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Öğe Determination of Dil Stream Contamination By Benthic Foraminifera and Molluscs in Bayramoglu Coasts (Tuzla-Istanbul, Turkey)(Parlar Scientific Publications (P S P), 2017) Yümün, Zeki Ünal; Meriç, Engin; Barut, İpek F.; Nazik, Atike; Avşar, Niyazi; Yokeş, Baki; Kaya, SeyhanThis study investigates the drill core 3.00 m in length obtained from DSK-3 drilling carried out in the depth of 10:00 m in the southeast of Tuzla (Istanbul) and in the northwest of Bayramoglu in order to present the marine pollution caused by Dil Stream through the instrumentality of bioindicators (foraminifera, ostracods and molluscs). The purpose of the study is to reveal the adverse conditions caused by the uncontrolled waste disposal from the industry which has been evolving for a long time around Dil Stream located in the provincial borders of Kocaeli. It is not possible under the present circumstances to do any research in the area where Dil Stream discharges into the sea. Therefore, the core obtained from the drilling carried out in Bayramoglu is analyzed by considering the flows in the western portion of Gulf of Izmit. In addition, this study also makes use of the results of the analysis of the samples collected at and around the mouth of the stream by TUBITAK in 2013 for the purpose of demonstrating the environmental pollution in the region. In conclusion, coloration and deformation of the heavy metals and benthic foraminifera which the core samples contain are determined and the adverse outcomes caused by the untreated waste discharged into Dil Stream are demonstrated.Öğe Drilling and core data from the Gulf of Gemlik (SE Sea of Marmara): Holocene fauna and flora assemblages(Maden Tetkik Ve Arama Genel Mudurlugu-Mta, 2020) Meriç, Engin; Yümün, Zeki Ünal; Nazik, Atike; Sağular, Enis Kemal; Yokes, M. Baki; Büyükmeriç, Yeşim; Yavuzlar, GülinThis study was conducted to determine fauna and flora assemblages of Holocene sequences from Gemlik Gulf (SE Marmara Sea) and to obtaine their similarities and differences between the assemblages of Gemlik and Izmit Bays. Total of 201 dark gray colored, fine to medium grained sandy clay samples were studied. In the drilled samples, 22 genera and 38 species were identified from the foraminifera characterizing the infralittoral zone. 40 genera and 58 species of foraminifera characterizing the upper circalittoral zone were identified. In addition, Black Sea originated Ammonia parasovica was found for the first time in cores taken from Gemlik Gulf. Nannofossil species characterizing the open-shallow marine environment Emiliania huxleyi, Reticulofenestra parvula, Coronosphaera spp., Syracosphaera spp., Helicosphaera spp. beside Gephyrocapsa oceanica, small Gephyrocapsa spp., Scyphosphaera porosa were obtained. A total of 27 genera and 37 species from ostracods were defined in the samples from gulf. Moreover, the quite abundant mollusc assemblage characterizing the shallow marine environment and fewer genera and species of diatoms were identified. The studied sequence is represented by NN21 Emiliania huxleyi biozone at the Holocene. Foraminifers and ostracods of the Gemlik Gulf are observed as Mediterranean-Aegean Sea originated assemblages. The mollusc shows the shallow marine community.Öğe Fauna and flora of drilling and core data from the Iznik Lake: the Marmara and the Black Sea connection(Pergamon-Elsevier Science Ltd, 2018) Meriç, Engin; Nazik, Atike; Yümün, Zeki Ünal; Büyükmeriç, Yeşim; Avşar, Niyazi; Yıldız, Ayşegül; Gokasan, ErkanThe study deals with on the Quaternary connection of the Iznik Lake between the Gemlik Gulf and the Black Sea located in the Marmara Region. The core and drilling data were evaluated. They were collected at two locations and depths from drilling cores and at the three deepest locations of the lake. A total of 510 samples were examined from the lake-bottom cores. Ostracod, mollusc, nannoplankton, ascidian spicule, and diatom assemblages observed at different levels of the drillings were studied. No foraminiferal data were recorded. Molluscan association such as Dreissena bugensis, D. caspia, Monodacna pontica, Clathrocaspia makarovi, Euxinipyrgula milachevitchi, Euxinipyrgula lincta indicate Neoeuxinian age. Amnicythere olivia, A. stepanaitysae, A. striatocostata, Tyrrhenocythere amnicola and Loxoconcha immodulata of the ostracod assemblage, exhibiting Ponto-Caspian origin, were found. In addition, fossil ascidian spicules comprising various species of Bonetia, Micrascidites, Monniotia, and Rigaudia genera were encountered, probably representing Late Pleistocene to Holocene ages. Campylodiscus echeneis, Cocconeis placentula var. lineata Epithemia turgida var. granulata, Epithemia adnata, Nitzschia commutate and N. vermicularis, from the diatom assemblage are genera and species also found in the Iznik Lake and in the Black Sea. Mollusc and ostracod fauna, the Ponto-Caspian origin indicates that the Iznik Lake was connected with the Black Sea and the Marmara Sea in the recent period. Thus, the Ponto-Caspian assemblages indicate the early Neoeuxinian (Surozhian) brackish water inundated the study area. Geochronological ages determined by the C-14 method from the deposits occurring at 53-54 m above present sea level in the Iznik Lake indicate the periods of connection via Iznik Lake during 33,630 to 32,920 cal BP (SK-1) and BP 27,335 to 27,070 cal BP (SK-2). When the position of the deposits is compared with the previously available Late Pleistocene C-14 data obtained from the molluscs identified in the nearby Gemlik Gulf at -76 m present water depth and also with the early Khazarian (Middle Pleistocene) age data on the molusc fauna at 130-150 m heights of uppermost terraces above present sea level to NW of the lake, we suggest the influence of a neo-tectonic regime for the occurrence of comparable age deposits at different levels in the region. It may be proposed that a vertical displacement in the order of a 100 m occurred since the late Pleistocene in the Iznik Lake area and the lake acquired its present features as a result of the tectonic movements. (C) 2017 Elsevier Ltd and INQUA. All rights reserved.