An analysis of the taxonomic diversity of benthic diatoms was carried out for near-shore biotopes of Crimea with different content of trace metals and organic pollutants (PCBs, PAHs, DDTs). Taxonomic distinctness indices such as average taxonomic distinctness, AvTD (Δ+) and variation in taxonomic distinctness, VarTD (Λ+) were used for evaluation of the hierarchical structure of diatom taxocenes of two intact sites (Dvuyakornaya Bay and Cape Fiolent) and two heavily polluted water areas (Sevastopol Bay and Balaklava Bay). The highest similarity of species was revealed between healthy biotopes, in spite of their differences in hydrological and hydrochemical conditions. AvTD values for Dvuyakornaya Bay and Cape Fiolent (Δ+ = and , respectively) were lower in comparison with expected average levels (Δ+ = ) evaluated for the flora of benthic Bacillariophyta (1094 species) registered for the Northern part of the Black Sea (NPBS). | Turkish Journal of Botany Turk J Bot 2019 43 608-618 http botany TÜBİTAK Research Article doi bot-1903-43 Assessment of benthic diatoms taxonomic diversity at coastal biotopes with different anthropogenic impact Crimea the Black Sea Elena L. NEVROVA Alexei N. PETROV Benthos Ecology Department Kovalevsky Institute of Marine Biological Research Russian Academy of Sciences Moscow Russian Federation Received Accepted Published Online Final Version Abstract An analysis of the taxonomic diversity of benthic diatoms was carried out for near-shore biotopes of Crimea with different content of trace metals and organic pollutants PCBs PAHs DDTs . Taxonomic distinctness indices such as average taxonomic distinctness AvTD Δ and variation in taxonomic distinctness VarTD Λ were used for evaluation of the hierarchical structure of diatom taxocenes of two intact sites Dvuyakornaya Bay and Cape Fiolent and two heavily polluted water areas Sevastopol Bay and Balaklava Bay . The highest similarity of species was revealed between healthy biotopes in spite of their differences in hydrological and hydrochemical conditions. AvTD values for Dvuyakornaya Bay and Cape Fiolent Δ and respectively were lower in comparison with expected average levels Δ evaluated for the flora of benthic Bacillariophyta 1094 species registered for the Northern part of the Black Sea NPBS . As established the taxonomic trees of the diatom taxocenes at pristine water areas are characterized by a moderate degree of vertical evenness and high variability of distances between neighboring clusters of species they are mainly formed by polyspecific branches close on the genus level. The AvTD values for diatom taxocenes of the heavily polluted Sevastopol Bay Δ and Balaklava Bay Δ were significantly higher than the corresponding indices for undisturbed biotopes and exceeded the expected average level for the entire list of .
