Search Results (105)

Understanding the impact of monsoonal oscillations during past climatic changes in the Arabian Sea is crucial for improving climate model predictions under ongoing global warming. This study investigates whether millennial-scale climate shifts in Greenland, specifically Dansgaard–Oeschger events 12–11, affected the Indian Ocean monsoon system and the associated productivity and oxygen minimum zone (OMZ) dynamics in the northwestern Arabian Sea. In the Arabian Sea, DO stadials correspond to reduced water-surface productivity, well-ventilated intermediate water masses, and a weakened or absent OMZ. Contrarily, DO interstadials are distinguished by enhanced water-surface productivity, a reorganization of intermediate water masses, and a reinvigoration of the OMZ. Eleven sediment samples from ODP Site 721A were analyzed using a multiproxy approach combining total organic carbon, C/N ratios, bulk-sediment isotopes (δ¹⁵N, δ¹³C), and the relative abundances of Globigerina bulloides and Globigerinoides ruber, complemented by isotopic data (δ¹³C, δ¹⁸O) from G. ruber shells. Further Mg/Ca–δ¹⁸O and δ¹⁸O_sw measurements were included to refine the reconstruction of surface-water hydrography linked to productivity changes. Results reveal significant oscillations in water-surface productivity and OMZ intensity, modulated by shifts in monsoon strength and water-column ventilation. Enriched δ¹⁵N values, elevated TOC, and increased G. bulloides relative abundances reflect intensified denitrification and organic matter preservation under a stronger southwest monsoon, whereas depleted δ¹⁵N, reduced TOC, and higher G. ruber abundance indicate enhanced ventilation and a weaker OMZ under northeast monsoon dominance. These findings provide new evidence that refines the paleoceanographic history of the Arabian Sea. Additionally, they demonstrate that high-latitude climatic forcing during DO events modulated Arabian Sea monsoon dynamics and oxygenation through strong interhemispheric teleconnections. Full article

Understanding the Holocene environmental history of desert landscapes in northern China contributes to elucidating the mechanisms driving desertification in the mid-latitudes of the Northern Hemisphere (NH). Based on a systematic and comparative analysis on integrated paleoclimatic data from both China and the international community, this paper reviews the environmental evolution history of the Alashan Plateau since the Holocene, drawing upon sedimentary and proxy records from three major sandy deserts on the plateau—the Badanjilin, Tenggeli, Wulanbuhe Deserts. The results indicate that the Alashan Plateau experienced generally humid conditions during the early and middle Holocene, characterized by the development of high-level lakes; in contrast, the late Holocene was marked by aridity and intensified aeolian activity. For the three deserts on the plateau, the environmental evolution of the Tenggeli Desert during the early Holocene diverges from that of the other two. Meanwhile, the mid-Holocene drought event in the Badanjilin Deserts remains debated, centering on whether its spatial scale was local or regional across the plateau. The driving mechanism of environmental evolution in the study area can be fundamentally understood through the atmospheric and oceanic circulation systems, combined with solar insolation in the middle latitudes of NH. This interplay is comprehensively reflected by the interactions between the westerlies and the East Asian summer monsoon (EASM) across different periods. Responses of the Alashan Plateau’s climate to global change involve the combined effects of multiple factors, including the Westerlies, the EASM, the Atlantic-Pacific-Ocean (APO) circulation anomalies, the ‘third polar’ environmental effect of the Qinghai–Tibet Plateau, and the hydrological influence of the Yellow River, etc. The Holocene environmental evolution history of the study area was primarily shaped by climate patterns characterized by cold-dry and cold–wet (or temperate-moist) regimes. Understanding these patterns may provide insights for forecasting future climate trends in the Alashan Plateau under current global warming. Full article

