Search Results (22)

Marine mollusk shells are a promising renewable source of calcium-based materials, offering a sustainable alternative for their synthesis. In this study, five types of marine shells—Chamelea gallina, Mya arenaria, Rapana venosa, Mytilus edulis, and Pecten maximus—were calcined at 900 °C for 2 h. The resulting powders were characterized by XRD, FTIR, SEM, PSD, and zeta potential analyses. XRD confirmed the dominant presence of CaO, with residual calcite and portlandite. FTIR spectra supported these findings, indicating the decomposition of carbonate phases and the formation of Ca–O bonds. SEM imaging revealed species-specific microstructures ranging from lamellar and wrinkled textures to compact aggregates, while particle size distributions varied from 15 to 37 μm. Thermogravimetric analysis revealed a two-step decomposition process for all samples, with significant species-dependent differences in mass loss and conversion efficiency, highlighting the influence of biogenic origin on the thermal stability and CaO yield of the resulting powders. Zeta potential measurements showed low colloidal stability, with the best performance found in Rapana venosa and Pecten maximus calcinated samples. Antibacterial activity was evaluated using a direct contact method against Escherichia coli and Enterococcus faecalis. All samples exhibited complete inactivation of E. coli, regardless of exposure time, while E. faecalis required prolonged contact (3.3 h) for full inhibition. The results highlight the potential of biogenic CaCO₃ and CaO powders as functional, antimicrobial materials suitable for environmental and biomedical applications. This study underscores the viability of marine shell waste valorization within a circular economy framework. Full article

Lightweight concrete (LWC) has emerged as a transformative material in sustainable and high-performance construction, driven by innovations in engineered lightweight aggregates, supplementary cementitious materials (SCMs), fiber reinforcements, and geopolymer binders. These advancements have enabled LWC to achieve compressive strengths surpassing 100 MPa while reducing density by up to 30% compared to conventional concrete. Fiber incorporation enhances flexural strength and fracture toughness by 20–40%, concurrently mitigating brittleness and improving ductility. The synergistic interaction between SCMs and lightweight aggregates optimizes matrix densification and interfacial transition zones, curtailing shrinkage and bolstering durability against chemical and environmental aggressors. Integration of recycled and bio-based aggregates substantially diminishes the embodied carbon footprint by approximately 40%—aligning LWC with circular economy principles. Nanomaterials such as nano-silica and carbon nanotubes augment early-age strength development by 25% and refine microstructural integrity. Thermal performance is markedly enhanced through advanced lightweight fillers, including expanded polystyrene and aerogels, achieving up to a 50% reduction in thermal conductivity, thereby facilitating energy-efficient building envelopes. Although challenges persist in cost and workability, the convergence of hybrid fiber systems, optimized mix designs, and sophisticated multi-scale modeling is expanding the applicability of LWC across demanding structural, marine, and prefabricated contexts. In essence, LWC’s holistic development embodies a paradigm shift toward resilient, low-carbon infrastructure, cementing its role as a pivotal material in the evolution of next-generation sustainable construction. Full article

This literature review critically examines the development and optimization of sustainable energy and exergy analysis software specifically designed for offshore wind farms, emphasizing the transformative role of machine learning (ML) in overcoming operational challenges. Offshore wind energy represents a cornerstone in the global transition to low-carbon economies due to its scalability and superior energy yields; however, its complex operational environment, characterized by harsh marine conditions and logistical constraints, necessitates innovative analytical tools. Traditional deterministic methods often fail to capture the dynamic interactions within wind farms, thereby underscoring the need for ML-integrated approaches that enhance precision in energy forecasting, fault detection, and exergy analysis. This PRISMA-ScR review synthesizes recent advancements in ML techniques, including Random Forest, Long Short-Term Memory networks, and hybrid models, demonstrating significant improvements in predictive accuracy and operational efficiency. In addition, it critically identifies current gaps in existing software tools, such as inadequate real-time data processing and limited user interface design, which hinder the practical implementation of ML solutions. By integrating theoretical insights with empirical evidence, this study proposes a unified framework that leverages ML algorithms to optimize turbine performance, reduce maintenance costs, and minimize environmental impacts. Emerging trends, such as incorporating digital twins and Internet of Things (IoT) technologies, further enhance the potential for real-time system monitoring and adaptive control. Overall, this review provides a comprehensive roadmap for the next generation of software tools to revolutionize offshore wind farm management, thereby aligning technological innovation with global renewable energy targets and sustainable development goals. Full article

