Special Issue "Taxonomy, Ecology and Biogeography of Diatoms"

A special issue of Diversity (ISSN 1424-2818). This special issue belongs to the section "Microbial Diversity and Culture Collections".

Deadline for manuscript submissions: closed (30 August 2020) | Viewed by 13120

Special Issue Editor

Dr. Agata Z. Wojtal
E-Mail Website
Guest Editor
Institute of Nature Conservation Polish Academy of Sciences, Adama Mickiewicza ave. 33, 31-120 Kraków, Poland
Interests: diatoms; taxonomy; climate and habitat change; nutrient loading and pollution; invasive species
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Diatoms are a group of unicellular, eukaryotic algae abundant in all aquatic habitats. They are a group of organisms that make up a significant part of the Earth’s biomass. The species diversity of diatom assemblages is also influenced by geographical factors. The dependence of diatom distribution on environmental conditions, especially in extreme borders, is still being investigated. A large number of ecologically sensitive species have allowed widespread monitoring of water quality using these algae. Among other organisms, many diatoms are considered endangered. This Special Edition introduces new data on the diversity and distribution of diatoms, the impact of human activity (anthropopressure), and climate change on algae communities.

Dr. Agata Wojtal
Guest Editor

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Keywords

  • Diatom ecology
  • Biogeography
  • Taxonomy
  • Estimation of water quality
  • Conservation of aquatic habitats

Published Papers (12 papers)