The purpose of this research was to investigate whether music empirically associated with therapeutic effects contains intrinsic informational structures that differentiate it from other sound sequences. Drawing on ontology, phenomenology, nonlinear dynamics, and complex systems theory, we hypothesize that therapeutic relevance may be linked to persistent structural patterns embedded in musical signals rather than to stylistic or genre-related attributes. This paper introduces the Discriminating Music Sequences (DiMuSes) method, an unsupervised, structure-oriented analytical framework designed to detect such patterns. The method applies 24 scalar evaluators derived from statistics, fractal geometry, nonlinear physics, and complex systems, transforming sound sequences into multidimensional vectors that characterize their global temporal organization. Principal Component Analysis (PCA) reduces this feature space to three dominant components (PC1–PC3), enabling visualization and comparison in a reduced informational space. Unsupervised k-Means clustering is subsequently applied in the PCA space to identify groups of structurally similar sound sequences, with cluster quality evaluated using Silhouette and Davies–Bouldin indices. Beyond clustering, DiMuSe implements ranking procedures based on relative positions in the PCA space, including distance to cluster centroids, inter-item proximity, and stability across clustering configurations, allowing melodies to be ordered according to their structural proximity to the therapeutic cluster. The method was first validated using synthetically generated nonlinear signals with known properties, confirming its capacity to discriminate structured time series. It was then applied to a dataset of 39 music and sound sequences spanning therapeutic, classical, folk, religious, vocal, natural, and noise categories. The results show that therapeutic music consistently forms a compact and well-separated cluster and ranks highly in structural proximity measures, suggesting shared informational characteristics. Notably, pink noise and ocean sounds also cluster near therapeutic music, aligning with independent evidence of their regulatory and relaxation effects. DiMuSe-derived rankings were consistent with two independent studies that identified the same musical pieces as highly therapeutic.The present research remains at a theoretical stage. Our method has not yet been tested in clinical or experimental therapeutic settings and does not account for individual preference, cultural background, or personal music history, all of which strongly influence therapeutic outcomes. Consequently, DiMuSe does not claim to predict individual efficacy but rather to identify structural potential at the signal level. Future work will focus on clinical validation, integration of biometric feedback, and the development of personalized extensions that combine intrinsic informational structure with listener-specific response data. Full article

Subsurface deposition determines whether soils, aquifers, or ocean sediment represent a sink or temporary reservoir for microplastics. Deposition is generally studied by applying the Smoluchowski–Levich equation to determine a particle’s sticking efficiency, which relates the number of particles filtered by sediment to the probability of attachment occurring from an interaction between particles and sediment. Sticking efficiency is typically measured using column experiments or estimated from theory using the Interaction Force Boundary Layer (IFBL) model. However, there is generally a large discrepancy (orders of magnitude) between the values predicted from IFBL theory and the experimental column measurements. One way to bridge this gap is to directly measure a microparticle’s interaction forces using Atomic Force Microscopy (AFM). Herein, an AFM method is presented to measure sticking efficiency for a model polystyrene microparticle (2 μm) on a model geomaterial surface (glass or quartz) in environmentally relevant, synthetic freshwaters of varying ionic strength (de-ionized water, soft water, hard water). These data, collected over nanometer length scales, are compared to sticking efficiencies determined through traditional approaches. Force measurement results show that AFM can detect extremely low sticking efficiencies, surpassing the sensitivity of column studies. These data also demonstrate that the 75th to 95th percentile, rather than the mean or median force values, provides a better approximation to values measured in model column experiments or field settings. This variability of the methods provides insight into the fundamental mechanics of microplastic deposition and suggests AFM is isolating the physicochemical interactions, while column experiments also include physical interactions like straining. Advantages of AFM over traditional column/field experiments include high throughput, small volumes, and speed of data collection. For example, at a ramp rate of 1 Hz, 60 sticking efficiency measurements could be made in only a minute. Compared to column or field experiments, the AFM requires much less liquid (μL volume) making it effortless to examine the impact of solution chemistry (temperature, pH, ionic strength, valency of dissolved ions, presence of organics, etc.). Potential limitations of this AFM approach are presented alongside possible solutions (e.g., baseline correction, numerical integration). If these challenges are successfully addressed, then AFM would provide a completely new approach to help elucidate which subsurface minerals represent a sink or temporary storage site for microparticles on their journey from terrestrial to oceanic environments. Full article

Citizen science approaches for monitoring, and even restoring, coral reefs have grown in popularity though tend to be restricted to those who have taken courses that expose them to the relevant methodologies. Now that cheap (~10 USD), waterproof pouches for smart phones are widely available, there is the potential for mass acquisition of coral reef images by non-scientists. Furthermore, with the emergence of better machine-learning-based image classification approaches, high-quality data can be extracted from low-resolution images (provided that key benthic organisms, namely corals, other invertebrates, & algae, can be distinguished). To determine whether informally captured images could yield comparable ecological data to point-intercept + photo-quadrat surveys conducted by highly proficient research divers, we trained an artificial intelligence (AI), CoralNet, with images taken before and during a bleaching event in 2015 in Chagos (Indian Ocean). The overall percent coral covers of the formal, “gold standard” method and the informal, “tourist diver” approach of 38.7 and 35.1%, respectively, were within ~10% of one another; coral bleaching percentages of 30.5 and 31.8%, respectively, were statistically comparable. Although the AI was prone to classifying bleached corals as healthy in ~one-third of cases, the fact that these data could be collected by someone with no knowledge of coral reef ecology might justify this approach in areas where divers or snorkelers have access to waterproof cameras and are keen to document coral reef condition. Full article

