Search Results (3,996)

Integrated multitrophic aquaculture (IMTA) emerges as a sustainable strategy to control the excess of solids and inorganic nutrients that tend to increase in the biofloc system (BFT) cycle, since the model integrates organisms from different trophic levels sharing the same system and nutrients. Thus, this study compared a Penaeus vannamei monoculture system with an integrated biofloc system including Mugil liza, Holothuria grisea, Crassostrea tulipa, and Salicornia neei, focusing on water quality and the performance of organisms and systems. This study consisted of three monoculture systems (16 m³; 375 shrimp m⁻³) and three IMTA systems, composed of a shrimp tank (16 m³), a mullet tank (4 m³; 30 ind m⁻³), a combined tank (3 m³) for oysters (45 ind m⁻³) and sea cucumbers (3 ind m⁻²), and a Salicornia neei bed (2.78 m²; 37 ind m⁻²). All IMTA systems operated in recirculation without water exchange, using 10% of the established biofloc inoculum. The IMTA system had half the hydrated lime use (2.13 vs. 4.29 kg), lower solids (299.56 vs. 373.33 mg L⁻¹), and reduced sludge production (9.37 vs. 15.87 kg). Shrimp growth was similar in both systems. Mullet grew adequately with a survival rate of 95.8%, but oysters showed a survival rate of 45.7%. Sea cucumber had a survival rate of 100% until day 28, when a marked decline appeared, strongly correlated with rising temperature (>28 °C; r = −0.71). This resulted in a significant increase in solids in the last weeks, suggesting that the population decline reduces solids control capacity. Furthermore, the biofloc in IMTA was dominated by coccoid forms, with lower proportions of filamentous and cyanobacterial forms. Full article

Cholera outbreaks are prevalent in coastal regions, where hydroclimatic factors play a critical role. However, evidence on their associations with different genotypes remains limited, and global projection remains lacking. We compiled cholera data from EnteroBase and WHO weekly reports covering 110 coastal countries from 1980 to 2022. A generalized additive model was used to examine the associations between hydroclimatic factors and different cholera serotypes and genotypes. We further projected future cholera occurrences for each coastal country under three climate change scenarios from 2025 to 2100. During the study period, Wave 3 of O1 replaced Wave 1 as the predominant genotype of cholera, while cholera O139 remained at low levels and only occurred in Asia. At the country–year level, each 1 °C increase in sea surface temperature (SST) was significantly associated with cholera occurrence (OR: 1.032, 95% CI: 1.023 to 1.040) and Wave 3 of O1 (OR: 1.149, 95% CI: 1.097 to 1.203). Drainage density (m/km²) and coastline ratio (%) were positively related to cholera, with ORs of 1.067 (95% CI: 1.046 to 1.087) and 1.022 (95% CI: 1.019 to 1.027). For future projections, five trend patterns were identified under different emission scenarios, with most countries showing increased cholera risk due to global hydroclimatic changes, peaking under the SSP585 scenario. Our findings reveal associations between hydroclimatic factors and different cholera genotypes and project future cholera risk across coastal countries, thereby providing evidence to inform genotype-specific surveillance and targeted prevention strategies at the global scale. Full article

This study aims to model and optimize the process parameters influencing the efficiency and yield of oil extraction from Mongolian sea buckthorn seeds using supercritical carbon dioxide (CO₂). The experiments were planned using response surface methodology (RSM) based on a central composite rotatable design (CCRD) to evaluate the effects of extraction pressure, temperature, and time, while maintaining a constant solvent flow rate of 2.0 L/min to balance extraction efficiency and selectivity. Following data refinement and outlier exclusion, the developed second-order polynomial model exhibited excellent accuracy with a coefficient of determination R² of 0.9375. Among the parameters studied, pressure was identified as the most critical factor affecting oil yield. Furthermore, significant interaction effects were observed, particularly between extraction time and the other variables, pressure–time (A * C) and temperature–time (B * C), indicating the time-dependent nature of mass transfer. The predicted optimal conditions for maximum yield were determined to be 5075 psi, 70 °C, and an extraction time of 10 h. Validation experiments under these conditions resulted in an oil yield of 800 g, confirming the reliability of the model. These findings demonstrate the feasibility of optimizing supercritical CO₂ extraction for the industrial-scale production of high-quality functional oils and nutraceuticals. Full article

