Comparative study of benthic diatom community using 18S rDNA metabarcoding and light microscopy in the Bosphorus, Turkey

Diatoms are one of the major algal groups having an important role in aquatic systems which they constitute main primary production with dinoflagellates coastal regions, and can contribute to photosynthesis at great rates. There had been intense effort reveal diatom community light microscopy (LM) scanning electron (SEM), on other hand, DNA barcoding techniques interest understand microbiome last decades. Barcoding provided rapid response targeted organisms introduced many new species. Recently, monocultural molecular studies showed that species could be described accurate reliable results. metabarcoding approaches yielded determine whole available data sample advances next-generation sequencing platforms enable widen application approach various environmental samples. The aim this study was perform a comparative assessment structures Bosphorus Istanbul, Turkey by LM 18S rDNA metabarcoding. Diatom samples were collected brushing from submerged stones 10 cm 2 area taken coast Beykoz Asian part Bosphorus, Istanbul processed for June 2020. To concentrate sample, scrapes biofilm filtered 0.22-micron filter, eDNA extracted filter paper using MN NucleoSpin Soil isolation kit (Macherey-Nagel, Germany) following manufacturer’s protocol profile analyzed targeting V4 region rRNA gene Illumina® MiSeq™. results revealed two classes Bacillariophyceae (91%) Mediophyceae (9%) (Fig. 1). While small-celled Hyalosira delicatula Kützing most abundant taxa 40% abundance it followed Licmophora spp. (33%). 28% sequences not assigned any remained as unidentified, gracilis (Ehrenberg) Grunow (4%), L . flabellata (0.9%) detected lower abundances. Besides, common genera diatoms, Navicula spp., relative 4% another genus Nitzschia represented only N commutata composed 0.5% community. 11 genera, investigation identified 17 belonging 21 4 both methods. Interestingly, small celled easily overlooked presented promising number methods 2). diatoms is research waters there few performed so far first relying Turkey. comparison indicated some significant differences composition. However, here 18 vice-versa confirms poor biodiversity Bosphorus. based sampling station methods, we more stations different seasons supporting biodiversity. scarce areas our comprise genera. Results provide further research, high determined