Three new Achnanthidium (Bacillariophyceae) species from Lake Salda (Anatolia, Turkey), a deep soda lake

[EN] Background and aims – Kützing separated the genus Achnanthidium from the genus Achnanthes based on two species: Achnanthes minutissima and Achnanthidium microcephalum. These two genera were distinguished by the presence of stalks in the Achnanthes genus and their absence in Achnanthidium. Before electron microscopy, the difference between Achnanthes and Achnanthidium was not clear, especially in Achnanthidium minustissimum sensu lato. The aim of the study is to describe three new species of Achnanthidium from Lake Salda. Material and methods – Lake Salda is located in southwestern Anatolia, in Turkey. The diatoms were collected seasonally from four stations in the lake between 2016 and 2020, from different substrata (epipelic, epiphytic, and epilithic). Key results – Three new species belonging to the genus Achnanthidium have been found in Lake Salda, Turkey. Based on the morphological observations, all new taxa are part of the Achnanthidium minutissimum complex. Achnanthidium barlasii sp. nov. and A. dumlupinarii sp. nov. show a high degree of similarity to each other, but can be separated based on valve outline and a denser areolation, especially in striae close to the apices of the raphe valve. Both species can be distinguished from A. minutissimum based on more separate apices and less elliptic valves. In the case of A. dumlupinarii sp. nov., large specimens show slight undulations of the valve, which is a unique feature. Achnanthidium anatolicum sp. nov. is the most characteristic based on its valve width, broadly rounded valve apices, and almost straight valves in girdle view. All newly described Achnanthidium species can be found in lentic environments, with alkaline water and high calcium ion content. Conclusion – The newly described taxa occurred in the unique habitat of a soda lake. The environment of the lake is highly alkaline, rich in magnesium and calcium, and derived from limestone and dolomitic limestone rocksS

Nitzschia anatoliensis sp. nov., a cryptic diatom species from the highly alkaline Van Lake (Turkey)

In this article we describe Nitzschia anatoliensis Górecka, Gastineau & Solak sp. nov., an example of a diatom species inhabiting extreme habitats. The new species has been isolated and successfully grown from the highly alkaline Van Lake in East Turkey. The description is based on morphology (light and scanning electron microscopy), the sequencing of its organellar genomes and several molecular phylogenies. This species could easily be overlooked because of its extreme similarity to Nitzschia aurariae but molecular phylogenies indicate that they are only distantly related. Furthermore, molecular data suggest that N. anatoliensis may occur in several alkaline lakes of Asia Minor and Siberia, but was previously misidentified as Nitzschia communis. It also revealed the very close genetic proximity between N. anatoliensis and the endosymbiont of the dinotom Kryptoperidinium foliaceum, providing additional clues on what might have been the original species of diatoms to enter symbiosis.info:eu-repo/semantics/publishedVersio

Distribution and morphology of the diatom genus Olifantiella Riaux-Gobin & Compère in Indonesian and Australian waters, including the description of O. gondwanensis sp. nov.

Samples from coastal tropical waters of Central Sulawesi, Bangka Island and Bawean Island in Indonesia and from the Great Barrier Reef at Fitzroy Island in Queensland, Australia were analysed for species composition of diatom assemblages with a focus on Olifantiella. Whereas samples from Fitzroy Island littoral in Australia retrieved only one species of Olifantiella, in Poso Bay, Indonesia, we observed at least six species. All established taxa were documented with light (LM) and scanning electron microscope (SEM) and principal component analysis (PCA) analysis was used to compare the species, based on the basic valve parameters of length, width, length to width ratio and striae density. A new species of the genus Olifantiella, O. gondwanensis is described from Australia. In addition, we showed the distinct nature of O. pilosella var. rhizophorae permitting to species status. Particular attention is placed on girdle bands in this genus

The Aerophytic Diatom Assemblages Developed on Mosses Covering the Bark of Populus alba L.

