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•Transboundary evaluation of HMs in coastal environments of the Yellow Sea was conducted.•Sediments moderately contaminated with HMs significantly contributed to waterborne ...HMs.•Environmental factors significantly associated to hot spots contaminated by specific HMs.•Integrated management for coastal HMs pollution was highlighted in site-specific manner.
The Yellow Sea Large Marine Ecosystem (YSLME) is an important socioeconomic zone in Asia, but has been deteriorated by various environmental pollutants over the last half century. However, comprehensive coastal pollution assessments, particularly for heavy metals (HMs), have been limited from an international perspective. Here, we first evaluate coastal HM pollution in sediment and water from 119 riverine, estuarine, and marine locations along the BS and Yellow Sea to perform a comparative assessment between the two countries of China and South Korea. The occurrence, distribution, sources, multimedia fate, interactions, associated environmental factors, and potential ecological risks relating to the HM pollution are widely addressed. Eight typical HMs (As, Hg, Zn, Cu, Pb, Cd, Cr, and Ni) were targeted in both sediments and water, and in situ water properties (pH, dissolved oxygen, salinity, and temperature) and sediment properties (pH and organic matter (OM) content) were analyzed. The results indicated that As, Cd, Cr, Cu, Ni, and Pb concentrations in water were higher in the estuarine area than those in riverine and marine areas and that particularly severe HM pollution was evidenced in the BS. The dominant elements in pollution hot spots varied greatly among the countries and regions. According to the geo-accumulation index (Igeo) and pollution load index (PLI) values, the sediments exhibited high Hg and Pb pollution in the BS; high As, Hg, and Pb pollution in the Yellow Sea of China; and high Cd and Hg pollution in the Yellow Sea of South Korea. In general, the sediments were moderately contaminated by HMs based on the high PLI (>1.0) and risk index (RI) values (>160). Ni and Cr in the sediment mainly originated from geogenic sources, while the other elements (Zn, As, Cd, Cu, Hg, and Pb) were primarily linked to anthropogenic sources. Based on the partial redundancy analysis, we found that environmental factors, especially OM, contributed significantly to the concentrations of HMs in both the sediments and water. The sediment HMs significantly contributed to the waterborne HMs due to their release from the sediments to the water column. An overall assessment of the contamination status, spatial distribution, and potential sources of HMs suggested that the water-sediment interaction of HMs and the influence by environmental factors should be subsequently considered for a better understanding of the multimedia fate of HMs in the given dynamic YSLME system or similar environments elsewhere.
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•Complexity and diversity of Blue Economy field in relation to UN’s SDGs remarked.•Conflicts of Blue Economy, growth & development vs. protection of ocean resources, ...addressed.•Uncertainty & conflicting goals reduced when stakeholders are identified under BE-SDGs.•An incremental approach by stakeholders is a key to addressing BE-SDGs complexities.•Current approaches in Blue Economy revisited for better achievement of SDGs in practice.
The “Blue Economy (BE)” is an increasingly popular concept as a strategy for safeguarding the world’s oceans and water resources. It may emerge when economic activity is in balance with the long term capacity of ocean ecosystems to support the activity in a sustainable manner. Importantly, the concept of BE posits the inherent conflicts between two discourses—growth and development, and protection of ocean resources. The inherent conflicts require solutions to embrace the opportunities associated with the ocean economy while recognizing and addressing its threats. The potential solutions on a global scale are advocated by the United Nations in their Sustainable Development Goals (SDGs). However, we notice that the identification of the scope and boundaries of the BE in line with the UN’s SDGs is vague even challenging, and the key stakeholders and their interests and roles in the BE are also vague. This review examines the scientific evidence of the association between the BE and the UN’s SDGs, and relevance and alignment of stakeholders on the link between the BE and SDGs. Based on a literature survey between 1998 and 2018, we find that BE is highly associated with SDGs 14–17. Notably, we find that stakeholders prefer SDG 3 Good Health & Well-Being and SDG 8 Decent Work & Economic Growth in the BE context. As stakeholder involvement shows some differences and variations in the relationship between the BE and SDGs, we consider that stakeholders can play some roles directly or indirectly in the BE-SDGs context. In order to set achievable goals and targets in BE-SDGs, we support that key stakeholders should be identified to play several important roles in prosperous economic, societal development and setting tolerable ranges for the ocean biosphere.
