This study investigated the role of biofilms formed on different mesoplastics (Polyethylene (PE), Polypropylene (PP), and Polystyrene (PS)) in the accumulation of contaminants in a laboratory model system simulating estuarine conditions. Also, the biofilm penetration of the primary pollutants (pharmaceuticals, total petroleum hydrocarbons (TPH), etc.), their persistence in biofilm, and their impact on the total microbial population were examined. Results showed that biofilm formation occurred on all the mesoplastic samples over six-month period. The biofilm on PP exhibited the highest cell count of aerobic heterotrophic bacteria (AHB) (8.7 × 106 cfu/cm2) by the end of the exposure period. In terms of pollutant concentrations, the biofilm on PE recorded the highest levels of gemfibrozil (GFZ), measuring 2.2 μg/cm2 during the experiment. Moreover, the biofilm formed on PP demonstrated the peak values for TPH accumulation, recorded at 57.1 μg/cm2. These findings indicate that mesoplastics serve as passive samplers, providing surfaces conducive to microbial colonization and thereby enhancing the accumulation and retention of pollutants from the surrounding aquatic environment within biofilms. Therefore, a comprehensive assessment of plastic pollution in marine ecosystems must incorporate considerations of the biological activity and interactions of plastics with environmental contaminants to fully understand their ecological impact.

The Sea of Marmara, T & uuml;rkiye's only inland sea, continues to be under significant anthropogenic pressure despite its designation as a Special Environmental Protection Area in November 2021. The massive mucilage event that occurred in 2021 further intensified concerns regarding microbial contamination and associated public health risks. This study evaluates post-mucilage microbial contamination in the SoM by analyzing fecal indicator bacteria (FIB) and selected pathogens (Salmonella spp. and Vibrio spp.), with a focus on sites near marine outfalls receiving effluents from wastewater treatment plants operating with varying levels of treatment (from preliminary to advanced biological treatment). Comprehensive microbial water quality monitoring across multiple sampling points and depths revealed that FIB concentrations were higher near marine outfalls compared with more distant sites. While Salmonella spp. were not detected in any sample, several Vibrio species, including V. cholerae, V. parahaemolyticus, V. fluvialis, and V. alginolyticus, were identified throughout the water column. These findings highlight the importance of basin-wide microbial monitoring not only at the surface but also throughout the water column to better understand the fate and transport of fecal contamination, particularly in regions influenced by wastewater effluents and in shellfish harvesting areas. Furthermore, upgrading wastewater treatment technologies, especially at facilities currently limited to preliminary physical treatment, is suggested to be beneficial. Such improvements are essential to protect both the ecological integrity of the SoM and public health.

The marine biorefinery concept, especially focusing on blue feed and food production, can be one of the key pillars to contribute to the Blue Economy. The secondary marine-based sources such as low-trophic organisms and marine industry waste such as fish processing and aquaculture waste can be utilized to extract carbohydrates, proteins, lipids, minerals and bio-active compounds that can be cascaded for the production of food packaging materials, food analogues and animal feed within the marine biorefinery concept to promote circular economy. This review explores the potential of these marine-based sources as raw materials not only for intermediate value-added products but also for three main related end-products: blue food, blue feed, and smart-active food packaging. The importance of environmental sustainability, techno-economic and social assessment to the implementation of these products in the concept of blue economy is also highlighted. This review illustrates the prospects of a blue economy based on secondary marine resources as a catalyst for a sustainable society and circular economy.

Superabsorbent polymers were synthesized from cross-linked acrylic acid using collagen and chitosan via the surface polymerization method, with N, N-methylene bis(acrylamide) as the cross-linker and ammonium persulfate as the initiator. Collagen obtained from jellyfish collected from the Sea of Marmara and marine-derived chitosan were chosen as monomers. Superabsorbent polymers were characterized using FT-IR, SEM, and DSC. The swelling capacities of superabsorbent polymers were measured and compared. The maximum water absorption capacities in saline solution were 79 and 136 g/g for chitosan-polyacrylic acid and collagen-polyacrylic acid superabsorbent polymers, respectively. The highest water retention capacities of chitosan-polyacrylic acid and collagen-polyacrylic acid superabsorbent polymers were calculated as approximately 70 times and 120 times their weight, respectively. Fickian diffusion and pseudo-second-order kinetics were applied to determine the swelling kinetics, revealing a perfect relationship. Consequently, the superabsorbent polymer synthesized with collagen obtained from jellyfish had a higher water absorption capacity. To our knowledge, no prior research has documented the production of a biobased superabsorbent derived from jellyfish (Aurelia aurita) in the Sea of Marmara. Hence, this study represents a novel and valuable contribution to the literature. Moreover, the increased use of biodegradable biobased superabsorbent polymers can help reduce the carbon footprint and mitigate environmental pollution.

