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    Abundance and distribution of microplastics in sediments of the Eastern Aegean Sea (Izmir Bay, Türkiye)
    (Elsevier, 2025) Ozkan, Ebru Yesim; Oztekin, Aysah; Bat, Levent; Kaya, Nusret
    Microplastics (MPs) have accumulated extensively in the marine environment due to the increasing use of plastic materials and their inadequate disposal. Several investigations have been focused on the presence of MPs in the marine environment but a few of them investigate the presence of MPs in the sediment profiles and distribution dynamics. The aim of the study was to investigate the abundance of MPs in the seabed sediments in the I(center dot)zmir Bay of the Aegean Sea, T & uuml;rkiye and to determine the distribution dynamics of MPs and the factors governing them. The abundance of MPs was 2979 +/- 1560 pieces/kg dry sediment. The dominant MP shape was fragment (59.54 %), followed by fiber (36.77 %), film (3.55 %), the remaining types were found to be less than 1 %. The majority of MPs are smaller than 1 mm. In the distribution of MPs by color, the dominant color was transparent (52 %) followed by blue with 11.07 % and other colors account for less than 10 %. It was determined from FT-IR and Raman analyses that the sediments of the Inner Gulf chemically contain 7 different MPs and polyethylene (PE) and polypropylene (PP), constituting the majority of identified particles. The distribution of MPs in the sediment may be explained by Fe, Mn, Calcite (CaCO3), Biogenic Silica (BSi) and hydrodynamic features in the water column (cyclonic, anticyclonic eddies in the water column, diatom substrate selection, littering and sinking with density increase).
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    Comprehensive risk assessment of metals in surface sediments of the Southern Black Sea coastal and transition waters
    (Elsevier, 2024) Bat, Levent; Sahin, Fatih; Oztekin, Aysah; Ozsandikci, Ugur; Ozkan, Ebru Yesim
    This study was carried out to determine metal levels accumulated in the sediments collected from the transitional and coastal waters of the southern Black Sea. Samples were taken from 32 stations in May and September 2018. The concentrations of elements were measured by an Inductively Coupled Plasma Mass Spectrophotometer (ICPMS). Enrichment Factor (EF), Geo -accumulation Index (Igeo), Pollution Load Index (PLI), Contamination Factor (C f ), and Modified Degree of Contamination (mC d ) were applied to the data for assessing the sediment quality. Associations between the variables were also revealed by factor analysis. Igeo of metals are obtained in coastal sediments only when Hg in May and Cr in September are classified as moderately polluted. PLIs exceeded one at stations in the industrial zone, indicating getting worse. It is necessary to prevent pollution from industrial, domestic, and agricultural sources and to control agricultural lands.
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    Effects of biogeochemical processes on spatial distribution of iron, manganese, reactive phosphates and nitrates in the Black Sea
    (Natl Inst Science Communication-Niscair, 2019) Ozkan, Ebru Yesim; Buyukisik, Baha; Bat, Levent
    The aim of this study was to identify differences in the distribution of Mn (Manganese), Fe (Iron), NO3- (Nitrates) and reactive phosphates (RP) in the water columns of the eastern and western basin of the Black Sea region. Accordingly, the selected sampling area covered offshore waters from west to east including Istanbul (station KD01), Eregli (KD2A, 2B, and 2C), Inebolu (KD03), Sinop (KD04), Ordu (KD5A, 5B, 5C) and Trabzon (KD06). The B and C codes for stations 2 and 5 indicate that the stations are towards the basin centers of the Black Sea. At all the stations of the study area, the Mn values were below the limit of detection (5 mu g/L) up to 100 m depth. The Mn concentration reached maximum at 200 m depth of stations KD2B, KD5B, KD5C and KD06. This situation could be due to mobilization of Mn from the continental slope sediments (Mn pump). Also, it was observed that relatively high values of nitrates were associated with low RP concentration in the deep waters of the eastern basin. If nitrate is present in the suboxic zone, bacteria prefers nitrate and reduce it as N-2 (g). Then, the FeOOH=RP (ferric oxyhydroxides equivalent to reactive phosphate) particulates sink into deeper layers without reduction by bacteria and cause the upper layers to become poor in phosphates. In case of low values of nitrate in suboxic zone, FeOOH equivalent to RP particulates are reduced to dissolved Fe+2 by the bacteria. Significantly higher levels of nitrate concentrations were observed at station KD06. In conclusion, the eastern basin center is characterized by relatively higher nitrate concentrations in water columns compared to those in the western basin center. Therefore, the eastern basin contains lower RP concentrations and this limits the phytoplankton growth. It is concluded that where nitrate concentrations are higher than 2 mu M, the bacteria preferred to reduce the nitrates. On the other hand, particulate Fe can be reduced chemically with H2S in the deeper layers, where there is lower nitrate concentration.
