Comparative analysis in the structure and taxonomic diversity of benthic diatom (Bacillariophyta) from two estuarines of SW Crimea: River Chernaya (Inkerman is heavy polluted area of Sevastopol Bay) and River Belbek (rather unpolluted open shore) was carried out. At Belbek area 275 sp. and ssp. were found and 116 ones – at Inkerman; the total number of diatoms registered altogether is set to 303 sp. and ssp. Based on abundance calculation results and using cluster and MDS analysis, 2 groups of stations were distinguished. First group consisted of Inkerman stations (6), whereas second group of stations (10) corresponded to Belbek area. These results bear out that the certain diatom complex is formed within each of the estuarine area and characterized by well-defined taxonomic structure. Among 21 most dominant species (61 % of total abundance at Belbek and 92 % – at Inkerman), 4 species are typically freshwater forms and 1 is ubiquitous. The most common 16 species in each of the estuaries are typically marine and brackish-water forms consisted of about 47 % (in Belbek) and 79 % (in Inkerman) of total assemlage density. Based on the updated inventory of Black Sea benthic diatoms (1093 sp. and ssp.), the indices of taxonomical distinctness were calculated. These values are close to the expected mode, corresponding to structure of whole Black Sea benthic diatoms inventory (AvTD = 83.5; VarTD = 306). Phylogenetic structure of Inkerman diatom assemblage was characterized to enclose the greater share of mono- and oligo-species branches, in comparison with the larger part of poly-species branches, wide variability and unevenness structure of diatom community at Belbek.
Keywords: benthic diatoms, Bacillariophyta, Black Sea, assemblage structure, taxonomic distinctness
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