Fatores determinantes da ocorrência e biomassa do dinoflagelado invasor Ceratium furcoides (Levander) Langhans 1995 em ambientes lóticos e lênticos neotropicais

Abstract

Ceratium furcoides (Levander) Langhans 1995 is a planktonic dinoflagellate that has gained prominence in recent decades for invading freshwater bodies in South America. With this work, we aimed to analyze the occurrence of C. furcoides in lotic and lentic environments in Northeast Brazil, as well as to understand which environmental factors may be related to the variation of its biomass in these environments. For this, 14 rivers and 38 reservoirs distributed in six river basins, located in the State of Paraíba, were sampled, where the collections were carried out quarterly over a period of two years (between February 2020 and November 2021). In the reservoirs, the samples were obtained in a single location, close to the water collection for public supply, in the subsurface of the water column. While for most rivers, samples were obtained from a single location, on the bank, in the subsurface of the water column. However, depending on the size of the source, collections were carried out in more than one location. For this data set, aspects related to the occurrence, biomass and relationship with physical, chemical and biological variables (cyanobacterial biomass) of the environments were analyzed. The results showed 18 new records of C. furcoides, four in rivers and 14 in reservoirs, covering three watersheds. These new records were made considering the results already published in a previous work. The increase in the number of records highlights the continued expansion of C. furcoides in South America, and the greater dispersion and biomass in reservoirs reveals the greater invasiveness of these environments, when compared to lotic environments. Despite this, C. furcoides remained with low relative biomass both in rivers and reservoirs (between 0.002 and 1.06% respectively). Furthermore, the environmental variables tested were not explanatory for its biomass. Therefore, the results of this work draw attention mainly to the dispersive advance of this species and to the high susceptibility of reservoirs to its expansion, requiring constant monitoring of these areas, since this species has morphophysiological characteristics that can favor the formation of blooms in future scenarios.