Temperature is a fundamental property of water that determines its quality and the course of both biotic and physical processes. Therefore, the distribution and future changes in thermal conditions are crucial for the functioning of the hydrosphere. In this study, a hybrid air2water model was used to determine the course of the sea surface temperature, which allows for its prediction using a minimal set of input data based on the air temperature. The widespread availability of air temperature measurements worldwide offers broad potential for the model’s application, which is especially important in coastal zones—the most dynamic and diverse areas of marine ecosystems, and simultaneously the most exposed to anthropogenic pressure. The study analyzes four hydrological stations in the southern part of the Baltic Sea, where the results confirm the high predictive capabilities of the air2water model for sea surface temperature. Depending on the adopted climate change scenarios, the average rate of sea surface temperature increase by the end of the 21st century is projected to be 0.15 °C per decade (SSP2-4.5) and 0.33 °C per decade (in the case of the SSP5-8.5 scenario). If these projections come true, they should be considered unfavorable, and such a situation will require taking into account changes in the thermal regime in the functioning of the Baltic Sea. More broadly, this simple yet effective method for predicting thermal conditions may be applied in interdisciplinary research as well as in the management of coastal marine zones. Full article

In recent years, the increasing frequency of strong and super typhoons has been attributed to rising sea surface temperatures due to global warming. This study utilized the Weather Research and Forecasting (WRF) and Simulating WAves Nearshore (SWAN) models to analyze 30 years of wind and wave data for the Yangjiang sea area in China. The accuracy of the numerical simulations was validated using observed data from typhoons Ty201213, Ty201522, Ty201822, and Ty202118, along with wind and wave data from December 2024. This study utilized the P-III distribution to analyze design wind parameters. At a height of 10 m, the 3 s and 10 min mean wind speeds for the 100- and 50-year return periods were 62.21 m/s, 47.85 m/s, 57.99 m/s, and 44.61 m/s, respectively. At hub height (170 m), the corresponding values were 80.27 m/s, 61.75 m/s, 74.84 m/s, and 57.57 m/s. Furthermore, this study successfully applied a 2D-KDE approach to construct a joint probability model and derive environmental contours for extreme environmental assessments. The HS and TP at project point P for the 100- and 50-year return periods are 13.61 m and 15.91 s, as well as 12.39 m and 15.07 s, respectively. Full article

Until recently, the Karpathos water frog (Pelophylax cerigensis) was considered endemic to Karpathos Island (Greece) and has recently been reclassified by the IUCN as Endangered (EN), having been previously assessed as Critically Endangered (CR). The species faces severe threats primarily associated with the scarcity of freshwater bodies in the southern Aegean Sea. Over the past decade, demographic assessments have revealed a marked population decline, driven by the intensifying effects of climate change, including reduced rainfall, and increasing summer temperatures. In addition, the few natural ponds that persist during the dry summer months are often shared with the Levantine freshwater crab (Potamon potamios), resulting in increased frog mortality due to predation. Despite these challenges, recent developments provide cautious optimism. These include the construction of a dam in southern Karpathos and the taxonomic reassessment of the water frog population on the neighboring island of Rhodes as conspecific with P. cerigensis. In response to the species’ precarious status, the Hellenic Herpetological Society designed and implemented a National Action Plan aimed at the protection and conservation of the Karpathos water frog. The Action Plan includes a series of targeted mitigation measures, such as the construction of artificial ponds to retain water during the summer, as well as a hydrological study addressing the seasonal drying of the ecologically important Eleimonitria spring. A key component of the Action Plan involves education and outreach initiatives targeting primary school students, local residents, and visitors, highlighting the frog’s ecological importance and conservation needs. Informational brochures will be distributed across the island to raise awareness of the species’ conservation status and the importance of safeguarding its habitat. The implementation of this Action Plan aims to secure the long-term survival of the Karpathos water frog and to strengthen integrated conservation efforts across its extremely limited range. Full article

