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Öğe Alabalık yetiştiriciliğinin Biga yarımadasındaki (Karamenderes ve Kocabaş çayları) akarsu balıklarının bazı biyolojik özellikleri ve trofik ilişkileri üzerine etkisi(Çanakkale Onsekiz Mart Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2018) Ertürk Gürkan, Selin; Yalçın Özdilek, ŞükranBu çalışmada alabalık yetiştiriciliğinin, tatlısu balıklarının çeşitlilik ve bollukları, beslenme özellikleri ve komünite ilişkileri üzerindeki olası etkilerinin değerlendirilmesi amaçlanmıştır. Bu kapsamda; üzerinde alabalık tesisi bulunan Çanakkale'deki iki akarsu sisteminde (Karamenderes ve Kocabaş) bir yıl boyunca aylık olarak örnekleme yapılmıştır. Balık ve ortam örnekleri, her iki akarsuda belirlenen 2 istasyondan (alabalık tesisisinin üst ve altında belirlenen iki istasyon) ve balık çiftliği etkisinin olmadığı bir kolundan seçilmiş kontrol istasyonlarından gerekli etik izin alınarak elektroşoker ve çeşitli av araçları ile toplanmıştır. Örnekler Ağustos 2015 ile Temmuz 2016 arasında aylık olarak toplanmıştır. Çalışma sonuçları yetiştiricilik ünitesinden etkilendiği düşünülen istasyonlardan yakalanan balıkların çeşitliliklerini etkilemediği; ancak bolluklarında artış meydana getirdiğini göstermiştir. Beslenme özellikleri sindirim kanalı içeriği ve kararlı izotop analizleriyle değerlendirilmiştir. Türlerin kaynak sıkıntısı çektiklerinde besin tercihlerinde değişiklikler meydana geldiği ve özellikle Salmo sp. ve Phoxinus phoxinus bireylerinin Kocabaş Çayı'nda çiftlik kaynaklı yem ile de beslendikleri belirlenmiştir. Komünite yapısını anlamaya yönelik yapılan niş genişliği ve niş çakışmaları tespiti ile yetiştiricilik ünitesinin özellikle altında bulunan istasyonlarda besin bolluğuna bağlı olarak niş çakışmalarının daha fazla olduğu belirlenmiştir. Bu çalışma ile, yetiştiricilik yapılan bölgelerdeki doğal balık populasyonlarının, yetiştiricilik faaliyetlerinden bolluk, besin tercihleri ve türler arası etkileşimler açısından etkilendiği gözlenmiştir. Akarsular üzerine kurulan yetiştiricilik işletmelerinde balık, yem ve atık geçişini sınırlayan kapalı sistemler tasarlanması yerinde olacaktır.Öğe Assessing spinel zinc ferrite nanoparticles in aquatic ecosystems: Toxic threat or beneficial detoxifier for aquatic life?(Elsevier B.V., 2025) Ertürk Gürkan, Selin; Gürkan, Mert; Yanik, Ece Büşra; Kutlu, Elif; Saritunç, Volkan; Güneş, Berkay; İbiş, Ezgi CanThe effectiveness of magnetic nanoparticles in removing pollutants during water treatment is well established, but their introduction into aquatic ecosystems raises significant toxicity concerns. This study investigates the histological and physiological effects of zinc ferrite magnetic nanoparticles (ZnFe2O4?MNPs) on the Mediterranean mussel (Mytilus galloprovincialis) and examines the impact of concurrent exposure to these nanoparticles and the insecticide thiomethoxam (TMX). Mussels were exposed to nominal concentrations of ZnFe2O4?MNPs (1, 10, 100 mg/L) both individually and with TMX. Physiological assessments included measuring antioxidant enzyme levels (superoxide dismutase, catalase, glutathione S-transferase) and oxidative stress markers (malondialdehyde). Results showed that ZnFe2O4?MNPs increased antioxidant activity but also caused dose-dependent pathological changes. In contrast, combined exposure with TMX significantly (p < 0.05) reduced antioxidant defenses, indicated by lower superoxide dismutase (SOD) levels and higher malondialdehyde (MDA) concentrations, suggesting oxidative stress and potential cellular damage. These findings highlight the need for comprehensive toxicity assessments of nanoparticles in aquatic environments and advocate for their complete removal from water sources post-treatment. Further research is crucial to define the toxicity profiles of spinel ferrites to ensure their safe application in environmental remediation. © 2024 Elsevier B.V.