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Marine environments are subject to various naturally occurring phenomena, including marine snow and mucilage. In 2021, the rapid emergence of mucilage in the Marmara Sea raised concerns about its environmental impact. This study investigates the microbial communities in mucilage and seawater samples from the Marmara Sea using metagenomic-scale comparative analyses. The results indicate significant differences in microbial composition and diversity, with mucilage samples showing higher levels of polysaccharide biosynthesis-related enzymes. Over 50% of reads in mucilage samples remained unclassified (dark matter), highlighting unknown microbial taxa. Clean seawater was characterized by a higher presence of Euryarchaeota, Proteobacteria, and Rhodothermaeota, while Chlamydiae and Fusobacteria were dominant in mucilage. The study underscores the necessity for comprehensive metagenomic analyses to understand microbial roles in mucilage formation and persistence. Early detection of microbial shifts could serve as a warning system for mucilage outbreaks, aiding in the development of management strategies. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the presence/abundance of microplastics and mold species in mussels and their implications for food safety and public health. Mussels, known to accumulate microplastics and mold species, were studied due to their role in the food chain. A sampling protocol covering a vast coastal area of Bursa Province along the Marmara Sea was implemented, gathering 410 raw mussel samples from 10 locations. After digestion with hydrogen peroxide, microplastics were examined using a stereomicroscope, and mold species were isolated and identified through matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis. A total of 496 microplastics were detected in the mussel samples, with fragment-type and black-colored microplastics being the predominant types. Results also revealed varying levels of microplastics contamination, with the highest rate recorded at Location 5 (28.02%). Notably, Location 5, characterized by its central yacht/boat harbor, exhibited the highest microplastics pollution, while Location 9, lacking such facilities, displayed the lowest contamination rate at 2.22%. Fragment-type microplastics were the most prevalent (26.1%), with black microplastics being the predominant color (38.51%). Among the 10 identified mold species, Penicillium and Aspergillus were the most prevalent. Notably, a remarkably high positive correlation was observed between fragment (r = .976; p < .001) and line (r = .888; p = .001) microplastics values. In the mussels collected from Location 5, where the highest microplastics were detected, three different species of mold were detected. In accordance with this result, the highest amount of mold belonging to two different genus were detected in the mussels from Location 2, where the second highest number of microplastics were detected. However, no correlation was found between the mold count and microplastics values. The presence of microplastics and mold in mussels underscores potential food safety and public health risks, emphasizing the need for ongoing monitoring and management to reduce these adverse effects. [ABSTRACT FROM AUTHOR]

There is an international pressure to increase the worldwide expanse of marine mussel farms. However, the mussel farms are challenged with environmental problems such as mucilage aggregate events. Thus, it is essential to assess the effects of mucilage on the mussel aquaculture and to eradicate the harm and socioeconomic effects they confer on society. Our study addressed this issue by establishing a demographic baseline for commercially important mussel species prior to the proposed aquaculture in the area. This baseline was established at a recently set up commercial mussel farm located approximately 4km north of Erdek port and around 2km from Ocaklar port in the Marmara Sea region of Türkiye. Monthly samples of spats attached to the collectors and mussel meat yields were addressed, and seawater temperature and chlorophyll a contents were measured throughout this study (36 months) conducted at a commercial mussel farm. Year-round biological data from 2019 to 2022 were recorded before, during, and after the mucilage event on the Mediterranean mussel, Mytilus galloprovincialis. Moreover, samples were taken from an area inside the mussel aquafarm. As a result of this study, differences before, during, and after the mucilage aggregate event were detected in the number of the Mediterranean mussel spat attached to the collectors and the meat yields of the farmed mussels. This demographic baseline is the only data available, at a sufficient spatial and temporal resolution, for evaluating the effects of a mucilage aggregate event in the mussel aquafarm, and it fills an important data gap for risk assessment. [ABSTRACT FROM AUTHOR]

This short communication reports an observation of a leatherback turtle Dermochelys coriacea in the İstanbul Strait (Bosphorus), Marmara Sea, on 9 July 2024. Leatherback turtles are occasionally reported in the Aegean and Mediterranean Seas of Türkiye. This is the northernmost record of the leatherback turtle in the Mediterranean Basin. As the importance of citizen science becomes more apparent and public awareness grows, access to observational information such as this will increase through digital technologies. [ABSTRACT FROM AUTHOR]

Thrace is a part of the Marmara Region northwest of Türkiye. This region hosts several lentic ecosystems used for irrigation and drinking water supply. The present study was conducted to analyze the temporal distributions of water quality parameters (WQPs) of lentic ecosystems (lacustrine habitats), including lakes (L1–L2), reservoirs (R1–R12), and ponds (P1–P19) of the Thrace Region. Thirty-three lacustrine habitats were identified in the region. Freshwaters were collected in the wet (end of winter) and dry (end of summer) seasons of 2021–2022 and tested for 12 WQPs. Data was evaluated for the water quality index (WQI) and nutrient pollution index (NPI) and their overall quality level. For the evaluation of non-carcinogenic health risk indices of WQPs, the chronic daily index (CDI), hazard quotient (HQ), and hazard index (HI) were applied. Cluster analysis (CA), Pearson correlation index (PCI), and principal component analysis (PCA) were used to classify the lacustrine habitats and identify the source of WQPs. The average values were as follows: 9.28 mg/L for dissolved oxygen (DO), 94.6% for oxygen (O2) saturation, 9.29 for pH, 613 μS/cm for electrical conductivity (EC), 3.96 NTU for turbidity, 358 mg/L for total dissolved solids (TDS), 3.17 mg/L for nitrate (NO3), 0.05 mg/L for nitrite (NO2), 1.01 mg/L for phosphate (PO4), 78.5 mg/L for sulfate (SO4), and 102 mg/L for chloride (Cl). Results showed a significant increase in WQPs, including NO3, NO2, and PO4, in the wet season, while the salinity decreased from the dry to wet season. Results revealed that HI values of water contaminants in lacustrine habitats were noted to be less than one. Based on determined WQPs, the present study recommends using lacustrine water habitats for irrigation, drinking, and other domestic and industrial purposes. [ABSTRACT FROM AUTHOR]