Marine ranching has become an important strategy for offshore ecological restoration and fisheries resource conservation in China. In this study, environmental DNA (eDNA) was applied to simultaneously monitor phytoplankton, invertebrates, and fish communities in the Tianjin Dashentang Marine Ranching, the Tianjin Binhai National Marine Park, and the Western Furong Island Marine Ranching Area. eDNA analyses detected more than 190 phytoplankton species, over 340 invertebrate species, and approximately 100 fish species across the three regions. Species richness and community diversity were consistently higher within marine ranching zones than in adjacent control areas, and ranching zones supported a higher proportion of endemic and ecologically important taxa. Redundancy analysis identified temperature, salinity, and pH as the main environmental drivers shaping community composition. Temperature had stronger effects on phytoplankton and invertebrate assemblages in the Dashentang and Furong Island ranches, whereas pH and conductivity were more influential in the Binhai National Marine Park. Temporal comparisons of fish eDNA data from 2021 to 2024 indicated increased alpha diversity, greater representation of key taxa, and higher community stability in 2024. Overall, these results demonstrate the utility of eDNA for integrated biodiversity monitoring and provide scientific support for evaluating and guiding marine ranching development in the Bohai Sea region. Full article

Greenhouse gases (GHG), accumulated in the atmosphere, are the main cause of climate change. In 2017, the increase in average temperature was about 1 °C (between 0.8 °C–1.2 °C) above pre-industrial levels. Global warming refers to the increase in air surface, sea surface, and soil surface temperature and according to IPCC (Intergovernmental Panel Climate Change), since the industrial revolution, C emissions are due to land use changes like deforestation, biomass burning, conversion of natural lands, drainage of wetlands, soil cultivation, and tillage. As the world population has increased, world food production has risen too with a subsequent increase in GHG emissions and agricultural production, which is worsened by climate change. Negative consequences are well known such as the loss in water availability and in soil fertility, and pest infestations which are climate change’s effects on agriculture activity. Climate change’s main aftermath is the frequency of extreme weather events influencing crop yields. As climate change exacerbates degradation processes, land management can mitigate its impact and aid adaptation strategies for climate change. About 21–37% of GHGs have been caused by the agriculture activity, so the application of Nature-based Solutions (NbS) like sustainable agriculture could be a way to reduce GHGs worldwide. The aim of this article is to review how NbS may mitigate GHG emissions from soil, with solutions defined as an integrated approach to tackle climate change and to sustainably restore and manage ecosystems, delivering multiple benefits. NbS is a low-cost tool working within and with nature, which holds many benefits for people and the environment. Full article

This paper examines the critical role of youth engagement in building urban climate resilience in secondary cities of West Africa, with a specific focus on Bo City, Sierra Leone. As one of the world’s most climate-vulnerable countries, Sierra Leone faces significant challenges exacerbated in urban environments where infrastructure gaps, rapid population growth, climate migration, and limited resources intersect with intensifying climate impacts (rising temperature, extreme weather events, rising sea levels, and socio-economic health impacts). We describe a pathway to invest in the adaptive capacity of this community by developing and implementing a Youth Climate Science Hub designed to inform and empower secondary school students as future climate leaders. Drawing on theories of social–ecological resilience and transformative education, we analyze how youth-centered approaches can bridge the knowledge–action gap in urban climate adaptation. The initiative represents an innovative practice-based example for building resilience in secondary cities expected to receive climate migrants while demonstrating the power of youth mobilization in creating locally appropriate climate solutions. Full article

