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Öğe Analysis and Detection of Mucilage Bloom from Multispectral Satellite Images(Ieee, 2022) Kucuk, Sefa; Abaci, Bahri; Dede, Murat; Yuksel, Seniha Esen; Yilmaz, MeteIn this paper, we aim to detect and observe the mucilage formations in the Sea of Marmara by means of Sentinel-2A satellite data. For this purpose, we produce mucilage index maps by utilizing the relationship between the spectral bands of Sentinel-2A. Sentinel-2A has four 10m fine bands and six 20m coarse bands. To compute the mucilage index, the spectral bands must have the same spatial resolution. Although the Sentinel-2A does not have a panchromatic band, the spatial resolution of the 20m bands can be increased to 10m thanks to its four fine bands. Based on the results of this analysis, we utilize seven of the existing image fusion approaches to enhance the spatial resolution of 20m bands to 10m. We monitor changes in mucilage formations over time with the mucilage maps acquired by using fused images through the mucilage index.Öğe DETECTION AND TRACKING OF MUCILAGE PHENOMENON IN THE SEA OF MARMARA BY REMOTE SENSING IMAGES(Istanbul Univ Press, Istanbul Univ Rectorate, 2025) Kucuk, Sefa; Abaci, Bahri; Dede, Murat; Yuksel, Seniha Esen; Yilmaz, MeteMarine mucilage is a collection of mucus-like organic matter released by marine microorganisms. Intense mucilage formation in the sea prevents fisheries, maritime, and tourism activities, reduces oxygen levels, and adversely affects biodiversity. The traditional method of detecting mucilage involves taking samples from the sea and analyzing them in a laboratory. However, detecting mucilage with these standard methods is laborious since it can spread over kilometers. On the other hand, several satellites in orbit regularly collect data from the Earth's surface, making it possible to monitor the presence of mucilage through satellite data analysis. Therefore, using both traditional and deep learning algorithms, we utilized PRISMA hyperspectral and Sentinel-2 multispectral data to detect mucilage in its early stages. Sentinel-2A has four 10m fine bands and six 20m coarse bands. To benefit from all bands of Sentinel 2A, the spectral bands must have the same spatial resolution. Although the Sentinel-2A does not have a panchromatic band, the spatial resolution of the 20m bands has been increased to 10m employing its four fine bands as a panchromatic band. We aim to identify or construct a suitable panchromatic band for coarse bands using seven of the existing pansharpening techniques to enhance the spatial resolution of 20m bands to 10m. After preprocessing, we comprehensively compare four different methods, namely Linear regression, Random forest, U-Net, and Vescovi index, on two datasets. On the multispectral dataset, we correctly detect 87.8% of the mucilage formations with the U-Net model and achieve the area under the curve (AUC) score of 0.977. However, the Random forest model has outperformed the other methods, identifying 89.8% of the mucilage formations on the hyperspectral dataset. Experimental results on satellite data with multiple resolutions, bands, different days, and times indicate that detecting mucilage from satellite data with high accuracy and without massive effort is possible.