Glacier retreat is a major long-standing global issue; however, the ecological impacts of such retreats on marine organisms remain unanswered. Here, we examined changes to the polar benthic community ...structure of "diatoms" under current global warming in a recently retreated glacial area of Marian Cove, Antarctica. The environments and spatiotemporal assemblages of benthic diatoms surveyed in 2018-2019 significantly varied between the intertidal (tidal height of 2.5 m) and subtidal zone (10 and 30 m). A distinct floral distribution along the cove (~ 4.5 km) was characterized by the adaptive strategy of species present, with chain-forming species predominating near the glacier. The predominant chain-forming diatoms, such as Fragilaria striatula and Paralia sp., are widely distributed in the innermost cove over years, indicating sensitive responses of benthic species to the fast-evolving polar environment. The site-specific and substrate-dependent distributions of certain indicator species (e.g., F. striatula, Navicula glaciei, Cocconeis cf. pinnata) generally reflected such shifts in the benthic community. Our review revealed that the inner glacier region reflected trophic association, featured with higher diversity, abundance, and biomass of benthic diatoms and macrofauna. Overall, the polar benthic community shift observed along the cove generally represented changing environmental conditions, (in)directly linked to ice-melting due to the recent glacier retreat.
Glass solid wastes were recycled in the synthesis of green zinc oxide/mesoporous silica (MCM-41) composite with significant surface area (661 m2/g) and bandgap energy (2.43 eV). It was assessed as a ...potential adsorbent and photocatalyst for Levofloxacin. The Levofloxacin adsorption reaction is of First-order kinetic (R2 = 0.99) and Langmuir isotherm properties (R2 > 0.95). A monolayer model with two energy sites was applied for more details about the adsorption process (R2 = 0.999). Considering the steric parameters, the adsorbed Levofloxacin molecules (n) are higher than 1 on both sites (n1 (2.6–5.15) and n2 (2.99–3.18)). This suggested vertical adsorption of several Levofloxacin molecules per site by a multimolecular mechanism. The active site densities of zinc oxide as the first site (Nm1) and saturation capacity (Qsat1) increased with temperature up to 45 °C (Nm1 = 17.8 mg/g and Qsat1 = 57.49 mg/g). The reverse occurred for the second sites (MCM-41) and the best values were reported at 25 °C (Nm2 = 23.35 mg/g and Qsat2 = 69.8 mg/g). The adsorption energy (−8.16 to −25.9 kJ/mol) and thermodynamic functions declare physical Levofloxacin uptake mechanisms of spontaneous and exothermic properties. G.Zn/MCM as photocatalyst (0.5 g/L) achieved 100% oxidation of Levofloxacin (50 mg/L) and 100% mineralization after 160 min and 240 min, respectively.
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The paper gives a historical overview, and a summary of key findings from 70 previously published research papers giving scientific data over the years from 1980 to 2019. They concern the flora ...and/or fauna in the mangrove forests along the Sri Lankan coast, addressing diversity, taxonomy, distribution, and ecological interactions. A total of 28 mangrove floral species from 13 plant families have been reported so far. Similarly, faunal diversity studies have reported 99 invertebrates, dominated by Arthropoda (n = 55) and Mollusca (n = 26), and 214 vertebrates comprising Pisces (n = 112), Aves (n = 72), Reptilia (n = 13) and Amphibia (n = 2). Most studies have been concentrated on the Southwestern coast (nflora = 20, nfauna = 6). Negombo has been a hotspot for mangrove research, with a higher number of studies (nflora = 11, nfauna = 5). The majority of the mangrove studies were focused on mangrove floral diversity and taxonomy and were conducted over recent years (2010–2019). Scientific data on mangrove fauna is restricted to a certain geographical extent. This paper intends to identify the research gaps in the field of Sri Lankan mangroves regarding various aspects and suggests advancement in future studies. Overall, outputs from the present study would be helpful for upcoming researchers to focus more on filling the gaps in knowledge.
