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The widespread presence of microplastics (MPs) in freshwater systems as an emerging environmental pollutant has caused a global environmental problem. The present study investigates the distribution and abundance of source pathway and abundance of microplastics in surface sediment samples from rivers discharging into the Gorgan Bay, southeast of the Caspian Sea. A total of 57 surface sediment samples were taken from 19 stations to investigate the potential hot spots of pollution in the four rivers leading to the Gorgan Bay. The average level of microplastics was 333 ± 268 particles/kg. The highest amount is in the estuary of the Qarasu River (1080 ± 380 particles/kg) due to the accumulation of fishing, boating and tourism activities and the lowest amount in the forest area (80 ± 19 particles/kg) in the Klak River. The most common type of microplastic was fiber (68%). Microplastic pollution in the studied rivers is mostly black and gray (75.39%), and about 53% of them were sized less than 1000 μm. Spectroscopic analysis (Fourier Transform Infrared (FT-IR) of the MP showed that 37% were polyethylene, polyethylene (37%) and polypropylene (27%) were the dominating groups. The sediments’ size was significantly correlated (p>0.05) with the presence of microplastics. Sediments with a coarse grain (sand) demonstrated a great potential to store microplastics. The results of this study can be used for the management and protection policies of Gorgan Bay. [ABSTRACT FROM AUTHOR]

Crude oil pollution can decrease the biodiversity in the marine environment. The Persian Gulf in Iran is an ecosystem rich in marine organisms that can effectively degrade crude oil. This study aimed to screen bacterial strains to degrade crude oil from the intestinal microbial flora of Mudskippers fish from the Persian Gulf. The identification of collected fish samples distinguished four diverse genera. Periophthalmus waltoni was the most common. Next, biochemical and molecular identification of isolated bacteria was performed. Some biochemical tests, such as catalase, oxidase, and motility, were done. Molecular identification was performed by polymerase chain reaction using general primers. Finally, the ability of bacterial isolates to degrade crude oil was investigated using spectrophotometric, gravimetric, gas chromatography, and FTIR methods. Bacteria identified in this study include Marinobacter hydrocarbonoclasticus, Pseudomonas aestusnigri, Thalassospira permensis, Microbacterium esteraromaticu, Oceanimonas sp, Halomonas Salaria, Halomonas beimenensis, Cobetia marina, Tenacibaculum discolor and Shewanella chilikensis. Halomonas salaria had the highest growth rate (OD= 1.6) and crude oil degradation (90%) among the studied strains. The results of our studies on five strains of T. permensis, S. chilikensis, M. hydrocarbonoclasticus, and Oceanimonas in concentrations of 1, 2.5, 4, 5.5, and 7 g/l crude oil show that with increasing concentration, crude oil reduces the ability of the strains to degradation (decrease degradation from 90 % to 20 %). Other studies have been conducted to recognize fish as an indicator of oil pollution. Still, the results of this research confirmed that crude oil pollution decreases the biodiversity in the intestinal microbial flora of these fish. The isolated bacteria can degrade crude oil and help degrade this pollution in aquatic ecosystems. By applying these bacteria, crude oil pollution in the Persian Gulf can be better managed and decreased. [ABSTRACT FROM AUTHOR]

The present study confidently delves into evaluating the proximate, chemical composition of various marine seaweeds, including the green species Hypnea pannosa and Spatoglossum solieri, as well as the brown species Padina boergesenii, collected from the coastal area of Jeddah in the Red Sea, Saudi Arabia. The findings indicate that S. solieri (42.2%) and P. boergesenii (41.5%) serve as richer sources of carbohydrates compared to H. pannosa (36.6%) seaweed. Among these species, P. boergesenii demonstrated the highest protein content (21.3 g), while H. pannosa displayed the lowest protein content (14.1 g). Regarding lipid content, S. solieri exhibited the highest lipid source (1.3 g) among the green algae, followed by P. boergesenii (0.82 g) among the brown algae. These seaweed species exhibit substantial quantities of nutritional compounds, holding promise for potential applications in the field of nutrition in the future. [ABSTRACT FROM AUTHOR]

