Deniz Teknolojileri Meslek Yüksekokulu Koleksiyonu

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https://hdl.handle.net/20.500.12428/3538

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Hydrochemical and Bacteriological Status of a High Altitude Karstic Cave Stream (Güvercinkaya Cave: Çanakkale, Turkey) with Aquatic Macroinvertebrates Findings
(Çanakkale Onsekiz Mart Üniversitesi, 2022) Odabaşı, Deniz Anıl; Odabaşı, Serpil; Deniz, Ozan; Çakır, Fikret; Elipek, Belgin; Arslan, Naime; Özbek, Onur; Özalp, H. Barış
Caves are laboratories for many disciplines that work in natural sciences including mineralogy, biology, hydrogeology, and archaeology. In this study, bi-monthly samplings were carried out from three smapling locations within and around the Güvercinkaya Cave, a high-altitude cave located in nortwestern Turkey, to evaluate the hydrochemical and microbiological properties and the aquatic macroinvertebrates of the cave stream. Some parameters of the water including pH, electrical conductivity, temperature, oxidation-reduction potential, dissolved oxygen were measured in-situ, while elemental (70 in total) and ionic composition of water were analyzed in the laboratory. Microbiological analyses of the cave stream were examined through analyses of total bacteria, total coliforms, fecal coliforms, fecal Streptococcus, and Escherichia coli. According to the Piper diagram of hydrochemical data, the cave stream had mainly Ca-Mg-HCO3 character, on the other hand, the Schoeller diagram indicated a common water source in Güvercinkaya cave due to the similar components of the main ionic components of the water. As a result of microbiological analysis, fecal contamination was determined, indicating an active wildlife in the cave. Additionally, several aquatic macroinvertebrates taxa, Rhynchelmis limosella, Dugesia sp., Gammarus uludagi which have non-troglobiont character were found in the cave stream. Rhynchelmis limosella detected in this study is the first record for the Turkish fauna.
BEM modelling of a hydrodynamic lifting surface working in ground proximity
(Elsevier Ltd, 2024) Coşgun, Taner; Özdemir, Yavuz Hakan
Present paper aims to assess the performance and limits of boundary element method for the reliable simulation of ground effect phenomena on hydrodynamic lifting surfaces. Benefitting from the ground effect, especially in extreme ground proximity, suggests a promising concept for lifting bodies. On the other hand, the more pronounced the ground effect, the more complicated flow physics it exhibits, making the problem harder to handle numerically. In this study, a potential-based boundary element method (BEM) is applied to the flow past a 3D rectangular wing within a wide range of ground clearances corresponding to out of ground effect (OGE), in ground effect (GE) and extreme ground effect (EGE) conditions. Both positive and negative angles of attack are tested to examine the lift and downforce producing cases. The potential flow around the airfoil is computed using the mixed constant-strength source and constant-strength dipole based panel method. The results show that BEM successfully predicts the lift force variation for a wing working in ground proximity (GE). However, approaching the bounds of extreme ground effect is seen to introduce a progressive decrease of the fidelity of the method. A similar tendency is observed in the downforce generating conditions, which is also an important scenario for ground vehicle aerodynamics. BEM remarkably overestimates the magnitude of the downforce when the ground clearance reaches up to the EGE conditions, still, it produces quite satisfactory results for the rest of the tested configurations. The pressure distributions are also provided to examine the flow field in the aforementioned cases. Overall, the results lead us to conclude that BEM stands as a robust and reliable prediction tool for ground effect on 3D wings but the extreme ground effect condition represents the limit of its accuracy range.
Multiple exposure to thunderstorm-sound in Nile tilapia (Oreochromis niloticus): physiological response and stress recovery
(Sciendo, 2023) Kuşku, Halit; Yiğit, Murat; Yılmaz, Sevdan; Yiğit, Ümüt; Ergün, Sebahattin
The present study investigated the impacts of multiple thunderstorm-sound exposures on growth and respiratory parameters in Nile tilapia (Oreochromis niloticus) in order to evaluate the acoustic stress response. Thunderstorm-sound exposure for 3 hours triggered respiration speed with an alarm reflex and rapid elevation of opercula beat rate (OBR) and pectoral wing rate (PWR), which increased two-fold over the control with no sound treatment, and peaked (OBR, 71.33±5.86 beat/min; PWR, 75.00±3.61 beat/min) in 10 hours after initiation of sound. Thereafter, respiration rates declined over the following days and returned to near-initial levels (45.33±4.04 beat/min OBR and 43.00±1.00 beat/min PWR) by day 3, an indication that fish recovered from thunderstorm-sound stress after 3 days of exposure. However, the same reaction course was observed each time of multiple sound exposures, repeated 20 times in a row with 4-day intervals, underlining that fish could not attune to repeated thunderstorm sound. Reduced voluntary feed intake as a result of anxiety and appetite loss was recorded in fish exposed to multiple thunderstorm sound, resulting in 50% less growth compared to those without sound treatment by the end of the 80-day experimentation. Therefore, it is advisable to monitor fish behavior during the 3-day stress period after a thunderstorm event in order to prevent waste from excess feeding, that in turn may contribute environment-friendly aquaculture for the future and sustainability of the oceans.
