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    Alginate modified collagen for rapid, durable and effective biosorption of Pb (II) ions from an aqueous solution
    (Elsevier, 2023) Ugurlu, Erkan; Duysak, Onder; Kardas, Gulfeza; Sayin, Selin; Saygili, Eyup Ilker; Dogan, Serdar
    The aim of this study is to define the biosorption properties of Alginate, AC1 and AC2 beads composed of collagen obtained from sea urchin Diadema setosum and alginate obtained from Sargassum vulgare, for Pb (II) from aqueous solutions. Raw alginate beads (A), 2:1 alginate-modified-collagen beads (AC1), and 3:1 alginate-modified collagen beads (AC2) were successfully synthesized, characterized, and removal capacity of Pb (II) in aqueous solutions studied. The biosorption of Pb (II) ions by the synthesized beads was studied and the effect of parameters such as initial concentration, contact time, and solution pH on the biosorption of Pb (II) ions was investigated. Langmuir isotherm model provides satisfactory estimations of homogeneous monolayer biosorption capacity, the highest Pb (II) determined values being 248.76 mg/g for Alginate beads, 344.83 mg/g for AC1 beads, and 303.03 mg/g for AC2 beads. Moreover, AC1 beads were determined to be homogeneous monolayer and multilayer at two different stages. In the former stage, Pb (II) were quickly diffused to the outer surface of absorbent, and in the latter stage, ions were slowly biosorbed to the inner surface. The results obtained in this study showed that Alginate, AC1 and AC2 beads can be used effectively to remove Pb (II) ions from aqueous solutions. Another finding from this study was that the AC1 beads did not disintegration and significantly swelled in size relative to the other beads. Another important finding of this study was that AC1 beads were not deformed and increased in size.& COPY; 2023 Elsevier B.V. All rights reserved.
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    A Biomonitoring Study: Heavy Metals in Monodonta turbinata (Mollusca: Gastropoda) From Iskenderun Bay, North-Eastern Mediterranean
    (Zoological Soc Pakistan, 2014) Duysak, Onder; Ersoy, Beyza
    Metal (Fe, Zn, Cd, Cu, Co, Ni, Al, Mn, Pb and Cr) revels were investigated in the muscle tissue of Monodonta turbinata from seven different stations in Iskenderun Bay. Accumulations of all elements were effected from seasonal changes in all stations. The highest levels of Zn (101.42 mu g/g), Cd (9.01 mu g/g), Cu (334.47 mu g/g) and Pb (90.8 mu g/g) were found in the station Cevlik. However, the highest levels of Fe (3176.85 mu g/g), Co (12.76 mu g/g), Ni (26.93 mu g/g), Al (409.30 mu g/g), Mn (49.40 mu g/g) and Cr (45.06 mu g/g) were observed in the station Kalekoy. Mean concentrations except Zn that was lower in the station Dortyol were generally lower in the station Yumurtalik. Fe showed the highest levels in all stations compared to the rest of the elements. The high concentration of heavy metals was observed during spring. The data indicate that M turbinata is very efficient heavy metal accumulator and, therefore, may be used successfully to monitor heavy metal presence in Iskenderun Bay.
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    Canonical Correlation Analysis for Determination of Relationships Between Different Length Measurements and Body Weights of Common Cuttlefish (Sepia officinalis)
    (Medwell Online, 2012) Sangun, Levent; Cankaya, Soner; Duysak, Onder
    In this study, canonical correlation analysis was applied to estimate relationships between length characters mantle length (cm), upper hood length (cm), lower hood length (cm), tittle bone line zone length (cm), cuttle bone free zone length (cm) and weights characters body weight (g), stomach weight (g), stomach wall weight (g), digestive gland weight (g) of 697 cuttlefish (Sepia officinalis) populations caught from Iskenderun bay from 2006-2007, Eastern Mediterranean region, Turkey. The first 3 of the estimated canonical correlation coefficients between the pairs of canonical variables were found significant (0.949, 0.358, 0.294 and p<0.011. The results obtained from canonical correlation analysis indicated that mantle length had largest contribution for the explanatory capacity of canonical variables estimated from length characters of 697 cuttlefish (Sepia officinalis) when compared with other length characters while body weight had largest contribution for the explanatory capacity of canonical variables estimated from weight characters when compared with other weight characters. The results of this study showed that mantle lenght should be used with the aim of estimating weight per Sepia officinalis individuals in common cuttlefish genotypes.
