Yazar "Öztekin, Ayşah" seçeneğine göre listele

Listeleniyor 1 - 10 / 10
  • [ X ]
    Öğe
    A new Alien Fish from the Southern Black Sea (Sinop, Türkiye): Sebastes schlegelii Hilgendorf, 1880 (Scorpaeniformes, Sebastidae)
    (2024) Uygun, Orçin; Öztekin, Hasan Can; Öztekin, Ayşah; Bat, Levent
    Sebastes schlegelii Hilgendorf, 1880 is an Indo-Pacific species with a widespread distribution in the coastal waters of the Far Eastern region. This study represents the first documentation of S. schlegelii off Sinop coast from the Southern Black Sea. The four specimens collected on 28 May 2023 and 18 June 2023 from rocky habitat at a depth of about 6 meters off Sinop coast had a total length range of 226 to 237 mm and weights ranging from 197.57 to 254.98 g. The spread of this species to the southern Black Sea coast is attributed to the transportation of early life stage individuals from the northern coast of the Black Sea to the southern coast via the cyclonic Rim Current.
  • [ X ]
    Öğe
    A review on heavy metal levels in sea cucumbers
    (2020) Bat, Levent; Ahmed, Quratulan; Öztekin, Ayşah; Arıcı, Elif
    Heavy metals can remain in the marine ecosystems for a long time, they may affect biota in the food chain as a result. Sometimes theexistence of xenobiotics causes so great a alter in the ecosystem that a return to earlier, natural conditions is not viable. Human pressureon the sea’s resources is increasing, it affects the health of many organisms, leading to changes in the food chains and influencingaccumulation in the tissues of biota. Sea cucumbers are being used for heavy metal pollution studies. They are preferred with theirmany features such as easy collection from the land, feeding with organic matter, contact with sediment, maintenance in laboratories,obtaining sufficient tissue, consuming some species. This review covers heavy metal studies with sea cucumbers in different seas. Theresults are compared with each other. In addition, the evaluation of the consumed sea cucumber species in terms of human health hasbeen discussed.
  • [ X ]
    Öğe
    Acute Toxicity of Cadmium on Ophelia bicornis Savigny, 1822
    (2019) Bat, Levent; Şahin, Fatih; Öztekin, Ayşah
    Static bioassays to assess acute toxicity of cadmium on Ophelia bicornis were first time conducted. Organisms wereexposed to the different concentrations of cadmium for 24, 48, 72 and 96-hr. The LC50 values for 24, 48, 72 and 96-h with95% confidence limits were estimated by the probit method and were found as 26 (22.8-29.4), 18 (15-22), 12 (9.1-14.4) and7.2 (6.8-7.5) mg/l for Group 1 (15 and 25 mm in length) and 28 (24.6-33.8), 24 (22.4-25.5), 18 (16.1-19) and 8.7 (7.8-9.6)mg/l for Group 2 (26 and 36 mm in length), respectively. Toxicity of Cd was dependent on concentration and exposure time.LC50 increased with increasing the length of organisms. Mortality of O. bicornis was increased by Cd concentration andexposure. Results showed that O. bicornis was sensitive to cadmium.
  • [ X ]
    Öğe
    Analysis of Microplastic in Holothuria leucospilota (Echinodermata-Holothuroidea) and Sediments from Karachi coast, (Northern Arabian Sea)
    (2023) Ahmed, Quratulan; Öztekin, Ayşah; Alı, Qadeer Mohammad; Bat, Levent; Shaikh, Iqra
    Microplastics are found in all aquatic environments, and they can have several negative impacts on marine life. In this study, the distribution of microplastics in the sediment and in the organs (gut, respiratory tree, and tentacles) of sea cucumber (Holothuria leucospilota) collected from Mubarak Village and Cape Monze on the Karachi coast of Pakistan were investigated. The microplastic amount in different organs of H. leucospilota was found as 15.3-40.45 pieces/individual in the gut, 15.45-23.9 pieces/individual in the respiratory tree, 8.9-9.55 pieces/individual in tentacles. The microplastic amount of sediment samples was 57.40-129.35 pieces/kg. Fibers were the dominant microplastic type, up to 99% of all samples. The results of the present study show that the region is contaminated with microplastics both in biota and in sediments.
  • [ X ]
    Öğe
    Assessment in Terms of Human Health Some Heavy Metals Concentrations Determined in Dicentrarchus labrax (Linnaeus, 1758) and Sparus aurata (Linnaeus, 1758) Marketed in Sinop (Turkey)
    (2018) Bat, Levent; Öztekin, Ayşah; Arici, Elif
    Mercury (Hg), cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) levels in European sea bass Dicentrarchus labrax (Linnaeus, 1758) and gilthead sea bream Sparus aurata Linnaeus, 1758 that are commercially sold on the Sinop fish markets were appraised. Selected heavy metals were assayed in edible tissues of the sampled fish, using an Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results are expressed in mg (kg wet wt.) -1 . In both fish species, Cu was detected in higher concentrations, followed by Cu. The means of metal concentrations in D. labrax were 0.030.008 mg (kg wet wt.) -1 for Hg; 0.0090.001 mg (kg wet wt.) -1 for Cd; 0.060.02 mg (kg wet wt.) -1 for Pb; 0.420.09 mg (kg wet wt.) -1 for Cu and 9.23.1 mg (kg wet wt.) -1 for Zn. Whereas the means of metal concentrations in S. aurata were 0.020.006 mg (kg wet wt.) -1 for Hg; 0.010.009 mg (kg wet wt.) -1 for Cd; 0.040.011 mg (kg wet wt.) -1 for Pb; 0.690.11 mg (kg wet wt.) -1 for Cu and 8.52.3 mg (kg wet wt.) -1 for Zn. None of the metals in European sea bass and gilthead sea bream were not above the permissible values.