The study was conducted in the old, historical park, in the northern part of Stalowa Wola city (south-eastern Poland). The aim of the study was to investigate the diversity of moss-inhabiting diatoms of the white poplar (Populus alba L.) bark. During the study, a total of 47 diatom taxa were found, of which three were considered as dominat. Three other species are mentioned in the Red List of the Algae in Poland: Achnanthes coarctata (Brébisson) Grunow, Luticola acidoclinata Lange-Bertalot and Stauroneis thermicola (Petersen) Lund. For three species: Luticola sparsipunctata Levkov, Metzeltin & Pavlov, L. vanheurckii Van de Vijver & Levkov and Hantzschia subrupestris Lange-Bertalot is the first report from Poland

Analysis of the type material of Gomphosphenia tackei (Bacillariophyceae) and comparison to epizoic diatom populations on freshwater snails

Background and aims – Hustedt (1942) originally described Gomphosphenia tackei from Germany under the name Gomphonema tackei. Because of the small cell size and the lack of scanning electron microscopy (SEM) images from the type material, it is often confused with other species from this genus, especially with G. stoermeri. The aim of this paper was to present detailed morphological characteristics of G. tackei based on the analysis of the type material and of several epizoic populations from Central Europe. Material and methods – The material in this study was collected from the shells of the freshwater snails Lymnaea stagnalis, Planorbarius corneus, and Planorbis planorbis. Additionally, for an unambiguous species identification, the type material for Gomphosphenia tackei was analyzed using light and scanning electron microscopes.Key results – The presence of Gomphosphenia tackei was confirmed in the studied material. The largest population (up to 19%) was recorded on the shell surfaces of living snails, whereas on empty shells, the diatom did not seem to be present or only in very low numbers. Valves are typically clavate with rounded apices. Valves are frequently observed in girdle view, often joint together in pairs. The valves in the studied populations had a valve length of 7–29 µm, a valve width of 3–4 µm, and a stria density of 25–29 striae in 10 µm. In the type population, valve length ranged from 7.5 to 27 µm with a valve width of 3.0–4.0 µm and a stria density of 23–29 striae per 10 µm. Striae were composed of 2–4 elongated to rounded areolae per stria. At the apices, the striae were composed of one single areola. The cells were attached to the substratum by their footpole.Conclusion – Published illustrations of Gomphosphenia tackei do not always correctly represent this species. Individual cells are attached to the substratum by secreted mucilage, probably via their areolae or girdle band pores located on the footpole

Diversity in Anthropogenic Environment – Permanent Puddle as a Place for Development of Diatoms

Specific conditions in urban areas favour large species richness, these are also places prone to the anthropogenic pressure. As a result, many studies on aquatic habitats in urban ecosystems have been carried out. The aim of this study was to investigate the diversity of diatom assemblages developing in artificial environment in relation to water chemical parameters. The study was performed on a small water outflow in south-eastern Poland, which started in the storm sewage. The water at the studied sites was characterized by alkaline pH and low content of nutrients. The values of other chemical parameters were highly variable, depending on the research season. A total of 113 taxa were identified in five research seasons; most of them prefer circumneutral and fertile habitats, with a high content of biogens and are tolerant to water pollutions. Aerophytic and terrestrial taxa were observed in the analyzed materials in high diversity

Study of terrestrial diatoms in corticolous assemblages from deciduous trees in Central Europe with descriptions of two new Luticola D.G.Mann taxa

