Engin Meriç

Black Sea-Marmara Sea Quaternary connections: new data from the Bosphorus, Istanbul, Turkey

Abstract Previous studies concluded that the Bosphorus Strait was formed during the Quaternary by fluvial incision of a valley between the Black Sea, to the north, and the Marmara Sea in the south. Hitherto, however, few details of the evolution of this connection have been elucidated from the sediments deposited within the Bosphorus itself. We report here details of sedimentological and palaeontological evidence relating to this history, obtained from five boreholes drilled into the unconsolidated sediment fill in the north-central sector of the Bosphorus, together with nearby geophysical profiles. The Quaternary fill of this part of the Bosphorus comprises two major facies associations. Yellow arkosic sands dominate the lower Facies Association A: these are assigned a Middle to Late Pleistocene age and the contained faunas have a lagoonal to lacustrine character and a Black Sea provenance (Paratethyan affinities). The abruptly succeeding units of Facies Association B comprise fining and coarsening upwards units of coarse to fine shelly and clayey sands that alternate with shell-bearing green clays. These sediments were formed in a range of marine and coastal settings and biostratigraphic evidence and absolute dating demonstrate the Mid–Late Holocene age of this upper unit. Initially brackish faunal assemblages in this upper unit show an upward increase in marine and Mediterranean affinities. Integrating these new data with previously published observations from coeval deposits in the southern Bosphorus and Izmit Bay (NE Marmara Sea) we conclude that during the Late Pleistocene and Early Holocene a topographic barrier existed in the south-central sector of the Bosphorus, on both sides of which estuarine and lagoonal sediments accumulated, with distinctive Black Sea and Mediterranean faunas. During a significant rise in sea level, between 7000 and 5300 years ago, this barrier was finally submerged, permitting interchange of marine waters between the Mediterranean and the Black Sea and creating the present oceanographic situation. This evolution conflicts with the cataclysmic role of the Bosphorus in the early Holocene as postulated in the ‘Catastrophic Flood’ hypothesis of Ryan et al. [Mar. Geol. 138 (1997) 119–126; Annu. Rev. Earth Planet. Sci. 31 (2003) 525–554]. It also contrasts with the history recorded from the Gulf of Izmit, where intermittent connection between these two bodies of water throughout much of the Quaternary is evident.

An aspect of Omphalocyclus macroporus (Lamarck)

Specimens of Omphalocyclus macroporus (Lamarck) exhibiting in thin section a trilocular, bilocular or unilocular megalospheric embryonic apparatus, instead of the normal quadrilocular apparatus, have been observed in upper Maestrichtian horizons of southeastern Turkey. The various appearances of the embryonic apparatus are strictly related to the various positions of the thin sections. Distinguishing new varieties on the basis of the different embryonic apparatus views observed is regarded as erroneous.

Distribution of Microflora, Meiofauna, and Macrofauna Assemblages in the Hypersaline Environment of Northeastern Aegean Sea Coasts

ABSTRACT Bassler-Veit, B.; Barut, I.F.; Meric, E.; Avsar, N.; Nazik, A.; Kapan-Yeşilyurt, S., and Yildiz, A., 2013. Distribution of microflora, meiofauna, and macrofauna assemblages in the hypersaline environment of northeastern Aegean Sea coasts. 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 Tasaltı 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.

Reply to Discussion: a critique of Possible waterways between the Marmara Sea and the Black Sea in the late Quaternary: evidence from ostracod and foraminifer assemblages in lakes İznik and Sapanca, Turkey, Geo-Marine Letters, 2011

In their discussion of our 2011 paper dealing with possible waterways between the Marmara Sea and the Black Sea in the “late” Quaternary, based on data from ostracod and foraminifer assemblages in lakes İznik and Sapanca, Turkey, Yaltırak et al. (Geo-Mar Lett 32:267–274, 2012) essentially reject the idea of any links whatsoever, be they between the Marmara Sea and the lakes İznik and Sapanca, or further to the Black Sea via the valley of the Sakarya River. The evidence they provide in support of their view, however, is essentially circumstantial, in part conjectural, and also inconclusive considering the findings in favour of linkage between the Marmara Sea and the lakes at the very least, while the proposed connection with the Sakarya River valley remains speculative because of the lack of unambiguous data. On the other hand, Yaltırak et al. (Geo-Mar Lett 32:267–274, 2012) do raise valid points of concern which deserve careful future investigation, the most important being the possibility of sample contamination from dumped marine sediment used for construction purposes along some parts of the shore of Lake İznik. We agree that a concerted multidisciplinary effort is required to address the many unresolved issues in connection with the potential waterways proposed by us and others before us.

Palaeoecology of Upper Pleistocene-Holocene bryozoan and foraminiferal assemblages from Kuşdili (Kadiköy, Istanbul, Turkey)

Abstract Bryozoan and foraminiferal assemblages from a core drilled in the Kusdili (Kadikoy, Istanbul) Upper Pleistocene–Holocene sequence were studied. Assemblages are absent from the very basal and top parts but they are well represented all along the middle part of the sequence. All the species found presently live in the Mediterranean. In the area sedimentation seemingly started about 13 000 years ago in very shallow near-shore environments with the deposition of pebbly sediments rapidly evolving to mud. Near the base, the presence of erosional surface allows to recognize three successive sedimentary cycles. Bryozoan and foraminiferal assemblages found in the middle part of the sequence testify to a shallow water, estuarine or lagoonal paleo-environment, in which effects of low salinity waters, more obvious toward the top, could be related to the reestablishment of a connection between the Marmara Sea and the Black Sea through the Bosphorus, about 7000 years BP.