Öğe Assessments of antioxidant capacities of Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) from the different stations of Dardenelles Strait (Turkey)(Universitatea din Oradea, 2020) Ertürk Gürkan, SelinThe use of biomarkers to determine the negative effects of chemical contaminations on the aquatic organisms is an important instrument for identifying and evaluating chemical pollution on environment. In this study, it was aimed to determine the effects on the Mediterranean mussel (Mytilus galloprovincialis) living in a coastline (Dardanelles Strait, Turkey), under the influence of urbanization, active ship / ferryboat traffic and agricultural activities using superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) antioxidant enzymes. M. galloprovincialis samples collected in October 2017 from 7 regions thought to be under the influence of different pollutants were used. The lowest SOD values measured (4.3-9.5) in the samples collected from Kepez station where the port is located and the highest values (14.1-43.3) were found in the samples of Kilitbahir station where ferry traffic is heavy. CAT and GSH-Px levels were higher in Güzelyalı (CAT: 81.6-96.4 and GSH-Px: 4.3-9.3) and Dardanos (CAT: 64-95.5 and GSH-Px: 6.7-7.9) stations where tourism was effective and Kepez station (CAT: 89.3-99 and GSH-Px: 6.2-7.2) where the port was located. According to statistical analysis, there is no significant difference in enzyme levels between stations. It is considered useful to investigate the seasonal variations of these levels in order to understand biomarker responses to pollutants and to assess changes between pollutant exposure and environmental conditions. © Biharean Biologist, Oradea, Romania, 2020Öğe Comparative Toxicity of Alpha and Gamma Iron Oxide Nanoparticles in Rainbow Trout: Histopathology, Hematology, Accumulation, and Oxidative Stress(Springer, 2021) Gürkan, Mert; Ertürk Gürkan, Selin; Yılmaz, Sevdan; Ateş, MehmetIn this study, alpha and gamma iron oxide nanoparticles, characterizations, toxic effects after being exposed to rainbow trout (Oncorhynchus mykiss) at 0, 1, 10 and 25 mg/L concentrations for 10 days, and then 10-day recovery period without any nanoparticle exposure were examined for histopathological (kidney, liver and gill), hematological, iron accumulation and potential for oxidative stress (TBARS and GSH). Histopathological damages significant at the exposure of increasing concentrations of both nanoparticles (increase in melanomacrophage aggregations, epithelial tissue deformations, cytoplasmic vacuolizations, fatty changes, necrosis, pyknosis, hyperplasia, hypertrophy, lamellar fusions, capillary dilatations). Gamma nanoparticles were determined to accumulate more than the alpha nanoparticles. The most Fe accumulation was detected in the liver. The findings of oxidative stress parameters showed that both nanoparticles have the potential to generate oxidative stress. It was concluded that the exposure of alpha and gamma nanoparticles at specified concentrations and durations had a toxic effect on rainbow trout and the toxicity of these nanoparticles was similar.Öğe Evaluation of the role of enzyme activities in the silvering process of European eels (Anguilla anguilla)(Springer, 2023) Ertürk Gürkan, Selin; Mestav, Burcu; Yalçın Özdilek, ŞükranThis study was carried out to determine the relationships between various morphological parameters, body condition data, and digestive and stress enzyme activities due to silvering in European eel (Anguilla anguilla L.) collected from four locations in Turkey. The yellow and silver eels were caught from Asi River, Köyceğiz, Güllük Bay, and Bafa Lake in November–December 2020. Total body length, eye diameter, and pectoral fin length were measured as morphological parameters. In addition, body fat percentage, gonado-somatic index, and Fulton’s condition factor were calculated, and also weight was assayed as body condition data. The variations of α-amylase, lipase, trypsin, and pepsin enzymes, and superoxide dismutase, catalase, and glutathione peroxidase enzyme activities were measured. The results supported the differences of yellow and silver stage samples in terms of both morphological and physiological parameters and also showed that the digestive and stress enzyme activities of the silver and yellow stage samples were significantly different (p ≤ 0.05). We think this study will make a physiological contribution in terms of digestive and stress enzyme levels to better understand and elaborate the silvering stage of eels.