Urban wastewater treatment plants (WWTPs) are major contributors of microplastics (MPs) in the environment, despite achieving relatively high removal percentages. This study conducted a comprehensive assessment of the abundance and characteristics of MPs in wastewater and sludge at various treatment stages at Gebze WWTP located in the Marmara Sea, for the first time. The influent exhibited an average MPs concentration of 70.1 ± 28.6 MPs/L. After undergoing the fine screen and grit chamber units, the MPs concentration significantly reduced to 19.7 ± 3.6 MPs/L, indicating an impressive removal rate of 71.8%. Upon completion of the secondary treatment, the effluent contained 7.1 ± 1.7 MPs/L, resulting in an overall MP removal of 89.9–91.0%. The findings indicated that fibers constituted the predominant particle shape, followed by fragments. Fibers were effectively removed through primary treatment (71.8%), while fragments were efficiently removed during secondary treatment (81.1%). The analysis of sludge samples from the aeration basin and sludge thickening tank revealed higher concentrations, with 14.3 and 25 folds increase compared to the influent, respectively indicating the accumulation of MPs in sludge. Despite the treatment process, it is noteworthy that the effluent still exhibited a significant abundance of fibers. Micro-Raman analysis identified polyethylene and polypropylene as the main polymer types present. Although the WWTP demonstrated a high overall removal rate, an estimated 1022.4 × 106 ± 244.8 × 106 MPs/d were still being discharged with the effluent into the Marmara Sea. Recognizing the potential impact of MPs on marine organisms, measures, such as introduction of tertiary treatment processes, were taken to mitigate this issue. [ABSTRACT FROM AUTHOR]

Background and Aims: Sediment is the general name given to the muddy structure located at the bottom of aquatic environments such as the sea. In our study, the amounts of steroid hormones were investigated in the sediment samples taken from the Marmara Sea. According to other studies, it has been determined that the excess of the hormone load in the sediments may be an indicator of human/animal sourced pollution, as well as the negative effects of the hormones mixed in the seas with the ecological cycle on the health of humans and animals. Methods: In our study, 31 selected human/animal, plant, natural and synthetic hormone-steroids were studied using Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry (LC-ESI/MS-MS). Methanol and QuEChERS were used as extraction methods. Sediment samples were taken from a total of 27 points selected for sampling at the Marmara Sea. Results: According to the results we found, the androgens: androsterone (24.50-1718.18 ng g-1), testosterone (86.30-1600.32 ng g-1); the estrogens: mestranol (33.73-228.32 ng g-1), equilin (53.44-1232.53 ng g-1); the progestagens; pregnenolone (37.50-374.76 ng g-1), progesterone (39.96-405.60 ng g-1); levonorgestrel (325.25 and 937.93 ng g-1); the fecal sterols: cholestanone (57.57-1726.32 ng g-1), coprostanol + epicoprostanol (51.43-1370.33 ng g-1); and the plant sterol; campesterol (35.30-1859.90 ng g-1) were the compounds detected. Conclusion: Estrogens and progestogens are active components of birth control pills, and cholestanone and coprostanol + epicoprostanol are steroids that are indicative of human/animal pollution. Coprostanol + epicoprostanol and cholestanone, which are indicators of fecal pollution, were detected in all sediment samples. In our study, steroid hormones were detected for the first time in Sea of Marmara sediments and possible environmental risks were evaluated. [ABSTRACT FROM AUTHOR]

In April of both 2018 and 2019, one specimen each time of live Calanus finmarchicus adult females was found during collections of zooplankton samples near Sivri Ada in the Sea of Marmara. This was the first observation of live C. finmarchicus ( a native species of northern Atlantic waters) in the eastern Mediterranean Sea. This morphological study illustrates the similarity of C. finmarchicus specimens found in the Sea of Marmara with existing illustrations and descriptions of this species. It also shows the clear differences between this species and Calanus helgolandicus specimens collected during the same or earlier periods from the Marmara Sea. Transportation of C. finmarchicus to the Sea of Marmara is possible either via the lower current from the Aegean Sea or through the ballast waters of vessels. In any case, the occurrence of C. finmarchicus as a cold-water species in the Sea of Marmara is striking and attracts further investigations.

Türkiye's seas are the scene of the spread of invasive species in the entire Mediterranean basin due to the marine transportation of alien species and intensive aquaculture activities. In order to protect the natural ecosystem and track invasive species' effects, these species must first be accurately identified and their distribution areas specified. The alien species, Magallana gigas (Pacific oyster), has introduced along the Turkish coasts. This study was carried out to determine the morphometric characteristics of Magallana gigas in the Bandırma Bay-Balıkesir between November 2013 and October 2014. Shell length varied between 68.08 mm (February) and 93.14 mm (April) during the year. Shell height was measured at the lowest 41.90 mm in February, and the highest 59.46 mm in June. Shell width was 35.80 mm in November when the study started, and it decreased gradually and reached its lowest value in February. W/L relationship of M. gigas was calculated as W=0.411×L2.653(R²=0.064) This study includes knowledges on morphometric relationships for the Pacific oyster which is crucial for the management of fisheries, aquaculture activities and native species (Ostrea edulis). [ABSTRACT FROM AUTHOR]

The first morphologic and genetic documentation of the short-beaked garfish Belone svetovidovi Collette & Parin, 1970 from the coast of the Marmara Sea (Yalova) and Black Sea (Akcakoca) is reported in the present study. The morphological characters and genetic (mtDNA COI) analyses confirmed the existence of this species both in the Marmara and Black Seas. B. svetovidovi is genetically distinct from the anther species of this genus Belone belone. All morphologic measurements, counts, and colour descriptions of B. svetovidovi agree with its previous descriptions. [ABSTRACT FROM AUTHOR]