Öğe Electrochemical Investigation of DNA Interactions with Cyanobacterial Toxins: Cylindrospermopsin and Saxitoxin(Wiley-V C H Verlag Gmbh, 2025) Kesici-Meco, Ece; Yilmaz, Mete; Unur-Yilmaz, EceAnthropogenic eutrophication threatens freshwater sources used for agricultural irrigation and increases the occurrence risk of cyanotoxins, such as cylindrospermopsin (CYN) and saxitoxin (STX). These toxins accumulate in surface waters and pose significant health risks, with CYN primarily affecting the liver and STX targeting the nervous system. In this study, dsDNA was immobilized on a pencil graphite electrode (PGE), and its interactions with CYN and STX were investigated by means of electrochemical impedance spectroscopy (EIS). Experimental conditions, including DNA concentration, cyanotoxin concentration, and DNA-cyanotoxin interaction time, were optimized to generate the most significant electrochemical signal (i.e., charge transfer resistance). The optimized PGE/DNA system established the foundation for an electrochemical biosensor that can be utilized for detection of cyanotoxins and detection limits of 0.12 ng mL-1 and 0.043 ng mL-1 were achieved for CYN and STX, respectively. The system was further analyzed using FTIR, UV-vis, and X-ray photoelectron spectroscopy (XPS), providing a comprehensive structural analysis of toxin-induced DNA alterations. The electrochemical system developed in this study by immobilizing DNA onto PGE allowed thorough investigation of the genotoxic effects of CYN and STX, as well as their sensitive detection.Öğe Growth performance of Scenedesmus sp. AQUAMEB-57. Ankistrodesmus sp. AQUAMEB-33, and Synechococcaceae AQUAMEB-32 cultivated at different light intensities(Taylor & Francis Ltd, 2025) Uguz, Seyit; Anderson, Gary; Simsek, Ercan; Ates, Kivilcim; Yilmaz, Mete; Yaslioglu, Erkan; Ulusoy, YahyaIncreasing air pollutants significantly contributes to climate change, requiring innovative mitigation strategies. Microalgae provide a promising solution by absorbing CO2 and pollutants like nitrogen oxides (NOx), sulfur oxides (SOx), and ammonia from agricultural and industrial emissions, while also generating biomass for biofuels and animal feed. This study investigated the effects of light intensity on the growth and biochemical composition of Scenedesmus sp. AQUAMEB-57, Ankistrodesmus sp. AQUAMEB-33, and Synechococcaceae AQUAMEB-32 cultivated in photobioreactors under two batch and continuous culture conditions. Scenedesmus sp. reached the highest cell concentration (8 x 106 cells ml-1) at 200 mu mol photons m-2s-1, while Ankistrodesmus sp. and Synechococcaceae peaked at 300 mu mol photons m-2s-1. Dry biomass was highest for all species at 300 mu mol photons m-2s-1. Scendesmus sp showed the highest protein content (15.6%) at a light intensity of 200 mu mol photons m-2s-1, Ankistrodesmus sp. (17.2%) at 300 mu mol photons m-2s-1, and Synechococcaceae (23.5%) at 100 mu mol photons m-2s-1. Maximum carbohydrate content for Scenedesmus sp., Ankistrodesmus sp., and Synechococcaceae was 56.0%, 20.5%, and 18.4%, respectively, at 300 mu mol photons m-2s-1. C16/C18 fatty acids significantly increased as light intensity was raised from 100 to 200 mu mol photons m-2s-1. The findings show that light intensity impacts growth rates and biochemical profiles, varying by species and cultivation mode. Continuous systems yield higher biomass than batch systems, emphasizing the need for optimized strategies to enhance algal productivity. This research enhances understanding of microalgal growth dynamics, offering insights into optimizing conditions for improved biomass yield and supporting sustainable biofuel production and other valuable products.Öğe İzmir Çamaltı Tuzlası’nın Mikrobiyal Çeşitliliği ve Bulunan Organizmaların Biyoteknolojik Potansiyellerinin Araştırılması(2017) Yilmaz, Mete; Koru, EdisIzmir Çamaltı Tuzlası?nda farklı tuzluluk gruplarından havuzlar 1 yıl boyunca örneklenmistir. Havuz tuzlulukları baslangıç havuzlarında 23 ppt?den, kristalizasyon havuzlarında 340 ppt?ye kadar degismistir. Mikroskobik yöntemlerle 41 alg ve siyanobakteri türü tespit edilmistir. Bunların %36?sını Dinophyceae, % 44?