Öğe Meiofauna, microflora and geochemical properties of the late quaternary (Holocene) core sediments in the Gulf of Izmir (Eastern Aegean Sea, Turkey)(Pergamon-Elsevier Science Ltd, 2016) Yümün, Zeki Ünal; Meriç, Engin; Avşar, Niyazi; Nazik, Atike; Barut, İpek F.; Yokeş, Baki; Kaya, SeyhanThe Gulf of Izmir has seen the construction of marinas at four locations; Karsiyaka, Bayrakli, inciralti and Urla (Cesmealti). Six drilling holes have been structured for each location. Morphological abnormities observed in foraminifer tests, obtained from these core drillings, and coloring encountered in both foraminifer tests and ostracod carapeces, provide evidence of natural and unnatural environmental pollution. The objectives of this study are to identify micro and macro fauna, foraminifers in particular, contained within sediments in the above-mentioned locations; to investigate the background of pollution in the Gulf Region; and to determine pollution's impact upon benthic foraminifer and ostracods. Cesmealti foraminifera tests did not lead to color and morphological changes. But foraminifera tests samples collected from Karsiyaka, Bayrakli and Inciralti led them to turn black (Plate 4-6). However, concentrations of heavy metals (Ni, Cr and Mn) obtained from the sediments of Karsiyaka, Bayrakli and Inciralti locations are higher than those obtained from the cesmealti samples and high concentrations of these elements may be the cause of the color change in the samples during the foraminifera tests. In Karsiyaka and Bayrakli ostracod samples, Bosquetina carinella, Pterygocythereis jonesi, Semicytherura species; in the Cesmealti/Urla zone, Cyprideis torosa; in Inciralti, Pseudopsammocythere reniformis; and in four zones, Loxoconcha and Xestoleberis species were observed in the range of relative frequency. The same analyses were done on nannoplankton but they did not lead to color and morphological changes. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Recent Marine Ostracods (Crustacea) around Hovgaard and Horseshoe Islands (Antarctica Peninsula)(Tmmob Jeoloji Muhendisleri Odasi, 2022) Nazik, Atike; Büyükmeriç, Yeşim; Kılıç, Ali Murat; Yümün, Zeki ÜnalOn the route of the II Turkish Antarctic Expedition (TAE-II) in the NW of the continent of Antarctica, twelve grab sediment samples were been collected from seven different locations at depths of -20 and -60 m between King George and Horseshoe islands in NW Antarctica. The collected samples consist of greenish gray silty clay and fine sandy silt, as well as brownish gray sandy silty clay units containing fine gravel grains. In the Hovgaard and Horseshoe islands, six genera and six species of ostracods were identified: Copytus caligula Skogsberg, Austrotrachyleberis antarctica (Neale), Australicy there devexa (Muller), Cativella bensoni Neale, Cytheropteron acuticaudatum Hartmann and Loxoreticulatum fallax (Maller). The species are cryophilic endemic ostracods. When the fossil and current findings are compared, Austrotrachyleberis antarctica, which has been known since the Oligocene, migrated from Antarctica to South America and Cativella bensoni migrated from South America to Antarctica.Öğe Subrecent charophyte flora from Çesşmealti (Izmir Gulf, Western Turkey): Palaeoecological implications(Elsevier, 2023) Demirci, Elvan; Sanjuan, Josep; Nazik, Atike; Meriç, Engin; Yümün, Zeki ÜnalA charophyte assemblage from lower Holocene sediments in ces,mealti (Izmir Gulf, Turkey) is described and illustrated for the first time here. This assemblage is composed of well-preserved gyrogonites and oospores of Lamprothamnium papulosum, which occur in association with seeds of Ruppia cf. maritima and up to eight ostracod species and 22 benthic foraminiferal taxa. The fossil assemblage was extracted from five clay intervals of the SK-2 borehole. The presence of monospecific assemblages of L. papulosum indicates that very shallow (up to 1 m deep), brackish, alkaline, and oligotrophic waters prevailed in the gulf under strong seasonality (marked cyclical changes in humidity and/or temperature). The dominance of germinated gyrogonites suggests that the water salinity of the lagoon decreased during the humid season, reaching at least 10 parts per thousand. The associated ostracod fauna supports the palaeoenvironmental conditions inferred from the flora. Despite the gulf receiving considerable freshwater input, it remained semiconnected to the sea, as indicated by the diverse foraminifera assemblage. The availability of freshwater in the Izmir Gulf during the early Holocene Climatic Optimum, between-9000 and 5000 years BP, might have played an important role for the first human settlements in the area dating back 5500 years BP.
