Diatoms blooms on the pebble/rock bottom in the upper part of the Ussuri River in February 2013 (a); periphyton diatoms in a side channel of the Olen’ja River in June 2010 (b); metaphyton (mainly Cyanobacteria) in the low part of rivers in the southern East Manchurian Mountains in May 2014 (c); periphyton (mainly Chlorophyta and Cyanobacteria) in the open channel of stream foothills of Sikhote-Alin in June (d) (photo V. Bogatov).