The Gulf of Izmir has seen the construction of marinas at four locations; Karşıyaka, Bayraklı, İnciraltı and Urla (Çeşmealtı). 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.
Çeşmealtı foraminifera tests did not lead to color and morphological changes. But foraminifera tests samples collected from Karşıyaka, Bayraklı and İnciraltı led them to turn black (Plate 4–6). However, concentrations of heavy metals (Ni, Cr and Mn) obtained from the sediments of Karşıyaka, Bayraklı and İnciraltı locations are higher than those obtained from the Çeşmealtı samples and high concentrations of these elements may be the cause of the color change in the samples during the foraminifera tests. In Karşıyaka and Bayraklı ostracod samples, Bosquetina carinella, Pterygocythereis jonesi, Semicytherura species; in the Çeşmealtı/Urla zone, Cyprideis torosa; in İnciraltı, 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.
•In this report; Organic and inorganic properties of Holocene sediments were firstly revealed in the Gulf of Izmir (Eastern Aegean Sea, Turkey). Studies have focused on the four locations; Karşıyaka, Bayraklı, İnciraltı and Urla (Çeşmealtı). Morphological abnormities observed in foraminifer tests, obtained from all core drillings, and coloring encountered in both foraminifer tests and ostracod carapeces, provide evidence of natural and unnatural environmental pollution.•Çeşmealtı foraminifera tests did not lead to color and morphological changes. But foraminifera tests samples collected from Karşıyaka, Bayraklı and İnciraltı led them to turn black. However, concentrations of heavy metals (Ni, Cr and Mn) obtained from the sediments of Karşıyaka, Bayraklı and İnciraltı locations are higher than those obtained from the Çeşmealtı samples and high concentrations of these elements may be the cause of the color change in the samples during the foraminifera tests.•In Karşıyaka and Bayraklı ostracod samples, Bosquetina carinella, Pterygocythereis jonesi, Semicytherura species; in the Çeşmealtı/Urla zone, Cyprideis torosa; in İnciraltı, Pseudopsammocythere reniformis; and in four zones, Loxoconcha and Xestoleberis species were observed in the range of relative frequency.
The concentrations of gross alpha and gross beta radioactivity were analyzed in Holocene sediments of the Gulf of Izmir (Eastern Aegean Sea). The sediments were collected from four different ...locations affected by industrial activities, overpopulation, and shipping in the Gulf of İzmir. Each sample was determined for gross alpha and gross beta radioactivity by using a low-background counter (Berthold, LB 770 10 - channel low-level counter). The obtained results show that natural gross alpha and gross beta activity concentrations in the drilling cores range from 537 77 to 1800 207 Bq kg-1 and 993 60 to 1842 102 Bq kg-1, respectively. These results were compared with previous studies throughout the world, and the study could be a reference data for the future researches related to radiological mapping or environmental monitoring in the area.
The 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 İznik Lake and in the Black Sea. Mollusc and ostracod fauna, the Ponto-Caspian origin indicates that the İznik 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 14C method from the deposits occurring at 53–54 m above present sea level in the İznik 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 14C 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 İznik Lake area and the lake acquired its present features as a result of the tectonic movements.
In this study, the heavy metal and radioactive properties of Iznik Lake were investigated. Concentration values of the first (Ag, Bi, Mo, Sn, Se, Zn, As, B, Cd, Co, Cr, Cu, Ni, Pb, Pt and Sb) and ...second (Na, Mg, K, Ca, P, S, Fe, Al and Mn) group of elements in borehole 1 (BH-1) drilling did not show much variation from the top to the bottom of the drilling. Concentration values of the first group of elements in borehole 2 (BH-2) drill samples decreased at higher levels of drilling. In addition, natural and anthropogenic radionuclides were measured by gamma spectrometry, and the results of environmental natural radioactivity of Iznik Lake and its surroundings were determined. In the measurement results, Ra-226 was found to be below the world average value at all locations. It is assumed that the determination of K-40 values above the average values was due to agricultural activities carried out intensively in the study area. Th-232 values were found to be below the world average value in drilling samples; Cs-137 values were below the background level in all samples. According to these results, the study area does not contain any unnatural radioactivity.