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Research

Article
Epilithic Diatom Community Shows a Higher Vulnerability of the River Sava to Pollution during the Winter
Diversity 2020, 12(12), 465; https://doi.org/10.3390/d12120465 - 05 Dec 2020
Cited by 4 | Viewed by 769
Abstract
The aim of the research was to investigate the influence of environmental factors on the structure of epilithic diatom communities in the Sava River from the source to the state border 220 km downstream. The river had numerous human influences along its course, [...] Read more.
The aim of the research was to investigate the influence of environmental factors on the structure of epilithic diatom communities in the Sava River from the source to the state border 220 km downstream. The river had numerous human influences along its course, such as municipal and industrial wastewater, agriculture, hydroelectric power plants, etc. The main objective of the research was to find out the influence of human pressure on the structure of the epilithic diatom community under winter and summer conditions. Winter and summer samples were taken at nine sites. At each sampling site, a set of abiotic factors was measured and another set of environmental parameters was evaluated. The analyses showed that nitrogen and phosphorus concentrations increased downstream. We identified 118 different species of diatoms. The most common taxa were Achnanthidium minutissimum and A. pyrenaicum. Planktonic species Cyclotella meneghiniana was only found in the samples of the lower part of the Sava, which is unusual for the epilithic community. The composition of the epilithic diatom community was significantly influenced by conductivity and water temperature, pH and distance from the source. The similarity between diatom communities closer to the source of the river was higher than between communities from the lower part of the Sava River. The values of the trophic and saprobic indices increased downstream and showed that the pollution of the river with nutrients and organic matter increases with the distance from the source. Both indices were significantly higher in winter and showed a more impaired river ecosystem during the winter. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Benthic Diatom Composition in Coastal Zone of Black Sea, Sasyk Reservoir (Ukraine)
Diversity 2020, 12(12), 458; https://doi.org/10.3390/d12120458 - 01 Dec 2020
Cited by 2 | Viewed by 867
Abstract
The Sasyk Reservoir is one of the largest seaside reservoirs in Ukraine, artificially maintained as a freshwater area including various floodplain areas. The Reservoir originated from an estuary to now being an almost freshwater reservoir. The diatoms (Bacillariophyta) in benthos were investigated for [...] Read more.
The Sasyk Reservoir is one of the largest seaside reservoirs in Ukraine, artificially maintained as a freshwater area including various floodplain areas. The Reservoir originated from an estuary to now being an almost freshwater reservoir. The diatoms (Bacillariophyta) in benthos were investigated for analyzing the coastal zone diversity of the Black Sea inside the borders of Ukraine. The indicated diatom composition was formed by 97 species (100 infraspecies taxa). Some rare marine and freshwater taxa were noted, as well as three species reported in Ukrainian territory for the first time (Navicula vandamii Schoeman et R.E.M. Archibald, Sellaphora difficillima (Hustedt) C.E. Wetzel, L. Ector et D.G. Mann, and Mastogloia laterostrata Hustedt). The bioindicative characteristics of the diatom composition testified to the freshwater condition of the reservoir. Changes to the salinity level of the Sasyk Reservoir were exposed due to the composition of benthic diatoms. The presence of mesohalobous species (7 taxa) acknowledges conditions that are typical for estuaries and mouths of rivers and reveals the salinity changes in the Sasyk Reservoir. Likewise, the prevailing number of oligohalobous diatoms (61 taxa) reveal presence of freshwater in the reservoir. The implementation of the Polish phytobenthos lake assessment method for the nearby Ukrainian Reservoir was conducted for the first time. The multimetric Diatom Index for lake values varied from 0.39 to 0.76, and revealed alterations in the status over the Sasyk sites, ranging from good, moderate, to poor. Thus, it may be concluded that the current ecological status relating to the composition of benthic diatoms of the reservoir located in the coastal zone of the Black Sea is evaluated as having a moderate status class with some exceptions. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Diatoms in Kamchatka’s Hot Spring Soils
Diversity 2020, 12(11), 435; https://doi.org/10.3390/d12110435 - 18 Nov 2020
Cited by 3 | Viewed by 1000
Abstract
Diatoms inhabiting terrestrial habitats that are affected by thermal activity remain poorly studied, despite significant interest in the biodiversity of hot springs. The Kamchatka peninsula is characterized by the presence of 30 active volcanoes associated with hydrotherms. Our study involved a survey of [...] Read more.
Diatoms inhabiting terrestrial habitats that are affected by thermal activity remain poorly studied, despite significant interest in the biodiversity of hot springs. The Kamchatka peninsula is characterized by the presence of 30 active volcanoes associated with hydrotherms. Our study involved a survey of diatom diversity in soils around the Malki, Upper Paratunka, and Dachnie thermal springs on the Kamchatka peninsula. A total of 49 diatom taxa were found. The genera Pinnularia, Planothidium, Fragilariforma, Epithemia, Halamphora, Gomphonema, Nitzschia, Aulocoseira, Sellaphora, Surirella, and Navicula were the most common. Pinnularia cf. subcapitata and Planothidium lanceolatum were dominant in all springs. Diatom communities in the soils near the thermal springs included both aquatic and terrestrial species, which may reflect the transitional nature of habitats at the borders of hot springs and soils. To gain a better understanding of the diversity of diatom communities in soils near thermal springs, broader worldwide studies are necessary. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