Tsunami risk is considered as the probability of a particular coastline being struck by a tsunami that may cause a certain level of impact (destructiveness). The impact metric of a tsunami is expressed in terms of tsunami intensity values, K, assigned on a 12-degree scale. To calculate tsunami risk we are based on the tsunami history of the region codified in tsunami catalogues. The probabilistic model adopted was used successfully for hazard assessment of earthquakes (Kijko et al. in Bull Seismol Soc Am 79:645–654, 2016) and of tsunamis (Smit et al. in Environmetrics 30:e2566, 2019) by considering seismic magnitude and tsunami height as metrics of the respective hazards. In this model, instead of hazard metrics we inserted risk metric, i.e. wave impact in terms of intensity values. The procedure allows utilization of the entire data set consisting not only from the complete (recent) part of tsunami catalogue but also from the highly incomplete and uncertain historical part of the catalogue. Risk is assessed in terms of probabilities of exceedance and return periods of certain intensity values in specific time frames. We applied the model using catalogues for the Mediterranean and connected seas. Sensitivity analysis showed that using complete data sets generally provided more realistic results than using entire data sets. Results indicated that the risk level depends on the seismicity level and not on the size of individual ocean basin. The highest tsunami risk level was found in the eastern Mediterranean (EM), with a significantly lower risk in the western Mediterranean (WM). In the Marmara Sea (MS), the tsunami risk was low, and the lowest was in the Black Sea (BS). The risk in the small Corinth Gulf (CG, Central Greece) was comparable to that of WM. The return period of damaging tsunamis (i.e. K ≥ 7) was 22 years in the entire Mediterranean basin and 31, 118, 135, 424, and 1660 years in the EM, WM, CG, MS, and BS basins, respectively. [ABSTRACT FROM AUTHOR]

In April of both 2018 and 2019, one specimen each time of live Calanus finmarchicus adult females was found during collections of zooplankton samples near Sivri Ada in the Sea of Marmara. This was the first observation of live C. finmarchicus (a native species of northern Atlantic waters) in the eastern Mediterranean Sea. This morphological study illustrates the similarity of C. finmarchicus specimens found in the Sea of Marmara with existing illustrations and descriptions of this species. It also shows the clear differences between this species and Calanus helgolandicus specimens collected during the same or earlier periods from the Marmara Sea. Transportation of C. finmarchicus to the Sea of Marmara is possible either via the lower current from the Aegean Sea or through the ballast waters of vessels. In any case, the occurrence of C. finmarchicus as a cold-water species in the Sea of Marmara is striking and attracts further investigations. [ABSTRACT FROM AUTHOR]

Strain energy from tectonic loading can be partly released through aseismic creep. Earthquake repeaters, repeatedly activated brittle fault patches surrounded by creep, indicate steady‐state creep that affects the amount of seismic energy available for the next large earthquake along a plate contact. The offshore Main Marmara Fault (MMF) of the North Anatolian Fault Zone represents a seismic gap capable of generating a M > 7 earthquake in direct vicinity to the mega‐city Istanbul. Based on a newly compiled seismicity catalog, we identify repeating earthquakes to resolve the spatial creep variability along the MMF during a 15‐year period. We observe a maximum of seismic repeaters indicating creep along the central and western MMF segments tapering off toward the locked onshore Ganos fault in the west, and the locked offshore Princes Islands segment immediately south of Istanbul in the east. This indicates a high degree of spatial creep variability along the Istanbul‐Marmara seismic gap. Plain Language Summary: The relative motion of tectonic plates deforms these plates along their contact zone until the plate contact ruptures in an earthquake. However, some of this deformation can be released without earthquakes by so‐called aseismic creep in which the plates creep past each other. Within this creep zone, sometimes some brittle patches exist that interlock during the plate creep and rupture repeatedly in smaller earthquakes that are very similar. They are called earthquake repeaters. In the Sea of Marmara south of Istanbul lies the contact between the Eurasian and the Anatolian plates, the so‐called Main Marmara Fault (MMF). This plate contact did not rupture for a long time and thus a large magnitude event is expected here. We observe a large number of earthquake repeaters in the western offshore part of the MMF while no earthquake repeaters are found toward the east south of Istanbul or onshore toward the west. These areas seem to be locked and might accumulate deformation for a future large earthquake. The zones in between show an intermediate behavior with fewer earthquake repeaters indicating less creep. These results are important for the seismic risk and hazard assessment for the mega‐city of Istanbul. Key Points: Earthquake repeaters along the Main Marmara Fault are identified based on a newly derived homogeneous earthquake catalog spanning 15 yearsSeismic creep estimated from these repeaters is highly variable along‐strike with higher creep values along the western partA repeating earthquake sequence showing accelerated activity after a nearby Mw 5.2 earthquake is observed [ABSTRACT FROM AUTHOR]

The scope of the study is to determine transtensional and transpressional features along the North Anatolian Fault beneath the Sea of Marmara, using seismic and geodetic data. For this purpose, focal mechanisms of small size NAF earthquakes, recorded by broadband stations and OBSs, have been derived and used as a tool to identify the transtensional and transpressional features. The focal mechanisms of: (1) small to moderate size events are obtained by the CMT inversion technique of Kuge (2003), using onshore waveform data from 2002-2015, (2) micro-earthquakes are obtained using the technique of Horiuchi (2015), using offshore waveform data recorded by 15 OBS stations from 2015-2016. Furthermore, published GPS velocities are used to determine the style of faulting and strain rates. The geodetic horizontal crustal strain rates are determined at equally spaced grid points by interpolating northing and easting components of the 112 GPS vectors from 1994-2013. The results indicate that extensional and strike-slip style deformation dominates the region, while contractional features are rare. Significant extension is observed in Çınarcık Basin and the area between Marmara Island and Central Basin. Yalova-Çınarcık region shows predominantly N-S extension while the Çınarcık Basin events show NE-SW extension. Compressional or transpressional features are derived to the west of Marmara Island and Ganos and in the Central segment extending from Central Basin toward Çınarcık Basin. The GPS strain rate results point out the highest values, 24 x 10-8/year, in Çınarcık Basin, while the lowest values, 11 x 10-8/year, are observed in Central Marmara. The highest strain rates in both edges of the fault segment in Çınarcık Basin can be indicative of a steadily creeping fault segment. In turn, lower strain rates in the Central Marmara region suggest that this segment of the NAF is locked. [ABSTRACT FROM AUTHOR]