Satellite tracking has dramatically improved research on wide-ranging large marine vertebrates such as sea turtles. Traditionally, sea turtle tracking has relied on Argos-based satellite telemetry tags, which estimate location via Doppler shift and can also transmit sensor data. GPS-equipped Argos satellite tags represented a significant evolution, offering higher location accuracy. More recently, GPS-equipped satellite tags transmitting via the Iridium satellite network have become available for sea turtle tracking, and this study aims to assess whether they offer additional advantages. The performance of three satellite tag types—Argos-only, Argos-GPS, and Iridium-GPS (Iridium)—was assessed using data on 116,074 positions from 48 sea turtles representing five species and multiple ocean basins. Performance was evaluated using three indicators: the proportion of days with location data, the duration of gaps between locations, and the number of positions per day. Bayesian generalized linear mixed models assessed the effect of satellite tag type, technical settings, species, and activity (migration, foraging, internesting). Results indicate that Iridium satellite tags generally perform similarly to both Argos-based satellite tags, but performance improves significantly when programmed with high-frequency GPS acquisition (>24 positions/day), a result made possible by their tenfold higher transmission capacity compared to Argos. This capacity also enables transmission of more sensor data. Performance, however, varied by species and activity. These findings highlight the potential of Iridium tags to enhance fine-scale movement studies by improving the spatial and temporal resolution of sea turtle tracking, with important implications for ecological research and conservation planning. Full article

The sustainable development of the marine industry is a vital pillar for achieving global ecological balance and economic prosperity. As a crucial repository of resources and a vital regulator of climate, the ocean plays an irreplaceable role in supporting humanity’s long-term development. Against this backdrop, digital technology drives modern development, supporting decision-making and resource allocation while profoundly transforming industrial models. The resulting digital economy has become one of the core drivers of sustainable global economic growth. Given the close connection between the marine industry and the digital economy, attention has been drawn to whether a correlation exists between their respective growth rates. This study employs a Panel Vector Autoregression (PVAR) model based on panel data from China’s coastal provinces between 2012 and 2023. The empirical analysis reveals: (1) After a certain period, the growth rates of the digital economy and the quality development of the marine industry exhibit a mutually reinforcing trend. Furthermore, the innovation coupling coordination rate and the upgrading rate within the marine industry also strengthen each other, injecting endogenous momentum into the sustainable development of the marine sector. (2) When simulating external shocks through local government expenditure, it was found that while local government spending positively impacts the growth rate of the digital economy, its effect on the quality development rate of marine industries is limited, exhibiting a “single-helix” upward trend. This suggests the need to optimize the precision of policy support to better balance the coordinated sustainable development of the digital economy and marine industries. (3) The growth rate of the digital economy exerts a dual threshold effect on the quality development of marine industries. That is, there are two thresholds: 0.0099 and 0.0725. Initially, the promotion effect is relatively small with a positive and significant coefficient of 0.120. When exceeding the first threshold, the coefficient becomes 0.416, which is positively significant. When exceeding the second threshold, the promotion effect disappears. This necessitates differentiated strategies tailored to distinct developmental stages to propel marine industries toward high-quality, sustainable development empowered by the digital economy. Based on these findings, this study focuses on the relationship between the growth rates of the digital economy and marine industries, offering actionable recommendations for marine nations like China to advance high-level sustainable industrial development. Full article

Etesian winds, the characteristic summer winds over large parts of Greece and the eastern Mediterranean, can cause coastal upwelling, especially over the eastern Aegean. The question that many studies address is whether these northern winds can cause upwelling processes that alter not only sea surface temperature but also chlorophyll concentrations, which are indicative of phytoplankton growth and overall ocean health. The present study is an effort to investigate the above matter over the eastern Aegean, from Lesvos to Ikaria and Samos islands, on a monthly basis, based on all the available satellite chlorophyll data up to now. Full article