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    Heavy Metal Levels in Sediment of the Turkish Black Sea Coast
    (Igi Global, 2019) Bat, Levent; Ozkan, Ebru Yesim
    Sediments are an important repository for various pollutants such as pesticides and heavy metals and also play a significant role as sensitive indicators for monitoring contaminants in aquatic systems. Heavy metals which are regarded as serious pollutants of aquatic ecosystems are a major environmental problem in the Black Sea. Contamination by heavy metals has not been extensively studied in the Black Sea coast of Turkey, even though these are subjected to intense discharges of pollutants. It is important, therefore, that sediment by heavy metals be assessed in order to facilitate better management and protection of these valuable coastal ecosystems. This is especially the case, since Turkish Black Sea coast represents a prominent area for fishing, industrial development and urban extension and tourism activities. In view of the economic importance of the Black Sea coastal region of Turkey, this review aims to analyses the distribution and concentrations of heavy metals in bottom sediment in the coastal sediment along the Black Sea.
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    Spatial geochemical structure of soft sediment on shallow littoral of the Gulf of Antalya, the eastern Mediterranean Sea
    (Pergamon-Elsevier Science Ltd, 2023) Yalcin, Mustafa Gurhan; Mutlu, Erhan; Olguner, Cansu; Atakoglu, Ozge Ozer; Bat, Levent; Ozkan, Ebru Yesim
    The concentrations of heavy metals in soft sediments of the Manavgat and Lara regions in Antalya, Turkiye were investigated to assess contamination levels and their potential sources, followed by multivariate statistical analysis and generation of spatial distribution maps. Results showed low contamination levels for As, Zn, and Cu, moderate contamination for Pb, Ni, and Mn, and very high accumulation for Co and Cr. Geoaccumulation index (Igeo) and contamination factor (CF) analyses revealed moderate enrichment for Mn and low enrichment for As, indicating no human-induced contamination in Cu, Pb, Zn, Mn, and As, while Ni, Co, and Cr originated mainly from agriculture. The maximum modified degree of contamination (mCd) value was at an extreme high level, with an average mCd of 4.12 indicating high contamination. Maximum pollution load index (PLI) value was 3.13, indicating high-grade pollution and an average value of 1.7 indicating moderate pollution.
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    Trace elements pollution in surface sediment of the Sea of Marmara coastal and transition water
    (Pergamon-Elsevier Science Ltd, 2025) Bat, Levent; Sahin, Fatih; Oztekin, Aysah; Ozsandikci, Ugur; Ozkan, Ebru Yesim
    The increasing anthropogenic activities in the Sea of Marmara, such as industrialization, maritime traffic, and urbanization, have significantly contributed to the introduction of various contaminants, into its sediments. The aim of this study is to determine the levels of trace elements accumulated in the transitional and coastal waters of the Sea of Marmara and to assess the pollution status of the region. Surface sediments were collected using a Van Veen Grab from 21 stations representing different water masses in May, July, and September 2018 and stored in plastic bags at -21 degrees C. The concentrations of elements (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) were analysed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS, Agilent 7700X). To evaluate sediment quality, Enrichment Factor (EF), Geo-accumulation Index (Igeo), Pollution Load Index (PLI), Contamination Factor (Cf), Contamination Degree (CD), and Factor Analysis were applied. The analysis revealed that Al and Fe were the most abundant elements in the sediments, while Hg and Cd were found at the lowest concentrations. These findings may be associated with the natural geochemical characteristics of the region as well as anthropogenic pollution sources. The index results indicated significant enrichment of certain elements in specific areas. This study provides important data on the accumulation of trace elements in the sediments of the Sea of Marmara. The applied pollution indices offered a comprehensive assessment of sediment contamination in the region, highlighting the localized accumulation of certain pollutant elements.