Although many studies have examined the algae associated with various habitats in tree trunks, the diatoms in these environments are still poorly studied. Studies of corticolous algae mainly focus on green algae and cyanobacteria, which are usually immediately visible, while diatoms are mostly overlooked or not reported. During the research, 143 species of diatoms were identified, including two new representatives of the genus Luticola: L. bryophila sp. nov. with relatively large central area and short distal raphe endings and L. confusa sp. nov. characterized by the presence of small depressions on central raphe endings. Both are described herein based on light and scanning electron microscopy observations and compared to similar taxa based on literature data. Basic morphological data for almost all the diatom taxa are noted, and their habitat requirements, and photographic documentation are also presented. The present research showed that the occurrence of diatom assemblages on tree trunks is influenced by various factors like host tree species, the area where the host tree grows, and the availability of suitable microhabitats within the trunk. However, the species composition of this assemblages depends mainly on the tree species

Diversity of the Rhopalodiaceae Diatoms (Bacillariophyta) on Macrophytes of Different Architecture in Small and Shallow Oxbow Lakes (SE Poland)

The research was conducted in July 2018 on six oxbow lakes of the San River. A total of 21 samples from various macrophyte species were collected. Over 400 species of diatoms were identified in the analyzed materials, 9 of which belonged to the Rhopalodiaceae family. Most of these Epithemia and Rhopalodia species developed as dominants in most of the studied samples. One of reported species – Epithemia selengaensis Vishnyakov, Kulikovskiy & Genkal was first time reported from Poland. The aim of the study was to present the taxonomic diversity of the representatives of the Rhopalodiaceae family growing different macrophyte species in oxbow lakes in the summer aspect

Description of four new terrestrial diatom species from Luticola and Microcostatus genera from South Africa

The knowledge about terrestrial diatom assemblages in southern Africa is rather limited, despite a long history of diatom research in this area. Terrestrial habitats are places of characteristic diatom floras, dominated by species resistant to desiccation which are able to thrive in conditions of limited water availability. The presented work expands the knowledge about these unique habitats. During the study on terrestrial moss-inhabiting diatoms from Western Cape Province (South Africa), four taxa with a unique set of valve features have been found and described herein as new species, based on light and scanning electron microscopy. These new species are: Luticola microcephala M. Rybak, Peszek & Kochman-Kędziora, sp. nov., Luticola asymmetrica M. Rybak, Kochman-Kędziora & Peszek, sp. nov., Luticola terrestris Kochman-Kędziora, M. Rybak & Peszek, sp. nov. and Microcostatus meridionalis Peszek, M. Rybak & Kochman-Kędziora, sp. nov. Algal community composition had low species richness (9–15 taxa per sample) and samples were dominated by: Humidophila contenta, Nitzschia brevissima and Eunotia aff. pseudominor. The three new Luticola species formed numerous populations, exceeding 10% of the share, whereas Microcostatus meridionalis reached 5.4%. Basic morphological data of associated diatom flora together with detailed micrographs are also provided

Effect of Different Doses of Ash from Biomass Combustion on the Development of Diatom Assemblages on Podzolic Soil under Oilseed Rape Cultivation

The aim of the study was to determine the effect of fertilization with various doses of ash from biomass combustion (balanced to the amount of K2O introduced into the soil) on the growth of representatives of soil microorganisms, i.e., diatoms. In a one-factor field experiment (control, NPK, 100, 200, 300, 400, 500 kg/ha), soil samples were collected from the 0–5 cm layer of podzolic soil under the cultivation of winter oilseed rape (Brassica napus L. var. napus) at the end of August 2019 and 2020. The biomass combustion ash used for soil fertilization was characterized by an alkaline reaction (pH = 12.83 ± 0.68) and high levels of basic macroelements required for proper plant growth and development. The particle size distribution in each plot was identified as loamy silt (pgl). Before the experiment (autumn 2018), the soil exhibited an acidic reaction (pHH2O = 5.8), low conductivity (EC = 68 µS), and 19.09% moisture at the 0–5 cm level. In total, 23 diatom species were identified in the material collected from the topsoil in all variants of the experiment. Hantzschia amphioxys, Mayamaea atomus, Mayamaea permitis, Nitzschia pusilla, Pinnularia obscura, Pinnularia schoenfelderi, and Stauroneis thermicola were the most abundant populations