Expanding the biogeographical range of the seagrass Posidonia oceanica: the discovery of meadows at Yer Island, the Sea of Marmara, Türkiye

**Expanding the biogeographical range of the seagrass Posidonia oceanica: the discovery of meadows at Yer Island, the Sea of Marmara, Türkiye**

Rıdvan Kaan Gürses, Orhun Hisli, Nisan Aydaş, Nehir Eryılmaz, Sare Sena Türk, Zeynep Gülenç

ORCID IDs: R.K.G. 0000-0001-5951-2308; O.H. 0000- 0002-9102-4125; N.A. 0009-0001-9811-8829; N.E. 0009-0001-5574-431X; S.S.T. 0000-0002-6822-8621; Z.G. 0009-0000-7879-3934

Turkish Marine Research Foundation (TUDAV), P.O. Box: 10, Beykoz, Istanbul, TÜRKİYE
Institute of Graduate Studies in Sciences, İstanbul University, 34116, Fatih, Istanbul, TÜRKİYE
Faculty of Aquatic Sciences, Istanbul University, Onaltı Mart Şehitleri Cad. No: 2, 34134, Fatih, Istanbul, TÜRKİYE
Department of Biological Sciences, Middle East Technical University, Dumlupınar Blv. No: 1 Üniversiteler Mah. 06800 Çankaya, Ankara, TÜRKİYE

Abstract

Posidonia oceanica is a key ecosystem engineer in the Mediterranean, playing a crucial role in maintaining biodiversity, enhancing habitat complexity, stabilising coastal environments, and contributing to carbon sequestration. The present study reports the discovery and spatial delineation of a previously unrecorded P. oceanica population on the coast of Yer Island, which is relatively smaller than other Marmara Islands. Through detailed georeferenced mapping and spatial analysis, we identified 37 discrete seagrass patches, covering a total area of 0.64 ha. These findings extend the known biogeographical range of P. oceanica and highlight the need for further research and conservation measures to protect these vulnerable habitats from ongoing anthropogenic impacts.

Keywords: Posidonia oceanica, Sea of Marmara, Yer Island, biogeographical range, seagrass meadow

Pages: 37-47

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