This study examines the body wave attenuation characteristics for the eastern section of the Marmara Region (NW Turkey). Qp and Qs values were obtained using the vertical and two horizontal components of the three-component broad-band data, respectively that recorded in a circular areal extent with 120 km radius centred at the ARMT station on the Armutlu Peninsula. The database was prepared according to back-azimuthal distributions, and data-packs representing 36 different back-azimuthal slices were subjected to the Extended-Coda-Normalization-Method to examine the azimuthal path-dependence of the attenuation characteristics of direct body waves in the region. While the region corresponding to the basins in the Marmara Sea with relatively low seismicity is represented by high Q values, low Q values were observed in areas with intense faulting and seismicity in the NE of the study area. Additionally, direction-independent attenuation functions for the region were calculated as Qp = 18 ± 1f0.92±0.2 and Qs = 38 ± 1f0.87±0.01 for P and S phases, respectively. [ABSTRACT FROM AUTHOR]

Caulerpa taxifolia var. distichophylla (Sonder) Verlaque, Huisman & Procacini is an alien marine green macroalga in the Mediterranean Sea where it was recorded for the first time from the Iskenderun Gulf (Türkiye). To date, this taxon, expanding its known distribution to Greece, Italy, Cyprus, Malta, Lebanon, Libya and Tunisia. In the present study, C. taxifolia var. distichophylla is reported for the first time from Paşalimanı Island (Erdek, Balıkesir, Türkiye) in the Marmara Sea. [ABSTRACT FROM AUTHOR]

Ballast water, an essential component of global shipping operations, plays a pivotal role in maintaining vessel stability and load distribution. However, its inadvertent discharge can introduce a myriad of physicochemical and microbiological hazards to marine ecosystems, necessitating rigorous investigation. This study presents a comprehensive analysis of ballast waters from ships operating in the ecologically significant Marmara Sea. Different than previous studies, physicochemical parameters, including pH, heavy metal concentrations (Cr, Fe, Co, Ni, Cu, Zn, and As), total organic carbon, turbidity, total nitrogen, and total phosphorus, were extensively assessed. Furthermore, microbial communities were examined through the identification of bacterial, archaeal, and algal taxa using 16S and 18S rRNA gene amplicon sequence data. Particular attention was given to potential pathogens and harmful algal species, employing advanced techniques to ensure accuracy and comprehensiveness. The findings reveal notable variations in the physicochemical profiles of ballast waters, attributed to diverse geographical origins and operational factors. Furthermore, the microbial analysis identifies a diverse array of species, including pathogenic strains and potentially toxin-producing algae, raising concerns about potential ecological and public health implications. These results underscore the urgent need for improved ballast water management strategies and the implementation of effective treatment technologies to mitigate the adverse effects of ballast water discharge in the Marmara Sea. By shedding light on the intricacies of ballast water composition, this study contributes valuable insights toward safeguarding marine biodiversity and human well-being in this ecologically sensitive region. • Ballast waters were physically and biologically investigated from the ships visiting the Marmara Sea. • Intense heavy metal pollution was observed in some ships in ballast waters. • Fish pathogen Tenacibaculum sp., white plague disease agent Thalassomonas sp., were identified. • Potentially toxic dinoflagellates Prorocentrum spp, and Pseudo-nitzschia spp were found. [ABSTRACT FROM AUTHOR]

Abstract Strain energy from tectonic loading can be partly released through aseismic creep. Earthquake repeaters, repeatedly activated brittle fault patches surrounded by creep, indicate steady‐state creep that affects the amount of seismic energy available for the next large earthquake along a plate contact. The offshore Main Marmara Fault (MMF) of the North Anatolian Fault Zone represents a seismic gap capable of generating a M > 7 earthquake in direct vicinity to the mega‐city Istanbul. Based on a newly compiled seismicity catalog, we identify repeating earthquakes to resolve the spatial creep variability along the MMF during a 15‐year period. We observe a maximum of seismic repeaters indicating creep along the central and western MMF segments tapering off toward the locked onshore Ganos fault in the west, and the locked offshore Princes Islands segment immediately south of Istanbul in the east. This indicates a high degree of spatial creep variability along the Istanbul‐Marmara seismic gap.

Copyright of Ankara Üniversitesi Dil ve Tarih-Cografya Fakültesi Dergisi DTCF Dergisi is the property of Ankara Universitesi Dil ve Tarih-Cografya Fakultesi (DTCF Dergisi) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Thus, it is important to protect the seas from pollution. Due to domestic pollution, especially in our Mediterranean coasts, the Endemic Sea Grasses known as Posidonia oceanic are affected due to habitat loss. Since the construction of steel ships, ballast water has been used to stabilize the ship in navigation. Ballast water is pumped throughout the voyage to ensure safe cruising conditions. Although ballast water is necessary for safe and efficient modern maritime operations, it can cause serious ecological, economic, and medical problems depending on the amount of marine life carried in it. These marine creatures transported, bacteria, microbes, small invertebrates, and eggs, cysts, and larvae of many species. Transferred species can survive long enough to form populations that can reproduce in their new environment, become invasive species, suppress native species, and reach difficult-to-manage numbers. Known as blowfish, this type of fish entering the Eastern Mediterranean and Turkish waters from the Red Sea is poisonous. It is a poisonous species for consumption. The Marmara Sea and its surroundings are an environment with some special conditions. First, it has a large surface area to be considered a sea, but it is also vulnerable to atmospheric precipitation and the limitation of its connection with the strait connections and large seas. However, the interactions between air-water and the discharge of polluted water have revealed that pollution will occur, which may lead to the cleaning of the water environment, with the significant pollution events that have occurred. Another important point is that there are important industrial zones in the Marmara Sea basin. Most of them discharge their waste waters to this inland sea or the streams reaching it without applying any treatment process. Nitrogen reaches the sea from domestic and industrial point sources and agricultural areal sources. Nitrogen and phosphorus are a source of nutrients that accelerate the growth of microorganisms in water and cause excessive growth of algae and water invasion. Pollution in the Marmara Sea has been one of the most serious problems in the region. With these events, decreases in the oxygen of the aquatic environment are observed. The excess of nitrogen and phosphorus in the environment can cause this excessive growth and the release of some poisons. [ABSTRACT FROM AUTHOR]

