13 research outputs found

    On the Presence of Alien Foraminifera Amphistegina lobifera Larsen on the coasts of the Maltese Islands

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    A novel application of queueing theory on the Caulerpenyne secreted by invasive Caulerpa taxifolia (Vahl) C.Agardh (Ulvophyceae, Caulerpales): a preliminary study

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    Aquarium originated marine green alga Caulerpa taxifolia was introduced into the Mediterranean Sea accidentally in 1984. This invasion has been negatively affecting the sub-littoral ecosystem of the Mediterranean. One of the important reasons for its success in the Mediterranean is its secondary toxic metabolite called caulerpenyne (CPN). Furthermore, CPN has anti-proliferative and apoptotic activities, therefore, CPN can be considered as a potential native source in cancer therapy. For that reason, modeling this metabolite might be of importance. Increase and decrease of the CPN level before reaching the critical level can be expressed by means of a queueing system in which the number of ‘customers' increases and decreases. In fact, production of CPN shows fluctuations for many environmental reasons, which allow us to apply queueing theory. In the present study, the expected time to reach the maximum caulerpenyne level was analyzed and evaluated using queueing theory

    The origin and dispersal pathway of the spotted sea hare Aplysia dactylomela (Mollusca : Opisthobranchia) in the Mediterranean Sea

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    The spotted sea hare Aplysia dactylomela Rang, 1828 is a large and conspicuous opisthobranch sea slug that since 2002 has rapidly colonized the eastern Mediterranean, establishing populations in numerous localities. The source of the Mediterranean populations has been the subject of debate, with two main hypotheses considered (Atlantic and Red Sea origin). A recent study on the taxonomy of A. dactylomela has shown that the spotted sea hare is a complex of at least two genetically distinct species (A. dactylomela in the Atlantic and A. argus in the Indo-Pacific), facilitating the correct identification of Mediterranean specimens by molecular means. We used sequence data from the mitochondrial cytochrome oxidase I gene to identify the Mediterranean individuals for the first time and to infer their origin. Our results confirmed that all the specimens collected in the Mediterranean belong to A. dactylomela and therefore have an Atlantic origin. The limited sample size does not allow identification of the dispersal pathway of A. dactylomela into the Mediterranean, but the colonization sequence is consistent with a “natural” dispersal event. This hypothesis is evaluated in light of local surface circulation patterns. Possible causes for the recent and rapid invasion of the eastern Mediterranean by A. dactylomela are discussed.peer-reviewe

    Palaentological Findings on Historical Coastal Inundation Events on the Eastern Coastal Plain of the Gulf of Saros, Turkey

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    WOS: 000486426300004Significantly rich assemblages of foraminifera (11 samples), ostracoda (8 samples) and mollusca (7 samples) have been detected from the 14 samples recovered from the salty swamp plain behind a dunefield along the eastern coast of the Gulf of Saros, North Aegean Sea. Preliminary paleontological findings, together with the Optically Stimulated Luminescence (OSL) late Quaternary dating technique, have indicated that big-scale storm waves and occasional tsunamis have inundated the large coastal areas at the eastern part of gulf, as much as a few kilometres, in the past, at least during the last 2200 years

    The effects of submarine springs on meiobenthic assemblages (benthic foraminifers, ostracods and molluscs) on the coasts of Aliaga (Izmir)

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    WOS: 000455157100002Many scientific researches have been done on different faunal assemblages in relation to the environmental condition from thermal sources located on the eastern Aegean Sea coast. Aliaga (Izmir) region has also thermal resources. These two thermal springs are closely located on the coast of Ilica Cape, northwest of Aliaga (Izmir) and northwest of Karaagac Cove. Their temperatures are 40 degrees C and 51 degrees C, respectively. The bottom deposits consist of rock fragments, gravel, sand, silt and clay units in the study area. In this research, 13 bottom sediment samples taken from different points and corresponding depths in the sea between the Ilica Cape and the Tasli Cape were examined. Heavy metal analysis in the sediment samples were done by using ICP-MS. In addition, the results of trace element analysis and total Alpha and Beta features in the samples taken from the sea surface and spring waters were evaluated. The aim is to interpret meiobenthic living conditions by investigating on the effect of thermal springs the benthic foraminifera, ostracod and mollusk assemblages in this region. It was observed that the typical Aegean Sea foraminifera fauna composed of 32 genera and 50 species predominated in the studied samples. An important peculiarity of the region is absence of amphistegina lobifera and peneroplid genera and species commonly observed in the Aegean coasts of Turkey. Widely known nineteen genera and twentyeight species from Ostracods were found in Mediterranean and Aegean Sea. Mollusc faunas consist of 9 genera and 10 species from gastropods, 14 genera and 14 species from bivalves. The other an important finding in the deposits are the presence of numerous gypsum crystals in sample A11. This finding is an indication of an old thermal source. Furthermore, distribution of zinc (Zn), lead (Pb), Cooper (Cu) and arsenic (As) as the heavy metals in the same sample were found to be the highest. In these examples, a few species of foraminifera and only one species from ostracods and bivalves were found

