The dominance of invasive algae Raphidiopsis raciborskii in lowland reservoirs in Bulgaria

Kostadin Dochin

Abstract: The aim of this publication is to warn for the presence, among the dominant algae, of blooms of the invasive Raphidiopsis raciborskii in six lowland reservoirs in Southeastern Bulgaria and for its increasing distribution in the country. Cyanoprokaryotic R. raciborskii has been broadly studied for toxicity and its invasive potential, which can seriously affect the health of the organisms and the environment they inhabit. Its increasing geographical distribution makes it a cosmopolitan species.The expansion of the range of R. raciborskii may be a result of the physiological plasticity, as well as the existence of different ecological types. It is known that this alga tolerates major changes in temperature and light conditions through a variety of life strategies, and the species abundance in the communities, where R. raciborskii is invasive, can be seriously disturbed. In the studied reservoirs, 34 Cyanoprokaryotic taxa is identified, 20 of which are dominant and at least 18 are known to be potential producers of cyanotoxins. Raphidiopsis raciborskii is among the most abundant algae in the studied reservoirs and in Troyan Reservoir, its blooms continue throughout the summer of 2019, with a share of total the algae biomass reaching 89.3%.

Keywords: blooms; cyanotoxins; dominant algae; invasive Raphidiopsis raciborskii; reservoirs

Date published: 2022-02-16