Thalassiosira duostra (Bacillariophyta), a new for the flora of Russia freshwater diatom species

2019 ◽  
Vol 53 (1) ◽  
pp. 7-14
Author(s):  
S. I. Genkal
Keyword(s):  
Species Composition ◽  
Original Description ◽  
Published Data ◽  
Diatom Species ◽  
Centric Diatoms ◽  
Internal Part ◽  
Quantitative Characteristics ◽  
Internal Arrangement ◽  
Freshwater Diatom

The study of archive materials has made it possible to specify species composition of the genus Thalassiosira and discover a new for the flora of Russia representative of centric diatoms, T. duostra, in Cheboksary and Tsimlyansk reservoirs and the Oka River. The valve diameter and number of central futoportulae in the examined material differ insignificantly from the original description and published data. By the general valve outline, structure and arrangement of central and marginal fultoportulae and quantitative characteristics, T. duostra is very similar to Сonticribra weissflogii and Thalassiosira faurii, which may result in inaccurate identification of these species. In the Сonticribra weissflogii the rimoportula is located not in a ring of marginal fultoportulae but closer to the valve center and its internal part is significantly larger than in Thalassiosira duostra. The external arrangement of marginal fultoportulae (tubes of the processes are outwardly directed at different angles) and their internal arrangement (the processes are arranged in two rings, they are more dense in the ring which is closer to the valve face) is a good specific feature that differentiates T. duostra and T. faurii.

New records of centric diatoms from Yakutia (Bolshoe Toko Lake): SEM morphology, ecology and distribution

2018 ◽  
Vol 52 (2) ◽  
pp. 245-252 ◽  
Author(s):  
S. I. Genkal ◽  
V. A. Gabyshev
Keyword(s):  
Species Composition ◽  
River Basin ◽  
New Records ◽  
Water Bodies ◽  
Centric Diatom ◽  
Diatom Species ◽  
Centric Diatoms ◽  
Sem Study ◽  
First Time ◽  
Sem Morphology

As a result of a SEM study of phytoplankton, the first data on centric diatom species composition in Bolshoye Toko Lake, Yakutia, were obtained. Ten species (Aulacoseira — 5, Cyclotella — 1, Discostella — 1, Handmannia — 1, Pliocaenicus — 1) were found, and one taxon from the genus Pliocaenicus was identified to the genus level. Of these, nine taxa are reported for the first time in the water bodies of the Aldan River basin and Discostella guslyakovyi in Yakutia.

scholarly journals Diatom (Bacillariophyceae) flora of early Holocene freshwater sediments from Skalafjord, Faeroe Islands

2003 ◽  
Vol 22 (2) ◽  
pp. 183-208 ◽  
Author(s):  
Ewa Witon ◽  
Andrzej Witkowski
Keyword(s):  
Species Composition ◽  
Northern Europe ◽  
Diatom Species ◽  
Marine Waters ◽  
Core Section ◽  
Lower Water Level ◽  
Storegga Slide ◽  
Marine Flora ◽  
Rising Sea Level ◽  
Freshwater Diatom

Abstract. Relative abundance data of diatom (Bacillariophyceae) species were generated for sediment core SKPC-01B from the Skalafjord, Faeroe Islands. The record shows distinct temporal changes in species composition. In the lowermost 65 cm of the 230 cm long core a species-rich freshwater diatom assemblage was found. Most of the taxa observed in this section are typical of oligotrophic to dystrophic lakes in northern Europe (Scandinavia, Iceland and Spitsbergen). Above this interval the diatom flora is dominated by marine taxa. The change from a freshwater to a marine flora is inferred to be caused by rising sea-level that took place about 7700–6400 years BP. Drastic changes in the diatom species composition within the transitional core section show that environmental change in the Skalafjord took place in several pulses. The first stage included strong inflow (possibly catastrophic) of marine waters. As a possible trigger of this phenomenon the tsunami released by the Storegga Slide is proposed. Before the final flooding by marine waters, freshwater conditions were re-established within the Skalafjord. These results have important implications for the interpretation of the palaeogeographical development of the Eysturoy area. Hence, it is suggested that the Storegga Slide led to inflow of marine waters at a distinctly lower water level in the area of the Skalafjord than proposed in recent publications and that the inundation of the threshold in the fjord happened after the tsunami.

scholarly journals Variation of Diatoms and Silicon in a Tributary of the Three Gorges Reservoir: Evidence of Interaction

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1369 ◽  
Author(s):  
Wei Xiao ◽  
Yubo Huang ◽  
Wujuan Mi ◽  
Hongyan Wu ◽  
Yonghong Bi
Keyword(s):  
Species Composition ◽  
Cell Density ◽  
Three Gorges Reservoir ◽  
Water Discharge ◽  
Three Gorges ◽  
Diatom Species ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Centric Diatoms ◽  
Pennate Diatoms