In 2024, Rio Grande do Sul (RS), Brazil, faced the most severe flood event in its recorded history, which compromised several ground-based hydrological gauges. The SWOT (Surface Water and Ocean Topography) satellite, capable of measuring water surface elevation (WSE) in continental waters, is a valuable tool for providing critical data. This study investigates whether node-level WSE data from the SWOT satellite can effectively function as virtual hydrological stations under such extreme conditions. The study was applied in all of RS state considering 100 in situ gauges and was subdivided into three sections: (i) an evaluation of the variation in SWOTʹs WSE data compared to the variation in in situ levels from telemetric gauges, considering subsequent cycles of passes between July 2023 and April 2025, yielding an MAE = 35 cm and an RMSE = 73 cm after outlier removal; (ii) an evaluation of the variation in SWOTʹs WSE data compared to the variation in telemetric level data, considering one window prior to and another during the extreme event, resulting an MAE = 26 cm and an RMSE = 34 cm; (iii) an analysis of SWOTʹs data availability during the extreme event, when in situ telemetric data were unavailable. The results demonstrate an agreement between the variation observed in SWOT data and that in telemetric gauges in RS, even during extreme events. Moreover, in the absence of in situ data, SWOT was still able to capture WSE data. Full article

The Mediterranean subpopulation of great white sharks (Carcharodon carcharias) is elusive and likely in decline, though long-term trends remain uncertain due to opportunistic record-keeping, misidentifications, and changing observation effort. We investigated whether spatial changes in shark occurrences during the 21st century correspond with shifts in Atlantic bluefin tuna (Thunnus thynnus) distribution and habitat conditions. We compiled geographically validated sighting and capture records from 1900 onward, mapped 20th- and 21st-century hotspots, and overlaid these with bluefin tuna potential habitat and long-term sea surface temperature (SST) data. Results reveal a clear redistribution of great white shark hotspots: historic coastal focal areas (e.g., Balearic Islands, Maltese Islands, eastern Adriatic, Sea of Marmara) have diminished or disappeared, while offshore zones (southern Strait of Sicily–Gulf of Gabes) and the Aegean coast of Turkey have emerged as contemporary hotspots. These patterns appear to align closely with shifts in tuna feeding grounds and cooler SST (<18 °C). We highlight limitations in using opportunistic and citizen-reported data due to detection biases and misidentifications, underscoring the need for models that correct detectability. Our findings are consistent with the hypothesis of a link between predator distribution, prey dynamics, and changing ocean conditions, and point toward targeted strategies for future conservation and monitoring of this apex predator in a warming Mediterranean. Full article

The environmental problem of abandoned fishing gear (e.g., ghost nets) exists on a world scale. It impacts marine biodiversity for decades after the nets has become lost in the ocean. In Cyprus (eastern Mediterranean), ghost nets are found almost everywhere around the island, threatening marine life and human activities, such as scuba diving, fishing and navigation. To achieve meaningful outcomes for biodiversity conservation and the management of an offshore site that is particularly affected by ghost nets, the Jubilee Shoals, this issue is addressed in this study with an evidence-based approach. Pre-removal surveys were necessary to assess the nets and produce the environmental, ecological and structural data for the calculation of the Gear Removal Index (GRI). The results of a revised version of the index (GRI+) that includes species of conservation interest and invasive species were cross-checked in the field by divers with experience in marine ecology and similar removals. About 3 km of nets in total were successfully removed. The implementation of the GRI+ was an important proof-of-concept for environmental managers, aiding them to decide whether it would be necessary (or not) to perform removals and highlighting the index as a useful tool for the protection and management of Cyprus’ marine habitats. Full article

During rapid-onset environmental catastrophes, scientists may not always have sufficient time to conduct proper environmental surveys in all representative areas. Although coral bleaching events can be predicted to a certain extent in some areas by tracking sea surface temperatures (SSTs), current models from NOAA’s Coral Reef Watch tend to underestimate severity of bleaching in the Indian Ocean, as was evident in March 2024 when corals began bleaching after only experiencing 1–2 degree-heating weeks. To characterize the impacts of this event, I conducted citizen science-style surveys at 22 sites along a 600-km stretch of the Kenyan coastline. Thereafter, I trained an artificial intelligence (AI) to extract coral abundance and bleaching data from 2300 coral reef images spanning 11–12 hectares of reef area to estimate both coral cover and bleaching prevalence. The AI’s accuracy was >80%, though it was prone to false-positive bleaching classifications. Bleaching severity varied significantly across sites, as well as over time, as seawater continued to warm over the duration of the study period; on average, over 75% of all reef-building scleractinians had bleached. Across the 22 sites, the mean healthy coral cover was only 7–8%, vs. >30% at sites in the same areas in the late 1990s. Whether these corals can recover, and then withstand such heatwaves in the future, will be known all too soon. Full article