Twin development in Discocyclinidae

This study concerns the development of a twin-form due to the delay of the breakage of reproductive cysts during the schizogony in Discocyclina cf. seunesi Douville found in the Paleocene sequence of NW Anatolia (Izmit, Turkey).

A new record in eastern Aegean Sea (Turkey): Polymorphina fistulosa

Numerous Indo-Pacific originated alien foraminifer species have been recorded in the eastern Mediterranean. Each year new species are being added. In the framework of a foraminiferal study conducted on the east Aegean coast the benthic foraminifer Polymorphina fistulosa is found in the foraminiferal assemblage around a hot water submarine spring in Ilica Bay (Cesme, Turkey). It is also observed in one sediment sample collected from the western entrance of the Dardanelles (Canakkale, Turkey). These records constitute the first record of this Pacific originated species in the Aegean Sea.

Dizerina, a new genus from the upper Maastrichtian of northeastern Turkey

In the upper Maastrichtian of northeastern Turkey a new foraminifer has been found which shows similarities to Lepidorbitoididae and Orbitoididae in various characters. This form is named here Dizerina anatolica Meric, n. gen., n. sp. Dizerina, a new genus from the upper Maastrichtian of northeastern Turkey

First report of Pararotalia calcariformata from the Hatay coastline (Turkey—north-eastern Mediterranean)

from the Hatay coastline (Turkey— north-eastern Mediterranean) engin meric‚, mehemet baki yokes, kadiko¤y niyazi avsar, elmas kirki-elmas, feyza dinc‚er, selahattin unsal karhan, evrim kalkan and volkan demir Moda Huseyin Bey Sk. No. 15/4, Kadikoy, Istanbul, Turkey, Halic University, Department of Molecular Biology and Genetics, Cukurova University, Department of Geological Engineering, Istanbul University, Institute of Marine Sciences and Management, Nevsehir University, Department of Geological Engineering, Istanbul University, Division of Hydrobiology, Department of Biology, Bogazici University, Department of Environmental Sciences, Turkey

THE EFFECT OF SUBMARINE THERMAL SPRINGS OF DOĞANBEY CAPE (SEFERİHİSAR-İZMİR) ON FORAMINIFER, OSTRACOD AND MOLLUSC ASSEMBLAGES

Bu calisma, Kusadasi Korfezi’nin kuzey ucunu olusturan Doganbey Burnu’nun kiyi alanindaki farkli noktalarda bulunan denizici sicak su cikislarinin, yakin cevrede yasamini surduren cesitli mikro ve makrofauna topluluklari uzerindeki etkisini arastirmak amaciyla yapilmistir. Doganbey Burnu’nun guneydogusunda farkli derinliklerde 15 noktadan kepce ile genc cokel ornekleri alinip, bunlarin icermis oldugu bentik foraminifer, ostrakod ve mollusk faunasi degerlendirilmistir. Bentik foraminiferler 35 cins, 61 tur, ostrakodlar 16 cins 20 tur, gastropodlar 14 cins ve 18 tur, bivalvler ise 14 cins ve 15 tur olarak bulunmustur.. Ayrica calisma alaninda, Ege kiyilarinda sikca rastlanilan foraminifer kavkilarindaki renklenme, sekil bozuklugu ile gocmen bentik foraminiferlerin varligi tespit edilmistir. Calisilan bolgede tanimlanan foraminifer, ostrakod ve mollusk faunasi tipik Ege faunasina paralellik sunmaktadir. Tipik Ege bentik foraminifer toplulugu icindeki Amphistegina lobifera Larsen bireylerinin yasadigi ekolojik kosullarinin bolluk dagilimi uzerinde etkisi bilinmektedir. Bolge icin Amphistegina lobifera Larsen’nin ideal yasam araligi 18.00-32.00 m derinlik ve yaklasik 19-20o C sicaklik olarak belirlenmistir. Bir diger ozellik olarak CTD cihazi ile yapilan olcumlerde iletkenlik degerlerinin sicak su kaynagina yaklastikca arttigi ancak birey sayisinin azaldigi tespit edilmistir. Sediment orneklerinde kimyasal analizler X-Isini Floresans Analiz Spektrometresi (WDXRF) ile yapilmistir. Sediment orneklerinde agir metallerden Cr, Mn, Co, Ni, Cu, Zn ve Pb degerlerine bakilmis, bu degerlerin. DB1-DB6 arasi orneklerde ve DB15 de Cr>Ni>Mn, DB8-DB11 arasi ornekler ile DB13 ve DB14 de Mn>Cr>Ni, DB7 ve DB12 de Cr>Mn>Ni, oldugu tespit edilmistir. Radyoaktif elementlerden U ve Th DB9, DB10 ve DB11 de yuksek degerdedir. Eser elementlerden Sr degeri DB7-DB11 arasi orneklerde yuksektir. Sedimentlerin kimyasal ve radyoaktif ozelliklerinin bentik foraminifer kavkilarinda etkisi gozlenirken ostrakod ve mollusk kavkilarinda herhangi bir etki belirlenmemistir.