An Assessment of the Influence of Host Species, Age, and Thallus Part on Kelp-Associated Diatoms
Diversity 2020, 12(10), 385; https://doi.org/10.3390/d12100385 - 08 Oct 2020
Cited by 1 | Viewed by 1066
Abstract
Diatom community composition and abundances on different thallus parts of adult and juvenile specimens of Eckloniamaxima and Laminariapallida were examined in False Bay, South Africa, using light and scanning electron microscopy. Altogether, 288 thallus portions were analysed. Diatom abundances ranged from [...] Read more.
Diatom community composition and abundances on different thallus parts of adult and juvenile specimens of Eckloniamaxima and Laminariapallida were examined in False Bay, South Africa, using light and scanning electron microscopy. Altogether, 288 thallus portions were analysed. Diatom abundances ranged from 0 to 404 cells mm−2 and were generally higher on E. maxima and juvenile thalli than L. pallida and adult specimens. Moreover, diatom abundances differed between the various thallus parts, being highest on the upper blade and lowest on the primary blade. A total of 48 diatom taxa belonging to 28 genera were found. Gomphoseptatum Medlin, Nagumoea Witkowski and Kociolek, Cocconeis Ehrenberg, and Navicula Bory were the most frequently occurring genera, being present in 84%, 65%, 62.5%, and 45% of the analysed samples, respectively. Among these, Cocconeis and Gomphoseptatum were the most abundant, contributing 50% and 27% of total diatom cells counted collectively across all samples. Permutational multivariate analysis of variance (PERMANOVA) revealed that all investigated main factors (kelp species and age and thallus part), as well as their two- and three-way interactions, except for the interaction between the host species and age, were significant. The high residual variance (72%) indicated that the sum of other unexamined factors contributed the largest component of the variation observed in the kelp-associated diatom communities, and grazing and possible defence strategies utilised by kelps are proposed as processes playing an important role in the structuring of epiphytic diatom communities. Possible endophytism of tissue-boring diatoms colonizing both kelp species is briefly discussed. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Diatom Diversity on the Skin of Frozen Historic Loggerhead Sea Turtle Specimens
Diversity 2020, 12(10), 383; https://doi.org/10.3390/d12100383 - 05 Oct 2020
Viewed by 1334
Abstract
In recent years, biofilm-forming diatoms have received increased attention as sea turtle epibionts. However, most of the research has focused on carapace-associated taxa and communities, while less is known about diatoms growing on sea turtle skin. The current study investigated diatom diversity on [...] Read more.
In recent years, biofilm-forming diatoms have received increased attention as sea turtle epibionts. However, most of the research has focused on carapace-associated taxa and communities, while less is known about diatoms growing on sea turtle skin. The current study investigated diatom diversity on the skin of loggerhead sea turtle heads detached from the carcasses found along the Adriatic coast between 1995 and 2004 and stored frozen for a prolonged period of time. By using both light and scanning electron microscopy we have found diatom frustules in 7 out of 14 analysed sea turtle samples. Altogether, 113 diatom taxa were recorded, with a minimum of seven and a maximum of 35 taxa per sample. Eight taxa, Achnanthes elongata, Berkeleya cf. fennica, Chelonicola sp., Licmophora hyalina, Nagumoea sp., Navicula sp., Nitzschia cf. lanceolata, and Poulinea lepidochelicola exceeded 5% of relative abundance in any one sample. The presumably obligately epizoic diatom taxa, A. elongata, Chelonicola sp., and P. lepidochelicola, dominated in six loggerhead samples, contributing up to 97.1% of the total diatom abundance. These observations suggest that on the sea turtle skin highly specialised taxa gain even greater ecological advantage and dominance over the co-occurring benthic forms than in the carapace biofilms. The suitability of frozen sea turtle skin specimens for diatom analysis and limitations of this approach are discussed. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Strategy for the Removal of Satellite Bacteria from the Cultivated Diatom
Diversity 2020, 12(10), 382; https://doi.org/10.3390/d12100382 - 03 Oct 2020
Cited by 2 | Viewed by 973
Abstract
Multiple ecological and genetic studies of diatom algae require an axenic culture. However, algae-associated bacterial biofilms often form in diatom-produced mucus, both during creation of monoclonal cultures from single cells and during biomass growth, and they may be difficult to remove. In this [...] Read more.