Against the backdrop of global warming, the marine low-carbon economy has emerged as a crucial pathway to achieving carbon peaking and carbon neutrality goals. This paper develops an evaluation index system for the marine low-carbon economy and carbon emission reduction. Using data from China’s coastal provinces (2012–2021), the study employs methods such as the entropy weight method, the coupled coordination model, K-means++ clustering, and grey correlation analysis to analyze the interaction between the marine low-carbon economy and carbon emission reduction. The study revealed the following findings: (1) From 2012 to 2022, the development of the marine low-carbon economy exhibited an “N”-shaped pattern, while the trend of carbon emission reduction generally followed the opposite pattern due to a “lag” effect. (2) The coordination between the two systems improved gradually, reaching an intermediate level from 2018 to 2021. (3) Among the internal factors related to the interaction between the marine low-carbon economy and carbon emission reduction, fossil energy consumption and wetland areas are the primary sensitivity factors. (4) External factor analysis through the use of grey correlation analysis revealed that the structure of the marine industry and technological innovation are the main drivers of the interaction, while carbon market trading showed the lowest correlation out of all the external factors, indicating that the mechanism design needs further improvement. (5) Compared with other coastal countries, China still has much room for progress in regard to the construction of MPAs and the restoration of blue carbon ecosystems. This paper introduces a method to quantify the development level of the marine low-carbon economy and assess the effects of marine carbon emission reduction, analyzing the coupling coordination between China’s marine low-carbon economy and carbon emission reduction. This research provides a foundation for Chinese policymakers and offers insights into green and sustainable development of the global marine economy. Full article

The marine industry’s low-carbon transition is critical to enhancing industrial competitiveness. This study empirically investigates how green finance, renewable energy development, and their synergistic effects influence the marine industry’s low-carbon transition, utilizing data from 11 Chinese coastal provinces and cities from 2006 to 2022 and employing fixed effects, moderating effects, and panel quantile regression models. The findings reveal the following: (1) Green finance and renewable energy development can promote the marine industry’s low-carbon transition. (2) Green finance and renewable energy development exhibit positive synergistic effects in driving the marine industry’s low-carbon transition. (3) Regression results across various stages of the marine industry’s low-carbon transition reveal that the influence of green finance and the synergistic effects intensify over time, whereas the effect of renewable energy development gradually weakens. (4) The heterogeneity results indicate that the influence of green finance and the synergistic effects on the marine industry’s low-carbon transition are more pronounced in the northern and eastern marine economic zones, while the impact of renewable energy development and the synergistic effects are stronger in provinces with moderate economic development levels. This study enriches the theoretical system of the low-carbon economy, expands the scope of application of green finance and renewable energy, provides scientific basis and policy recommendations for China to promote the green development of the marine economy under the goal of “dual carbon”, and provides practical experience for reference to countries for addressing climate change and promoting the low-carbon transition of the marine industry. Full article

The demand for Critical Raw Materials (CRM) is increasing due to the need to decarbonize economies and transition to a sustainable low-carbon future achieving climate goals. To address this, the European Union is investing in the discovery of new mineral deposits within its territory. The S34I project (Secure and Sustainable Supply of Raw Materials for EU Industry) is developing Earth observation (EO) methods to support this goal. This study compares the performance of two satellites, Sentinel-2 and Landsat-9, for mineral exploration in two geologically distinct areas in northern Spain. The first area, Ria de Vigo, contains marine placer deposits of heavy minerals, while the second, Aramo, hosts Co-Ni epithermal deposits. These sites provide exceptional case studies to improve EO-based methods for CRM exploration onshore and coastal regions, focusing on deposits often overlooked in remote sensing studies. Standard remote sensing methods such as RGB combinations, Principal Component Analysis (PCA), and band ratios were adapted and compared for both satellites. The results showed similar performance in the Ria de Vigo area, but Sentinel-2 performed better in Aramo, identifying a higher number of zones of mineral alterations. The study highlights the advantages of Sentinel-2’s higher spatial resolution, especially for mapping smaller or more scattered mineral deposits. These findings suggest that Sentinel-2 could play a larger role in mineral exploration. This research provides valuable insights into using EO data for diverse CRM deposits. Full article

