Evaluation of a dinoflagellate bloom in a perennial endorheic Mediterranean pond

Abstract

This study is the first to describe a dense dinoflagellate bloom from an inland water body in the Maltese Islands. The bloom in the perennial pond at L-Għadira ta’ Sarraflu, in Gozo, Malta was first noted towards the end of April 2020 and was investigated in May 2020. Microscopic analysis indicated a unialgal bloom comprised predominantly of Peridinium cf. cinctum (O.F. Müller) Ehrenberg (Dinoflagellata Dinophyceae Peridiniaceae) at a mean density of ca. 358118 ± 165227 cells mL-1. Five water quality parameters (pH, oxidation-reduction potential, dissolved oxygen concentration, electrical conductivity and temperature) were measured to provide a preliminary assessment against which future studies could compare. The absence of any long-term abiotic data from the pool precludes any definite causes of the bloom from being identified and highlights the necessity of such a programme.