NEW RECORDS AND RARE TAXA FOR THE FRESHWATER EPILITHIC DIATOMS OF COTE DIVOIRE

The aim of the present study was to contribute to knowledge of the freshwater epilithic diatoms flora of Cote dIvoire. Diatoms were sampled in February and July 2012 on glass slides previously immersed during a period of 30 days at ten stations.The species composition of new and rare taxa was compiled, accompanied by illustrations. Forty two taxa distributed among 16 genera, 8 families and 5 orders were recorded in the temporal survey.Based on species occurrence frequency, 32 rare, 2 occasional, and 8 common species were registered. According to geographic distribution, taxa recorded were mostly cosmopolitan (47.72%) and tropical (43.18%), while 9.09% were endemic.Taking into account their affinity towards pH, 3 classes of diatoms : acidophilic taxa (35.47%), indifferent taxa (59.52%) and alkaliphilic taxa (4.76%)were found in the Me River.

Kelkit Çayı (Tokat) Epilitik Diyatomeleri

In this study, monthly variations of epilithic diatoms in Kelkit Creek (Tokat) were studied from stone samples taken from two stations between March - December 2018: one station below the settlement area and the other one below agricultural areas. During this study, 18 taxa which belong to epilithic diatoms were recorded. Cymbella (3 taxa) and Nitzschia (3 taxa) were the diatoms mostly represented by the taxa, and Ulnaria ulna had the highest relative density recorded in both stations throughout the months. Sorensen Similarity Index was calculated as %56.41 between the two station diatoms. Also, temperature and dissolved oxygen measurements were done on the water samples taken from the stations. The measured variables were confirmed to make positive effects on the growth of diatoms in epiliton. Relative densities of the types of diatoms that were found in the epilithic flora were determined. In hand according to the results, the lowest relative density was recorded as 4.76 in march (Cymbella affinis) at Station 1 and 2.83 in march (Lindavia glomerata) at Station 2. Considering the highest relative density values, Navicula radiosa and Ulnaria ulna species were determined in december (13.56) at Station 1 and in march (9.43) for Ulnaria ulna at Station 2.

Geographic distribution of epilithic diatoms (Bacillariophyceae) in Antarctic lakes, South Shetland Islands, Maritime Antarctica Region

Organisms adapt to the environment by establishing themselves in suitable locations. Adaptation to the harsh Antarctic environment is no different. In this work the communities of epilithic diatoms in ice-free areas of water systems of five Antarctic islands are studied. The samples were oxidized, and permanent sheets were later prepared for analysis of the material. They were examined using an optical microscope and mounted on stubs for identification of the taxon in an electron microscope. Fifty-nine species distributed in 28 genera were collected. Only four species were observed in all study areas. Deception Island had unique species in comparison with those on other islands. Knowing the diatom community is a first step in understanding the systems that they inhabit. The polar environment is challenging due to the difficulty of sampling and low diversity and abundance.

Benthic Diatom Communities in Korean Estuaries: Species Appearances in Relation to Environmental Variables

In the Korean Peninsula’s southern estuaries, the distributive characteristics of epilithic diatoms and the important environmental factors predicting species occurrence were examined. The collection of diatoms and measurements of water quality and land-use were performed every May between 2009 and 2016, with no influence from the Asian monsoon and snow. Throughout the study, 564 diatoms were classified with first and second dominant species of Nitzschia inconspicua and N. perminuta. Based on diatom appearance and standing crops, the 512 sampling stations were divided into four groups by cluster analysis, and two regions, namely the West and East Sea. Geographically, G1, G2, G3, and G4 were located in the East Sea, Southeast Sea, West Sea, and Southwest Sea, respectively. Canonical correspondence analysis (CCA) results indicated that environmental factors, such as turbidity, electric conductivity (EC), and total phosphorus (TP), significantly influenced the distribution of epilithic diatoms. A random forest model showed that major environmental factors influencing the diatom species appearance included EC, salinity, turbidity, and total nitrogen. This study demonstrated that the spatial distribution of epilithic diatoms in the southern estuaries of the Korean Peninsula was determined by several factors, including a geographically higher tidal current-driven turbidity increase and higher industrial or anthropogenic nutrient-loading.

Epilithic diatom flora in Cali River hydrographical basin, Colombia

This research aimed to study the composition of epilithic diatom flora found in samples collected in Cali River hydrographical basin, Colombia. Quarterly excursions (March, June, September and December of 2012 and March of 2013) were performed in six sampling sites to collect samples for identification of diatom organisms (Class Bacillariophyceae). The results indicated the occurrence of 82 taxa distributed in 26 families and 38 genera. 32 of these are new occurrences in Colombia. The most representative families were Gomphonemataceae, Naviculaceae and Bacillariaceae. The genera richest in species were Navicula, Gomphonema and Nitzschia. Eight species occurred in all sampling sites: Achnanthidium minutissimum, Cocconeis lineata, Cymbella affinis, Gomphonema pumilum var. rigidum, Melosira varians, Navicula symmetrica, Reimeria sinuata and Rhoicosphenia abbreviata. The results indicated 13 species considered dominant and characterize the flora of epilithic diatoms in Cali River hydrographical basin, Colombia.