In this study, monthly heavy metal concentrations in the whole-body tissue of Patella caerulea (Mediterranean limpets), a bioindicator species living in the coastal zone of the Gulf of Izmit (Marmara Sea), were examined for the first time. The mean metal concentrations in Patella caerulea (mg kg−1 dw) were 2.01–5.74 Cd, 2.45–12.90 Cu, 0.74–1.95 Pb, 21.12–109.57 Zn, 16.31–154.67 Ni, and 1120.67–3086.00 Fe. Cd levels in all months and Pb levels in October and November were found to be above the safe limits set by international organizations. The estimated daily intakes and estimated weekly intakes determined for each heavy metal were below the acceptable daily intakes and provisional tolerable weekly intakes. However, the target hazard quotient and total target hazard quotient values calculated for Cd, Ni, and Fe were found to be higher than 1. The carcinogenic risk value was also found to be high. [ABSTRACT FROM AUTHOR]

Length-weight relationships and condition factor of Spicara flexuosum collected from İstanbul, Rize, Çanakkale and Sinop-Kastamonu by using commercial gill nets and handline fishing methods were evaluated between 2013 and 2014 in this study. The overall length-weight equation (W=0.0236 L2.7334) indicated negative allometric growth from all sampling periods. Samples collected from Istanbul and Çanakkale exhibited positive allometric growth while S. flexuosum showed negative allometric growth in Rize and Sinop-Kastamonu in December 2013 and January 2014 respectively. The relative condition factor among regions varied from 0.99 to 1.08, indicating a state of wellbeing among all locations. This study provides the baseline data of length-weight relationships and condition factor analyses for S. flexuosum species from Turkish coastal waters for future management purposes for this species. [ABSTRACT FROM AUTHOR]

The Marmara Sea is an important acclimatization zone and biological transition for the biota of the Mediterranean Sea and the Black Sea. Overfishing, pollution, and changes due to global climate change put constant pressure on marine organisms in the Sea of Marmara. Therefore, monitoring and management of fishery resources of the Sea of Marmara have specific importance. The health level and temporal variation of 16 different demersal fish species in the Sea of Marmara were investigated based on length–weight relationship parameters and condition factors. Five of them are new length–weight relationship records in the Sea of Marmara (Raja miraletus, Lepidorhombus boscii, Scophthalmus maximus, Trachinus draco and Zeus faber); additional records expand the known size range for six species (Mullus surmuletus, R. clavata, Scorpaena porcus, Scyliorhinus canicula, Squalus acanthias and Torpedo marmorata). The values of a (intercept) varied between 0.0024 and 0.0564, whereas the b (slope) values varied between 2.6284 and 3.2084. The coefficient of determination was relatively high in most species (R2 ≥ 0.95), except for S. porcus and T. marmorata. The condition factor of some species (Merlangius merlangus, Merluccius merluccius, M. barbatus, L. boscii, S. maximus, Solea solea, S. acanthias, T. marmorata and Z. faber) were low (K < 1). The results obtained can be beneficial for the fisheries management and conservation purpose of studied species in future studies. [ABSTRACT FROM AUTHOR]

The current status of whiting (Merlangius merlangus Linnaeus, 1758) populations in the Sea of Marmara (Turkey) was evaluated by estimating growth and mortality rates in this study. The overall sex ratio (M:F) was calculated as 1:1.36. b value of LWR computed as 2.8904 for both sex groups, and M. merlangus showed a negative allometric growth type by Pauly's t-test result. The age of individuals in the population ranged from I to VI. The growth parameters were estimated as L∞ = 35.74 cm, k = 0.124 yr-1, and t0 = -1.338 years for all individuals. Total mortality (Z), natural mortality (M), and fishing mortality (F) rates were calculated as 1.35 yr-1, 0.34 yr-1, and 1.01 yr-1, respectively. The Phi-prime growth index (φ′) and exploitation rate (E) of the population were calculated as 2.20 and 0.75 yr-1 . According to the results, it is obvious that the whiting stocks in the Marmara Sea are currently used at a high capacity (E = 0.75 yr-1 ). The impact of over-fishing can have increasingly detrimental effects on the overall population size of this population. Fisheries management practices in the Marmara Sea should be regulated by taking into account the ecosystem change, fishing fleet, and unreported catch data. In addition, temporal or spatial fishing bans can be applied by increasing the selectivity of fishing gear. [ABSTRACT FROM AUTHOR]

In this study, the new record of the non-indigenous Rhodophyta Antithamnionella spirographidis (Schiffner) Wollaston (1968) has been reported from the Marmara Sea that the connection area between the Mediterranean Sea and the Black Sea. The species, originally described from Trieste (Northern Adriatic Sea), is currently known throughout the Central and Western Mediterranean Sea. Our finding is the easternmost record of this tiny filamentous alga in the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

Copyright of Marine & Life Sciences is the property of Emrah Simsek and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report the first occurrence of a diatom species, Nitzschia navis-varingica in the Sea of Marmara. Previously, this species was observed in the Mediterranean Sea in 2016. Samples were collected from the coast of Darıca, Istanbul, Turkey, on 22 June 2021 during a large-scale mucilage event. The species was isolated, cultured under laboratory conditions, and investigated with scanning electron microscopy and light microscopy. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Çankırı Karatekin University Journal of the Faculty of Economics & Administrative Sciences is the property of Cankiri Karatekin University, Faculty of Economics & Administrative Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aims to suppress the multiple reflections from the multi-channel seismic reflection data, which collected on the profile M97-29 at the Sea of Marmara with the MTA Sismik-1 Vessel in 1997 by the General Directorate of Mineral Research and Exploration (MTA), both at the preand post-stack stages separately, by using predictive deconvolution and to compare both results. The stack section obtained by applying predictive deconvolution to the pre-stack shot gathers, is compared with the stack section obtained by applying predictive deconvolution to the post-stack section, which has no predictive deconvolution application before stack. The multiple reflections are mostly suppressed in both sections, but the amplitudes of the primary reflections are much more noticeable and have much higher amplitudes on the stack section obtained by applying predictive deconvolution to the pre-stack shot gathers. Considering the data used in this study, which obtained from a shallow seabed section of the Sea of Marmara including slopped structures, it has been observed that the result obtained by applying the predictive deconvolution process to the pre-stack shot gathers are more successful than the other. [ABSTRACT FROM AUTHOR]