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•Confirmed the world's longest man-made dike impact on tidal flat food web dynamics.•Revealed eutrophic water discharge impact on the nutritional and microalgal ...distribution.•Characterized the greater MPB contribution to benthos by eutrophic water input.•Identified distinct discharge water impact on diet utilization of filter/deposit feeders.
The man-made sea dike has disrupted the natural link between riverine and marine ecosystems and caused eutrophication within the aquatic ecosystem. The eutrophic water discharge has also raised concerns. As a representative tidal flat with the longest dike in the world, Saemangeum has experienced the problem of eutrophication. To elucidate the discharge water effects on the benthic food web dynamics, a four-year round sampling was conducted in/outside of the Saemangeum sea dike. Stable isotope analysis was applied to benthos (a total of 54 species) and their potential diets. Water discharge tripled in period II (2021–2022) compared to the period I (2019–2020). However, there were no significant impact changes in food web structure between the two periods due to improved lake water quality in period II. A positive correlation of nutrient concentration between the inner and outer areas of the dike revealed a direct effect of the water discharge on the outer tidal flat. The water discharge altered the spatial environmental conditions and the food web structure of the outer tidal flat. High TN concentrations stimulated the biomass of microphytobenthos (MPB) near the water gates, which in turn increased MPB consumption by benthos, demonstrating the in/direct impacts of water discharge on the food web. Furthermore, filter feeders exhibited a more sensitive response to spatial organic matter distribution compared to deposit feeders in diet utilization. Overall, our novel findings on food web dynamics in a representative tidal flat with artificial structures emphasize the necessity of continuous monitoring to ensure the sustainability of coastal ecosystems.
Effect-directed analysis was used to identify previously unidentified aryl hydrocarbon receptor (AhR) agonists in sediments collected from a highly industrialized area of Ulsan Bay, Korea. The ...specific objectives were to (i) investigate potent fractions of sediment extracts using the H4IIE-luc bioassay, (ii) determine the concentrations of known AhR agonists (polycyclic aromatic hydrocarbons (PAHs) and styrene oligomers (SOs)), (iii) identify previously unreported AhR agonists in fractions by use of GC-QTOFMS, and (iv) evaluate contributions of individual compounds to overall AhR-mediated potencies, found primarily in fractions containing aromatics with log K ow 5–8. Greater concentrations of PAHs and SOs were also found in those fractions. On the basis of GC-QTOFMS and GC-MSD analyses, 16 candidates for AhR agonists were identified in extracts of sediments. Of these, seven compounds, including 1-methylchrysene, benzojfluoranthene, 3-methylchrysene, 5-methylbenzaanthracene, 11H-benzobfluorene, benzobnaphtho2,3-dfuran, and benzobnaphtho2,1-dthiophene, exhibited significant AhR activity. Relative potency values of newly identified AhR agonists were found to be greater than or comparable to that of benzoapyrene (BaP). The potency balance analysis showed that newly identified AhR agonists explained 0.07–16% of bioassay-derived BaP-EQs. These chemicals were widely distributed in industrial sediments; thus, it is of immediate importance to conduct studies on sources and potential effects of those chemicals.
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•Halophilic bacteria accumulate osmolytes in the cytoplasms to adapt to osmotic pressure.•The osmolytes accumulated by Halomonas sp. YJPS3-3 are P3HB.•Developed gamma-irradiated ...Halomonas mutants boost PHA by 11%.•Creating halotolerance enhanced mutations in halophiles is a pioneering approach.
