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Öğe Decapod crustaceans on the Gokceada (Imbros) island continental shelf (north-eastern Aegean Sea)(Natl Centre Marine Research, 2006) Ates, A. S.; Katagan, T.; Kocatas, A.; Sezgin, M.The present composition of decapod crustaceans found at the sublittoral depths (5-104 m) off the coast of the island of Gokceada (north-eastern Aegean Sea) is presented. A total of 28 species (11 caridean shrimps, 1 thalassinid ghost crab, 7 anomurans and 9 brachyuran crabs) and 277 specimens were recorded. The caridean shrimp, Athanas nitescens had the highest abundance with a dominance value of 20.94% in samples. The dominant group is caridean, represented by a total of 11 species and an occurrence frequency of 39.29%.Öğe DIVERSITY AND BATHYMETRIC DISTRIBUTION OF DECAPOD CRUSTACEANS ATTRACTED TO BAITED TRAPS FROM THE MIDDLE SLOPE OF THE NORTHERN AEGEAN SEA(Brill Academic Publishers, 2014) Gonulal, O.; Sezgin, M.; Ozturk, B.We sampled the decapod crustaceans inhabiting the depth zone between 500 and 1500 m off Gokceada Island (northern Aegean Sea) from May 2010 to November 2011. The deep-slope decapod fauna of the northern Aegean Sea was sampled with baited traps. A total of 23 species of decapods have been identified at 32 stations. The results were analysed in terms of composition and distribution of benthic and benthopelagic bait-attracted species between regions. In addition, they were compared between stations in relation to the depth gradient. The results are discussed in relation to previous studies carried out in the eastern and western Mediterranean. Also, the use of traps is commented for different regions and the effects of the sampler on benthic species are discussed. The most common species was the penaeid shrimp, Parapenaeus longirostris in samples taken between 500 and 600 m. It is followed by Polycheles typhlops and the pandalid shrimp Plesionika martia martia. These species constitute more than 50% of all decapods. Differences among the strata at 500-1500 m depth were tentatively explained using the Shannon-Weaver diversity index (H'). The highest H' value was found for the 800-1000 m depth strata. The lowest number of species was observed between 1000 and 1500 m, which lowered the diversity index values (H'). The results of similarity percentage analysis (SIMPER) showed a change in the decapod fauna below 1000 m depth. The present results are preliminary; further data collection and analysis will be required to evaluate the role of palaeoecolgical conditions and trophic factors, and how these could be supposed to interact.Öğe LIKELY EFFECTS OF GLOBAL CLIMATE CHANGE ON THE BLACK SEA BENTHIC ECOSYSTEM(Scibulcom Ltd, 2010) Sezgin, M.; Bat, L.; Katagan, T.; Ates, A. S.Occurrence and distribution of species in the Black sea are primarily determined by seawater temperature and salinity. The most recent predictions suggest that, by 2100, average air temperatures may be between 2 and 4 degrees C higher than at present and seawater temperatures may be as much as 2 degrees C higher than in 2000. The rise of the coastal zone seawater temperature may be higher than the open sea water average. It is expected that a warming of air and seawater temperatures will result in increased diversity of benthic marine life in the Black sea with adverse effects limited mainly to declines in abundance or loss of a small number of native species. Changes to a minority of biotopes might occur in the long-term. Depending on the temperature increase Mediterranisation of the Black sea fauna is in progress and occurs owing to immigration of new species. The aim of this article is discussing the global warming and the range of likely effects on marine benthic species. These effects may be related to changing water temperatures, changing water circulation or changing habitat. At present, to predict or detect the effects of climate change on marine benthic communities are quite difficult. But we can only provide educated guesses about potential changes and the consequences of those changes for the Black sea.Öğe NEW RECORDS OF DECAPOD CRUSTACEANS FROM THE DEEP AEGEAN SEA OF TURKEY(Brill Academic Publishers, 2014) Gonulal, O.; Sezgin, M.; Ozturk, B.[No abstract available]Öğe Persistence of phylogeographic footprints helps to understand cryptic diversity detected in two marine amphipods widespread in the Mediterranean basin(Academic Press Inc Elsevier Science, 2019) Hupalo, K.; Teixeira, M. A. L.; Rewicz, T.; Sezgin, M.; Iannilli, V.; Karaman, G. S.; Grabowski, M.Amphipods of the genus Gammarus are a vital component of macrozoobenthic communities in European inland and coastal, marine and brackish waters of the Mediterranean and the Black Sea. Exceptional levels of cryptic diversity have been revealed for several widespread freshwater Gammarus species in Europe. No comprehensive assessment has yet been made for brackishwater counterparts, such as Gammarus aequicauda and G. insensibilis, which are among the most widely dispersed members of the so-called G. locusta group in the Mediterranean and in the Black Sea. Here we probe the diversity of these morphospecies examining the partitioning of mtDNA and nDNA across multiple populations along their distribution range and discuss it within the regional paleogeographic framework. We gathered molecular data from a collection of 166 individuals of G. aequicauda and G. insensibilis from 47 locations along their distribution range in the Mediterranean including the Black Sea. They were amplified for both mitochondrial COI and 16S rRNA as well as the nuclear 28S rRNA. All five MOTU delimitation methods (ABGD, BIN, bPTP, GMYC single and multiple threshold models) applied revealed deep divergence between Black Sea and Mediterranean populations in both G. aequicauda and G. insensibilis. There were eight distinct MOTUs delimited for G. aequicauda (6-18% K2P) and 4 MOTUs for G. insensibilis (4-14% K2P). No sympatric MOTUs were detected throughout their distribution range. Multimarker time-calibrated phylogeny indicated that divergence of both G. aequicauda and G. insensibilis species complexes started already in the late Oligocene/early Miocene with the split between clades inhabiting eastern and western part of the Mediterranean occurring in both species at the similar time. Our results indicate a high cryptic diversity within Mediterranean brackishwater Gammarus, similar to that observed for freshwater counterparts. Moreover, the phylogenetic history combined with the current geographic distribution indicate that the evolution of both studied Gammarus morphogroups has been strongly connected with the geological events in the Mediterranean Basin and it reflect the turbulent history of the area.