Establishment of offshore wind farms requires an optimum selection of ports on which installation and operation and maintenance will be done. Although there are studies on offshore wind farm suitability for Turkey in the literature, there is a lack of port suitability study for offshore wind farms in the country. In this study, the suitability of container ports is investigated using a combination of geographical information system (GIS) and analytic hierarchy process (AHP) to enable an easy and fast decision-making process along with visualization of the results. A case study is demonstrated to help decision-makers select the most suitable container ports for potential offshore wind farm areas on the Marmara Sea. Results show that for an offshore wind farm in the Tekirdağ area, Asya Port carries the highest weight followed by İçdaş Port with nearly twofold of the final scores of the following candidate port for both types of ports. For a potential offshore wind farm at Saroz, Port of Çanakkale was found as the best selection with final scores of 0.13 and 0.15, as installation and operation and maintenance (O&M) ports, respectively. Çelebi Port has the highest final scores of both types of ports for a potential İmralı offshore wind farm while İçdaş port has the greatest final score for Karabiga offshore wind farm. Distance to wind farm criteria is found to be the overwhelming criterion for selecting suitable OWF installation and (O&M) ports. [ABSTRACT FROM AUTHOR]

This paper reviews reconstructions of the the evolution of the Ponto-Caspian basin system to certain parts of the Pontian-Mediterranean system in order to analyze their correlation and response of the systems to the global climate change. The Ponto–Caspian and Mediterranean basins belong to different types of water basins and evolved differently in the Late Pleistocene responding in different ways to the global climate change. The paleogeographic reconstructions and correlation analysis of the Late Pleistocene events (within the last climatic macrocycle) made it possible to view the evolution of the basins as parts of a single system allowing to identify certain specific features and patterns in their functioning. The study is based on the analysis and integration of the data published by numerous researchers including the author of the paper and numerous colleagues from many countries who have been studying the paleogeography of the Ponto-Caspian and Mediterranean regions in the Late Pleistocene.

In this study, diet composition of bluefish Pomatomus saltatrix (Linnaeus, 1766) was investigated. A total of 512 bluefish samples were monthly collected from commercial fishing boats operating in the Sea of Marmara between January and December 2014. It was determined that the total length distribution of the samples varied between 12.3-47.3 cm. 367 of them (71.67%) were found to be the full of the stomach. The nutritional composition of stomach contents only two main prey groups (teleostei and crustacean) were identified. In evaluation, relative importance indexes (IRI) food groups were calculated. According to the relative importance index (IRI=91.8%) anchovy (Engraulis encrasicolus) has been found to be the most preferred food group. The number of individuals whose stomachs were found to be full was low in the winter months; it started to rise with spring and reached the highest level in the autumn months. It was determined that the increase in the total number of stomachs occurred between August and October in relation to the reproductive period. It was found that stomach fullness rates significantly relationship between sex and seasons (p

The Pacific oyster (Crassostrea gigas) has a very important economic potential for aquaculture, but on the other hand, is among the highly invasive species in the world and within the Mediterranean ecosystem. In the 1960s, C. gigas was brought to Europe for aquaculture in the Mediterranean and Black Sea regions from Japan and Canada. The Turkish waters are the part of the Mediterranean Sea, which is the world’s most invaded sea. The invasion of alien species results from marine transportation and aquaculture activities of non-native species. A heavy maritime traffic is also present in the Marmara Sea, which connects the Black Sea and Mediterranean Sea. The identification of the invasive species and their distributions is very prominent in terms of protecting natural habitat and monitoring the effects of invasive species. In this study, 30 individuals, morphologically identified as C. gigas, were collected from Bandırma bay. The genomic DNAs were extracted from each sample’s muscle tissue using universal salt extraction method. Partial sequences of COI and 16S Mitochondrial DNA loci of the sample DNAs were obtained for species identification. The sequences were searched against the database and results were retrieved from BLAST. All the sequences obtained in this study showed significant similarity with the C. gigas sequences present in the database (E=0). The sample sequences resulted in 9 different haplotypes for the COI locus (hd: 0.5296 and variance: 0.01256±0.112) and 5 different haplotypes for the 16S rDNA locus (hd: 0.2529, Variance: 0.01076±0.104). The results of this study provided the first molecular evidence for the presence of non-native Pacific oyster individuals in the Marmara Sea.

This paper aimed to understand the potential effects of the mucilage event on the critically endangered Pinna nobilis in Ocaklar Bay located at the southern Marmara Sea. Underwater surveys were carried out in October 2020 and July 2021. The study area covers 500 m2 that was divided into 5 main zones having 100 m2 areas (10×10 m). Then, each main zone was separated into sub areas covering 25 m2 (5×5 m). The habitat structure, depth, and availability of the mucilage event were observed by SCUBA diving equipment in sub areas. During the underwater observations, the total number of dead and alive individuals was counted as 228 of which 130 individuals were alive and 98 were dead. The minimum and maximum population density (including both dead and alive individuals) of P. nobilis was found to be between 10 individuals per 100 m2 and 112 individuals per 100 m2 in the study area, respectively. The mortality rates were calculated as 35.96% and 16.12% for the years 2020 and 2021, respectively. This paper puts forward that the P. nobilis population could be resistant to extreme environmental stress and even juvenile individuals (smaller than 15 cm) were recruited in the study area during the mucilage event. [ABSTRACT FROM AUTHOR]

An analysis of the impact of the recent massive mucilage event in the Marmara Sea is necessary in order to manage the crisis and introduce mitigation measures for the sustainability of tourism in the area. Legislation and preventive measures can help to prevent large-scale disasters and destruction, particularly in the marine industry. Yet, despite early signs and warnings, no measures of any impact have been taken to limit the outbreak of mucilage. Consequently, the Marmara region, well known for its unique inland sea, history and culture, is now in great jeopardy. Mucilage is a threat to the tourism sector, an important contributor to the regional and national economy, and its underwater cultural heritage. This study aims to show the short-term and long-term effect of mucilage on the tourism sector and on under water cultural heritage. The data was collected through interviews with local business owners, an examination of beach's health throughout years in the Marmara Sea and the impact of tourism on the Turkish GDP. Lastly, previous cases of mucilage were taken as an example for a more accurate prediction. [ABSTRACT FROM AUTHOR]