ünü Bacillariophyceae, %10?unu Chlorophyceae, %10?unu da Cyanobacteria olusturmustur. Ancak tür bollugu açısından Chlorophyceae baskın olarak görülmüs ve tüm fitoplankton sayısının %62?sini olusturmustur. Ribosomal RNA küçük alt-grup genlerine dayalı yapılan metagenomik analiz sonucunda Çamaltı Tuzlası havuzlarında 2526 bakteri, arke ve ökaryot taksonu belirlenmistir. Bu taksonlardan 11?i siyanobakterilere, 91?i alglere aittir. Dolayısıyla metagenomik çalısmalar çok daha zengin bir alg/siyanobakteri çesitliligi ortaya koymustur. Metagenomik analizde arkelere ait diziler tüm dizilerin yaklasık %20?sini, bakteriler yaklasık %64?ünü, ökaryotlar ise yaklasık %16?sını olusturmustur. En baskın olarak tespit edilen filum %36 ile Proteobacteria olmustur. Çamaltı Tuzlası?ndan 24 halofilik veya halotolerant mikroalg / siyanobakteri susu izole edilmistir. Tüm izolatlar bu proje kapsamında olusturulan Bursa Teknik Üniversitesi Alg ve Siyanobakteri Kültür Koleksiyonuna dâhil edilmistir. Bu suslar genetik, morfolojik, fizyolojik ve biyokimyasal olarak karakterize edilmistir. Morfolojik ve genetik özelliklerine göre izole edilen suslardan 18 tanesinin Dunaliella cinsine ait oldugu belirlenmistir. Bu suslardan 10 tanesinin D. salina benzeri, 2 tanesinin de D. viridis benzeri oldugu belirlenmistir. Izole edilen diger alg ve siyanobakteriler arasında Tetraselmis sp., Cryptophyceae sınıfından bir mikroalg, Halothece/Euhalothece/Cyanothece kompleksinden bir siyanobakteri, Phormidium sp. ve Alexandrium minutum vardır. Üç Dunaliella salina benzeri susta HPLC ile 4-5 mg.g-1 beta karoten tespit edilmistir. Bu suslar pigment üretiminde kullanılma potansiyeline sahiptir. Diger taraftan Cryptophceae AQUAMEB-1 susunun toplam yag asitlerinin %38.3?ünü omega-3 çoklu doymamıs yag asitlerinin olusturdugu GC-FID ile belirlenmistir. Omega-3?lerin de yaklasık %33?ünü EPA ve DHA olusturmustur. Bu mikroalg de yag asidi üretimi için kullanılma potansiyeline sahiptir.Öğe Mechanical, UV protection, and antibacterial properties of poly(vinyl alcohol)/marine mucilage biocomposite films(John Wiley and Sons Ltd, 2024) Soydan, Nazli; Gümüş, Omer Yunus; Yilmaz, MeteThe mucilage that accumulated in the Sea of Marmara in 2021 turned into an environmental disaster that threatened not only marine life but also the shipping and tourism industries. However, because of the partially organic structure of marine mucilage, it has the potential to be used as an additive for polymer films. In this study, bioplastic films were prepared from PVA with a series of mucilage content from 0% to 50% by mass, and their properties were investigated. The FT-IR spectra revealed a shift in hydroxyl peaks, suggesting an interaction between the mucilage and PVA. SEM images showed the formation of crystal forms at the higher mucilage content of 20%, indicating ionic saturation of the PVA matrix. EDX and XRD analyses revealed that the crystal was NaCl coming from the mucilage composition. The tensile strength of the neat PVA film was measured as 9.86 MPa and improved to 14.56 MPa with 5% mucilage content, which is attributed to the ionic cross-linking. The tensile properties were preserved up to 20% of the mucilage content, and then sudden decrements were observed. The transmittance percentage (T%) of the neat PVA film in UV–Vis spectra (800–200 nm) was detected as 75% at 500 nm and decreased down to 39% with increased mucilage content up to 50%. Furthermore, a rising limit of linearity (LOL) of the spectrums was observed from 350 to 580 nm, with increasing mucilage content from 5% to 50%. The biofilms showed antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. Hence, a robust and biodegradable film having UV protection and antibacterial activity was developed from the marine mucilage bio-waste. Highlights: Poly(vinyl alcohol)/marine mucilage biocomposite films were prepared. Biocomposite films showed increased UV-A, UV-B, and UV-C protection with increased mucilage content. Enhanced tensile strength of biocomposite films up to 20 wt% mucilage content was determined due to ionic crosslink formed by NaCl salt ions. Biocomposite exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus. © 2023 The Authors. Journal of Vinyl & Additive Technology published by Wiley Periodicals LLC on behalf of Society of Plastics Engineers.