Comparison of Kızılırmak and Yeşilırmak (Southern Black Sea) Estuarine Ecosystems Based on Macrobenthic Biodiversity and Environmental Variables and New Records for the Macroinvertebrate Fauna of Turkey

Abstract

This study investigates the K & imath;z & imath;l & imath;rmak and Ye & scedil;ilirmak estuarine ecosystems in Turkey, which provide significant freshwater and nutrient inputs to the Samsun Shelf area along the midsouthern Black Sea. The objective was to determine the current ecological status and to detect any significant differences between two estuarine ecosystems (restored-K & imath;z & imath;l & imath;rmak-and natural-Ye & scedil;il & imath;rmak) in terms of macrobenthic invertebrates and environmental variables. Macrobenthic invertebrates were collected with a 500 mu m mesh size kick-net. A total of four samplings, one in each season, were collected during February, May, August, and November of 2017. A total of 90 taxa, mainly oligochaetas and chironomids, were identified, composed of 51 species in K & imath;z & imath;l & imath;rmak and 60 in Ye & scedil;il & imath;rmak. Orthocladius (Orthocladius) dentifer, O. (O.) clarkei, O. (O.) dorenus, O. (O.) wetterenesis, O. (O.) mixtus, and Mystacides longicornis were found to be new records for Turkey. The distribution of macrobenthic invertebrates was compared between season, estuary, grain size and stations. In K & imath;z & imath;l & imath;rmak and Ye & scedil;il & imath;rmak, the region characterized as estuarine was found to be small transitional waters. In K & imath;z & imath;l & imath;rmak, a high similarity was observed among stations, accompanied by relatively low diversity across sampling sites. This phenomenon is thought to be a natural consequence of the reconstruction activities along the river, which have deleteriously affected the ecosystem. The Ye & scedil;il & imath;rmak estuary has a more diverse macrobenthic community and appeared to be better preserved than the K & imath;z & imath;l & imath;rmak area.