    The effect of submarine thermal springs of Doganbey Cape (Seferihisar - Izmir) on foraminifer, ostracod and mollusc assemblages

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    WOS: 000438832800005The aim of this study was to figure out the effects of the submarine hot water springs located on the coast of Doganbey Cape (north of Kusadasi Bay) on various micro- and macrofaunal assemblages living around these springs. Young sediment samples were collected from different depths at 15 stations. The benthic foraminifer, ostracod and mollusc faunas were investigated. 35 genera and 61 species of benthic foraminifers, 16 genera and 20 species of ostracods and 14 genera and 15 species of molluscs were identified. Typical Aeegan foraminifer fauna was found to be dominant. Besides, individuals with colored tests or abnormal morphology, as well as alien species, which are frequently observed on the Aegean coasts were also observed in the study area. The foraminifer, ostracod and mollusc species also constituted typical Aegean fauna. It is known that the ecological conditions experienced of the Amphistegina lobifera Larsen individuals in typical Aegean benthic foraminifer assemblage have an effect on the abundance distribution. Ideal conditions for Amphistegina lobifera Larsen was found to be 18.00-32.00 m depth range and 19-20 degrees C temperatures. CTD conductivity values gradually increased near to the hot water spring but a decrease in the number of individuals were observed. Chemical analyzes in sediment samples were performed with X-Ray Fluorescence Analysis Spectrometer (WDXRF). Heavy metal ingredients (Cr, Mn, Co, Ni, Cu, Zn and Pb) of the sediments were evaluated, concentrations were recorded as Cr>Ni>Mn in samples DB1-DB6 and also in DB15; Mn>Cr>Ni in DB8-DB11 and DB13-DB14; Cr>Mn>Ni in DB7 and in DB12. The radioactive elements U and Th were found to be high in DB9, DB10 and DB11. The chemical and radioactive properties of the sediments were observed to affect the tests of benthic foraminifers, where as no such effect was found on ostracod and mollusc tests

    Did Amphistegina lobifera Larsen reach the Mediterranean via the Suez Canal?

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    WOS: 000374478500007It has been accepted by many researchers that Amphistegina lobifera Larsen migrated to the Mediterranean Sea via Suez Canal like many other Indo-Pacific originated foraminifers and organisms. This idea was also supported in the studies performed on the Turkish Aegean and Mediterranean coast in the last ten years, due to the discovery of alien benthic foraminifers. However, during field research in the Akkuyu (Mersin) region, a rich benthic foraminifera assemblage was found in the sediment samples, in which Amphistegina lobifera Larsen was abundant. In the present study, when and how Amphistegina lobifera Larsen migrated to the Mediterranean was investigated. Most of the Amphistegina lobifera Larsen individuals observed are found to show similar morphological characteristics with recent samples collected from Turkish coastline, which at first indicated that the individuals from Akkuyu might also be of Holocene age, but the OSL method produced dates of 227.3 +/- 17.8, 87.7 +/- 9.6 and 6.0 +/- 0.6 ka. These ages are Middle Pleistocene, Late Pleistocene and Holocene. In one sample, aged 427.5 +/- 29.4 ka, Spiroloculina antillarum d'Orbigny, which was suggested to be introduced to Mediterranean via the Suez Canal, was found together with Articulina carinata Wiesner. The presence of Spiroloculina antillarum d'Orbigny with Amphistegina lobifera Larsen together with in an other sample, aged 227.3 +/- 17.8 ka, indicates that these foraminifers have been introduced to the Mediterranean in Middle Pleistocene and they might have been living in the Eastern Mediterranean since then. As a result, these age data show that Amphistegina lobifera Larsen individuals did not migrate to the eastern Mediterranean via the Suez Canal which was opened in 1869, but much earlier than that via a different natural water way connecting Indo-Pacific to the Eastern Mediterranean. (C) 2015 Elsevier Ltd and INQUA. All rights reserved
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