Currently, in the two technological approaches for using diesel pilot injection to ignite methanol and partially substituting diesel fuel with methanol, neither can fully achieve carbon neutrality in the context of internal combustion engines. Compression-ignition direct-injection methanol marine engines exhibit significant application potential because of their superior fuel economy and lower carbon emissions. However, the low cetane number of methanol, coupled with its high ignition temperature and latent heat of vaporization, poses challenges, especially amidst increasingly stringent marine emission regulations. It is imperative to comprehensively explore the impacts of the engine geometry, intake boundary conditions, and injection strategies on the engine performance. This paper first investigates the influence of the compression ratio on the engine performance, subsequently analyzes the effects of intake conditions on methanol ignition characteristics, and finally compares the combustion characteristics of the engine under different fuel injection timings. When the compression ratio is set at 13.5, only an injection timing of −30 °CA can initiate methanol compression ignition, but the combustion is not ideal. For compression ratios of 15.5 and 17.5, all the injection timings studied can ignite methanol. Reasonable increases in the intake pressure and intake temperature are beneficial for methanol compression ignition. However, when the intake temperature rises from 400 K to 500 K, a decrease in the thermal efficiency is observed. Particularly, at an injection timing of −30 °CA, both the peak cylinder pressure and peak cylinder temperature are higher, the ignition occurs earlier, the combustion process shifts forward, and the combustion efficiency and indicated thermal efficiency are at higher levels. Furthermore, the overall emissions of NO_X, HC, and CO are relatively low. Therefore, selecting an appropriate injection timing is crucial to facilitate the compression ignition and combustion of methanol under low-load conditions. Full article

This study explores the impact of regional financial development on the sustainable growth of the marine economy across 14 coastal cities in Guangdong Province from 2004 to 2022. To assess this, a comprehensive index system was developed to measure marine economic sustainability, incorporating key factors such as capital investment, production efficiency, and processing and trade. The findings indicate that financial development significantly enhances the sustainable growth of the marine economy. However, the interaction between financial development, technology digitalization, and low-carbon initiatives leads to diminishing returns in terms of sustainability. Through the use of the Moran index and the spatial Durbin model, the analysis reveals a dual outcome: while financial development positively influences a city’s marine economic sustainability, it exerts negative spillover effects on neighboring cities. Previous studies have primarily focused on the relationship between financial development and the marine economy at the national or provincial level, leaving a gap in understanding these dynamics at the city level. Furthermore, the coordination between financial development and marine economic sustainability across cities within the same region remains largely unexplored. This study addresses these gaps by investigating city-level dynamics and examining intercity coordination between financial development and marine economic growth. The results offer a novel perspective for policymakers, highlighting strategies to balance regional financing for the marine economy with targeted investments in science, technology, digitalization, and low-carbon initiatives. This approach seeks to optimize resource allocation and mitigate potential substitution effects. Ultimately, this research contributes to a more nuanced understanding of the complex interplay between financial development and the marine economy at both city and regional levels. Full article

The present study conducted a Life Cycle Assessment (LCA) to evaluate the carbon emissions associated with large yellow croaker farming on Aquaculture Vessel “Conson No. 1”. The functional unit considered was 1 kg of fresh large yellow croakers delivered to a wholesaler. The life cycle of large yellow croaker farming on the aquaculture vessel was divided into five processes: feed production (FP), ship construction (SC), fingerling breeding (FB), adult fish farming (AF), and fish distribution (FD). Results showed that the carbon footprint (CF, kgCO₂e/kg LW) for the complete life cycle amounted to 6.2170 kgCO₂e/kg LW, while the CF per unit economic value of “Conson No. 1” large yellow croaker was estimated at 31 gCO₂e/CNY. Among all processes, AF and FP had the highest CF contribution rates at 69.30% and 24.86%, respectively. Notably, energy consumption by aquaculture equipment on board emerged as the primary contributor across all sources of CF comparative analysis demonstrated that the CF of marine fish farming on the aquaculture vessel was lower than that of closed aquaculture systems’ average level and it was a viable option for implementing low-carbon aquaculture in the deep sea. In order to reduce energy consumption and promote a low-carbon economy in aquaculture vessels, several suggestions were proposed, including adjusting energy structure, enhancing energy efficiency, improving feed ratio, and optimizing feeding methods. Full article