In the present study, phytoplankton composition in relation to mucilage and accompanied physicochemical conditions were investigated in the sea water samples collected from four stations in İzmit-Kocaeli, Fatih-İstanbul, Biga-Çanakkale (in the Marmara Sea), and Rivaİstanbul (in the Black Sea). Samplings were carried out before (i.e., during September 2020) and at the beginning stage of the mucilage formations (i.e., during April 2021) which was observed in the Marmara Sea during spring and summer months of 2021. Seawater temperature, salinity, pH, and dissolved oxygen levels were measured in situ. Inorganic nitrogen, orthophosphate, and chlorophyll-a concentrations were analyzed spectrophotometrically. In total 83 phytoplankton species (44 Bacillariophyceae-BAC, 36 Dinophyceae-DIN, 2 Dictyochophyceae-DIC, and 1 Chlorophyceae-CHL) were identified during the study. BAC species were generally dominant. Among the 83 phytoplankton taxa identified, Cerataulina pelagica, Cylindrotheca closterium, Pseudo-nitzschia sp., Skeletonema costatum, Thalassiosira rotula, Alexandrium tamarense, Dinophysis acuminata, Dinophysis caudata, Dinophysis fortii, Gonyaulax fragilis, Gonyaulax spinifera, Gymnodinium sp., Gyrodinium sp., and Prorocentrum micans are known as the species associated with mucilage formation. The highest number of species was determined at the Biga-Çanakkale station (MDG25) with 38 taxa in September 2020. [ABSTRACT FROM AUTHOR]

The control of the Turkish Straits was and will continue to be a subject of conflict and perpetual negotiations, given the geostrategic importance of these maritime passages. The stated purpose of the Istanbul Canal is to reduce maritime traffic through the Bosphorus Strait, but a closer look at the implications of this infrastructure project may reveal a hidden objective – to give Turkey control over the transit between the Black Sea and the Sea of Marmara. The construction of the canal has the potential to strengthen the strategic role of Ankara on the regional and international stages, since Turkey will have full authority over the project, probably without the limitations of the Montreux Convention. Henceforth, the Turkish authorities will have the power to grant passage through the new canal, and this kind of decision power alone has geostrategic implications that can alter the security in the region and especially in the Black Sea. [ABSTRACT FROM AUTHOR]

It is becoming increasingly important to monitor zoobenthic biodiversity in seas that are under industrial and anthropogenic pollution pressure, such as the Black Sea and the Marmara Sea. This study covers crustacean species in the Turkish waters of the Black Sea and the Marmara Sea, both of which are closed systems. Sampling was carried out in July–August 2019 and yielded 32 crustacean species from the Black Sea and 77 species from the Marmara Sea. In the Marmara Sea, two species [Kupellonura mediterranea and Leucon (Macrauloleucon) siphonatus] represent new records for the Turkish waters, and 12 species [Cirolana cranchii, Cumella (Cumella) pygmaea, Cyathura carinata, Cymodoce truncata, Eurydice pulchra, Gammaropsis sophiae, Harpinia truncata, Iphinoe serrata, Iphinoe trispinosa, Liocarcinus pusillus, Nebalia strausi and Synchelidium maculatum] are new to the Marmara Sea. The following species: Gammaropsis palmata, Pontocrates arenarius, and Synchelidium haplocheles are new records for the Black Sea. The order Amphipoda dominated in both seas in terms of the number of species and the number of individuals. [ABSTRACT FROM AUTHOR]

In this study, the Toxic element pollution and radioactivity of marine sediments in the Gulf of Gemlik was determined. Enrichment factor (EF) and Pollution index (PI) analyses have been applied to determine toxic element pollution. According to the enrichment factor results, the EFNi in BH-1 was between 3 < EFNi < 5, and the other EF values are all below 3. In radionuclide analysis, the Ra-226 and Th-232 values were found to be below the global average value in all locations. It is estimated that the K40 values, which are above the world average values in the BH-1 drillings, are due to the intensive agricultural activities in that part of the study area. Cs-137 values were found to be 5.3 Bq/kg in the BH1/1 drilling location. This finding is very important in terms of environmental pollution. In other locations, samples have been found to be below the Cs-137 MDA. The K-40 value has been found to be the highest in Kurşunlu. The Th-232 value has been found to be highest in Fıstıklı, which was below the world average value. There is a parallel between Pollution Index, Enrichment Factor and Radioactivity analysis. [ABSTRACT FROM AUTHOR]

Underwater Archaeology first started to gain public attention with the discovery of shipwrecks carrying works of art in the early-20th century, although the scientific value of the field truly became apparent with the excavation of the Gelidonya Wreck in 1960. Since that time, the number of underwater archaeological researches has increased steadily in number, and these studies have left their mark on the history of maritime activity on the Anatolian peninsula with the discovery of, for example, the Uluburun wreck and the Antalya wreck. Underwater archaeological researches in Turkey were concentrated on the Mediterranean and Aegean coasts for many years, expanding to the Marmara Sea only in the 1980s. The Marmara Sea was a significant source of food for the settlements established around it in the Neolithic Period, and the period following the first millennium BC is particularly important in maritime history, when many new cities were established on its shores during the colonization movements. While the maritime history of the Marmara Sea is still largely shrouded in mystery, the abundance of shipwrecks dating back to the Late-Roman and Byzantine periods point to an increase in maritime activity in the Marmara Sea at the time, when it was host to the capital of the East Roman Empire. There is, however, a lack of knowledge of earlier periods, but this may be attributed to the scarcity of studies conducted to date. The focus of the present study is the Marmara Sea and the important position it has held in every period due to its geopolitical location. Although the Yenikapı Excavations are considered underwater archaeology in terms of the foundling group, they were excluded from this study due to the difference in the adopted technical approaches. [ABSTRACT FROM AUTHOR]