Multiple ecological and genetic studies of diatom algae require an axenic culture. However, algae-associated bacterial biofilms often form in diatom-produced mucus, both during creation of monoclonal cultures from single cells and during biomass growth, and they may be difficult to remove. In this work, we describe a protocol for removing associated bacteria from a monoclonal culture of Ulnaria danica isolated from Lake Baikal. The axenization strategy involves selecting the latent phase of diatom growth, multiple washes to remove extracellular polymeric substances and bacterial cells, filter deposition, and treatment with antibiotics that are not toxic for diatoms. The absence of bacteria during these stages was controlled by light microscopy with Alcian blue staining for mucus, epifluorescent microscopy with DAPI (4′,6-diamino-2-phenylindole) staining for bacterial DNA, and scanning electron microscopy of the diatom cell surface. High-throughput sequencing of a 16S rRNA fragment, amplified with universal bacterial primers, from total DNA of a final culture failed to detect any bacterial contamination, confirming successful axenization. A detailed comparative description of all stages of our protocol may prove useful in developing axenic cultures of other diatoms for various ecological and genetic studies. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Achnanthes Bory Sensu Stricto (Bacillariophyta) from Terrestrial Habitats of Rio de Janeiro (Brazil), with Description of Achnanthes pseudoinflata sp. nov.
Diversity 2020, 12(10), 375; https://doi.org/10.3390/d12100375 - 29 Sep 2020
Cited by 2 | Viewed by 924
Abstract
The aim of the present work was to present the ecological and morphological characteristics of species from the genus Achnanthes Bory sensu stricto, which develops in terrestrial mosses near the Rio de Janeiro Botanic Garden, Brazil. A literature comparison was made with [...] Read more.
The aim of the present work was to present the ecological and morphological characteristics of species from the genus Achnanthes Bory sensu stricto, which develops in terrestrial mosses near the Rio de Janeiro Botanic Garden, Brazil. A literature comparison was made with other similar species, including the LM and SEM analysis of original material bearing Achnanthes inflata (Kützing) Grunow housed at the Grunow Collection in Vienna, and data from the available literature. Samples were collected from clumps of moss growing on tree trunks, and from a concrete wall within the botanic garden. Four taxa from the genus Achnanthes were recorded: A. coarctata, A. inflata var. gibba, A. mauiensis and Achnanthes pseudoinflata sp. nov. The main morphological differences between these taxa were cell dimensions (length and width), striae and areolae density. The most common diatom species found in these samples were Humidophila sp. (90%), Humidophila contenta (74.8%), Luticola moreirae (17.9%), and Achnanthes pseudoinflata sp. nov. (7.4%). Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Limnological Characteristics and Diatom Dominants in Lakes of Northeastern Poland
Diversity 2020, 12(10), 374; https://doi.org/10.3390/d12100374 - 28 Sep 2020
Cited by 3 | Viewed by 1099
Abstract
Determination of the relationships between environmental factors and diatom assemblages is usually made for several hundred lakes spread over a large area. However, the analysis of several lakes located near Lake Wigry also gives interesting results. Lakes in Wigry National Park (Poland) with [...] Read more.
Determination of the relationships between environmental factors and diatom assemblages is usually made for several hundred lakes spread over a large area. However, the analysis of several lakes located near Lake Wigry also gives interesting results. Lakes in Wigry National Park (Poland) with broad similarity of geological origin show clear limnological, physical, and chemical differences. Here, we report on an investigation into how these dissimilarities influence diatom assemblages. Hierarchical Cluster Analysis showed that the studied lakes can be divided into three groups: (1) disharmonic, (2) harmonious with greater human impact on the environment, and (3) harmonious with a more limited human impact. The harmonious lakes could be divided into two groups that are mainly in line with the contents of the chloride and sulfates ions taken as indicative of human impacts on the environment. Overall, the three groups had different dominance structures, as reference to the Dominance Index (DI) made clear (mean values being: (1) −70.54%, (2) −72%, and (3) −54.58%, Generalized Linear Models with the categorical independent variable (group) showed significant differences between groups (for 1–3, 2–3) p value < 0.05). Lakes impacted by anthropopressure and disharmonic ones had the strongest dominance structure. More broadly, DI differences between the groups are consistent with the Species Pool Hypothesis (SPH), while studied differences can be said to result from natural geological dissimilarities, as well as disparate anthropogenic impacts. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Temporal Evolution of Diatoms in a Temporary Pond Situated in the Massif du Sancy Mountains (Massif Central, France) and Description of a New Pinnularia Species
Diversity 2020, 12(10), 367; https://doi.org/10.3390/d12100367 - 24 Sep 2020
Cited by 3 | Viewed by 971
Abstract
A floristic survey was performed on a temporary pond, “Laqui du Seignavoux”, situated in the Mont-Dore massif of the French Massif Central, between 2017 and 2019. Except in 2017, each year, we performed four sampling campaigns from April/May to December. Water samples and [...] Read more.