Öğe Microalgae cultivation using ammonia and carbon dioxide concentrations typical of pig barns(Taylor & Francis Ltd, 2024) Uguz, Seyit; Anderson, Gary; Yang, Xufei; Simsek, Ercan; Osabutey, Augustina; Yilmaz, Mete; Min, KyungnanWhile global population growth drives increased production efficiency in animal agriculture, there is a growing demand for environmentally friendly practices, particularly in reducing air pollutant emissions from concentrated animal feeding operations. This study explores the potential of cultivating microalgae in photobioreactors (PBRs) as an eco-friendly and cost-effective approach to mitigate NH3 and CO2 emissions from pig barns. Unlike traditional physicochemical mitigation systems, microalgae offer a renewable solution by converting pollutants into valuable biomass. The research focused on Scenedesmus dimorphus growth under typical NH3 and CO2 concentrations found in the indoor air of pig barns. Four NH3 (0, 12, 25, and 50 ppm) and four CO2 concentrations (350, 1200, 2350, and 3500 ppm) were tested using photobioreactors. Results showed a maximum specific growth rate of 0.83 d(-1) with 12 ppm NH3 and 3500 ppm CO2. The dry biomass concentration was significantly higher (1.16 +/- 0.08 g L-1; p < 0.01) at 25 ppm NH3 and 2350 ppm CO2 than other test conditions. S. dimorphus demonstrated the peak NH3 and CO2 fixation rates (23.8 +/- 2.26 mg NH3 L-1 d(-1) and 432.24 +/- 41.09 mg CO2 L-1 d(-1)) at 25 ppm NH3 and 2350 ppm CO2. These findings support the feasibility of using algae to effectively remove air pollutants in pig barns, thereby improving indoor air quality. [GRAPHICS] .Öğe Mucilage Detection from Hyperspectral and Multispectral Satellite Data(Spie-Int Soc Optical Engineering, 2022) Abaci, Bahri; Dede, Murat; Yuksel, Seniha Esen; Yilmaz, MeteMucilage also called sea snot or sea saliva is a collection of mucus-like organic matter found in the sea. Although not harmful in the beginning, when mucilage increases over time, it covers the sea creatures and forms thick layers in the sea. Its existence and long duration change the oxygen balance in the seas, reduce biodiversity, fisheries, and tourism. Since April 2021, mucilage has emerged as both an ecological and economical problem in Turkey, spreading over an area of kilometers, clogging the fishing nets, causing problems in marine vessels, and disrupting the industry. These findings indicate that mucilage monitoring, early detection, and intervention before the economic and ecological damages grow out of proportion is quite necessary. Through the analysis of satellite data, it is possible to observe the existence of mucilage as thin, extended layers of white substance. Therefore, in this work, we analyze the Sentinel-2 multispectral data and PRISMA hyperspectral data to detect the mucilage in the early stages through the use of both traditional as well as deep learning algorithms. Our results indicate that it is possible to detect mucilage from satellite data with high accuracy, saving time and money for the cleaning efforts.Öğe Physicochemical and microbiological investigation of ballast waters of the ships operating in the Marmara Sea(Elsevier Sci Ltd, 2024) Dobrucali, Erinc; Uyanik, Sinan; Altuntas, Volkan; Yilmaz, Mete; Balci, Muharrem; Sahan, Aybuke Nur; Ucar, DenizBallast 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 wellbeing in this ecologically sensitive region.