Eco-Assessment of Streams of Konya Closed River Basin (Turkey) Using Various Ecoregional Diatom Indices

Ecological assessments of freshwater ecosystems based on diatom metrics are an important issue to attain environmental sustainability. The present study aimed to evaluate differences in the diatom-stressors relationship in relatively least disturbed streams in the Konya closed river basin using multivariate analyses and to bio-assess streams by application of different ecoregional diatom indices. Cocconeis euglypta, Cymbella excisa, Cocconeis placentula, and Achnanthidium minutissimum are the most contributing species to the dissimilarity of sampling stations between rainy and dry seasons and also between altitude (A2 800-<1600 m and A3 ≥1600 m) groups. A strong (82.8%) correlation between diatom species and stressors was expressed by the first two axes of canonical correspondence analysis. Diatom species displayed distinct responses to environmental variables (electrical conductivity, Ni, Cu, B, and altitude) playing important roles on the distribution of diatom species. Diatom indices indicated different ecological statuses of stations from a bad to a high. European diatom indices except Duero Diatom Index-DDI and Trophic Diatom Index-TDI showed well responses to the eco-assessment of streams and indicated high ecological status for the least disturbed sampling stations symbolized as S16, S20, S24, S25, S27-29, S37, and 39. These results were also supported by abiotic evaluation. Among diatom indices, although TIT was more competitive in the bio-assessment of streams, it is necessary to increase its species list by determining their trophic weights in future studies. This indicates that the revision of ecoregional specific diatom metrics with the enhancement of diatom species numbers according to their ecological preferences is needed to correctly interpret the water quality.

Achnanthidium gladius sp. nov. (Bacillariophyceae) – a new monoraphid diatom species from Indonesia

A new monoraphid diatom species Achnanthidium gladiussp. nov. is described from Indonesia. The description is based on molecular data (18SV4), morphological analysis and comparison with similar species. According to molecular data, Achnanthidium gladius sp. nov. is closely related to Achnanthidium minutissimum. Morphologically, the new species differs from similar species by the absence of a fascia on raphe valve, cell size, and striae density and pattern. The new species is only known from the type locality in Indonesia. Comparison with close related species is given.

Phytoplankton Growth Rate and Microzooplankton Grazing under Conditions of Climatic Changes and Anthropogenic Pollution in the Coastal Waters of the Black Sea (Sevastopol Region)

In the coastal waters of the Black Sea near Sevastopol, a gradual temperature elevation and an increase in anthropogenic pressure since the early 2000s have caused significant structural and functional changes in phytoplankton. Currently, there is a significant decrease in the contribution of small diatom species (Skeletonema sp. and Chaetoceros socialis H.S.Lauder as well as coccolithophorids Emiliania huxleyi (Lohmann) W.W.Hay and H.P.Mohler) to the total phytoplankton biomass in these waters. Previously these species caused regular weak blooms. In the warm periods (from May to October), during which the main phytoplankton biomass is formed, large diatom species Pseudosolenia calcar-avis (Schultze) B.G.Sundström, 1986, Proboscia alata (Brightwell) Sundström and dinoflagellates predominate. Therefore, the maximum values of the phytoplankton community’s specific growth rate are about two times lower than in the preceding periods and do not exceed 1.10–1.40 day−1. There was also a decrease observed in the microzooplankton grazing rate, which, during the year, was no higher than 0.70–1.20 day−1. This is primarily conditioned by the increased role of large algae in phytoplankton, which means a decline in nutrition quality for microzooplankton. As a result of the joint influence of nutrition quality and water pollution, the relative share of net primary production consumed by microzooplankton in the warm periods of the year averaged only 32%, which is two times lower than the average values generally accepted for marine ecosystems. This means that the transfer of matter and energy from phytoplankton to higher trophic levels is significantly decreased.

Study of Diatom Flora of Kaalesar Ghat of Rapti River at Gorakhpur for Forensic Consideration

Diatoms are unique algae. They are scientifically known as Bacillariophyceae. Diatoms have been used in forensic science in a variety of ways, the most frequent being the diagnosis of death by drowning. When a person drowns, water will enter the lungs and then enter the bloodstream through ruptures in the peripheral alveoli before being carried to the other organs such as the liver and heart. Naturally, the microscopic contents of the water, which will include diatoms, will pass into the blood as well. The detection of diatoms in the organs can contribute to a diagnosis of death by drowning, a process referred to as the ‘diatom test’. A study was conducted in the department of Forensic Science, SHUATS, Prayagraj which included the extraction and identification of diatoms from the collected water samples from three different sites of Kaalesar Ghat of Rapti River in Gorakhpur. The acid digestion method was used for diatom extraction. And, after analysis total 13 diatom species were found. The identified diatoms were of great ecological assessment that plays an important role in criminal investigations related to premortem or ante-mortem drowning. Keywords: Diatom, Drowning, D-mapping, Rapti-River

