Sedat Ozan Güreşen

Canakkale Onsekiz Mart Universitesi Tip Fakultesi Hastanesi

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Onur Gönülal

Istanbul University

Aysu Güreşen

Manisa Celal Bayar University

Yelda Aktan

Istanbul University

BÖ

Bayram Öztürk

Istanbul University

Mİ

Melek İşinibilir Okyar

Istanbul University

İÖ

İdil Öz

Çanakkale Onsekiz Mart Üniversitesi

Gérard Pergent

Centre National de la Recherche Scientifique

Esin Yüksel Durmaz

Esra Billur Balcıoğlu

Istanbul University

Onur Gönülal

Istanbul University

Cooperative Institutions

Istanbul University

Akdeniz University

Institut de Ciències del Mar

Marine Research Foundation

University of Potsdam

Sivas State Hospital

Birds Canada

Çanakkale Onsekiz Mart Üniversitesi

Centre National de la Recherche Scientifique

Université de Corse Pascal Paoli

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Abundance and composition of marine litter around Gökçeada Island (Northern Aegean Sea)

Aquatic Ecosystem Health & Management (2016)

Onur Gönülal İdil Öz Sedat Ozan Güreşen Bayram Öztürk

Marine debris are frequently studied on beaches and occasionally in coastal waters, but links between these two environments have rarely been studied. Litter items were collected by hand in the Gökçeada beaches supralittoral zone, consisting of sandy or rocky beaches, and collected from subtidal areas between 50–450 m depth range on the continental shelf with bottom trawling. Collected litter were sorted and categorized by type, usage and origin. On the beaches, litter density varied from 0.1 to 22.1 items per 100 m2. Plastic materials dominated the composition of waste materials (59%) followed by soft plastic, nylon (11.5%). Eight percent of litter was of foreign in origin coming from two countries (Greece and Bulgaria). Offshore, during 32 hauls only 12 items were collected, and the number of debris ranged from 0 to 1.6 items km−2. Gökçeada Island should be further monitored in order to develop regional marine litter management solutions.

Marine debris

Supralittoral zone

Litter

Bottom trawling

Plage

10.1080/14634988.2016.1257898

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Citations (14)

The First Record of Geryonia proboscidalis (Forskål, 1775), (Cnidaria: Hydrozoa) on the Coasts of Gökçeada, the Aegean Sea, Turkey

AQUATIC SCIENCES AND ENGINEERING (2021)

Melek İşinibilir Okyar Esin Yüksel Durmaz Sedat Ozan Güreşen

The present study represents the first record of Hydrozoan medusae Geryonia proboscidalis off of Gökçeada island in June 2021. Although this species is found in the Mediterranean, it is the first record specifically in the coastal areas of Gökçeada island. Holidaymakers are extremely irritated by the sting of Geryonia proboscidalis, especially with its sudden accumulation in the coastal areas of Gökçeada island.

Hydrozoa

Hydroid (botany)

Scyphozoa

10.26650/ase2021962514

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Citations (2)

Temporal and Bathymetric Variation of Epiphytic Microalgae on Posidonia oceanica (L.) Delile Leaves in Gökçeada (North Aegean, Turkey)

Turkish Journal of Fisheries and Aquatic Sciences (2020)

Aysu Güreşen Sedat Ozan Güreşen Yelda Aktan

Epiphytic microalgae attached to Posidonia oceanica leaves play a significant role through primary production, nutrient cycling and trophic fluxes in benthic ecosystems. Due to their sensitivity, epiphytic microalgae respond to environmental alterations more quickly than their host. The aim of this study is therefore to evaluate the ecological quality in Gökçeada Underwater Park (North Aegean) using epiphytic microalgal composition and abundance. In this respect, P. oceanica shoots are collected at 6m, 15m and 28m in May, July, October 2009 and January 2010 to estimate the microalgal composition and abundance. Also, P. oceanica descriptors and physico-chemical parameters in the water column of the meadow lower limit are measured. Leaf surface improvement through greater depths, have provided a convenient substratum for epiphytic colonization. A total of 56 taxa belonging to epiphytic microalgae are composed of Bacillariophyceae (91%), Cyanophyceae (7%) and Dinophyceae (2%). Temporal and bathymetric dynamics of the epiphytic community structure and abundance depend on the environmental parameters; such as leaf surface, nutrients and turbidity. Also, a mucilage phenomenon, resulted in a low diversity due to the dominancy of filamentous cyanobacteria. Necessary data is supplied for a less evaluated region affected by agricultural activities and urbanization in the recent years.