Surface sediments, mussels, and macroalgae were collected to investigate metal accumulation, distribution, pollution levels, and sources from Gemlik Bay in the southeastern Sea of Marmara. The elements Cu, Zn, V, Co, Cr, Pb, Ni, and Mn were determined in macroalgae (Ulva lactuca Linnaeus,1753), (Ulva intestinalis, Linnaeus, 1753) and mussel (Mytilus galloprovincialis, Lamarck, 1819) samples, while Al and Fe were also determined in sediment samples in addition to these metals. Element accumulation and metal contamination levels were determined, and health risks from mussel and macroalgae consumption were assessed across age groups. The average enrichment factor (EF) calculated for sediment samples indicates that the contamination originates from anthropogenic sources, while the contamination factor (Cf) indicates that the contamination is at a low level. Additionally, the potential ecological risk (Er) and index (PERI) reveal that, except for lead (Pb), the ecological factors for other metals are low. In addition, according to the average geochemical index (Igeo) results, sediments were uncontaminated with Mn and Al, slightly contaminated with Fe, slightly to moderately with Cr and Pb, and moderately with Zn. Detected metals in mussels and macroalgae were assessed for health risks across age groups for the first time. Accordingly, the daily chronic intake (CDI) was calculated, and separate hazard index (HI) and target hazard quotient (THQ) values were determined for each age group. Children were identified as the most vulnerable group, highlighting the need for caution in their consumption of seafood, especially mussels and macroalgae.

Scientists have identified chemical pollutants that are toxic and persistent in the environment, posing a risk to the health of water, sediment, and living organisms. These pollutants, known as persistent organic pollutants, include substances such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). PCBs and OCPs, which are categorized as persistent pollutants, accumulate in the environment and the food chain, thus posing a threat to numerous ecosystems. These pollutants can enter aquatic ecosystems through various pathways, and it is crucial to monitor their presence in water, sediment, and living organisms due to their potential adverse effects on both humans and the environment. The Sea of Marmara, located in a densely populated and industrially developed area within Turkey's borders, is of particular importance for evaluating these pollutants. Additionally, the Sea of Marmara serves as a significant sea route due to its strategic location. This study aims to present the research conducted in the water, sediment, and biota of the Sea of Marmara regarding these pollutants, spanning from the past to the present, along with relevant literature. The findings of studies conducted in the Sea of Marmara reveal that traces of these chemicals can still be detected, even though they are no longer in use today. Results indicate that these pollutants have been found in sediments and biota such as fish and mussels at various times. It has been emphasized that consuming these organisms may pose health risks due to the excessive presence of these pollutants in some cases.

Pharmaceutical pollution refers to the introduction of metabolites of drugs into the environment because of their use by humans and animals, leading to chemical and biological contamination. Recently, pharmaceutically active substances have been detected in many aquatic environments. In this study, the occurrence of fluoxetine and serotonin hormone was examined in the water column of Istanbul Strait, Türkiye, and environmental risk assessment was conducted in June, August, and October of 2022. Liquid–liquid extraction (LLE) and solid phase extraction (SPE) methods were employed for the extraction of analytes from water samples, followed by derivatization and analysis via the gas chromatography–mass spectrometry (GC–MS) technique. Pharmaceutical and hormone levels were detected under the intermediate layer and bottom layer, but the concentrations of the target compounds at the upper layer were < method detection limit (MDL). In this study, fluoxetine concentration were found between 4.05–69.8 ng/L and serotonin concentration were found between 1.42 and 32.84 ng/L. Based on the environmental risk assessment results, fluoxetine poses a moderate risk for daphnia but a low risk for algae and fish. The risk associated with serotonin was accepted as negligible in the assessment. This study represents the first investigation of pharmaceutical pollution caused by deep-sea discharge in the Istanbul Strait and the first study to examine the presence of serotonin hormone in the marine environment globally.

