Deliceırmak, Selin
Despite the many important roles, they play, bacteria are one of the least known components of the marine biogeochemical cycles. In order to determine the temporal dynamics of the species composition, and active metabolisms playing significant roles in the nitrogen cycling we used the power of novel genetic analyses and integrate biochemical measurements. Community dynamics were studied using 16S rRNA amplicon sequencing approach. Samples were collected with monthly intervals for one year from different depths of monitoring station (bottom depth 200 m) in the NE Mediterranean. mRNA expressions of genes that are responsible for nitrogen cycling were investigated seasonally using metatranscriptomics. In total, 2213 sequence variants were observed among which Proteobacteria, Bacteroidetes and Cyanobacteria were the mostly observed phylum. In the higher taxonomic level, SAR 11 clade belonging to Pelagibacteriaceae was highly dominant in our samples and its ecotypes show variation with depth. While Clade Ia more dominant in the surface waters, Clade Ib was abundant in the deeper waters. Seasonality found to be the main driver for patterns in bacterial communities. Prochlorococcus MIT 9313 was more abundant than Synechococcus CC9902 in the surface during fall. Prochlorococcus MIT 9313 contributes more to the formation of DCM in our region. Additionally, metatranscriptomics results showed that the nitrogen fixation is not the dominant process in the study region. Genus Nitrospinae are responsible for the high concentrations of nitrate in the deeper waters. We showed the importance of bacteria in the carbon and nitrogen cycling in the NE Mediterranean.


Modelling phytoplankton succession on the Bering Sea shelf: role of climate influences and trophic interactions in generating Emiliania huxleyi blooms 1997-2000
Merico, A; Tyrrell, T; Lessard, EJ; Oguz, T; Stabeno, PJ; Zeeman, SI; Whitledge, TE (Elsevier BV, 2004-12-01)
Several years of continuous physical and biological anomalies have been affecting the Bering Sea shelf ecosystem starting from 1997. Such anomalies reached their peak in a striking visual phenomenon: the first appearance in the area of bright waters caused by massive blooms of the coccolithophore Emiliania huxleyi (E huxleyi). This study is intended to provide an insight into the mechanisms of phytoplankton succession in the south-eastern part of the shelf during such years and addresses the causes of E. hu...
Application of in situ Solid-Phase Microextraction on Mediterranean Sponges for Untargeted Exometabolome Screening and Environmental Monitoring
Bojko, Barbara; Onat, Bora; Boyacı, Ezel; Psillakis, Eleftheria; Dailianis, Thanos; Pawliszyn, Janusz (Frontiers Media SA, 2019-10-11)
In marine ecosystems, sponges are ubiquitous sessile organisms that contain a wide range of specialized metabolites. These metabolites point to a diverse range of biochemical pathways. Some of these compounds are biomarkers that indicate the presence of bacteria that form symbiotic relationships with a host sponge (microsymbionts). Sponges hold considerable promise as bioindicators for seawater quality monitoring, as they are exposed to, and accumulate, significant levels of anthropogenic contamination in c...
Comparison of Offshore and River Influenced Coastal Waters in the Eastern Mediterranean
Doğan Sağlamtimur, Neslihan; Tuğrul, Süleyman (2008-01-01)
Depending on the environmental condition and antropogenic nutrient supply, organic matter production and chemical composition show spatial and temporal variabilities in marine environment. The Eastern Mediterranean is known to be one of the oligotrophic seas, where the surface inorganic phosphate and nitrate concentrations vary in the range of 10 to 20 nM and 0.10 to 0.30 mu M, respectively. Primary production is, therefore, mainly controlled by phosphate. The exceptionally low phosphate concentrations have...
Simulation of an integrated microfluidic device for bioparticle wash separation and concentration
Çetin, Barbaros; Süleyman, Büyükkoçak; Soheila, Zeinali; Özer, Mehmet Bülent (null; 2013-12-14)
Washing, separation and concentration of bioparticles are key operations for many biological and chemical analyses. In this study, the simulation of an integrated microfluidic device is studied. The proposed device has the capability to wash the bioparticles (transferring the bioparticles from one buffer solution to another), to separate the particles based on their dielectric properties and to concentrate the bioparticles. Washing and concentration of bioparticles are performed by acoustophoresis and the s...
Investigation of gas seepages in Thessaloniki mud volcano in the Mediterranean Sea
MEREY, ŞÜKRÜ; Longinos, Sotirios Nik (2018-09-01)
Gas seepages are commonly observed in marine environment. Especially, gas seepages due to anthropogenic gas hydrate dissociation are big concerns recently. In the Eastern Mediterranean Sea, Thessaloniki mud volcano was detected. Gas hydrate stability conditions in this mud volcano is very fragile. For this reason, in this study, gas seepages were predicted by using HydrateResSim at different seafloor temperature increments varying from 1 to 5 degrees C and different sediment permeability values varying from...
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