A floristic survey was performed on a temporary pond, “Laqui du Seignavoux”, situated in the Mont-Dore massif of the French Massif Central, between 2017 and 2019. Except in 2017, each year, we performed four sampling campaigns from April/May to December. Water samples and diatoms were collected. The temporary pond evolved from a poorly mineralized ecosystem due to snow, inducing oligotrophic and oligosaprobic water, well oxygenated in spring, to a more mineralized, less oxygenated, eutrophic–hypereutrophic, and polysaprobic environment in summer. This change in abiotic conditions was found to be linked to the presence of cattle, beginning in May, that trample and excrete in the pond, leading to higher ammonium and nitrate concentrations. During this period, the dominant species were Pinnularia sp., Nitzschia palea, and Nitzschia palea var. tenuirostris. In spring and winter, different species of Eunotia dominated the community such as Eunotia pseudogroenlandica. Finally, light microscopy (LM) and scanning electron microscopy (SEM) observations on a new species of the genus Pinnularia from the temporary pond are presented and the ecological preferences are discussed. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Frustulia tunariensis sp. nov. (Bacillariophyceae) from the Andes of Bolivia, South America
Diversity 2020, 12(9), 362; https://doi.org/10.3390/d12090362 - 22 Sep 2020
Cited by 1 | Viewed by 1030
Abstract
Frustulia tunariensis sp. nov. is originated from a high-altitude peatland in the Tunari Cordillera, a branch of the Andean range in Bolivia. The new taxon is distinguished by the thick longitudinal ribs, the globose polar nodule with faint helictoglossa that does not produce [...] Read more.
Frustulia tunariensis sp. nov. is originated from a high-altitude peatland in the Tunari Cordillera, a branch of the Andean range in Bolivia. The new taxon is distinguished by the thick longitudinal ribs, the globose polar nodule with faint helictoglossa that does not produce an apical extension, and by the high areola and stria density, not found in any of the morphologically closely related taxa. Features of the folded valvocopula, such as the presence of a siliceous membrane as pars interior, and poroids present in the tube-like portion opening as slits to the valve interior and as a single row of poroids to the exterior, are also unique characters in the new taxon. Based on a literature review, a comparison of the newly proposed species with morphologically similar taxa was made. Also, published information shows the potential of girdle bands to distinguish groups of species and species themselves within Frustulia. Likewise, remarks on the ecological and distribution aspects of Frustulia in the Bolivian Altiplano are included, focusing on taxonomic quality, geographic coverage and sampling, and potential to represent the genus in the high Bolivian Andean plateau. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Species Composition and New Records of Diatom Taxa on Phyllodictyon pulcherrimum (Chlorophyceae) from the Gulf of California
Diversity 2020, 12(9), 339; https://doi.org/10.3390/d12090339 - 04 Sep 2020
Cited by 2 | Viewed by 1157
Abstract
A taxonomic analysis of diatoms found on Phyllodictyon pulcherrimum yielded a total of 244 diatom taxa (all illustrated) within 27 orders, 45 families, and 86 genera. The Taxa were briefly documented in a list including identification references and morphometric data. Thirty-eight of the [...] Read more.
A taxonomic analysis of diatoms found on Phyllodictyon pulcherrimum yielded a total of 244 diatom taxa (all illustrated) within 27 orders, 45 families, and 86 genera. The Taxa were briefly documented in a list including identification references and morphometric data. Thirty-eight of the taxa identified at the species and infraspecific levels represent new records for the coasts of Mexico. Seven were recorded for the first time on the American continent: Auricula flabelliformis, A. pulchra, Campylodiscus scalaris, Coscinodiscus mesoleius, Dimeregramma fulvum, Navicula palpebralis var. angulosa, and Seminavis barbarae, and one, Nitzschia fusiformis, for the Pacific Ocean. This is the second record of the chlorophyte P. pulcherrimum in the north Pacific and the third for Mexican waters. The results confirm that surveying rare macroalgae species as hosts for epiphytic diatoms provides opportunities to seek new records of diatom taxa, or even new taxa, in regions around the world. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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Article
Two New Benthic Diatoms of the Genus Achnanthidium (Bacillariophyceae) from the Hangang River, Korea
Diversity 2020, 12(7), 285; https://doi.org/10.3390/d12070285 - 21 Jul 2020
Cited by 2 | Viewed by 1218
Abstract
Two new benthic freshwater species belonging to the genus Achnanthidium were found in Korea. Achnanthidium ovale sp. nov. and A. cavitatum sp. nov. are described as new species based on light and scanning electron microscopy observations and molecular analyses. Both species are compared [...] Read more.
Two new benthic freshwater species belonging to the genus Achnanthidium were found in Korea. Achnanthidium ovale sp. nov. and A. cavitatum sp. nov. are described as new species based on light and scanning electron microscopy observations and molecular analyses. Both species are compared with the type material of morphologically similar taxa. Achnanthidium ovale differs from other species belonging to the A. pyrenaicum complex in outline, striation pattern, raphe central endings, and freestanding areolae at the apices. Achnanthidium cavitatum differs from other species in the A. minutissimum complex in outline, broad axial central area in the raphel ess valve, and slit-like areolae near the axial central area. We assessed their molecular characteristics by analyzing nuclear small subunit (SSU) rRNA and chloroplast-encoded rbcL gene sequences. Both the morphological comparison and the SSU and rbcL sequence analyses provide strong evidence to support the recognition of A. ovale and A. cavitatum as new species. Full article
(This article belongs to the Special Issue Taxonomy, Ecology and Biogeography of Diatoms)
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