Posidonia oceanica

Epiphyte

10.4194/1303-2712-v20_10_02

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Citations (4)

Evaluating the coastal ecosystem status of two Western and Eastern Mediterranean islands using the seagrass Posidonia oceanica

Ecological Indicators (2019)

Aysu Güreşen Gérard Pergent Sedat Ozan Güreşen Yelda Aktan

Posidonia oceanica

Mediterranean Basin

Ecological indicator

Water Framework Directive

Marine ecosystem

10.1016/j.ecolind.2019.105734

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Citations (8)

Comparison and origins of polycyclic aromatic hydrocarbons (PAHs) in the entrance and the exit of the Turkish Straits System (TSS)

Marine Pollution Bulletin (2018)

Esra Billur Balcıoğlu Onur Gönülal Sedat Ozan Güreşen Abdullah Aksu Bayram Öztürk

Black Sea

10.1016/j.marpolbul.2018.08.066

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Citations (19)

A catalogue of the marine species: Gokceada Marine Museum

DOAJ (DOAJ: Directory of Open Access Journals) (2017)

Onur Gönülal Sedat Ozan Güreşen

Marine research

Marine species

Source

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Citations (1)

New records of pelagic fauna from the Turkish waters

TURKISH JOURNAL OF ZOOLOGY (2018)

Sedat Ozan Güreşen Onur Gönülal

In this work, three pelagic species have been recorded in the Northern Aegean Sea. The species were collected from depths between 500 and 800 m from 5 stations in summer 2016. While Euphausia krohnii is first recorded from the Turkish coast of the Aegean Sea, Allosergestes sargassi and Flaccisagitta hexaptera are reported for the first time from the Turkish seas. The results of the current study will contribute to the knowledge on the deep-water pelagic fauna of the Northern Aegean Sea.

10.3906/zoo-1705-64

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Citations (0)

Combined synthetic and biotic indices of Posidonia oceanica to qualify the status of coastal ecosystems in the North Aegean

Ecological Indicators (2020)

Aysu Güreşen Sedat Ozan Güreşen Yelda Aktan

Mediterranean seagrass Posidonia oceanica is used as a common biological indicator in the monitoring programmes of the Water Framework Directive (WFD) due to its structural and functional features providing information about the status of coastal ecosystems. In this respect synthetic seascape ecological indices using P. oceanica: the Conservation Index (CI), the Substitution Index (SI), the Phase Shift Index (PSI) and the Patchiness Index (PI) provide supplementary data on the meadow status and on the pressures affecting the meadows besides evaluating the water quality. However, these indices have not been adopted by the European Union Water Framework Directive (WFD). This survey is, therefore focused on the qualification of the status of coastal ecosystems in the North Aegean Sea with an integrated approach based on the synthetic (the CI, the SI, the PSI and the PI) and biotic indices (Biotic Index of Posidonia and Ecosystem Based Quality Index) of P. oceanica. Measurements of several parameters are conducted in four sites (2 natural, 2 anthropized) in Gökçeada (North Aegean). The preliminary results confirm the efficiency of synthetic and biotic indices to evaluate the ecosystem status in relation with anthropogenic pressures at a local extent. The mean value of the CI corresponds to a "good" status, while the value of the BiPo Index corresponds to a "moderate" and the value of the EBQI corresponds to a "poor" status for Gökçeada. Maximum values of the synthetic and biotic indices are recorded in natural sites. On the contrary, minimum values are recorded in anthropized sites close to marine-based activities. In addition, an early stage of a phase shift (PSI < 0.25) is recorded due to a low substitution with Caulerpa cylindracea spread around fragmented meadows and dead matte areas. Also, relations (p < 0.05) between the scores of the Land Uses Simplified Index (LUSI) and combined synthetic and biotic indices of P. oceanica, verified the negative impacts of anthropogenic pressures on the benthic ecosystems of the North Aegean Sea where the data is deficient.

Posidonia oceanica

Biotic index

Water Framework Directive

Marine ecosystem

10.1016/j.ecolind.2020.106149

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Citations (3)

A list of macrofauna on the continental shelf of Gökçeada Island (northern Aegean Sea) with a new record (Gryphus vitreus Born, 1778) (Brachiopoda, Rhynchonellata) for the Turkish seas

Journal of Black Sea / Mediterranean Environment (2014)

Onur Gönülal Sedat Ozan Güreşen

Abstract Long-term sampling (1974-2013) of macro fauna of the Gokceada Island (northern Aegean Sea) provided qualitative information on many taxa including Porifera, Cnidaria Mollusca, Arthropoda, Brachiopoda, Bryozoa, Spinculida, Echinodermata, Chordata. Gryphus vitreus (Brachiopoda) and Funiculina quadrangularis (Pallas, 1766) are the first records for the Turkish seas and the Aegean coast of Turkey, respectively. The present paper aims to describe macrofauna occurring on the continental shelf of Gokceada Island. This checklist yes,was based mainly on review of the literature published since 1974 and studies conducted at Gokceada Marine Research Department in 2007-2013. The present paper also reports a total of 10 alien species along the continental shelf of Gokceada Island. Calinectes sapidus Rathbun, 1896 is one of the alien species of commercial importance.

Bryozoa

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Citations (7)