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    Heavy Metal Concentrations in Tissues of Short-Finned Squid Illex coindetii (Cephalopoda: Ommastrephidae) (Verany, 1839) in Iskenderun Bay, North-Eastern Mediterranean
    (Zoological Soc Pakistan, 2015) Duysak, Onder; Dural, Meltem
    Metal levels (Cd, Cr, Cu, Fe, Mn, Pb and Zn) in the gill, digestive gland, arm and mantle of female and male short-finned squid (Illex coindetii) in Iskenderun Bay were investigated. All elements differed in accumulation in tissues and sex significantly (p<0.05). Concentrations of Cd in the tissues of male and female short-finned squid samples ranged between 0.68-9.51 mu g/g. Cu concentrations in all tissues were found and ranged between 5.97 and 324.1 mu g/g. Fe concentrations in the mantle of female and male samples were found 9.13 and 9.83 mu g/g, respectively. Pb concentrations in the mantles of female and male samples were found between 1.49-2.37 mu g/g. The highest Zn concentrations in hepatopancreas of male and female samples were found 85.29 and 66.8 mu g/g respectively (P<0.05). In the mantle tissue of I. coindetii, metal levels independent of sex were in the following order: Zn > Cu > Fe > Pb > Mn. > Cd > Cr. In accordance with limit values, the present study found out that the mantle tissue of cuttlefish, I. coindetii, was overlimited with Cd and Pb.
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    Metal Concentrations in Different Tissues of Cuttlefish (Sepia officinalis) in Iskenderun Bay, Northeastern Mediterranean
    (Central Fisheries Research Inst, 2013) Duysak, Onder; Ersoy, Beyza; Dural, Meltem
    Metal levels (Cd, Cr, Cu, Fe, Mn, Pb and Zn) in the gill, hepatopancreas, ovary, testis and mantle of male and female cuttlefish Sepia officinalis in Iskenderun Bay were investigated. All elements differ in accumulation in tissues and sex significantly (p<0.05). Concentrations of Cd in the tissues of male and female cuttlefish samples ranged between 0.12-34.7 mg/kg. Cr levels in tissues of males and females ranged between 0.59-1.26 mg/kg. Cu concentrations in all tissues were found and ranged between 8.83 and 1296 mg/kg. Fe concentrations in the mantle of female and male samples were found 0.35 and 0.36 mg/kg, respectively. Pb concentrations in the mantles of female and male samples were found between 1.74-1.79 mg/kg. The highest Zn concentrations in hepatopancreas of male and female samples were found 181 mg/kg and 272 mg/kg respectively (P<0.05). In the mantle tissue of S. officinalis, metal levels independent of sex were in the following order: Cu>Zn>Cd>Pb>Cr>Mn>Fe. In accordance with limit values, the present study found out that the mantle tissue of cuttlefish, S. officinalis, was overlimited with Cd and Pb
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    Metal concentrations in different tissues of jellyfish (rhopilema nomadica galil, 1990) in Iskenderun Bay, Northeastern Mediterranean
    (2013) Duysak, Onder; Yilmaz, Ayse Bahar; Mazlum, Yavuz
    In this study, the concentrations of heavy metals (Cd, Cr, Cu, Fe, Mn, Pb and Zn) were determined in gastral, tentacular and epidermal (umbrella) tissues of jellyfish Ropilema nomadica from 2 stations (Yumurtalik and Arsuz) in Iskenderun Bay, Turkey. Heavy metal concentrations varied significantly depending on the type of the tissue and location of stations. The average metal concentrations in gastral and tentacular were found higher than umbrella tissues in all samples. The level of Mn and Zn concentrations were significantly different among the tissues in both stations (p<0.05). The aim of this study was to imply potential of heavy metal accumulation in jellyfish which plays an important role in biological transfer and Summer blooms. Moreover, this is the first study of the heavy metal bioaccumulation on R. nomadica in Northeastern Mediterranean. © Medwell Journals, 2013.