  • [ X ]
    Öğe
    Deniz stratejisi çerçeve direktifi kapsamında Sinop Sarıkum lagünü deniz çöplerinin durumu: Bir örnek çalışma
    (Sinop Üniversitesi, 2016) Öztekin, Ayşah; Bat, Levent
    Avrupa Birliği (AB) tarafından 2008 yılında yayınlanan Deniz Stratejisi Çerçeve Direktifi (2008/56/EC) (DSÇD), 2020 yılına kadar Üye Devletlerin "İyi Çevre Durumu" (İÇD) sağlamaları veya sürdürmeleri için gerekli önlemleri içermektedir. DSÇD'de belirlenen on bir niteleyici 'tanımlayıcı' doğrultusunda deniz bölgesi veya alt bölgesi düzeyinde İÇD belirlenmektedir ve bulunan 11 tanımlayıcıdan Tanımlayıcı 10 deniz katı atıkları ile ilgilidir. Karadeniz'in sayılı sulak alanlarından birisi olan Sarıkum Lagünü 1987 yılında Tabiatı Koruma Alanı, lagün çevresi ise 1991 yılında Doğal Sit alanı olarak ilan edilmiştir. Lagün ve çevresi, hem komşu ülkelerden deniz akıntılarıyla hem de Sinop bölgesinde hakim rüzgarların etkisiyle bölgenin coğrafi konumundan dolayı ciddi bir katı atık birikimine maruz kalmaktadır. AB DSÇD Deniz Çöpü Alt Teknik Grubu tarafından yayınlanan Avrupa Denizlerindeki Deniz Çöplerinin İzlenmesi için Kılavuz'da önerilen yöntemler bölgeye uyarlanarak kullanılmıştır. Bu kapsamda çalışma ile Sinop Sarıkum Lagünü'nde makro deniz çöpleri için sahil ve deniz tabanındaki çöplerin istasyonlar arası ve zamana bağlı olarak değişimleri, miktarları, dağılımları, kompozisyonları ve orijinleri belirlenmiştir. Mikroplastikler için ise sahil, deniz tabanı ve deniz suyunda istasyonlar arası ve zamana bağlı olarak değişimleri, miktarları belirlenmiş ve olası kaynakları tahmin edilmeye çalışılmıştır. Bölge canlılarının denizel çöplerden etkilenip etkilenmediğini belirlemek için çerçeveli trol ile deniz tabanı çöplerinin belirlenmesi amacıyla yapılan taramalar sırasında ağa yakalanan balıklardan yararlanılmıştır. Sinop Sarıkum Lagünü için Avrupa Birliği tarafından yayınlanan DSÇD kapsamında Tanımlayıcı 10 açısından bölgenin mevcut durumunun belirlenmiştir. Bölgenin yoğun miktarda çöp ile kontamine olduğu çalışma sonuçlarıyla belirlenmiş olup araştırma bölgesinde rastlanılan canlılarda herhangi bir çöp kalıntısına rastlanmamıştır. Çalışmanın sonucunda elde edilen veriler, daha sonra yapılacak olan benzer çalışmalara ışık tutma niteliğindedir.
  • [ X ]
    Öğe
    Karadeniz'in Türkiye kıyılarının mikroplastik kirliliği
    (Sinop Üniversitesi, 2021) Öztekin, Ayşah; Bat, Levent
    Plastik kirliliği, günümüzün en önemli kirlilik problemlerinden biri olarak tüm sucul ekosistemde karşımıza çıkmaktadır. Bu çalışmada, Karadeniz'in Türkiye kıyılarından seçilen göl ve nehirlerin geçiş suyu sistemlerinin yüzey sedimanlarındaki mikroplastik varlığı, mikroplastiklerin miktarı, tipleri ve dağılımı araştırılmıştır. Araştırma sonucunda toplam 2532 adet mikroplastiğe rastlanmıştır. Araştırma istasyonlarında sedimandaki mikroplastik miktarları en düşük ve en yüksek 31,6±14,2-258,9±368,8 adet.kg-1 yaş sediman, 37,9±16-347,8±122,1 adet.kg-1 kuru sediman ve 53±20-514,3±742 adet.L-1 sediman arasında bulunmuştur. Örneklerde en sık rastlanan mikroplastik tipi parça (%52,4) olmuş, bunu fiber (%26,1), film (%19,2), köpük (%2,2) ve boncuk (%0,1) izlemiştir. Araştırma sırasında karşılaşılan mikroplastiklerdeki baskın renk grubu %51,7 oranla şeffaf olmuş ve bunu sırasıyla beyaz (%13,3) mavi (%9,8), gri (%6,6), siyah (%5,9), yeşil (%3,9), kırmızı (%3,9), sarı/turuncu (%3), pembe/mor (%1,4) ve çok renkli (%0,5) plastikler izlemiştir. Mikroplastiklerin boy gruplarının oransal miktarları ise <0,25 mm: %29,9; 0,25-0,5 mm: %30,3; 0,5-1 mm: %19,8; 1-2 mm: %12,4; 2-5 mm: %7,6 olmuştur. Mevcut çalışma ile Karadeniz'in ülkemiz sularından seçilen göl ve nehirlerin geçiş suyu sistemlerinden örneklenen tüm sedimanlarda mikroplastik ile karşılaşılmıştır.
