Algal and cyanobacterial diversity in saline rivers of the Elton Lake Basin (Russia) studied via light microscopy and next-generation sequencing

Naturally saline rivers are known in various regions of the world. Saline rivers with a salinity gradient from the source to the mouth are particularly interesting, because the range of salinity is the structure-forming factor of the hydrobiont assemblage. Such rivers are represented by saline rivers of the Elton Lake Basin in Volgograd region of Russia (the Bolshaya Samoroda River and the Malaya Samoroda River). Herein, we analyzed taxonomic structure and species diversity of microalgae and Cyanobacteria of the saline rivers flowing into the Elton Lake by light microscopy and next-generation sequencing. The differences and possible causes of inconsistencies in the results obtained by these methods are discussed. In total, 91 taxa of microorganisms were identified by integrated approach in the assemblages of microalgae and Cyanobacteria in the middle course of the Bolshaya Samoroda River, and 60 taxa – in the river mouth. The species diversity of those assemblages in the hypersaline Malaya Samoroda River was lower: 27 taxa from the middle course and 23 taxa from the mouth. Next-generation sequencing allowed us to refine and expand the list of microalgae taxa in the studied saline rivers due to detection of species which were hard to identify, low-abundance taxa, as well as extremely small-cell forms. Some discrepancies between the data obtained by light microscopy and next-generation sequencing indicate the advantage of simultaneous use of both methods for study of the algae communities. Such a comprehensive approach provides the most accurate and correct list of taxa added with the morphological descriptions and 18S rRNA and 16S rRNA partial sequences. Generally, 18 taxa have been recorded for the first time in the Bolshaya Samoroda River, belonging to the phyla Chlorophyta (Borodinellopsis sp., Chlorochytrium lemnae Cohn, Caespitella sp., Halochlorococcum sp., Tetraselmis cordiformis (H. J. Carter) F. Stein), Ochrophyta (Pseudocharaciopsis ovalis (Chodat) D. J. Hibberd, Characiopsis sp., Poterioochromonas stipitata Scherffel, Chrysolepidomonas sp.), Euglenozoa (Euglena bucharica I. Kisselev, Lepocinclis tripteris (Dujardin) B. Marin & Melkonian, Phacus orbicularis K. Hübner, P. parvulus G. A. Klebs), Cryptophyta (Hemiselmis cryptochromatica C. E. Lane & J. M. Archibald, Rhodomonas sp., Hanusia phi J. A. Deane), Haptophyta (Pavlova sp.), Cyanobacteria (Johanseninema constrictum (Szafer) Hasler, Dvorák & Poulícková). Seven taxa have been detected for the first time in the algal and cyanobacterial assemblages of the Malaya Samoroda River from the phyla Chlorophyta (Tetraselmis cordiformis, T. arnoldii (Proschkina-Lavrenko) R. E. Norris, Hori & Chihara, T. tetrathele (West) Butcher, Pyrobotrys elongatus Korshikov), Cryptophyta (Hanusia phi), and Cyanobacteria (Synechococcus elongatus (Nägeli) Nägeli, Oscillatoria simplicissima Gomont)

Halotolerant strain of Chlorococcum oleofaciens from the Lake Elton Biosphere Reserve

Chlorococcum oleofaciens is one of the most studied representatives of the Chlorococcum genus, both on the ultrastructural and molecular levels. This alga is very interesting due to its ability to hypersynthetize saturated and unsaturated fatty acids and the possibility of using it as a promising object for biofuel production. This research is devoted to the study of the halotolerant strain of Ch. oleofaciens Ch-1 extracted from the water of the Khara River (Lake Elton Biosphere Reserve, Russia, a UNESCO World Heritage site), mineralization of 14‰. The strain Ch. oleofaciens Ch-1 was studied at the morphological level (light microscopy), as well as using molecular genetics methods (18S rDNA). The objectives of the study included establishing the range of halotolerance of the allocated strain of Ch. oleofaciens as a whole, revealing borders of level of mineralization that are optimum for algae growth, and also tracing features of its morphology and cycle of development in the conditions of various salinity. In the course of the studies performed it was established that the extracted strain of Ch. oleofaciens Ch-1 differed from the typical one by greater variability of some morphological features and had a wide ecological valence: the range of its halotolerance was 0–60‰. The maximum values of quantitative development of Ch. oleofaciens Ch-1 were registered at mineralization of 0–14‰. It is shown that with increasing salinity in the development cycle of the strain, the duration of the adaptation phase increases, the exponential phase decreases, small celled forms are replaced by large celled forms and reproduction features are noted. The obtained results can be used for selection of optimal conditions for cultivation of the halotolerant strain of Ch. oleofaciens for biotechnological purposes