Seaweed culture is of great significance in giving full play to the function of marine carbon sequestration and strengthening the protection and repair of the marine ecosystem. Its green efficiency measurement can provide China with a means for a global low-carbon economy. From the ecological perspective of net carbon sink, this paper selects three indexes: input, expected output and unexpected output. The total carbon sink and carbon emissions are included in the evaluation index system of green efficiency of seaweed culture in China. The green efficiency of seaweed culture in China from 2008 to 2020 is calculated by the super-SBM model. Through the redundancy rate of input and output, the influencing factors of net carbon sink output of seaweed culture are put forward. According to the empirical calculation results and influencing factors of green efficiency, the countermeasures and suggestions for green seaweed culture in China under the dual-carbon target are put forward. The results showed that: (1) the net carbon sink and green efficiency level of seaweed culture in China showed an overall growth trend, and there was a lot of room for growth in economic and ecological benefits; (2) influenced by index factors and non-index factors such as marine resource economy and planning, there are differences in seaweed culture and green efficiency in the three major sea areas of China; (3) the indexes of green efficiency of seaweed culture in different study areas are different; and (4) the improvement of green efficiency can promote the Chinese seaweed culture industry. Green technology progress effect, structure effect, and input–output scale effect are the main influencing mechanisms of green efficiency of seaweed culture. It is suggested that in the future, we should optimize the structure of seaweed culture, innovate seaweed culture technology, improve carbon sink trading policy and strengthen the training of carbon sink talents. This will accelerate the realization of the goal of green and double carbon seaweed culture and promote the global low-carbon economy. Full article

With the continuous development of China’s marine economy and the increasing pollution in marine-related industries, how to implement a sustainable development strategy in the marine economy has become an important issue. Under the stochastic frontier analysis framework, this paper measures the technical efficiency of the marine economy in 11 coastal provinces in China under carbon emission constraints from 2006 to 2016 and analyzes regional differences and the dynamic evolution of technical efficiency and its influencing factors. Panel unit root test is applied to analyze the stochastic convergence of technical efficiency of the inter-regional marine economy. The result shows that: in the reference period, the technical efficiency of the marine economy is on the rise. Guangdong and Shanghai are in the lead. Technical level and industrial structure have a positive impact on technical efficiency, while the structure of property rights, FDI, energy prices, and energy structure have a negative effect on it. On the whole, the changes in the technical efficiency of coastal provinces present a process from concentration to differentiation. There is a stochastic convergence between the Pan-Pearl River Delta and the Yangtze River Delta. Raising the technological level, promoting low-carbon production in the marine industry, and strengthening inter-regional cooperation have a certain effect on the improvement of the technical efficiency of the marine economy. Full article

In the framework of a sustainable marine bioeconomy, the present work describes an advanced, eco-friendly, fully integrated biorefinery process for marine Ulva fasciata macroalgae. That would serve as a solution for ecosystem bioremediation, an effective utilization of marine macroalgal resources, and a new initiative to promote a green and low-carbon economy. Ulva fasciata biomass can be utilized as an organic fertilizer with total N, P₂O₅, and K₂O contents of 3.17% and a C/N ratio of 11.71. It can also be used as a solid biofuel with a sufficient calorific value of 15.19 MJ/kg. It has high carbohydrate content and low lignin content of approximately 44.85% and 1.5%, respectively, which recommend its applicability in bioethanol and biobutanol production. Its protein, fiber, lipid, and ash contents of approximately 13.13%, 9.9%, 3.27%, and 21%, respectively with relatively high concentrations of omega-3 fatty acids (n-3 PUFAs) and omega-9 fatty acids (n-9 MUFAs) and relatively low omega-6 fatty acids (n-6 PUFAs) and a n-6/n-3 ratio of 0.13 also recommend its applicability as food additives and animal feeders. Moreover, the suggested sequential zero-waste biomass residue process yielded 34.89% mineral-rich water extract (MRWE), 2.61% chlorophyll_a,b, 0.41% carotenoids, 12.55% starch, 3.27% lipids, 22.24% ulvan, 13.37% proteins, and 10.66% cellulose of Ulva fasciata dry weight. The efficient biocidal activity of extracted ulvan against pathogenic microorganisms and sulfate-reducing bacteria recommends its application for medical purposes, water densification, and mitigation of microbially induced corrosion in the oil and gas industry. Full article