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    Metal toxicity risk of commercial cephalopod species and public health concerns
    (Elsevier, 2023) Duysak, Onder; Kilic, Ece; Ugurlu, Erkan; Dogan, Serdar
    Metals in the marine environment threaten aquatic animals and their upper trophic level predators, as they not only jeopardize their well-being but accumulate in their tissues, posing potential health risks. The present study focused on sampling Eledone moschata, Octopus vulgaris, and Illex coindetii from the Marmara, Aegean, and Mediterranean Seas. The study aimed to assess the accumulation levels of aluminum (Al), chromium (Cr), cobalt (Co), nickel (Ni), cadmium (Cd), lead (Pb), manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn) in the mantle, gill, and hepatopancreas tissues. Significant variations in metal accumulation levels were observed depending on the sampled station and tissues. Iron, copper, and zinc exhibited the highest concentrations in the tissues, whereas nickel and cadmium showed the lowest concentrations. The mantle exhibited the lowest metal concentration, whereas the hepatopancreas showed the highest concentration among the studied tissues. Furthermore, a health risk analysis was conducted using the Target Hazard Quotient (THQ) and lifetime cancer risk (CR) assessments. The analysis results indicated no significant health risk associated with the consumption of the studied species from the Marmara Sea, Aegean Sea, and the Mediterranean Sea.& COPY; 2023 Elsevier B.V. All rights reserved.
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    Reproductive biology of the common cuttlefish (Sepia officinalis Linnaeus, 1758) in Iskenderun Bay (Northeastern Mediterranean Sea)
    (Natl Inst Science Communication-Niscair, 2014) Duysak, Onder; Ozcan, Gulnaz; Cek, Sehriban; Tureli, Canan
    Morphometric characters and reproductive biology were studied in S. officinalis collected at different seasons from the Iskenderun Bay, Turkey. A total of 2006 specimens (992 female, 1014 male) were sampled from September 2005 to August using a Mediterranean type deep trawl (22 mm mesh size). Mean mantle lengths for female and male were 9.83 +/- 1.66, 9.40 +/- 1.76 cm and the mean weights were 135.78 +/- 6.71g, 115.34 +/- 6.29g, respectively. Sexual maturity lengths were calculated as 12.04 for females and 10.30 cm for males. Mean diameter of eggs was measured as 5.367 +/- 9.12 mm per spawning period. Spermatophore lengths were estimated to range from 2.8 +/- 1.05 to 12.4 +/- 2.11mm. Population consisted of gonochoristic induviduals. Although, sex ratio of Sepia officinalis were not significantly different from the expected 1:1 ratio (p>0.05), a slightly male biased sex ratio was recorded.
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    Width/Length-Weight and Width-Length Relationships for 8 Crab Species from the North-Eastern Mediterranean Coast of Turkey
    (Medwell Online, 2009) Sangun, Levent; Tureli, Canan; Akamca, Erhan; Duysak, Onder
    In this study, relationships between width/length-weight and width-length by sex and combine were estimated 1133 individuals belonging to 8 species from 5 families in the North-eastern Mediterranean coast of Turkey. Regression coefficient between the regression of W-CL, W-CW and CL-CW for female, male and both were found very high (p<0.001) and the median value of b W-CL were 3.135, 3.132 and 3.081; W-CW were 3.135, 3.132 and 3.081, respectively. The r(2) values ranged from 0.91-0.99.