Chrysotila carterae R. A. Andersen, J. I. Kim, Tittley & H. S. Yoon 2014

<i>Chrysotila carterae</i> (Braarud & Fagerland) R.A. Andersen, J.I. Kim, Tittley & H.S. Yoon (Figs. 8, 9) <p> ≡ <i>Pleurochrysis carterae</i> (Braarud & Fagerland) T. Christensen (1978: 68)</p> <p>A disc-shaped coccolith (placolith), composed of two interlocking cycles of crystal units, V and R units, which represent the calcite crystals with subvertical (V units) and subradial (R units) orientations of the c-axis relative to the base plate; 2.2–6 × 1.4–1.7 µm in size.</p> <p>This species was recorded from Zhetykol Lake and Aschisaysky Рond (see Table 2).</p>Published as part of <i>Ignatenko, Marina & Yatsenko-Stepanova, Tatyana, 2023, Coccolithophores in the algal flora from South Urals (Russia) with the description of a new Hymenomonas species, pp. 55-64 in Phytotaxa 609 (1)</i> on pages 59-60, DOI: 10.11646/phytotaxa.609.1.5, <a href="http://zenodo.org/record/8254620">http://zenodo.org/record/8254620</a&gt

Hymenomonas uralensis Ignatenko & Yatsenko-Stepanova 2023, sp. nov.

<i>Hymenomonas uralensis</i> Ignatenko & Yatsenko-Stepanova <i>sp. nov.</i> (Fig. 15) <p>Coccoliths are elliptical muroliths. Each coccoliths composed of an organic base plate and calcified elements. The base of the coccolith (0.93–1.2 × 0.8–0.96 µm, n=15) has a jagged edge, followed by a tubular part with more or less straight sides and the expanding part (1.3–1.6 × 0.97–1.3 µm) is formed by overlapping elements. The height of the coccolith is 0.36–0.51 µm, the width of the rim is 0.22–0.3 µm. In most coccoliths a single rim element at each end of the coccolith is extended distally as a rectangular block protruding above the rim (width 0.18–0.33 µm, height 0.25–0.43 µm).</p> <p> <b>Type:</b> —The specimen with <i>Hymenomonas uralensis</i> coccoliths on SEM stub number 49_I_3 deposited at the Herbarium of the Steppe Institute of the Ural Branch of the Russian Academy of Sciences, Orenburg (ORIS). Material from the Ural River (51°25ʼ55”N, 56°28ʼ58”E), Orenburg Region, Russia. Sample collected 27th of July, 2021, by M. Ignatenko.</p> <p> <b>Type Locality:</b> —RUSSIA: Orenburg region, Ural River. 51°25ʼ55”N, 56°28ʼ58”E. 27 July 2021.</p> <p> <b>Etymology:</b> — <i>Hymenomonas uralensis</i> is named after the Ural River, where this species was discovered.</p> <p> <b>Distribution:</b> —Besides the type locality this species was found from the backwater of the Ural River in the vicinity of the Nikolskoye village (see Table 2).</p>Published as part of <i>Ignatenko, Marina & Yatsenko-Stepanova, Tatyana, 2023, Coccolithophores in the algal flora from South Urals (Russia) with the description of a new Hymenomonas species, pp. 55-64 in Phytotaxa 609 (1)</i> on pages 60-61, DOI: 10.11646/phytotaxa.609.1.5, <a href="http://zenodo.org/record/8254620">http://zenodo.org/record/8254620</a&gt

Jomonlithus littoralis Inouye & Chihara 1983

<i>Jomonlithus littoralis</i> Inouye & Chihara (Figs. 5–7) <p> The diameter of the coccolith-bearing cell is 10.5–12.0 µm. The surface of the cell is covered by small oval-shaped coccoliths (muroliths), 1.07–1.39 × 0.77–0.92 µm; rim width 0.11–0.17 µm, rim height 0.2–0.29 µm. The coccolith structure corresponds to the description of Probert <i>et al.</i> (2014) to that which is composed of an organic base plate scale with a lightly calcified rim made up of small rectangular inner and outer sub-elements.</p> <p>This species was observed from a backwater of the Ural River and Zhetykol Lake (see Table 2).</p>Published as part of <i>Ignatenko, Marina & Yatsenko-Stepanova, Tatyana, 2023, Coccolithophores in the algal flora from South Urals (Russia) with the description of a new Hymenomonas species, pp. 55-64 in Phytotaxa 609 (1)</i> on page 58, DOI: 10.11646/phytotaxa.609.1.5, <a href="http://zenodo.org/record/8254620">http://zenodo.org/record/8254620</a&gt

