Russian Journal of Marine Biology

Monitoring of the Black Sea algal viruses in Sevastopol bays and Crimean water areas has been carried out since 2002. Based on the methods that were developed and patented by the author, more than 200 strains of algal viruses of five species of microalgae that are new to science were isolated: TvV (Tetraselmis viridis virus), DvV (Dunaliella viridis virus), PtV (Phaeodactylum tricornutum virus), PpV (Prorocentrum pusillum virus) and IgV (Isochrysis galbana virus). For the first time in the Black Sea, the Emiliania huxleyi virus (EhV) of microalgae was isolated. Using the method of electron microscopy, the Black Sea algal viruses were identified as icosahedral virions with respective sizes of 56–60, 45–48, 50–53, 88–92, and 128–132 nm, for the TvV, PtV, DvV, PpV and IgV viruses. The EhV size, as determined by the method of filtration, was within the range of 50–200 nm. In the IgV and EhV viruses we revealed a viral envelope. Based on their characters the isolated algal viruses were attributed to the Phycodnaeviridae. The maximum number of algal viruses was observed in the spring and autumn seasons, which is typical for their host phytoplankton species. The Black Sea algal viruses, TvV, PpV, IgV, and EhV, displayed no strict species specificity and have a wide range of available hosts.