Search Results (35)

Widespread in coastal environments, artificial light at night (ALAN) is suspected to disrupt organisms’ biological rhythms by altering natural light cycles and thus constitutes a growing threat to these ecosystems. This study evaluates the effects of ALAN exposure at low and realistic intensity (~1 lx) on a coastal keystone species, the oyster Crassostrea gigas. The results reveal that ALAN significantly impairs the expression of core circadian clock genes (CgClock and CgBmal1) as well as the valve opening behavior, affecting rhythmic characteristics such as its robustness and daily profile. At the same time, ALAN leads to a decrease in daily shell growth and to a disruption of the gill microbiota, associated with an obliterated day/night difference in microbial alpha diversity. A direct correlation between a decrease in daily rhythm robustness, limitation of shell growth, and some microbial strands is shown, suggesting that biological rhythm disruption caused by ALAN might have harmful physiological consequences in oysters. Full article

Lebanon’s cereals production holds historical importance in the Bekaa region, which has served as Lebanon’s agricultural heartland for centuries. Today, this vital area for food security faces environmental challenges that threaten the viability of its cereals farming sector. This study examines the current state of agricultural resources and territorial features of cereals through the lens of farmers and the local community using Perception-Based Regional Mapping (PBRM). The resulting maps were digitized and analyzed using QGIS to highlight spatial disparities across the region. The study was conducted during the summer of 2023. A total of 36 maps were developed with local farmers who first identified the areas relevant to cereals cultivation, and then reflected the spatialized perceptions covered 93% of the total study area and delineated it into distinct zones based on eight criteria identified by farmers: water availability, water quality, type of water resources, soil type, soil fertility, agricultural productivity, landform, and size of arable land. The primary cereal crops grown in the region are wheat, barley, and corn, with wheat dominating cultivation. Farmers use both traditional and mechanized methods, apply nitrogen-based fertilizers and herbicides, and rely on rainfall or limited irrigation. The resulting maps highlighted the distinct agricultural zones within the basin, of which 1030 km² (74%) were identified as appropriate for cereals cultivation. The findings underscore the value of local knowledge in identifying environmentally and economically favorable zones for cereals production, and contribute to the design of targeted, region-specific policies and interventions aimed at enhancing the resilience of cereals farming systems in the Bekaa—especially in light of ongoing socio-environmental pressures. Full article

Industrial tree plantations (ITPs) are increasingly recognized as a sustainable response to deforestation and the decline in native wood resources in the Philippines. This study presents LUNTIAN (Labor, UNiversity, Timber Investment, and Agent-based Nexus), an agent-based model that simulates an experimental ITP operation within a mountain forest managed by University of the Philippines Los Baños. The model integrates biophysical processes—such as tree growth, hydrology, and stand dynamics—with socio-economic components such as investment decision making based on risk preferences, employment allocation influenced by local labor availability, and informal harvesting behavior driven by job scarcity. These are complemented by institutional enforcement mechanisms such as forest patrolling, reflecting the complex interplay between financial incentives and rule compliance. To assess the model’s validity, its outputs were compared to those of the 3PG forest growth model, with results demonstrating alignment in growth trends and spatial distributions, thereby supporting LUNTIAN’s potential to represent key ecological dynamics. Sensitivity analysis identified investor earnings share and community member count as significant factors influencing net earnings and management costs. Parameter calibration using the Non-dominated Sorting Genetic Algorithm yielded an optimal configuration that ensured profitability for resource managers, investors, and community-hired laborers while minimizing unauthorized independent harvesting. Notably, even with continuous harvesting during a 17-year rotation, the final tree population increased by 55%. These findings illustrate the potential of LUNTIAN to support the exploration of sustainable ITP management strategies in the Philippines by offering a robust framework for analyzing complex social–ecological interactions. Full article

This study aims to estimate the shear wave velocity and identify the depth of the bedrock and the engineering site characterization utilizing the multichannel analysis of surface waves (MASW) method for sustainable urban development in the Al-Madinah Al-Munawarah area. Twenty-seven MASW profiles were carried out using Geode digital seismographs with a 24-geophone array of 4.5 Hz in the urban expansion area of Al-Madinah Al-Munawarah. The methodology entailed rigorous calibration during data collection, processing, and inversion to ensure precise shear velocity measurements. Results reflect subsurface conditions accurately where shear wave velocity (Vs) varies between 180 m/s and 1200 m/s across three main layers: alluvium deposits, which transfer laterally in some areas into vesicular basalt with Vs ranges from 180 to 360 m/s; fractured basalt where Vs varies between 360 and 760 m/s; and weathered basaltic rock with Vs that spans from 760 to 1200 m/s. Moreover, the average shear wave velocity of up to 30 m depth (Vs30) and ranging from 180–480 m/s indicate Site Class D (stiff soil) and Class C (soft rock and dense soil) according to National Earthquake Hazards Reduction Program (NEHRP). Furthermore, the depth of bedrock varies between 18 and 29 mm indicating the great thickness of soil deposits throughout the study area. These results provide civil engineers and urban planners with vital data about soil deposits characterization and geotechnical conditions in the area where alluvium deposits and vesicular basalt represent weak zones that require more attention during urban construction. Results will contribute as well, to a great extent, in achieving the sustainable development plans of Saudi Vision 2030. Full article

