The use of metabarcoding approach to determine the diatom composition of mucilage in the sea of Marmara

Marmara Basin has been adversely affected by industrial activities in the recent years. As a result of the rising industrial activities, the occurrence of harmful algal blooms, red-tides and mucilage events have increased in the Sea of Marmara. Mucilage problem has reached peak levels recently due to industrial wastes and the water discharged from wastewater treatment plants without biological treatment. Negative effects of industrial waste and untreated wastewater on the marine ecosystem resulted in a decrease in water quality and became a serious threat to biodiversity. To act against the problems arising in the marine ecosystem, bio-monitoring studies have become tremendously important to ensure the proper management of integrated water resources and to maintain sustainable marine ecosystem services. As a part of bio-monitoring studies, DNA metabarcoding applications based on next-generation DNA sequencing technologies offer reliable and effective approaches in the detection of microorganisms and plankton groups. Such technologies play an important role in the monitoring of the harmful effects of mucilage events and can help as early warning systems for the health of the marine ecosystems. In this thesis, I will study the effects of excessive plankton and mucilage increase, and the impacts of mucilage on water quality by examining diatom genera. According to our results, Skeletonema and Nitzschia diatom genera are the dominant organism groups for 10 species hits; however, Guinardia and Pseudo-nitzschia are the dominant ones for 100 species hits. These genera might have a potential effect on the mucilage formation.