In naturally accretional salt marshes, pioneer species typically expand seaward and colonize tidal flats. However, this process can be influenced by disturbances such as human activities and species invasions. Understanding the spatiotemporal patterns and driving mechanisms of vegetation succession in salt marshes is critical for wetland conservation, restoration, and management. Using southern Hangzhou Bay as a case study, we developed a remote sensing algorithm to distinguish the dominant species Scirpus mariqueter (S. mariqueter) and Spartina alterniflora (S. alterniflora). Based on long-term time-series remote sensing data (1990–2023) and twelve parameters representing environmental variables, human activity, and interspecific competition, we analyzed the seaward expansion of the dominant salt marsh species and quantified the effects of various drivers on vegetation. The results showed that as a pioneer species, S. mariqueter expanded at a rate of 0.26 km² yr⁻¹ and was gradually replaced by S. alterniflora, which expanded at a rate of 0.52 km² yr⁻¹. Over the 34-year period, both species exhibited phased expansion–decline–recovery dynamics. During the relatively stable periods (1990–2003 and 2015–2023), temperature, sea level anomaly, and sea surface salinity were the key drivers of vegetation succession. During the disturbance period (2004–2014), S. mariqueter remained primarily influenced by environmental factors, whereas S. alterniflora was primarily influenced by human activities. This study provides the first satellite-based analysis of salt marsh species dynamics in southern Hangzhou Bay over a 34-year period, revealing nonlinear, staged, and species-specific succession patterns and providing new perspectives for invasive species management and the conservation of dynamic coastal wetlands. Full article

Coastal waters worldwide are increasingly threatened by excessive nutrient inputs, a key driver of eutrophication. Dissolved inorganic nitrogen (DIN) serves as a vital indicator for assessing the eutrophic status of nearshore marine environments, underscoring the necessity for precise monitoring to ensure effective protection and restoration of marine ecosystems. To address the current limitations in DIN retrieval methods, this study builds on MODIS satellite imagery data and introduces a novel one-dimensional convolutional neural network (1D-CNN) model synergistically co-optimized by the Bald Eagle Search (BES) and Bayesian Optimization (BO) algorithms. The proposed BES-BO-CNN framework was applied to the retrieval of DIN concentrations in the coastal waters of Shandong Province from 2015 to 2024. Based on the retrieval results, we further investigated the spatiotemporal evolution patterns and dominant environmental drivers. The findings demonstrated that (1) the BES-BO-CNN model substantially outperforms conventional approaches, with the coefficient of determination (R²) reaching 0.81; (2) the ten-year reconstruction reveals distinct land–sea gradient patterns and seasonal variations in DIN concentrations, with the Yellow River Estuary persistently exhibiting elevated levels due to terrestrial inputs; (3) correlation analysis indicated that DIN is significantly negatively correlated with sea surface temperature but positively correlated with sea level pressure. In summary, the proposed BES-BO-CNN framework, via the synergistic optimization of multiple algorithms, enables high-precision DIN monitoring, thus providing scientific support for integrated land–sea management and targeted control of nitrogen pollution in coastal waters. Full article

To overcome the high cost, marine ecological risks of traditional coral sand reinforcement, and the insufficient mechanical performance of standalone Enzyme-Induced Carbonate Precipitation (EICP), this study proposes a novel soil improvement method integrating EICP with aluminum chloride hexahydrate (AlCl₃·6H₂O). The objectives are to identify optimal EICP curing parameters, evaluate AlCl₃·6H₂O’s enhancement effect, and reveal the synergistic micro-mechanism. Through aqueous solution, unconfined compressive strength, permeability, X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and Scanning Electron Microscope (SEM) tests, this study systematically investigated the reaction conditions, mechanical properties, anti-seepage performance, mineral composition, and pore structure. The results demonstrate that EICP achieves the best curing effect under specific conditions: temperature of 30 °C, pH of 8, and cementing solution concentration of 1 mol/L. Under these optimal conditions, the unconfined compressive strength of EICP-solidified coral sand columns reaches 761.6 kPa, and the permeability coefficient is reduced by one order of magnitude compared to unsolidified samples. Notably, AlCl₃·6H₂O incorporation yields a significant synergistic effect, boosting the UCS to 2389.1 kPa (3.14 times standalone EICP) and further reducing permeability by 26%. Micro-mechanism analysis reveals that AlCl₃·6H₂O acts both by generating cementitious aggregates that provide nucleation sites for uniform calcite deposition and by accelerating the transformation of metastable aragonite and vaterite to stable calcite, thereby enhancing cementation stability. This study delivers a cost-effective, eco-friendly solution for coral sand reinforcement, providing practical technical support for marine engineering in environments like the South China Sea. By addressing the core limitations of conventional bio-cementation, it opens new avenues for advancing soil improvement science and applications. Full article