Analysis of the economic performance of salmon farming in submerged and surface cages in the Black Sea
(Springer Science and Business Media Deutschland GmbH, 2023) Yiğit, Umut; Yiğit, Murat; Ergün, Sebahattin; Kuşku, Halit; Ek, Hüseyin; Maita, Masashi
The production period for salmon farming in the Black Sea comprises the winter period and is limited to seven months, due to high water temperatures during the summer time. As an alternative strategy, temporary cage submersion during the summer season might be a solution for salmon grow-out throughout the year. Therefore, this study was conducted for comparative evaluation of economic performance of submerged and surface cages, by analyzing structural costs and returns for Turkish salmon farming in the Black Sea. As a result of the temporary cage submersion strategy, economic profits increased by nearly 70%, granting higher values of financial indicators with increased net profit (685,652.5 $ year−1) and margin of safety (89.6%), compared to the traditional surface cage (397,058.5 $ year−1 net profit and 88.4% margin of safety). The “What-if” analysis showed that profits from both cage systems were sensitive to variations in sale price, and the simulation by 10% reduced export market value may decrease revenues, with less financial profit loss for the submerged cage over the surface once. Hence, temporary cage submersion seems to be an alternative farm management strategy with extended production cycle and higher profits for the sustainable development of Turkish salmon farming in the Black Sea.
Temporal and spatial effects of environmental variables on crustacean communities in Çardak Lagoon (Turkish Straits System) under the influence of domestic pollution
(Springer Science and Business Media Deutschland GmbH, 2023) Ateş, Abdullah Suat; Mülayim, Ayşegül; Bakır, Ahmet Kerem; Acar, Seçil; Büyükateş, Yeşim; Dağlı, Ertan; Doğan, Alper; Uzundumlu, Sinan; Kedioğlu, Çetin
This study presents the temporal and spatial effects of domestic pollution on crustacean assemblages in a protected area, Çardak Lagoon (Turkish Straits System). The samplings were performed from sandy and mud (silt + clay) bottoms between 1 and 1.8 m depths in October 2018, February, April, and June 2019. A total of 6920 specimens and 26 species (1 Isopoda, 1 Tanaidacea, 2 Mysidacea, 3 Cumacea, 5 Decapoda, 14 Amphipoda) belonging to crustaceans was found. Highest crustacea abundances were in autumn and winter. Considering the environmental variables, NO2 + NO3 (mg L− 1) and COD (mg L− 1) levels in the water had the highest correlations with abundance for the sampling periods. According to sampling points, the highest correlation value was found between anionic detergent content in the water and the abundance. Crustacean community structure was modified by environmental variables of anthropogenic origin at a higher level. Oxygen, oxygen reduction potential, NO2 + NO3, total nitrogen, chemical oxygen demand and anionic surfactant levels in water and sediment sand content % were major environmental variables affecting the crustacean abundance in the study area temporally.
Wave field generated by finite-span hydrofoils operating beneath a free surface
(Brodarski Institute, 2021) Özdemir, Yavuz Hakan; Coşgun, Taner; Barlas, Barış
The present paper focuses on the numerical investigation of the flow around the fully submerged 2D and 3D hydrofoils operating close to a free surface. Iterative boundary element method is implemented to predict the flow field. This study aims to investigate the aspect ratio effect on the free surface interactions and hydrodynamic performance of the hydrofoils under a free surface by using potential flow theory. Three different submergence depths and aspect ratios are studied in the wide range of Froude Numbers. In 3D cases, spanwise width of the numerical wave tank model is selected both equal and wider to the foil span, to observe the sidewall effects. Wave field seems to be two dimensional at low Froude numbers. On the other hand, signs of three dimensionalities are observed on the free surface structure for higher Fn, even the predicted wave elevations are very close to 2D calculations in the midsection. Increment in the Fn give a rise to the amplitude of the generated waves first, however a further increase in Fn has a lowering effect with the beginning of waves spill in the spanwise direction in the form of Kelvin waves. Free surface proximity and resultant wave field are also seeming to be linked with the lift force on the hydrofoil. As aspect ratio of the foil increase, 3D lift values are getting closer to those of 2D calculations. However, it is seen that, 3D BEM predictions of a hydrofoil under free surface effect cannot be considered twodimensional even the aspect ratio is equal to 8.