Öğe Self-Activated SiO2/C Nanocomposite from Silica-Rich Marine Mucilage for Supercapacitor Applications(Iop Publishing Ltd, 2023) Tatli, Neriman Sinan; Yilmaz, Mete; Yilmaz, Ece UnurBioresources are continually being explored as potential precursors for sustainable supercapacitor electrode materials. In this work, diatom-rich marine mucilage (MM) collected from the Marmara Sea, Turkey was used as a biomass source and converted to SiO2/Carbon nanocomposite (SiO 2 /C) through pyrolysis and acid etching. Diatom frustules acted as a highly porous silica source while algal organic matter delivered the carbonaceous part of the composite. The natural salts found in marine mucilage served as a self-activating agent and avoided the use of corrosive chemicals for the development of pores. The SiO 2 /C exhibited a competitive capacitance of 210 F g-1 at a current rate of 0.5 A g-1 in 1 M sodium sulfate (Na2SO4) aqueous electrolyte solution. The porous and durable silica skeleton improved capacitance by expanding the electrode/electrolyte interface, and the interconnected hierarchical pores ensured high electrochemical stability during long-term cycling. The mucilage-derived nanocomposite retained 80% and 70% of its capacitance after 4000 and 10,000 charge-discharge cycles, respectively. This work presents a potential solution for the management of marine mucilage by converting it into a high-value electrode material.Öğe Uluabat Gölü Siyanobakteri (Mavi-Yeşil Alg) Çesitliliğinin, Mevcut Siyanobakteri Toksinlerinin ve Toksik SiyanobakteriTürlerinin Belirlenmesi(2017) Yilmaz, Mete; Demir, Ayşe Nilsun; Balcı, MuharremBir RAMSAR alanı olan Uluabat Gölü Marmara Bölgesi?nde Bursa ilinin batısında yer alan sığ bir göldür. 1960?lı yıllardan itibaren artan insan nüfusu, tarım faaliyetleri, hayvancılık ve madencilik gibi faktörlerden dolayı Uluabat Gölü?nde belirgin bir ötrofikasyon gözlemlenmektedir. Uluabat Gölü?nde toksin oluşturma potansiyeli olan siyanobakteriler ve yaz aylarında siyanobakteri çoğalmaları da bildirilmiştir. Ancak bu gölde fitoplankton çeşitliliği üzerine yapılan çalışmalar kısıtlıdır ve siyanobakteriyel toksinler için yapılmış bir çalışma yoktur. Bu projenin amaçları göldeki fiziko-kimyasal parametreler ile fitoplankton çeşitliliği arasındaki ilişkileri incelemek, özellikle siyanobakteri çeşitliliğini ortaya koymak, mevcut siyanobakteri toksinlerini tespit etmek ve üreticilerini belirlemek olmuştur. Bu doğrultuda çeşitli biyokimyasal, kimyasal ve genetik yöntemler kullanılmıştır. Uluabat Gölü arazi çalışmaları 2015 ve 2016 yıllarının yaz aylarında gölün 4 farklı noktasında gerçekleştirilmiş ve toplamda 48 örnekleme yapılmıştır. İki yıl arasında ciddi farklılıklar gözlenmiş ve toplam azot, toplam fosfor, çözünmüş silika ve klorofil-a derişimleri 2016 yılında %50?nin üzerinde artış göstermiştir. Su kalitesi kriterlerine, döneme ve örnekleme noktasına bağlı olarak göl mezotrofik ve hipertrofik arasında değişim göstermiştir. 2015 yılında siyanobakterilerin toplam fitoplankton biyokütlesi içindeki oranı %31 ile %80 arasında değişim gösterirken, 2016 yılında bu değer %14 ile %55 arasında değişim göstermiştir. Gölden toplanan tüm örnekler siyanobakteriyel toksinlerden mikrosistin, nodülarin, silindrospermopsin, saksitoksin ve anatoksin için biyokimyasal ve genetik yöntemlerle incelenmiştir. Tüm örneklerin yüksek derişimde mikrosistin içerdiği tespit edilmiştir. LC MS/MS analizi Uluabat Gölü?nde 19 farklı mikrosistin çeşidinin var olduğunu ortaya koymuştur. Aynı örneklerden izole edilen genomik DNA?larda PZR ile mcyA genleri tespit edilmiş, klonlanmış ve dizilenmiştir. Filogenetik analiz göldeki mikrosistin üreticisinin Microcystis sp. olduğunu ortaya koymuştur. Gölden 17 adet siyanobakteri suşu izole edilmiş, 9 tanesi ELISA?da, 5 tanesi PZR?de mikrosistin için pozitif sonuç vermiştir. Her iki yöntemle de doğrulanan mikrosistin üreticileri Microcystis sp olmuştur. LC-MS/MS analizi yapılan bir Microcystis aeruginosa izolatının 22 farklı mikrosistin çeşidi ürettiği belirlenmiştir. Gölde ve izolatta tespit edilen mikrosistin çeşitliliği dünyadaki benzerleri içinde ilk sıralardadır.
