Fottea, 2023 (vol. 23), issue 2
Original article
Unravelling the hidden complexity in diversity and pigment composition of a colonial flagellate Synura sphagnicola (Chrysophyceae, Stramenopiles)
Pavel Škaloud, Magda Škaloudová, Iva Jadrná, Jana Pilátová, Woonnghi Shin, Jiří Kopecký
Fottea 2023, 23(2):149-163 | DOI: 10.5507/fot.2022.021 
In this study, we aim to taxonomically evaluate a unique example of cryptic diversity in a freshwater protist species Synura sphagnicola, occurring at two evolutionary levels. First, we characterize two species, S. sphagnicola and S. rubra sp. nov., that diverged from one another approx. 14 Mya. These species are morphologically well differentiated by the morphology of silica scales. Second, we propose seven evolutionary young, but ecologically and geographically well differentiated lineages as separate sub-species, sphagnicola, agilis, borealis (within S. sphagnicola), rubra, ampla, bella...
Tracing lineages of scale-bearing Chrysophyceae over geologic time
Peter A. Siver
Fottea 2023, 23(2):164-176 | DOI: 10.5507/fot.2022.018
Until the discovery of a massive number of fossil specimens in the early Eocene locality known as Giraffe Pipe, little was known about Chrysophyceae that bear siliceous scales from the geologic record. More recently, remains of chrysophyte scales have been reported from another Eocene site known as Horsefly, and uncovered from a Late Cretaceous site known as the Wombat locality. The aims of this investigation were to add the additional records from the Eocene and Cretaceous sites and to trace the known distributions of lineages, both with and without modern congeners, over the last 83 Ma. Twenty-nine scale types, referred to herein as lineages, have...
Comparing continental and local distribution patterns of protists: A case study of silica-scaled chrysophytes
Yvonne Nemcova, Jana Faturova, Pavel Škaloud
Fottea 2023, 23(2):177-189 | DOI: 10.5507/fot.2022.022
Free-living protists play important roles in biogeochemical cycling and food-web chains in both aquatic and terrestrial environments. However, their biogeography and spatial distribution remain poorly resolved. Here, we used silica-scaled chrysophytes to determine the most important climatic, historical, and environmental variables that explain biodiversity patterns across different geographical scales; the continental scale was represented by 473 European sites (gradient of 3,800 km), the local scale comprised 69 Aquitanien (France) sites (gradient of 186 km). Generalized Additive Models were used to evaluate the relationship between species richness...
The effect of patterned structures on the mechanical resistance of microscopic silica scales
Petr Knotek, Pavel Škaloud
Fottea 2023, 23(2):190-200 | DOI: 10.5507/fot.2023.007
Surfaces of microscopic organisms are often adorned with various patterns whose putative functions are largely unexplored. In this study, we tested the hypothesis that the formation of parallel-arranged ribs improves the mechanical resistance of microscopic silica scales. Computer models of scales were constructed for chrysophyte species Mallomonas striata and Synura petersenii, varying the ribs number and orientation. The finite element method was used to evaluate the model static parameters. Our results showed a large difference in the function of ribs depending on the species studied. In S. petersenii, the ribs play...
High abundances and negligible grazing during winter by the mixotrophic chrysophyte Dinobryon
Sarah DeVaul Princiotta, Tiffany Nguyen, Robert W. Sanders
Fottea 2023, 23(2):201-207 | DOI: 10.5507/fot.2022.020
Grazing on bacteria by planktonic organisms is a channel for the biological transfer of organic matter through the aquatic food web. Much attention has been given to the importance of heterotrophic nanoflagellates and ciliates as primary grazers of bacteria. However, the prevalence of phagotrophy by phytoplankton across many environments emphasizes a need to include mixotrophy in studies of the protistan food web. Few studies have addressed the seasonal dynamics nor grazing activity of mixotrophs in freshwater environments, especially those that extend below surface waters. The goal of this work was to examine temporal patterns in mixotroph abundance...
Encystment by the mixotrophic flagellate Ochromonas pinguis Conrad (Chrysophyceae) under manipulated laboratory conditions
Dale A. Holen, Sarah Princiotta
Fottea 2023, 23(2):208-216 | DOI: 10.5507/fot.2023.004
Chrysophyte stomatocysts are well documented in lake sediments, but except for a few studies on sexually reproducing colonial chrysophytes, little is known regarding encystment cues in these algae. Ochromonas pinguis Conrad, a mixotrophic chrysophyte with an unknown sexual history was observed to produce stomatocysts, albeit at a low frequency. To determine if the low rate of encystment was typical or whether manipulating environmental conditions might enhance the rate of resting cyst production O. pinguis was subjected to various physical and chemical conditions in a batch culture. O. pinguis cultures were manipulated by culturing...