The Chagai porphyry copper belt is a major component of the Tethyan metallogenic domain, which spans approximately 300 km and hosts several giant porphyry copper deposits. The tectonic setting, whether subduction-related or post-collisional, and the deep dynamic processes governing the formation of these giant deposits remain poorly understood. Mafic microgranular enclaves (MMEs), mafic dikes, and multiple porphyries have been documented in the Saindak mining area. This work examines both the ore-rich and non-ore intrusions in the Saindak porphyry Cu-Au deposit, using methods like molybdenite Re-Os dating, U-Pb zircon ages, Hf isotopes, and bulk-rock geochemical data. Geochronological results indicate that ore-fertile and barren porphyries yield ages of 22.15 ± 0.22 Ma and 22.21 ± 0.33 Ma, respectively. Both MMEs and mafic dikes have zircons with nearly identical ²⁰⁶Pb/²³⁸U weighted mean ages (21.21 ± 0.18 Ma and 21.21 ± 0.16 Ma, respectively), corresponding to the age of the host rock. Geochemical and Sr–Nd–Hf isotopic evidence indicates that the Saindak adakites were generated by the subduction of the Arabian oceanic lithosphere under the Eurasian plate, rather than through continental collision. The adakites were mainly formed by the partial melting of a metasomatized mantle wedge, induced by fluids from the dehydrating subducting slab, with minor input from subducted sediments and later crust–mantle interactions during magma ascent. We conclude that shallow subduction of the Arabian plate during the Oligocene–Miocene may have increased the flow of subducted fluids into the sub-arc mantle source of the Chagai arc. This process may have facilitated the widespread deposition of porphyry copper and copper–gold mineralization in the region. Full article

In this paper, the time-series model is used to predict whether an ocean buoy is about to be inside a vortex. Marine buoys are an important tool for collecting ocean data and studying ocean dynamics, climate change, and ecosystem health. A vortex is an important ocean dynamic process. If we can predict that a buoy is about to enter a vortex, we can automatically adjust the buoy’s sampling frequency to better observe the vortex’s structure and development. To address this requirement, based on the profile data, including latitude and longitude, temperature, and salinity, collected by 56 buoys in the Arctic Ocean from 2014 to 2023, this paper uses the TSMixer time-series model to predict whether an ocean buoy is about to be inside a vortex. The TSMixer model effectively captures the spatio-temporal characteristics of multivariate time series through time-mixing and feature-mixing mechanisms, and the accuracy of the model reaches 84.6%. The proposed model is computationally efficient and has a low memory footprint, which is suitable for real-time applications and provides accurate prediction support for marine monitoring. Full article

Given the unstable input of electricity generated by offshore renewable energy in connection to the power grid at present, one solution is energy storage technology. In recent years, the new marine gravitational energy storage technology has received wide attention in China and worldwide. To apply this new energy storage technology for use in the ocean, in view of the structural characteristics of the new offshore gravitational energy storage system, a support structure based on the foundation of a wind-powered pipe frame is proposed. In order to verify the feasibility of the support structure, a finite element model is established using SACS to analyze whether it meets the requirements. The construction of this structure in a specific sea is simulated through finite element simulation. Then, in accordance with the hydrogeological conditions of the sea area, the wind turbine data, and the dimensional parameters of the energy storage system’s structure, a finite element model is established with SACS for static analysis, modal analysis, random wave response analysis, and wave spectrum fatigue analysis, thereby determining whether the structure meets the requirements for strength, deformation, and fatigue. The research results show that the UC value of the static strength of the support structure of the new offshore gravitational energy storage system is less than 1. In the modal analysis, the natural frequencies of the first- and second-order modes are not within the danger range. In the corresponding random wave analysis, it is found that the natural frequencies of the first four orders are the greatest contributors to the dynamic response during the normal operation of the turbine. In fatigue analysis, it is concluded that the structure meets all the requirements of DNV specifications. The research results provide a reference for the engineering application of the support structure of the new gravitational energy storage system in the ocean. Full article