Polyhydroxyalkanoates (PHA) have emerged as a promising bio-compound in the industrial application due to their potential to replace conventional petroleum-based plastics with sustainable bioplastics. This study focuses on Halomonas sp. YJPS3-3, a halophilic bacterium, and presents a novel approach to enhance PHA production by exploiting its salt tolerance toward PHA biosynthesis. Through gamma irradiation-induced mutants with enhanced salt tolerance from 15% NaCl to 20% NaCl, mutant halo6 showing a significant 11% increase in PHA yield, was achieved. Moreover, the mutants displayed not only higher PHA content but also remarkable cell morphology with elongation. In addition, this research unravels the genetic determinants behind the elevated PHA content and identifies a corresponding shift in fatty acid composition favoring PHA accumulation. This novel mutant obtained from gamma irradiation with enhanced salt tolerance in halophilic bacteria opens up new avenues not only for the bioplastic industry but also for applications in the production of high-value metabolites.
Today, the synthesis of green metal nanoparticles is a potential approach in material science and nanotechnology. Aluminum nanoparticles (Al2O3NPs) were produced in a high-efficiency, cost-effective, ...green, and easy method using Lyngbyamajucula algae extract. Thealuminium oxide nanoparticles were evaluated using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). This study also determines the antibacterial activity and minimum inhibitory concentration (MIC) of Al2O3 nanoparticles against pathogens such as Streptococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Salmonella paratyphi, Candida albicans, and Aspergillus flavus. The average crystallite size of Al2O3 nanoparticles was determined to be 326 nm and 382 nm in UV, 28 nm in XRD, and peaks at 407 and 428 in the FT-IR spectra, which were attributed to aluminium oxide stretching. Klebsiella pneumoniae and Candida albicans displayed a peak zone of inhibition (22 mm) in the antimicrobial experiment at a dose of 100 mg/ml of Al2O3 nanoparticles. Finally, aluminium oxide is a powerful antibacterial agent that may be used to treat a wide range of human illnesses.
•Al2O3NPs synthesized using the L.majucula algae extract by greenapproach.•L.majuscula have shown tremendous potential as an agent for producing Al2O3NPs.•UV, FTIR, XRD, and SEM analyses were used to evaluate Al2O3NPs.•Al2O3NPs are a powerful antibacterial agent.
Dispersion and biodegradation of petroleum hydrocarbons are significantly enhanced by formation of oil-suspended particulate matter aggregates (OSAs), but little is known about their adverse effects ...on benthic invertebrates or microbes. In this study, we investigated: (1) bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) by the marine bivalve, Mactra veneriformis and (2) changes in composition and relative abundances of microbes, during 50-d of an OSAs feeding experiment. Total concentrations of PAHs increased more rapidly during the first week of exposure, peaked at Day 30, then gradually declined to the end of experiment. While bioaccumulation of PAHs by clams varied among the 20 target compounds, two major groups of PAHs were identified by cluster analysis. One group including 3-methylphenanthrene, 1,6-dimethylphenanthrene, 1,2,6,9-tetramethylphenanthrene, and benzoaanthracene showed a fairly constant rate of accumulation, while the second group including 2-methyldibenzothiophene, 2,4-dimethyldibenzothiophene, 2,4,7-trimethyldibenzothiophene, 3-methylchrysene, 6-ethylchrysene, and 1,3,6-trimethylchrysene exhibited a bell-shaped pattern. Bioaccumulation of PAHs by clams was dependent on changes in abundance of Gammaproteobacteria, indicating active degradations of hydrocarbons by selected species. Six key species included: Porticoccus litoralis, Porticoccus hydrocarbonoclasticus, Cycloclasticus spirillensus, Alcanivorax borkumensis, Alcanivorax dieselolei, and Alkalimarinus sediminis. These results are the first to demonstrate interactions of OSAs and macrofauna/microbe in oil cleanup operations.
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