viabilitY of the cultured diatom Fragilaria crotonensis and natural diatoms in Lake Erie. Frontiers in Microbiology, 12, Article 598736. https://doi.org/10.3389/fmicb.2021.598736 google scholar