Lake Salda in Türkiye serves as a valuable Earth analog for studies of the properties of Mars due to its mineralogical and microbiological similarities to Jezero Crater on Mars. This study investigated the role of sulfate-reducing bacteria (SRB) enrichment culture isolated from Lake Salda on the microbiologically influenced corrosion (MIC) of an aluminum alloy (AA7075) using electrochemical, microbiological, molecular, and spectroscopic methods. Potentiodynamic polarization (PDP) tests confirmed SRB-enriched biofilm significantly accelerated corrosion. Fourier Transformed Infrared Spectroscopy (FTIR) further distinguished the control and biotic surfaces, showing the replacement of a 980 cm−1 polysaccharide band with a 1075 cm−1 cyclic polysaccharide vibration in SRB-colonized coupons. This spectral transition reflects biofilm maturation and EPS accumulation, providing molecular evidence for SRB-driven MIC. Molecular analysis identified Proteobacteria and Firmicutes as dominant phyla, and Desulfofustis limnaeus was detected in Lake Salda for the first time. Moreover, benthic foraminifera and ostracods were observed, some with morphological anomalies. These results provide mechanistic insight into the biochemical and electrochemical interactions driving SRB-induced corrosion, highlighting Lake Salda’s importance for studying microbial–material interactions in extreme environments.

Pharmaceuticals are a particular class of emerging contaminants, and their significance is becoming increasingly understood due to their physiological impacts on humans, even at low doses. According to the literature, different pharmaceutical compounds are frequently found in varied water, soil, and biota samples. In this study, eleven commonly used pharmaceutical compounds were reviewed in seawater, sediment, and biota in the Sea of Marmara. The studied compounds consist of four groups which are anti-inflammatory (naproxen, diclofenac, ibuprofen, ketoprofen, fenoprofen), hormones (estrone, 17 beta-estradiol, 17 alpha-ethynylestradiol), antiepileptic (carbamazepine), lipid regulators (gemfibrozil and clofibric acid). Gemfibrozil, ibuprofen, and 17-ethynylestradiol were among the pharmaceutical substances that were frequently found in the Sea of Marmara. Gemfibrozil was detected in concentrations ranging from < 0.054 to 9.71 mu g/L for seawater, 124 ng/g for sediment, and < 3.2 to 9135 ng/g for biota. Ibuprofen was detected in the range of < 0.015 - 2.46 mu g/L, 215 ng/g, and < 3 - 5098 ng/g in seawater, sediment and biota, respectively. 17 alpha-ethynylestradiol was found in concentrations ranging from < 0.010 - 3.55 mu g/L for seawater, 319 ng/g for sediment, < 2 - 1258 ng/g for biota. The negative impacts that these substances may have on both human health and the ecosystems in which they are found are thus of utmost significance. Furthermore, research on the trophic transfer of pharmaceuticals is relatively few and remains a gap in the literature despite the potential bioaccumulation of these substances. The present study reviews the current knowledge on the sources, transport, and degradation of pharmaceuticals in the seawater environment and assesses the environmental risk they pose in light of the criteria of permanence, bioaccumulation, and toxicity. Environmental risk evaluations and the identification of various pharmaceutical residues in water, sediment, and biota samples collected from the Sea of Marmara were thoroughly examined. 17-estradiol, gemfibrozil, and 17-ethynylestradiol pose a significant risk to aquatic life in the Sea of Marmara based on the risk quotient. Due to their extensive usage, the study focused on antiinflammatory medications, steroid hormones, antiepileptic medicines, and lipid regulators. Finally, future perspectives are discussed while considering the research gaps found in the context of the available information.