Levels of toxic metals in edible fish species of the Tigris River (Turkey); Threat to public health
(Elsevier B.V., 2021) Töre, Yalçın; Ustaoğlu, Fikret; Tepe, Yalçın; Kalıpcı, Erkan
Tigris River has international importance as it runs through the borders of three countries. The levels and probable public health risks of heavy metals (Mn, Cd, Fe, Cu, Ni, Zn, Co, Pb, Cr, As) in 72 muscle and gill samples out of six fish species in Tigris River, Turkey were determined then compared with results of prior studies. Furthermore, human health risk levels from fish consumption were assessed using multiple approaches. The mean maximum heavy metal levels in the muscles were as follow; 175.88 > 22.34 > 10.29 > 2.81 > 2.76 > 1.68 > 0.33 > 0.25 > 0.05 = 0.05 mg kg−1 for Fe > Zn > Mn > Cu > Ni > Cr > Pb > As > Cd = Co, respectively. The highest muscle tissue levels for 8 heavy metals out of 10 measured were found in C. macrostomus species. The mean max. levels of Cu and Pb, the remaining two heavy metals, were measured in muscle tissue of L. abu species. The mean maximum concentrations of heavy metals of Cr, Cu, and Zn in all fish samples were below the maximum permissible limits (MPLs). The carcinogenic risk (CR) values for Pb, Cr, Ni and As were calculated and evaluated respectively in all of the Tigris River's fish species. While CR values calculated for Pb in all species did not pose a risk, it was found above the threshold value of 10−4 for some fish species for Cr, Ni and As. Target hazard quotients (THQs) from metal intake by consuming fish species were below 1 for all heavy metals which indicated no hazard from consumption. In addition, since the hazard index (HI) is lower than “1″, it has been concluded that the consumption of fish species will not pose a potential health risk. Considering by CR values exclusively, the results disclosed that the intake of the analyzed fish species might cause a toxicological hazard and impend to community health.
Length-weight relationships for 57 fish species of Bakircay river estuary in Candarli bay
(Parlar Scientific Publications, 2021) Babauglu, Ali Ozcan; Bayhan, Bahar; Kara, Ali; Acarlı, Deniz
Known as the fourth longest river in the Aegean sea with its 129 km length, the Bakircay River flows into candarli Bay in the north of Aegean sea. This study was conducted to measure length weight relationships (LWRs) of fishes captured with different fishing gears in the estuary of Bakircay River. This is the first study on this subject. The fishes that caught by each gear and carried in boxes to the lab were measured for total length (TL) as cm and wet weighed (W) as g. The length-weight (LW) relationships were estimated by W=aL(b). The level of statistical significance for r(2) was determined with LogW=loga +blogn. LW relationships were calculated in 57 fish species of 27 families from Bakircay River Estuary in candarli Bay. 3487 fish samples were caught with beach seines, handlines, longlines, fyke nets, scoop nets, cast net and trammel net between November 2012 and December 2015. The number of the samples ranged from 9 individuals for Gusterosteus actileants to 133 ones for Solen spiera, r(2) values varied from 0.84 to 0.99. All regressions were highly significant (p<0.01). The value h of the LW regression changed between 2.371 in Engraulis efricrasicohrs and 3.490 in Syngnathus acus with a median of 3.134 where 25-75% of the values changed from 3.010 and 3,170. Species of Sparidae. Mugilidae and Gobiidae families were captured more than others, which can be accepted as a typical feature for Mediterranean estuarine areas.
Biodiversity of freshwater macroinvertebrates on Gokceada Island (North Aegean Sea, Turkey)
(University of Gdańsk, 2021) Odabaşı, Serpil
Island ecosystems have attracted the attention of scientists since the early days of science because of their formation and biodiversity. Despite their abundant freshwater resources, data on freshwater diversity of Gökçeada are incomplete, especially for macroinvertebrates. This study was conducted in a wide range of freshwater ecosystems on Gökçeada between May 2016 and September 2018. Sampling of macroinvertebrates was performed using a hand net from 34 pre-selected sampling sites on the island. A total of 78 aquatic macroinvertebrate taxa were found, 46 of which are new records for the island. The most common species during the study were Gammarus komareki and Bythinella gokceadaensis with a frequency of 25.93%, followed by Tubifex tubifex, Gammarus sp. and Caenis sp. with a frequency of 22.22%. Endemic and invasive species on the island were assessed according to their presence and frequency values. Based on the results of the current study and previous data, it can be concluded that Gökçeada is characterized by a remarkable species diversity compared to aquatic macroinvertebrates on other Aegean islands.
Occurrence of Two Non-indigenous Alien Sea Slugs, Bursatella leachii (Blainville, 1817) and Melibe viridis (Kelaart, 1858) (Gastropoda: Heterobranchia), from the Canakkale Strait, Turkish Straits System
(Institute of Biodiversity and Ecosystem Research - Bulgarian Academy of Sciences, 2021) Özalp, Barış H.; Ovalis, Panayotis; Culha, Mehmet
This study reports the heterobranch mollusks Bursatella leachii (Blainville, 1817) and Melibe viridis (Kelaart, 1858) for the first time from the Dardanelles (Çanakkale Strait), Turkey. Individuals of these two species were observed in January 2020 on a sandy and seagrass bed of Cymodocea nodosa (Ucria) Ascherson and in groups among the algae Caulerpa racemosa (Forsskål) J. Agardh. Although the Dardanelles is one of the biodiversity hotspots in Turkish Seas and the abundance of marine invertebrates in particular regions is significantly high, the inventory of the sea slugs in the region is limited. This study improves the existing knowledge on the molluscan fauna of the Turkish Straits System, the species abundance in the region and their ecological characteristics. The current finding also represents the northernmost records in an invaded area at the Çanakkale Strait of Aegean Sea.

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