Hymenomonas roseola F. Stein 1878

<i>Hymenomonas roseola</i> F. Stein (Figs. 2–4) <p>Coccolith is bowl-shape (murolith), with more or less straight sides. The funnel-shaped part of the coccolith expands towards the top and has a jagged edge. The number of calcite “teeth” (crystal units) of coccoliths belonging to single cell varies from 11 to 15. The height of coccoliths in the discovered specimens varies within 0.50–1.12 µm; the height of the base and the height of the funnel are approximately the same.</p> <p>This species was observed in Ural River and Ushkotinsky Reservoir (see Table 2).</p>Published as part of <i>Ignatenko, Marina & Yatsenko-Stepanova, Tatyana, 2023, Coccolithophores in the algal flora from South Urals (Russia) with the description of a new Hymenomonas species, pp. 55-64 in Phytotaxa 609 (1)</i> on page 57, DOI: 10.11646/phytotaxa.609.1.5, <a href="http://zenodo.org/record/8254620">http://zenodo.org/record/8254620</a&gt

Chrysotila roscoffensis R. A. Andersen, J. I. Kim, Tittley & H. S. Yoon 2015

<i>Chrysotila roscoffensis</i> (P.A. Dangeard) R.A. Andersen, J.I. Kim, Tittley & H.S. Yoon (Figs. 10–14) <p> ≡ <i>Pleurochrysis roscoffensis</i> (P.A. Dangeard) Fresnel & Billard (1991: 77)</p> <p>A disc-shaped coccolith (placolith), that consists of a central vertical tube bounded on each side by shield, there are small nodes on the distal shield of the placolith and within the tube, extending into the central area; 2.46–2.85 × 1.74–1.98 µm in size.</p> <p>This species was recorded from Zhetykol Lake and Aschisaysky Рond (see Table 2).</p> <p> In this study, we found coccoliths in freshwater (Fig. 15), which we could not correlate with any of the described species. We described their as <i>Hymenomonas uralensis sp. nov.</i></p>Published as part of <i>Ignatenko, Marina & Yatsenko-Stepanova, Tatyana, 2023, Coccolithophores in the algal flora from South Urals (Russia) with the description of a new Hymenomonas species, pp. 55-64 in Phytotaxa 609 (1)</i> on page 60, DOI: 10.11646/phytotaxa.609.1.5, <a href="http://zenodo.org/record/8254620">http://zenodo.org/record/8254620</a&gt

POTENTIALLY DANGEROUS CYANOBACTERIA OF THERAPEUTIC MUD

Aim. Determination of Cyanobacteria species composition in the Tuzlukkol River part with mud and brine and identification of potentially dangerous representatives of this group of microorganisms. Materials and methods. 270 samples were analyzed (135 of them - quantitatively), selected in the spring-autumn periods 2012-2017 in accordance with generally accepted methods. Identification of cyanobacteria was carried out according to the algae identification guides of domestic and foreign authors, the chamber of Najotta with a volume of 0.01 cm3 was used to calculate the algae quantity. The algae biomass was calculated taking into account the volume of the cells. Results. 25 species, varieties and forms of Cyanobacteria have been identified. Four genera (Anabaena, Oscillatoria, Nodularia and Lyngbya) were potentially capable to produce hepato-, neuro- and dermatotoxins. In some periods the total number of cyanobacteria exceeded almost 5 times the standard recommended by WHO in bathing waters. Conclusion. The results of the study demonstrate the necessity of Cyanobacteria monitoring (species composition and quantity) to prove the mud safety for people health during balneotherapy

Study of the algae flora of the Orenburg region: history and modernity

The article deals with the history of studying the species richness of algae in the Orenburg region from the first publications of the early nineteenth century to the present.</jats:p

Morphological variability of stomatocyst 131 Pang &amp;amp; Wang (Chrysophyceae) from a freshwater shallow lake in South Urals, Russia

Stomatocyst 131 Pang &amp; Wang was described from the sedge mires and puddles in the Aershan Geological Park, China and it has not been reported from other localities since its description. We recorded stomatocyst 131 from a shallow lake Zhurmankol in South Urals, Russia. Morphological variability of this morphotype was studied using scanning electron microscopy. We showed that the width of hexagonal pattern as well as the height of the mesh edges significantly varied depending on the maturation stage of the stomatocyst. An amended diagnosis of this stomatocyst is provided.</jats:p