This study focuses on the estimation of antioxidant, antifungicidal and antibacterial activities, as well as the composition of chemical (secondary metabolites) of seaweeds composed from Red Sea in the southern region of Jeddah, Saudi Arabia. The Red Sea ecosystem is known for its unique marine biodiversity and remains relatively underexplored in terms of the bioactivity of its seaweed species. Seaweed samples Hypnea pannosa, Spatoglossum soleri and Padina boergesenii were composed from dissimilar locations along the southern coast of Jeddah. The collected samples were subjected to extraction processes to obtain crude extracts, which were then assessed for their antioxidant potential using various assays, including free radical scavenging and lipid oxidation inhibition. Additionally, antimicrobial activity was evaluated alongside a section of clinically pertinent microbial strains, including bacteria and fungi. Preliminary results indicate significant antioxidant activity in the crude extracts of the collected seaweeds. Notably, several species demonstrated promising scavenging abilities against reactive oxygen species, highlighting their potential as natural sources of antioxidants, the antimicrobial assays revealed untrustworthy degrees of inhibition effects against the tested fungal and bacterial species. This finding provided insights into the attendance of specific bioactive compounds, including flavonoids, polyphenols and other secondary metabolites associated with antioxidant and antimicrobial properties. [ABSTRACT FROM AUTHOR]

Enormous quantities of marine macrophytes have been accumulated in shorelines by tidal actions, which considered as organic pollution. There is a necessity to collect macrophytic biomasses from shorelines to protect the environment. This paper focused on the collection and utilization of waste macrophytic biomass for the production of silver nanoparticles. Two representative candidates, Cymodocea serrulata (Seagrass) and Padina australis (Seaweed) were selected for the study. Synthesized nanoparticles were characterized by UV-Spectrophotometer, FTIR, SEM, EDS and AFM and their anti-phytopathogenic activity also assessed. Results of this study revealed that C. serrulata mediated silver nanoparticles (Cs-AgNP) exhibited effective anti-fungal activity against Pyriporia oryzea (14 ± 1.5 mm), Helminthisporium oryzea (12 ± 1.4 mm), Alternaria sp. (10 ± 1.2 mm) and Padina australis mediated silver nanoparticles (Pa-AgNPs) showed potential activity against Rhizoctonia solani (16 ± 1.6 mm), Xanthomanas oryzae (15 ± 1.3 mm). The current study findings could pave a way to collect the organic waste from shorelines and deploying them for the production of value added products. The manuscript consists of information about the utilization of marine waste macrophytic biomass for the synthesis of silver nanoparticles, characterization and their novel approach in the treatment against agro-phyto fungi. [ABSTRACT FROM AUTHOR]

Synthesis of silver nanoparticles (AgNPs) using microorganisms has gained considerable attention as an efficient alternative for conventional chemical synthesis. Earlier, we have demonstrated biosynthesis of silver nanoparticles using marine Escherichia coli VM1. Here, we investigated antibacterial, antifungal and antioxidant efficacy of the synthesized silver nanoparticles using standard techniques. The results have shown that the AgNPs synthesized using the marine Escherichia coli have potential antibacterial activity against both Gram positive (Staphylococcus aureus) and Gram negative (E. coli, Klebsiella pneumoniae, S. paratyphi, Vibrio parahaemolyticus, V. cholerae and Proteus mirabilis) pathogenic bacteria and moderate antifungal activity was observed against Aspergillus niger, Penicillium sp., Trichothecium roseum and Trichophyton rubrum. Further, in vitro antioxidant study was examined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. We observed significant effect on scavenging of free radicals suggesting that the AgNPs biosynthesized using E. coli could be an efficient and eco-friendly material for biomedical applications. [ABSTRACT FROM AUTHOR]