To gain insight into the variation of diatoms and silicon and their interaction in a tributary of the Three Gorges Reservoir (TGR), the Xiangxi River was chosen as a representative tributary, and dissolved silicon (DSi) and biogenic silicon (BSi) were investigated monthly from February 2015 to December 2016, accompanied by diatom species composition and cell density analyses. The results showed that the diatom population and its relationship with silicon concentration were significantly different between the lacustrine zone and riverine zone (P < 0.05). The cell density in the lacustrine zone (6.20 × 105 ~ 9.97 × 107 cells/L) was significantly higher than that in the riverine zone (7.90 × 104 ~ 1.81 × 107 cells/L) (P < 0.01). Water velocity was a key factor in determining the diatom species composition. Centric diatoms were the dominant species in the lacustrine zone, and pennate diatoms were the primary species in the riverine zone, which indicated that centric diatoms outcompete pennate diatoms under the influence of the TGR’s operation. BSi showed a significant linear relationship with the cell density. DSi had a significant negative relationship with the cell density in the lacustrine zone, while no significant relationship was found in the riverine zone. This meant that the main contributor to BSi was diatoms, but DSi was primarily affected by water discharge, not diatom uptake. It could be deduced that the spatiotemporal heterogeneity of diatom communities was influenced by the TGR’s operation. Silicon cycling in the tributary was significantly affected by diatoms, and the current concentration of DSi was sufficient for diatom growth and showed no significant effects on the diatom community.

Distribution of moss-inhabiting diatoms along an altitudinal gradient at sub-Antarctic Îles Kerguelen

2007 ◽  
Vol 19 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Niek J.M. Gremmen ◽  
Bart van de Vijver ◽  
Yves Frenot ◽  
Marc Lebouvier
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Altitudinal Gradient ◽  
Cross Validation ◽  
Strong Relationship ◽  
Distribution Patterns ◽  
Common Species ◽  
Important Variable ◽  
Diatom Species ◽  
Expected Species Richness

Altitudinal gradients provide excellent opportunities to study relationships between species distribution and climatic variables. We studied the species composition of 39 samples of moss-inhabiting diatoms, collected at 50 m intervals from 100–650 m above sea level. The samples contained a total of 130 diatom species, of which 51 occurred in 10 or more samples. Altitude appeared to be the most important variable explaining variation in species composition. Of the 51 common species, 33 showed a significant relationship with altitude. Although the majority of the latter declined with increasing altitude, for nine species the probability of occurrence first increased with increasing elevation, but decreased again at higher altitudes, and four species increased systematically with elevation. As a result, expected species richness per sample decreased from an estimated 43 at 100 m to 25 species per sample at 650 m. Diatom distribution patterns proved to be suitable predictors of the altitudinal position of sample sites. Cross-validation yielded a strong relationship between predicted and observed altitudes.

scholarly journals Amphipod (Crustacea, Amphipoda) Communities in the North-Western Part of the Black Sea

2016 ◽  
Vol 50 (5) ◽  
pp. 387-394
Author(s):  
S. A. Kudrenko
Keyword(s):  
Species Composition ◽  
Community Composition ◽  
Black Sea ◽  
The Black Sea ◽  
Published Data ◽  
Amphipod Species ◽  
Quantitative Parameters ◽  
The North ◽  
North Western

Abstract The data about the community composition, number and biomass of amphipods in three gulfs of the North-Western Black Sea are presented. The amphipod communities of the gulfs of Yahorlyk, Karkinit, and Tendra were studied and the species composition was compared with the previously published data. For each particular gulf, the list of amphipod species was composed. The quantitative parameters of the amphipod communities in the studied localities in different years were described.

scholarly journals Shaping our Taxonomic Legacy through Openly Sharing Primary Biodiversity Data in Taxonomic Revisions

2019 ◽  
Vol 3 ◽  
Author(s):  
Torsten Dikow
Keyword(s):  
Data Dissemination ◽  
Original Description ◽  
Published Data ◽  
Data Standards ◽  
Global Biodiversity Information Facility ◽  
High Quality ◽  
Data Repositories ◽  
The Past ◽  
Text Document ◽  
Digital Format