Antifouling chemicals are mainly used on water-contact surfaces to prevent biofouling formation on ships or submarine hulls. This study focuses on examining the presence of antifouling paint biocides (Irgarol 1051, chlorothalonil, and dichlofluanid) in the seawater of Beylikduzu Marina, Istanbul, and includes an assessment of their environmental risks. Surface seawater samples were collected from six stations around the marina in the spring, summer, autumn, and winter of 2023. The collected water samples were processed using both liquid-liquid extraction and stir bar sorptive extraction methods, and analyses were carried out using gas chromatography-mass spectrometry. Wilcoxon and Bland-Altman tests confirmed the higher efficiency of stir bar sorptive extraction. The highest concentrations of chlorothalonil, dichlofluanid, and Irgarol 1051 were determined as g/L, and 0.24 mu g/L, respectively, by liquid-liquid extraction method, while the highest concentrations of these compounds were measured as 0.5 mu g/L, 0.81 mu g/L, and 1.57 mu g/L, respectively, by magnetic stir bar extraction method. One-way analysis of variance (ANOVA) showed no significant seasonal variation in biocide concentrations, while regression analysis suggested a limited influence of water quality parameters, particularly for Irgarol 1051. Hierarchical cluster analysis grouped stations based on biocide concentrations, linking M2-M3 to boat mooring, M5-M4 to restricted circulation, M1 to maintenance, and M6 to external influences, emphasizing the role of anthropogenic and hydrodynamic factors in biocide distribution. The risk assessment indicates that the examined antifouling biocides may pose a threat to aquatic life. Irgarol 1051, in particular, requires attention due to its significant risk quotients.

Microplastic pollution has become one of the most important pollutant parameters in marine environments as in all environmental medias in the last 10 years. Moreover, as with all pollutants, microplastics (MPs) tend to accumulate in sediments as the final destination after their circulation in the marine environment, causing a threat to living organism dependent on sediments. In this study, it was aimed to determine the amount, distribution and morphological properties of MP in surface sediments collected from the Sea of Eastern Marmara in 2019. While the MPs amount was found in the range of 1699-12911 MPs/kg with an average of 3430 ± 3350 MPs/kg, the most dominant colours were brown (31%) and yellow (26%) and the most dominant shape was fragment (41%). Our study was also compared with current studies and it was revealed that the amounts found were lower than the data in studies conducted after the COVID-19 pandemic.

Limited resources in energy storage systems and the increasing need for batteries have spurred researchers to explore innovative, low-cost, and environmentally friendly sources. This study, which pioneers macro and microalgae as anode-active material in lithium-ion batteries and employs alginate extracted from brown algae as a binder in silicon anodes, represents a significant leap toward a more sustainable future. The need for sustainable energy storage solutions is not just a possibility but a promising reality that offers more environmentally friendly energy storage solutions. In the first study performed in this context, Ulva lactuca and Spirulina biomass were prepared as anodes and showed 131.9 and 36.6 mAh/g initial specific capacity values, respectively. Studies conducted to elucidate the reaction mechanism determined that the carbohydrate/protein ratio significantly affects the theoretical capacity of the algal species. In the second study, where alginate extracted from Cystoseira barbata was tested as a binder in silicon anodes, the highest initial capacity was 3517 mAh/g, and a capacity retention rate of 28.7% was obtained after 100 cycles. For future studies, higher capacity retention rates might be achieved by making the alginate more flexible with the higher Mannuronate/Guluronate ratio in alginate, which varies depending on the type of brown algae.

Melatonin is a powerful endogenous antioxidant hormone. Its healing effects on energy balance and neuronal damage associated with oxidative metabolism disorders have been reported in pathologic conditions. We aimed to determinate the utility of melatonin on neuronal damage, synaptic transmission, and energy balance in the brain tissue of rats with sepsis induced with LPS. Rats was divided into four groups such as control, LPS (20 mg/kg i.p.), melatonin (10 mg/kg i.p. × 3), and LPS + Melatonin (LPS + Mel). After 6 h from the first injection, rats were decapitated, and also tissue and serum samples were taken. Lipid peroxidation and neuron-specific enolase (NSE) levels were determined from the serum in all group. High energy compounds, creatine, and creatine phosphate are measured by HPLC methods from the homogenized tissue. Counts of living neurons are marked with NeuN (neuronal nuclei), degenerated neurons are marked with S100-ß and synaptic vesicles transmission is analyzed with synaptophysin antibodies immunoreactivities. One-way ANOVA and post hoc Tukey tests were used to statistical analysis. In LPS group, AMP, ATP, creatine, and creatine phosphate levels were significantly decreased (p < 0.05), and also ADP levels were significantly increased compared with the other groups (p < 0.01). Living neurons counts were significantly decreased in LPS (p < 0.01), melatonin, and LPS + Melatonin (p < 0.05) groups compared with control. Degenerated neurons counts were increased in LPS group compared with control (p < 0.01) and also decreased in both of melatonin and LPS + Melatonin groups (p < 0.01). Synaptophysin immunoreactivity was decreased in LPS group compared with the other groups (p < 0.05). We observed that melatonin administration prevents neuronal damage, regulates energy metabolism, and protects synaptic vesicle proteins from sepsis-induced reduction.

