A NEW RECORD OF POTENTIALLY ICHTYOTOXIC HAPTOPHYTE SPECIES, PRYMNESIUM PARVUM F. PATELLIFERUM, IN THE SEA OF MARMARA DURING A LARGE-SCALE MUCILAGE EVENT IN JUNE 2021

Abstract

A non-calcifying haptophyte species, Prymnesium parvum f. patelliferum (Green, Hibberd & Pienaar) Larsen, is reported for the first time in the Sea of Marmara from the mucilage event on 11 June 2021. The species was identified with a light microscope and scanning electron microscope. In addition, the 18S rRNA gene was partially sequenced in this study. Amplified gDNA of the expected size was sequenced and analyzed via bioinformatics applications. Results of the analysis vigorously recommended that a 672 bp PCR product was component of a small subunit ribosomal RNA gene sequence. The isolate was named MEUE1, and the partial 18S rRNA sequence of MEUE1 was submitted to the NCBI database (accession number OQ740296). Sequence analysis of isolated culture also verified that it was P. parvum f. patelliferum. The species became dominant in a flask that was saturated with sodium bicarbonate to have a basic pH of 8. Although this pH is close to the pH of the culture medium (7-7.5) before the addition of bicarbonate, all the other species died in this flask, which could be possibly related to toxin production of the species under high pH. It appears that P. parvum f. patelliferum was introduced to the Marmara Sea, similar to some lakes, ponds, and coastal areas with brackish or freshwater character in/around the Mediterranean Sea. Ichtyotoxicity of prymnesin, produced by this haptophyte, is a risk for fishery and mariculture activities performed in this enclosed sea.