The Sea of Marmara is under the influence of the Black Sea and the Mediterranean. The salinity difference between these two seas causes the formation of two-layer stratification in the Sea of ...Marmara, an upper layer formed by the fresh waters of the Black Sea and a denser layer formed below 25 m of depth, by the more saline waters of the Mediterranean. The salinity difference, together with the seasonally changing meteorological events are the major factors which shape the main current system. The Mediterranean waters enter the Dardanelles cross the Sea of Marmara and flows into the Black Sea via İstanbul Strait, which enables the dispersion of the alien foraminifer species already established on the Aegean coasts into the Sea of Marmara. Besides, the Sea of Marmara includes important harbors, suggesting that there is an extensive pressure of alien species introduced by ballast waters. In this study, 322 sediment samples, obtained from different localities in Dardanelles, İstanbul Strait and Sea of Marmara, were investigated for the alien foraminifer species. The results are combined with the previous records in the literature for creating an alien foraminifer checklist for the Sea of Marmara. 10 alien foraminifer species belonging to 9 genera were found in Dardanelles, 32 alien species from 28 genera in the Sea of Marmara, and only 2 alien species from 2 genera were found in İstanbul Strait. Majority of these alien species have Indo-Pacific or Atlantic origin, suggesting that shipping may be the most possible mode of introduction. But it is also observed that some of the Indo-Pacific originated species which were introduced Suez Canal and formed established populations along the Turkish coastline are also found in Dardanelles, indicating that major currents systems are also playing a role in the dispersion patterns of the alien foraminifers in the Sea of Marmara. Another important factor may be the thermal submarine springs found on the bottom of the Sea of Marmara, which may create suitable environmental conditions and enhance the establishment of thermophilic alien species.
Four alien foraminifer species are found in the recent
sediment samples collected from the Aegean coast of Turkey. Nodobaculariella cristobalensis McCulloch and N.
galapagosensis McCulloch are ...observed in Güllük Bay (Muğla), Karşıyaka
(İzmir) and Babakale (Balıkesir). These two species have not yet been recorded
in the Mediterranean. Their absence in the Indian Ocean fauna suggests an
introduction via ballast waters. Two individuals of Indo-Pacific originated
foraminifer species, Pseudonodosaria
brevis (d'Orbigny, 1846) are found in the recent sediment samples from
Ildır Bay (İzmir) and Akköy (Aydın). This constitutes the first records of
these species in the Mediterranean Sea. Cornuspiroides
striolata (Brady) specimens are observed in grab samples collected from
seven different stations in Ildır Bay. This is the second record of this
species from the Turkish coastline and extends its range of distribution.
This study was carried out in order to calculate the
concentrations of radioactivity in the natural Kulakcayırı Lake of Istanbul
(Turkey). Three core samples were taken from Kulakcayırı Lake by ...drilling and
taken from heights of 5-5.5 m, 10-10.5 m and 15-15.5 m at the same point and
then moved to the laboratory. According to the laboratory results, the K-40
concentrations of the samples were 325 ± 18 Bq/kg, 353 ± 19 Bq/kg and 367 ± 19
Bq/kg, while their Th-232 concentrations were 38 ± 6 Bq/kg, 43 ± 6 Bq/kg and 42
± 6 Bq/kg, respectively. Their concentrations of Ra-226 were calculated as 29 ±
5 Bq/kg, 26 ± 5 Bq/kg and 26 ± 5 Bq/kg, while the Cs-137 concentrations of the
three samples were calculated as ≤MDA (Minimum Detectable Activity) and existed
at very low concentrations. The average activities of K-40, Th-232, Ra-226 and
Cs-137 were found to be 348 ± 186 Bq/kg, 41 ± 6.3 Bq/kg, 27 ± 5.1 and ≤MDA,
respectively. The results were compared with those of similar studies. These findings and assessments are expected to be an example for future
studies and to be of reference quality.
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