Diclofenac, ibuprofen, and carbamazepine are commonly used in medicine, and they have been frequently detected in aquatic environments. Since they cannot be fully treated in treatment plants and can threaten the lives of aquatic life, effective treatment methods are needed to remove they from wastewater and contaminated waters. The removal of these compounds from synthetic seawater was investigated by utilizing the super adsorbent property of silica-chitosan nanocomposite material synthesized using domestic chitosan. 1.25

The occurrence of seven commonly used pharmaceuticals, including diclofenac, fenoprofen, ketoprofen, ibuprofen, naproxen, carbamazepine, clofibric acid, gemfibrozil, estrone, 17 beta-estradiol, and 17 alpha-ethynylestradiol, was investigated in the seawater of the Arctic during the summer of 2022. Seawater samples were subject to liquid-liquid extraction and solid-phase extraction (SPE). The concentrations of pharmaceuticals in the seawater samples were quantified with high-performance liquid chromatography (HPLC) and a DAD detector. The most abundant pharmaceuticals in the seawater were ibuprofen, with a range of 130-220 ng/L, and the highest concentration was obtained for 17 alpha-ethynylestradiol with a level of 350 ng/L. We discussed possible reasons for pharmaceutical pollution, including the impact on marine species, the role of wastewater treatment technologies, and the potential long-range transportation of pharmaceutical residues via sea surface currents.

Water is an indispensable resource for life on Earth, with its importance being highlighted by the vast range of applications that require it. Advanced oxidation techniques, well-known for their ability to generate hydroxyl radicals, have proven successful in treating water and wastewater. When different advanced oxidation processes are combined, a synergistic impact is shown, such as reduced chemical consumption or a more rapid reaction than with the processes alone. For this reason, hybrid processes in which different processes are applied together are called synergistic advanced oxidation processes. However, the use of these processes is limited by chemical and energy requirements. Currently, green synthesis is an emerging process for producing chemicals and materials in a more environmentally friendly way. It involves the use of various chemical treatments and reagents to remove organic and heterogeneous materials, while producing nontoxic, eco-friendly byproducts. Green synthesis has been used for a variety of purposes, such as gas absorption, water splitting, catalytic uses, sensors, and renewable energy. Heterogeneous catalysts have been identified as the strongest candidate for use in industry because of their functionalized structures, thermal stability, and well-defined surfaces. They also have suitably sized active sites for carrying out different chemical reactions. In this review, the focus is on heterogeneous catalysts, metal oxides, double-layered hydroxides, perovskites, metal organic frameworks (MOFs) and graphene. Furthermore, the various advantages and disadvantages of Fenton process catalysts fabrication methods have been discussed with an emphasis on green synthesis, are discussed in detail.

The increasing impact of global warming has made it crucial to monitor greenhouse gases (GHG). Carbon dioxide (CO2) is especially important due to its significant increase. Oceans and seas play a vital role in absorbing excess CO2 from the atmosphere, but they are facing challenges such as ocean acidification and damage to coral reefs. Therefore, it's essential to thoroughly understand climate change and its human-caused effects and to take necessary precautions or improve existing measures. In this direction, in seawater, determining alkalinity is crucial for monitoring CO2, along with other physical and chemical parameters, in order to help set carbon budgets and reduce environmental pressures. For this purpose, in this study in the Sea of Marmara, alkalinity and CO2 measurements were conducted for the first time at stations CG2, CG3, MD26, and MD24. The CO2 partial pressure (pCO2) values ranged from 95 to 165 µatm at the surface of all stations, and total alkalinity values ranged from 1.075 to 1.46 mmol kg-1 at specified depths. Based on these measurements, flux values were calculated between −1.10 and −5.39 mmol m2 day-1, indicating that the Sea of Marmara acted as a net CO2 sink.