Energy is an essential material foundation for ensuring economic sustainability and national security. With the development of digitalization, the importance of digital finance in promoting the green and low-carbon transformation of the economy has emerged. The ocean is a national energy treasure house. In order to explore whether digital finance improves the carbon emission efficiency of marine energy, this paper selects panel data from 11 coastal areas from 2011 to 2019 in China and uses the panel fixed effect model, mediation, and moderation model to analyze the mechanism between them empirically. The results show that: (1) digital finance improves marine energy carbon emission efficiency, and the depth of use has the most obvious effect; (2) the incentive effect is heterogeneous due to different geographical locations, resource endowment degree, and digitalization degree; (3) the marine energy consumption structure plays a mediating effect, and marine industrial structure and technological innovation can enhance the impact of the digital finance on marine energy carbon emission efficiency. Therefore, optimizing the energy consumption structure and giving full play to the effect of digital finance in promoting the efficiency of marine energy carbon emission to help accelerate the low-carbon development of China’s economy and the realization of carbon emission reduction. Full article

Through the Tapio model, this paper measures the “decoupling and coupling” relationship between carbon emissions, carbon sinks, and economic growth of marine fisheries in nine coastal provinces of China in 2009–2019, objectively evaluates the economic benefits of carbon emissions and low-carbon development potential, and then discusses the economic development models of marine fisheries in detail. The results showed that the total carbon sink and carbon emission of China’s marine fisheries are increasing. Guangdong is dominated by “double low” economic benefits and low-carbon potential, and “double high” provinces have better resource endowment conditions; China’s marine fishery economic development is still dominated by conventional types. To further promote the sustainable development of China’s marine fisheries, all provinces should define the development orientation of marine fisheries, improve the production methods of marine fisheries according to local conditions, and adjust the industrial structure of marine fisheries in a timely manner, to achieve the low-carbon fishery goal of reducing carbon emissions and growing the economy. Full article

Plastics are present in the majority of daily-use products worldwide. Due to society’s production and consumption patterns, plastics are accumulating in the environment, causing global pollution issues and intergenerational impacts. Our work aims to contribute to the development of solutions and sustainable methods to mitigate this pressing problem, focusing on the ability of marine-derived actinomycetes to accelerate plastics biodegradation and produce polyhydroxyalkanoates (PHAs), which are biodegradable bioplastics. The thin plastic films’ biodegradation was monitored by weight loss, changes in the surface chemical structure (Infra-Red spectroscopy FTIR-ATR), and by mechanical properties (tensile strength tests). Thirty-six marine-derived actinomycete strains were screened for their plastic biodegradability potential. Among these, Streptomyces gougerotti, Micromonospora matsumotoense, and Nocardiopsis prasina revealed ability to degrade plastic films—low-density polyethylene (LDPE), polystyrene (PS) and polylactic acid (PLA) in varying conditions, namely upon the addition of yeast extract to the culture media and the use of UV pre-treated thin plastic films. Enhanced biodegradation by these bacteria was observed in both cases. S. gougerotti degraded 0.56% of LDPE films treated with UV radiation and 0.67% of PS films when inoculated with yeast extract. Additionally, N. prasina degraded 1.27% of PLA films when these were treated with UV radiation, and yeast extract was added to the culture medium. The main and most frequent differences observed in FTIR-ATR spectra during biodegradation occurred at 1740 cm⁻¹, indicating the formation of carbonyl groups and an increase in the intensity of the bands, which indicates oxidation. Young Modulus decreased by 30% on average. In addition, S. gougerotti and M. matsumotoense, besides biodegrading conventional plastics (LDPE and PS), were also able to use these as a carbon source to produce degradable PHA bioplastics in a circular economy concept. Full article