Elucidating the phylogeny and taxonomic position of the genus Spiniferomonas Takahashi (Chrysophyceae)
Martin Pusztai, Iva Jadrná, Pavel Škaloud
Fottea 2023, 23(2):217-222 | DOI: 10.5507/fot.2023.006
Spiniferomonas represents a strictly single-celled plastid-bearing genus of silica-scaled chrysophytes, with a well-characterised morphology and ultrastructure, as well as a pretty known ecology based on scale records. However, the taxonomic status of this genus remains ambiguous due to the absence of relevant sequence data. Spiniferomonas has historically been classified in the Synurales, Paraphysomonadales, or "Chrysosphaerellaceae" based upon interpretations of the silica scale morphology. In this study, we have aimed to genetically characterize a newly established Spiniferomonas trioralis culture as well as culture of...
Differences in pigment composition and concentration between phototrophic, mixotrophic, and heterotrophic Chrysophyceae
Jens Boenigk, Daniela Beisser, Luise Franke, Lea Klar, Maja Ilić, Patrick Fink
Fottea 2023, 23(2):223-234 | DOI: 10.5507/fot.2023.001
The presence of distinct pigments is characteristic of different algal groups while the relative concentration of these pigments may vary with light conditions. Here we investigate the pigment pattern of 35 strains of Chrysophyceae by means of high-performance liquid chromatography. We further investigated shifts in pigment concentrations between light and dark conditions and the conservation of these pigment patterns in heterotrophic, mixotrophic, and phototrophic taxa. We did not find chlorophyll in heterotrophic strains but carotenoids were present in all taxa. In phototrophs and mixotrophs, we confirm the presence of the chlorophylls-a, c1,...
Effects of stressors on growth and competition between different cryptic taxa affiliated with Ochromonadales (Chrysophyceae)
Lisa Boden, Guido Sieber, Jens Boenigk
Fottea 2023, 23(2):235-245 | DOI: 10.5507/fot.2023.003
Morphologically similar flagellate taxa comprise a high cryptic diversity. This diversity evolved partly through parallel evolution in several phylogenetically distinct taxa. Here we investigate the effects of heat waves and salinization on growth and competition between cryptic taxa. For this purpose, we developed specific FISH probes targeting the phylogenetic clades comprising Pedospumella encystans, Spumella rivalis, and Poteriospumella lacustris, respectively. Exposure to salt resulted in a decreasing growth rate for all three taxa. In contrast, a sudden increase in temperature to 27 °C stimulated particularly the growth of...
A first account of Mallomonas specimens representing section Torquatae from the fossil record: descriptions of two species from the Eocene
Peter A. Siver, Anne Marie Lott
Fottea 2023, 23(2):246-255 | DOI: 10.5507/fot.2022.019
Mallomonas Perty is a genus of photosynthetic and heterokont algae belonging to the order Synurales, within the class Chrysophyceae. It is the most speciose genus within the Synurales, and consists of motile unicells with a cell covering composed of highly sculptured and precisely arranged siliceous scales and bristles. The genus is a common and often important element of planktic habitats with species found in numerous types of aquatic environments. Mallomonas is divided into 19 sections, many of which are further divided into multiple series. The section Torquatae is one of the larger sections of the genus comprised of species with...
Personalia
10th International Chrysophyte Symposium
Jens Boenigk
Fottea 2023, 23(2)
The 10th International Chrysophyte Symposium was organized by the Department Biodiversity, Faculty of Biology, University of Duisburg-Essen. A total of 25 participants, including scientists from Czech Republic, Germany, Mexico, USA and South Korea presented 18 lectures and 7 posters.
Anniversary of RNDr. Jaromír Lukavský, CSc.
Linda Nedbalová
Fottea 2023, 23(2)
Jaromír Lukavský was born on 22 September 1943 in Neumětely. In the 1960s, he studied in Prague at the Department of Botany, Faculty of Science, Charles University under the guidance of the legend of world algology, professor Bohuslav Fott. Thanks to this, he gained a very solid background in the determination of algae, and this is also probably where his lifelong interest in floristic work stems from. Although the current advancements of molecular methods offer possibilities that were difficult to imagine previously, we increasingly find that a well-founded view on a sample under the light microscope is indispensable. Jaromír belongs to a small group...