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    Benthic Faunal Assemblages of the Holocene Sediments from the Southwest Black Sea Shelf
    (Tubitak Scientific & Technological Research Council Turkey, 2009) Ongan, Demet; Algan, Oya; Kapan-Yesilyurt, Sevinc; Nazik, Atike; Ergin, Mustafa; Eastoe, Christ
    Benthic faunal content (benthic foraminifera, mollusca and ostracoda) of sediment cores from the SW Black Sea shelf were examined. Based on the vertical distribution of abundance and diversity of the benthic fauna, three benthic assemblages were distinguished. These assemblages are BF1, BF2 and BF3, and reflect the changes in bottom water from the termination of the Neoeuxinian period to present. BF1 displays high abundance and diversity in the surroundings of the Bosporus channel, diminishing in the shelf sediments further away from the channel. In the Mid-Shelf and Outer Shelf, it displays low abundance and low diversity. BF1 which started to be deposited at about 6 ky BP reflects the source effect of the saline Mediterranean lower layer, diminishing in strength toward more distal areas. In the Outer Shelf, changing foraminiferal faunal content may suggest that relatively low salinity conditions in the bottom water were established after similar to 4 ky BP. BF2 consists of a mixed fauna (brackish and euryhaline Mediterranean species), suggesting transitional conditions with intrusion of Mediterranean water earlier than similar to 8 ky BP. BF3 corresponds to the Neoeuxinian lake phase of the Black Sea.
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    Öğe
    Distribution of Microflora, Meiofauna, and Macrofauna Assemblages in the Hypersaline Environment of Northeastern Aegean Sea Coasts
    (Coastal Education & Research Foundation, 2013) Bassler-Veit, Barbara; Barut, Ipek F.; Meric, Engin; Avsar, Niyazi; Nazik, Atike; Kapan-Yesilyurt, Sevinc; Yildiz, Aysegul
    In this study, the morphology and taxonomy of microflora (charophytes and diatoms), meiofauna (benthic foraminifera and ostracoda), and macrofauna (mollusk) assemblages of the recent surface sediments from saltpans, hypersaline lagoons, and salt lakes of the Gulf of Saros (NW Turkey) were investigated. In total, 44 samples were collected from recent surface sediments in salt pans, hypersaline lagoons, and salt lakes of the Gulf of Saros (Enez Salt Lake, Isik Lake, Kuvalak Lake, Enez Gala Lake, Dalyan Lake, and Tasalti Lake; Karagol, Vakif, and Erikli salt pans; and Uzungol Lagoon), Gallipoli Peninsula (salt pan), Biga Peninsula (Diremin and Azmak Lagoons and Dalyan Salt Lake), and Gokceada Island (salt lake). Surface sediments were collected, and some physical properties were measured, such as temperature, pH, and salt content. Grain size was determined and classified for each sample. In this study, foraminifera, ostracoda, and mollusca faunas in the normal marine environment were used as indicators and compared with the lagoonal environment, which has increased salt content during the summer months.
  • Küçük Resim
    Öğe
    Ponto-caspian and mediterranean faunal and floral records of upper pleistocene-holocene sediments from the Izmit Gulf (Marmara Sea, Turkey)
    (Romanian Society of Palaeontologists, 2021) Kırcı-Elmas, Elmas; Nazik, Atike; Kapan, Sevinç; Meriç, Engin; Zor, Emine Şeker; Kalkan, Beste; Doǧan, Tamer; Güney, Ayşegül
    İzmit Gulf is located between Kocaeli and Armutlu peninsulas at east of Marmara Sea and the interaction area of North Anatolian Fault Zone (NAFZ) and Marmara Graben systems. In this study, the faunal and floral contents (ostracod, foraminifer, mollusc and diatom) of the samples belonging to seven drilling cores were studied and obtained the radiocarbon and optically stimulated luminescence (OSL) age data in order to establish on the Black Sea – Marmara Sea - Mediterranean water connections and palaeoenvironmental changes. The sediments in this study are Late Pleistocene-Holocene aged and only cover the Marine Isotope Stages MIS-5 (interglacial), MIS-3 (an interstadial period between MIS-4 and MIS-2 glacial epochs) and MIS-1. The determination of ostracod and mollusc fauna of the Mediterranean and Ponto-Caspian origin provide important clues to water exchange between the Mediterranean and the Black Sea. Although some Mediterranean originated ostracods occur sporadically with low abundance, absence of foraminiferal fauna and existence of Ponto-Caspian ostracods together with fresh water and cosmopolitan diatom flora indicate that the area strongly interacted with the Black Sea waters during MIS-5. The faunal and floral characteristics of the sediments deposited during MIS-3, clearly denote that the Izmit Gulf was connected with the Black Sea and the Mediterranean Sea at the beginning of MIS-3 (ca. 52.0 - 40.0 ky BP) and the shallow shelf areas were frequently affected by both the Black Sea discharge and Mediterranean input. A thick Holocene sedimentary sequence recovered from the southern Hersek Burnu drilling cores reflects the environmental changes after the latest Black-Mediterranean seas connection. The studied ostracod and mollusc assemblages are mainly characterized by the Mediterranean originated species with a few relict Ponto-Caspian fauna. Also, the benthic foraminiferal assemblages are dominated by normal marine and euryhaline species, reflecting the salinity fluctuations in the Holocene interval.
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    Öğe
    The aspects of the Late Quaternary (Holocene) setting belong to the eastern Gulf of Izmit, Adapazari, the delta of Sakarya and their environments
    (2004) Kerey, I. Erdal; Meriç, Engin; Nazik, Atike; Tuno?lu, Cemal; Avşar, Niyazi; Kapan-Yeşilyurt, Sevinç; Akgün, Funda
    This study is carried out on the settings of Holocene at eastern Gulf of ?Izmit, Adapazari, Sakarya Delta and its vicinity, and based on 86 samples collected from the boreholes. The pollen diagram, based on the data from the boreholes drilled at Adapazari and its vicinity, suggested that high herbaceous pollen percentages of particularly Chenopodiaceae and Compositae, and Pinus and Quercus were present during the Early Holocene (approximately 11.300 BP years). Absent of the foraminifers in deltaik environment indicates that there was no any sea effect on the delta. In addition, the Gulf of Izmit, which was connected to Sakarya River in the Middle Pleistocene, moved to west. Moreover, when the elevations of the boreholes and different numerical ages (11.000-3.780 BP years) assigned at different depths are considered, it can be concluded that the region was under the control of tectonic activities in the forms of subsidence and uplift.