Three New Diatom Species from Spring Habitats in the Northern Apennines (Emilia-Romagna, Italy)

Using light (LM, including plastid characterization on fresh material) and scanning electron microscopy (SEM), as well as a thorough morphological, physical, chemical, and biological characterization of the habitats, the present study aims at describing three species new to science. They belong to the genera Eunotia Ehrenb., Planothidium Round and L. Bukht., and Delicatophycus M.J. Wynne, and were found in two contrasting spring types in the northern Apennines. The three new species described differ morphologically from the most similar species by: less dense striae and areolae, and the absence of a ridge at the valve face-mantle transition (SEM feature) [Eunotia crassiminor Lange-Bert. et Cantonati sp. nov.; closest established species: Eunotia minor (Kütz.) Grunow]; narrower and shorter cells [Planothidium angustilanceolatum Lange-Bert. et Cantonati sp. nov.; most similar species: Planothidium lanceolatum (Bréb. ex Kütz.) Lange-Bert.]; barely-dorsiventral symmetry, set off ends, and lower density of the central dorsal striae [Delicatophycus crassiminutus Lange-Bert. et Cantonati sp. nov.; most similar species: Delicatophycus minutus M.J.Wynne]. Two of the three species we described are separated from the closest species by dimensions. Their description improved knowledge on two taxa (Eunotia minor s.l. and Planothidium lanceolatum s.l.) likely to be only partially resolved species complexes. We could also refine knowledge on the ecological profiles of the three newly-described species. Eunotia crassiminor sp. nov., as compared to Eunotia minor, appears to occur in colder inland waters with a circumneutral pH and a strict oligotrophy as well with respect to nitrogen. The typical habitat of Planothidium angustilanceolatum sp. nov. appears to be oligotrophic mountain flowing springs with low conductivity. Delicatophycus crassiminutus sp. nov. was observed only in limestone-precipitating springs, and is therefore likely to be restricted to hard water springs and comparable habitats where CO2 degassing leads to carbonate precipitation. Springs are a unique but severely threatened wetland type. Therefore, the in-depth knowledge of the taxonomy and ecology of characteristic diatom species is important, because diatoms are excellent indicators of the quality and integrity of these peculiar ecosystems in the face of direct and indirect human impacts.

Relations between Benthic Diatom Community and Characteristics of Karst Ponds in the Alpine Region of Slovenia

The aim of this research was to investigate the structure of the benthic diatom community and its relations to selected environmental parameters. We collected samples in 16 karst ponds in the alpine region of Slovenia, where the Alpine karst is found. Since the predominating substrate in these ponds was clay, the epipelic community was analyzed. Hydromorphological characteristics, and physical and chemical conditions were also measured at each site. We found 105 species of diatoms, which belonged to 32 genera. The most frequent taxa were Gomphonema parvulum (Kützing) Kützing, Navicula cryptocephala Kützing, Sellaphora pupula (Kützing) Mereschkowsky (species group) and Achnanthidium pyrenaicum (Hustedt) Kobayasi. The pond with the lowest diversity was found at the highest altitude, while, on the other hand, the most species-rich pond was found at the lowest altitude. Regarding the ecological types, the most common were motile species. We confirmed a positive correlation between the number of diatom species and the saturation of water with oxygen, while correlation between species richness and NH4-N was negative. The content of NO3-N and NH4-N explained almost 20% of the total variability of diatom community. Unlike our expectations, we calculated a negative correlation between the diversity of macroinvertebrates and diatoms, which is probably a consequence of different responses to environmental conditions.

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.

Cymbopleura natellia – a new species from Transbaikal area (Russia, Siberia) described on the basis of molecular and morphological investigation

A new cymbelloid diatom species from the genus Cymbopleura (Krammer) Krammer is described on the basis of molecular and morphological investigations. Cymbopleura natellia Glushchenko, Kulikovskiy &amp; Kociolek, sp. nov. is, on the basis of results with molecular data, close to C. naviculiformis (Auerswald ex Heiberg) Krammer. The two species differ both by molecular distance and morphological features. Morphologically, C. natelliasp. nov. is compared with several other species in the genus. This work is a pioneer investigation of cymbelloid taxa using molecular tool from Transbaikal area.