Consumption rates of polystyrene microplastics (beads of 6, 12, and 26 μm diameter) and their effects on energy metabolism and motor activity of the copepod Calanus helgolandicus living in the Marmara Sea were investigated. All sizes of microplastic particles were actively consumed and excreted via fecal pellets, however, copepods displayed a significant preference for beads sized 6 μm. In a mixture of algae and microplastics beads of 6 μm, microplastics consumption rates linearly (r2 = 0.78, n = 154) increased 800 times from 50.8 ± 17.3 to 8,612 ± 5,972 beads ind–1 day–1 with an increase in bead concentration from 10 to 44,000 beads ml–1. The total and basal metabolic rates as well as time spent swimming for C. helgolandicus, decreased 1.7, 1.8 and about 3-fold, respectively after 7–8 days exposure to microplastic treatments, which was similar to the metabolism and activity of starving animals in filtered water. In copepods consuming microplastics, all vital parameters decreased on the first day of exposure, indicating either accelerated starvation, probably due to increased losses of energy and biological matter in the formation of fecal pellets and/or traumatic/toxic effects of the polystyrene beads on the copepods. Our data from laboratory experiments indicate that the presence of large concentrations of microplastics in water, even when mixed with algae, lowered energy metabolism levels of C. helgolandicus.

Yarı kapalı Marmara Denizi, Ege Denizi (Kuzeydoğu Akdeniz) ve Karadeniz arasındaki bir geçiş denizidir. Marmara Denizi, sırasıyla İstanbul Boğazı (Bosporus) ve Çanakkale Boğazı (Dardanelles) ile Karadeniz ve Ege Deniz’lerine bağlantılıdır. Denizler arasındaki, Geç Pleistosen-Holosen dönemi bağlantıları pek çok bilim adamı tarafından araştırılmasına rağmen, bağlantıların doğası ve zamanlaması konusunda hala belirsizlikler süregelmektedir. Bu çalışma kapsamında, Karadeniz, Marmara Denizi ve Ege Denizi arasındaki Buzul Sonrası dönemde meydana gelen bağlantılar için yeni bir yaklaşım sergilenmektedir.Bu çalışma, Marmara Denizi'nin kuzeydoğu şelfinde (Silivri ile Haliç arasında) toplanan 80 adet sığ sismik yansıma profiline, çok ışınlı batimetrik verilerine ve 15 adet kısa ağırlıklı karot verilerine dayanmaktadır. Büyükçekmece / Küçükçekmece lagünlerinin Marmara Denizi ile bağlantı ve daha doğuda Marmara-İstanbul Boğazı etkileşim alanlarında, deniz tabanı ve akustik taban morfolojileri, çok karmaşık bir yapıya sahiptirler. Bu karmaşık deniz tabanı ve akustik taban morfolojileri, temel olarak havzanın yapısı, şelfin mevcut hidrografik rejimi, kıyı drenaj sistemleri, deniz/göl su seviyesi değişiklikleri (iklimin kontrol ettiği) ve boğazların derinlikleri tarafından kontrol edilmektedir. Aynı zamanda, tüm bu faktörlerin denizler arasındaki su alış verişini kontrol eden önemli faktörler olduğu düşünülmektedir.Sismik yansıma profillerinin ve ağırlıklı karot verilerinin sedimantolojik olarak incelenmesi sonucunda, akustik taban üzerinde, beş farklı stratigrafik birimin (S1-S5) ve dört farklı sedimanter katmanın (A-D) ayırt edilmiştir. Akustik taban üzerinde yer alan alt stratigrafik birimler ve sedimanter tabakalar, karmaşık, paralel ve yüksek genlikli sismik yansımalarla ayırt edilmiştir. Akustik tabana ait tabakaların deniz yönüne doğru dalma göstermesi, karada yaygın olarak görülen Oligosen-Üst Miyosen birimlerinin deniz tabanında da devam etmekte olduğununun bir kanıtıdır. Marmara Denizi'nin kuzeydoğu şelfinde yer alan akustik taban yüzeyinde ayırt edilen üç farklı deniz taraçası (T1-T3) buzul sonrası dönemdeki küresel deniz seviyesi değişimlerine ait altı farklı eğri ile ilişkilendirilmiştir. İstatistiksel açıdan, en belirgin taraçaların -78 m ila -80 m (T1), -58 m ila -62 m (T2) ve -28 ila -32 m (T3) arasında yer aldığı saptanmıştır. Küresel deniz seviyesi eğrileri göz önüne alındığında, bu taraçaların yaşları sırasıyla, 9.25, 12.25 ve 13.75 Cal kyr BP olarak tarihlendirilmiştir.

The purpose of the study is to determine the water quality for the continuity of the aquatic life' diversity and the health of the citizens and tourists swimming in the Kucuksu, Fenerbahce and Suadiye beaches. Between 5 June 2019 and 29 August 2019, water temperature, pH, dissolved oxygen and salinity were measured weekly onsite and seawater samples were collected to analyze heavy metal concentrations (Ba, Cr, Mn, Ni, Cu, Zn, Pb, Cd and Se) via ICP-OES. Results showed that values are under the limits and there is no harm to human health and aquatic life. The measurements were compared with the literature data of beaches in the Mediterranean and of the same beaches in the previous studies. [ABSTRACT FROM AUTHOR]

Turkey has announced its plan to construct a new waterway, Canal Istanbul, parallel to the Bosphorus. In this study, the influence of Canal Istanbul on salinity distribution in the northern Marmara Sea is investigated using a previously calibrated 3D hydrodynamic and salinity model. Moreover, the salinity field of the canal and its propagation are examined based on various meteorological cases. Finally, the flow structure of the canal is determined. It is calculated that at the southern end of the canal, mainly unidirectional flow (from the Black Sea to the Marmara Sea) occurs during 68% of the simulation period. A two-layer flow is seen only 28% of the time with a weak lower layer flow, whereas this value decreases to 4% at the north end of the canal. In the southward direction (to the Marmara Sea), velocities higher than 1.5 m/s are rarely observed along the canal. The average surface salinity difference in the northern Marmara Sea due to the construction of the canal is calculated to be smaller than 0.50 ppt. The salinity difference gradually diminishes as water depth increases and after 25 m (from the surface) almost no difference is observed. [ABSTRACT FROM AUTHOR]