Taxonomy has a long tradition of describing earth’s biodiversity. For the past 20 years or so, taxonomic revisions have become available in PDF format, which is regarded by most practicing taxonomists to be a good means of digital dissemination. However, a PDF document is nothing more than a text document that can be transferred easily for viewing among researchers and computer platforms. In today’s world, traditional taxonomic techniques need to be met with novel tools to make data dissemination a reality, make species hypotheses more robust, and open the field up to rigorous scientific testing. Here, I argue that high-quality taxonomic output is not just the publication of detailed species descriptions and re-descriptions, precise taxon delimitations, easy-to-use identification keys, and comprehensively undertaken and illustrated revisions. Rather, in addition high-quality taxonomic output embraces digital workflows and data standards to disseminate captured and published data in structured, machine-readable formats to data repositories so as to make all data openly accessible. Imagine that a taxonomist today has every original description and every subsequent re-description of a species at her/his fingertips online, has every specimen photograph produced by a previous reviser digitally available in the original resolution, and can take advantage of existing, openly accessible data and resources produced by peers in digital format in the past. When we as taxonomists provide such findable, accessible, interoperable, and reusable (FAIR) data, the future of biodiversity discovery will accelerate and our own taxonomic legacy will be enhanced. Cybertaxonomic tools provide methods to accomplish this goal and their use and implementation is here summarized in the context of revisionary taxonomy from the standpoint of a publishing taxonomist. While many of the tools have been around for some time now, very few taxonomists embrace and utilize these tools in their publications. This presentation will provide information on what kind of data can and should be openly shared (e.g., specimen occurrence data, digital images, names, descriptions, authors) and outline best practices utilizing globally unique identifiers for specimens and data. Data standards and the best-suited data repositories such as the Global Biodiversity Information Facility (GBIF) and Zenodo, with its Biodiversity Literature Repository, and the Plazi TreatmentBank, an emerging species portal, are discussed to illustrate retrospective and prospective data capture of taxonomic revisions.

scholarly journals Distrionella coxiana, a new fragilarioid diatom species (Bacillariophyceae) from Tierra del Fuego, Patagonia, Argentina

2019 ◽  
Vol 152 (2) ◽  
pp. 385-391
Author(s):  
Valeria Casa ◽  
Gabriela Mataloni ◽  
Bart Van de Vijver
Keyword(s):  
Typical Feature ◽  
Morphological Features ◽  
Tierra Del Fuego ◽  
New Taxon ◽  
Diatom Species ◽  
Unique Combination ◽  
Diatom Flora ◽  
Electron Microscopical ◽  
Scanning Electron ◽  
Freshwater Diatom

Background and aims – A few years ago, a new survey started of the freshwater diatom flora from peatbogs of Tierra del Fuego (southern Argentina). During this survey, an unknown fragilarioid diatom belonging to the genus Distrionella that could not be identified using the currently available literature was discovered. Methods – Using both Light Microscopical and Scanning Electron Microscopical techniques, the morphology of the unknown Distrionella species has been analysed. The new taxon is properly described, illustrated and compared with all other possible similar Distrionella taxa, known worldwide. Key results – Distrionella coxiana possesses a unique combination of morphological features that excludes conspecificity with all other members of the genus; it is characterized in having narrow, linear valves with small, capitate apices. Transapical ribs, a typical feature of the genus Distrionella, are only weakly developed. One rimoportula is observed close to the apices. Both apices have well-developed apical porefields. The girdle bands bear one complete row of poroids often accompanied by a second, incomplete row of small poroids. Notes on the occurrence and ecology of the new taxon are added.

Diatom species composition along a thermal gradient in the Portneuf River, Idaho, USA

Hydrobiologia ◽  
1989 ◽  
Vol 185 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Deanna K. Vinson ◽  
Samuel R. Rushforth
Keyword(s):  
Species Composition ◽  
Thermal Gradient ◽  
Diatom Species ◽  
Portneuf River

Encyonema aquasedis sp. nov. and Kurtkrammeria salesopolensis sp. nov.: two new freshwater diatom species (Cymbellales, Bacillariophyceae) from an oligotrophic reservoir in southeastern Brazil

Phytotaxa ◽  
2016 ◽  
Vol 247 (1) ◽  
pp. 62 ◽  
Author(s):  
Gisele Carolina Marquardt ◽  
Angélica Cristina Righetii Da Rocha ◽  
Carlos Eduardo Wetzel ◽  
Luc Ector ◽  
Carlos Eduardo de Mattos Bicudo
Keyword(s):  
New Species ◽  
Surface Sediments ◽  
Low Ph ◽  
Southeastern Brazil ◽  
Diatom Species ◽  
Southeast Brazil ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron ◽  
Freshwater Diatom

Recent research of the plankton and the surface sediments from Ribeirão do Campo reservoir (São Paulo, southeast Brazil) led to identification of two new cymbelloid diatom species: Encyonema acquasedis sp. nov. and Kurtkrammeria salesopolensis sp. nov. Their morphology was studied under both light and scanning electron microscopes aiming at describing the two species in detail. The morphology of each species is compared and discussed with morphologically similar taxa. The new species are different from all others in the Cymbellales due to a combination of characteristics including valve outline, striae, areolae structure, and raphe system. Both species were collected from an oligotrophic environment with both low pH and conductivity.

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