Remotely operated underwater vehicles (ROUVs) have been attracting more attention lately as they are considered to be operationally versatile, capable of real-time communication, and can be fitted with various sensor payloads for environmental monitoring purposes. This study presents the design, development, and field validation of a sensor-enhanced ROUV platform tailored for environmental monitoring and aquaculture applications. The vehicle is equipped with a modular set of sensors for temperature, pH, dissolved oxygen (DO), and electrical conductivity (EC) along with separate signal-conditioning circuits for each sensor and real-time data acquisition from tethered architecture. The general system concept is modularity, reproducibility, and robustness in a marine environment. In situ measurements were performed at an active aquaculture site in the North Aegean Sea throughout several seasons during 2025. Using this system, depth-resolved measurements were obtained with sensor accuracies of ±0.1 °C (temperature), ±0.05 pH units, ±0.05 mg/L (dissolved oxygen), and ±2% (electrical conductivity). The following sections describe the development and aquaculture testing of the platform, which yielded stable and repeatable operation in real conditions. Full article

The vertical structure and optical–microphysical properties of ice clouds determine their radiative effects. With an average altitude above 3000 m above mean sea level (AMSL) and unique thermal circulation, the Tibetan Plateau forms ice clouds with seasonally varying microphysical characteristics. In this study, satellite lidar observations from CALIPSO and ERA5 reanalysis from 2006 to 2023 reveal significant seasonal variation in ice clouds over the Tibetan Plateau and adjacent regions. In winter, maximums of the backscatter coefficient (β₅₃₂) and ice water content (IWC) were found south of the Qinling-Huaihe Line, as well as in the Sichuan Basin and the Yangtze Plain. In summer, these maximums move onto the Plateau, and the cloud height rises by about 1 km. The altitude of the β₅₃₂ maximum rises from about 4 km in winter to nearly 6 km in summer. Among four cloud categories defined by joint geometric and optical thickness thresholds, clouds with small geometric thickness and large optical thickness (thin and dense clouds) are the most radiatively important. While these clouds are seldom observed over the Tibetan Plateau in winter, they contribute to over thirty percent of local ice cloud occurrences during summer. Their preferred altitude rises from 3–4 km to 6–7 km, occurring under comparatively warmer environmental temperatures. Although limited in geometric depth, the thin and dense clouds exhibit the highest β₅₃₂ and IWC, the lowest multiple scattering coefficient (η₅₃₂), and the highest depolarization ratio (δ₅₃₂). They contribute about thirty percent of the total extinction and backscatter, despite representing only ten to twenty percent of all cases. Full article

Sea surface temperature (SST) modes of climate variability in the South Atlantic Ocean remain a challenging topic. To improve the understanding of this subject, this study assesses the influence of two commonly discussed SST variability modes, the South Atlantic Dipole (SAD) and the Southwestern South Atlantic (SWSA), on South America (SA) during the present-day climate conditions and discusses, based on the previous literature, their development. Complementing previous analyses based on annual or seasonal scales, the analysis is performed at the monthly scale, given its relevance for subseasonal-to-seasonal (S2S) forecasts. Empirical Orthogonal Function (EOF) analysis was applied to standardized monthly SST anomalies relative to the period 1991–2020, using data from the Extended Reconstructed Sea Surface Temperature (ERSST). After characterizing the SAD and SWSA modes, composites of different variables, such as precipitation anomalies, were constructed for the different phases of each pattern. The results show that the SAD is the dominant mode of SST variability, mainly influencing tropical latitudes by modulating the Intertropical Convergence Zone (ITCZ). During its positive (negative) phase, the ITCZ shifts southward (northward). In contrast, the SWSA exhibits a more localized subtropical–extratropical structure, characterized by SST anomalies along the south–southeastern coast of Brazil, and is closely associated with variability in the South Atlantic Convergence Zone (SACZ). The relationship between the SWSA and SACZ appears strong during the austral extended summer, when warmer waters during the positive (negative) SWSA phase are associated with wetter (drier) conditions over southeastern SA and drier (wetter) conditions over the continental and oceanic branches of the SACZ. Full article