Algal distribution along the maritime model of Komarovka River (Primorsky Territory, Russia)

We studied algal distribution in the Komarovka River, located in the southwest Sikhote-Alin Mountain system (the Sea of Japan, Primorsky Territory, Russia). A total of 412 species, varieties and forms were recorded. Studies of algal taxonomic composition made defining crenal, rhithral (including the subzones of epi-, meta- and hyporhithral) and epipotamal zones of the river possible. During the transition from the crenal to epirhithral zones, which is characterized by significant improvement in watercourse illumination, an abrupt increase in algal taxonomic diversity (approximately 50 taxa per km of the river) was recorded. This indicated the vital role of light in forming species richness of benthic algae in minor rivers. In the transition from hyporhithral to epipotamal zones, the number of phytobenthic species decreased conspicuously. This was due to the decrease of rheophilic algae and to the insignificant number of potamophiles present in the river community. Based on this algal community composition, the crenal zone received the highest Shannon index values, while hyporhitral and epipotamal zones received the lowest. In general the number of algal taxa (D, individual) in the Komarovka River was related to the watershed area of the river (S, km²) by the power function: D = 92.72 S ^0.199;  r² = 0.98.