  • [ X ]
    Öğe
    Metal Levels in Trachurus mediterraneus ponticus Aleev, 1956 and Their Health Fisk Appraisal for Consumers
    (2023) Bat, Levent; Yardım, Öztekin; Öztekin, Ayşah
    This research was carried out to determine the levels of Cd, Hg, Pb, As, Al, Cu, Fe and Zn in the muscles of Trachurus mediterraneus ponticus. The fish samples were collected from the Samsun coasts of the Black Sea between September and December in both 2021 and 2022 and were analysed by using Inductively Coupled Plasma Mass Spectrophotometer. The metal values in the muscle tissues of horse mackerel were below the permissible values. Zn has the higher mean concentration (5.475 mg/kg wet weight (w.w.)) followed by Fe (mean concentration of 3.887 mg/kg w.w.) and Cu (mean concentration of 0.178 mg/kg w.w.) The Cd was found at the lowest (0.0077 mg/kg w.w.) mean concentration followed by Hg (0.0096 mg/kg w.w.), Pb (0.0453 mg/kg w.w.), and Al (0. 1077 mg/kg w.w.). The target hazard quotients (THQs) for individual metals and the total target hazard quotients (TTHQs) were <1 in horse mackerel indicating no health risk for consumption by infants, children, and adults. The risk indexes (RIs) for Pb were from 1.93x10-7 for adults in 2022 to 5.75x10-7 for infants in 2021, indicating their insignificant carcinogenic risks, whereas for As RIs were from 8.61x10-5 for adults in 2022 to 2.29x10-4 for infants in 2021, indicating their tolerable or acceptable carcinogenic risks.
  • [ X ]
    Öğe
    Preliminary Observation on Microplastic Contamination in the Scombridae Species From Coastal Waters of Pakistan
    (2022) Yousuf, Farzana; Bat, Levent; Öztekin, Ayşah; Alı, Qadeer Mohammad; Ahmed, Quratulan; Shaikh, Iqra
    Microplastics are one of the major pollution problems nowadays, have been found in both marine environments and various fish species worldwide. In this study, the presence of microplastics in the digestive systems and the gills of 6 species from the Scombridae family on the coast of Karachi in Pakistan was investigated. A total of 336 fish were examined for the presence of microplastic in gills and the digestive systems. Microplastics were detected in digestive systems and gills in 11.11%-19.51% and 58.62%-85.71% of total individuals, respectively. The number of microplastics varied from 0.19 to 1.12 items.ind-1 in digestive system and 1.5 to 7.04 items.ind-1 in gill. Fibre was dominant in both gills (98.67-99.17%) and digestive systems (100%). More extensive and further investigations are needed on microplastic contamination of the biota on the Pakistan coast.
  • [ X ]
    Öğe
    Risk assessment of elements in muscle of two biomonitored fish species from the southern Black Sea
    (Elsevier, 2023) Bat, Levent; Öztekin, Ayşah; Öztürk, Dilara Kaya; Arıcı, Elif; Şahin, Fatih; Hasançavuşoğlu, Zeynep
    Trace elements (Cd, Hg, Pb, Cu, Zn, and Fe) concentrations in the muscle of Mullus barbatus (red mullet) and Merlangius merlangus (whiting) were measured by inductively coupled plasma mass spectrometry from the southern Black Sea. Fe showed the highest amount in edible tissues of both fish species followed by Zn and Cu. The lowest element measured was Cd, followed by Hg and Pb. Element amounts in edible tissues were compared with national and international permissible limits and were within the permissible safety levels for human consumption. The risk assessment, related to the consumption of red mullet and whiting, was implemented, considering the concentrations of six metals, the estimated weekly intake (EWI), the provisional tolerable weekly intake (PTWI), the target hazard quotient (THQ), hazard index (HI), and risk index (RI). The HI values for both red mullet and whiting were found to be less than one, indicating that eating these fish poses no health risk. Moreover, RI due to Pb exposure through fish consumption may also have no chance of contracting cancer in the future. © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.