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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

Eker-Develi, Elif | Tekdal, Dilek

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 c...

Diatoms isolated from the marine mucilage in the Sea of Marmara in 2021

Tekdal Dilek | Eker-Develi Elif

This study presents five new records of diatoms based on light and electron microscopy results from the surface water of the Sea of Marmara coast during a large-scale mucilage event in 2021. Three of these diatoms are small nanoplanktic; Cyclotella cryptica, Nitzschia amabilis, Thalassiosira pseudonana, and the two of them are larger diatoms; Conticribra weissflogii and Entomoneis cf. pusilla. In addition, a species frequently seen in mucilage samples in the Adriatic Sea and the the Sea of Marmara, Cylindrotheca closterium, was also isolated and described. The chloroplast rbcL region, SSU, and 18S rDNA of C. closterium, C. cryptica and N. amabilis were amplified using primers in other previous studies. The rbcL, SSU, and 18S rDNA partial sequences were submitted to the NCBI database. Molecular phylogeny (based on 18S, rbcL, and SSU V4 DNA sequences) confirmed that the analysed species were those identified by SEM images.

Moringa oleifera Lam. as a bioflocculant for harvesting microalgae grown on agricultural wastewaters for feed production

Eker-Develi, Elif | Tekdal, Dilek

Harvesting impacts the costs of microalgae production and affects the characteristics of the final product. Therefore, this study evaluated Moringa oleifera seed powder (MP) as a bioflocculant compared to two chemicals (Aluminium Sulphate—AS and Iron Chloride—IC) to harvest a mixed microalgae culture (Chlorella vulgaris and Desmodesmus sp.) grown on digestate. MP was the most stable flocculant but resulted in the lowest harvesting efficiency of 75%, compared to 94% for AS and 100% for IC. Process parameters such as pH, duration of mixing, grinding method for obtaining the powder, and granulometry had no significant effect on the harvesting efficiency of MP, reinforcing that this is a robust flocculant. The use of a water extraction step increased the harvesting efficiency of MP to 91%, albeit with the need for a higher dosage of flocculant. The algae harvested with MP complied with maximum tolerable levels for swine, cattle, and poultry regarding most trace elements. Nevertheless, all algae samples had Fe and Al contents above the recommended levels, possibly due to the entrapment of metal‐rich digestate particles. Therefore, more attention should be paid to the final composition of algae when proposing flocculation as a harvesting method for feed production.

A gene-rich and compact chloroplast genome of the green alga Nephroselmis pyriformis (N.Carter) Ettl 1982 from the shores of Mersin (Eastern Mediterranean Sea).

Eker-Develi, Elif | Tekdal, Dilek

We report the complete chloroplast genome of the MED1 strain of Nephroselmis pyriformis from the Eastern Mediterranean Sea. At 111,026 bp, this genome is smaller and more compact than those of Nephroselmis olivacea and Nephroselmis astigmatica, and in contrast to the latter taxa, its inverted repeat contains no complete protein-coding genes. It encodes 3 rRNAs, 33 tRNAs and 94 proteins. Maximum likelihood analysis of a concatenated set of chloroplast genes from green algae belonging to deep-diverging lineages positioned the three Nephroselmis species in a strongly supported clade in which N. pyriformis is sister to N. astigmatica.