Temporal occurrence of Ceratium furcoides (Dinophyceae: Ceratiaceae) during an extreme drought season in Pernambuco state, Northeast Brazil

Ceratium furcoides is an invasive species that has caused ecological imbalance in several reservoirs in Brazil. This study investigates the main factors that may favor the occurrence of Ceratium furcoides blooms in a tropical reservoir from the Northeast Brazil, during an extreme drought season. Samples containing phytoplankton were collected monthly from February to September 2017. Quantitative analysis of C. furcoides was performed and the cell volume was estimated using geometric formulas. Mean biovolume of C. furcoides showed significant differences, ranging from 0.78 mm³ L^-1 to 11.29 mm³ L^-1 reported in March and September, respectively. Environmental parameters presented low oscillation throughout the study, except the conductivity. Significant relationships among the C. furcoides biovolume, water temperature and soluble reactive phosphate were observed. The findings reported here suggest that adverse conditions caused by a drought season did not negatively affect this species.

Key words:
bioinvasion; dinoflagellate blooms; drought season; phytoplankton; reservoirs