Determining the mechanisms of the formation of giant crystals is a challenging subject. Gypsum, calcium sulfate dihydrate (CaSO₄·2H₂O), is known to form crystals larger than one meter in several locations worldwide. These selenite crystals grow at different temperatures, either in sedimentary or hydrothermal systems. The famous selenite crystals of the geode of Pulpí (Almería, Spain) are known to have grown at a temperature T = 20 ± 5 °C and have been proposed to form in a subaqueous environment by a self-feeding mechanism triggered by anhydrite dissolution and the ripening of microcrystalline gypsum, enhanced by oscillations in temperature. This paper reports the monitored crystallization of gypsum crystals, from anhydrite powder dissolution, inside airtight evaporation-free reactors under oscillating low temperatures (15 °C < T < 25 °C). These crystals are clearly smaller than the ones in the Pulpí mine but exhibit similar habits (i.e., single blocky crystals and twins following the 100 twinning law). The growth rate of gypsum single crystals has been measured to be between 3.8 and 35.3 µm/day. Noteworthy, we document the occurrence of the 100 contact twinning law of gypsum, which is the most widespread twinning law in natural environments but never univocally reported in laboratory experiments. The selection of the 100 contact twinning law has been correlated to the low supersaturation values obtained in the experiment, where the concentration in these long-duration experiments can be safely assumed to be the equilibrium concentration, i.e., 0.3 (at 25 °C) ≤ SI ≤ 0.4 (at 15 °C). We discuss the relevance of our experiment for forming the gypsum crystals of Pulpí in the framework of the geological history of Pulpí mineralization. These laboratory model experiments contribute to a deeper understanding of mineral nucleation and growth processes in natural environments. Full article

Unmanned aerial vehicles (UAVs) provide images at decametric spatial resolutions. Their flexibility, efficiency, and low cost make it possible to apply UAV remote sensing to multisensor data acquisition. In this frame, the present study aims at employing RGB UAV images (at a 3 cm resolution) and multispectral images (at a 16 cm resolution) with related vegetation indices (VIs) for mapping surfaces according to their illumination. The aim is to map land cover in order to access temperature distribution and compare NDVI and MTVI2 dynamics as a function of their illuminance. The method, which is based on a linear discriminant analysis, is validated at different periods during the phenological cycle of the crops in place. A model based on a given date is evaluated, as well as the use of a generic model. The method provides a good capacity of separation between four classes: vegetation, no-vegetation, shade, and sun (average kappa of 0.93). The effects of agricultural practices on two adjacent plots of maize respectively submitted to conventional and conservation farming are assessed. The transition from shade to sun increases the brightness temperature by 2.4 °C and reduces the NDVI by 26% for non-vegetated surfaces. The conservation farming plot is found to be 1.9 °C warmer on the 11th of July 2019, with no significant difference between vegetation in the sun or shade. The results also indicate that the NDVI of non-vegetated areas is increased by the presence of crop residues on the conservation agriculture plot and by the effect of shade on the conventional plot which is different for MTVI2. Full article

Agate geodes contain spheroidal patterns characterized by spectacularly coloured and circularly concentric laminations with radially aligned quartz crystals, yet the origin of these geometric patterns has remained enigmatic. Here, detailed comparisons are documented between these kinds of patterns in a selection of geodes and concretions and those produced by abiotic chemically oscillating reactions. We find strikingly comparable self-similar, fractal patterns in both natural volcanogenic geodes and sedimentary concretions as well as in these benchtop experiments. In addition, the mineralogical composition of patterns and associated organic matter point to the oxidation of organic compounds in both geodes and concretions. This process occurred during diagenetic or supergene alteration, and it is consistent with spontaneous and abiotic chemically oscillating reactions. It is concluded that the oxidation of organic acids was involved in the formation of these patterns and that these rocks indicate oxidation–reduction reactions involving organic carbon, which itself may be abiotic or biological in origin. Hence, agate geodes and concretions represent the abiotic biosignatures of possible biological origin in volcanic and sedimentary rocks. Full article

The Tevinskoye agate deposit is located in the North of the Kamchatka peninsula (Russia) and represented by agate-bearing Eocene basaltic and andesitic rocks of the Kinkilsk complex. Agate mineralization occurs in lavas and tuffs as amygdales, geodes, lenses and veins, which are the main sources of the resupply of coastal agate placers. The present study aimed to perform a comprehensive mineralogical, geochemical, and O-isotope investigation of amethyst-bearing agates, and to evaluate data concerning the origin of mineralization and the conditions for amethyst formation. Agates exhibit spectacular textures, with variation in the sequence of silica filling of amygdales and geodes. The mineral composition of the agates is mainly represented by micro- and macro-crystalline quartz, amethyst, length-fast and zebraic chalcedony, moganite, goethite, and clinoptilolite. Carbonate forms individual bands in the outer zones of some agates. The presence of small amounts of native copper, covellite, chalcopyrite and pyrite is a feature of these agates. Copper and iron mineralization are probably typomorphic features related to the host rock composition. The measured values of crystallite size (525–560 Å) and the high moganite content (up to 50%) of agate with amethyst are evidenced by the young age (~45 Ma) of agate-hosting rocks. Agate formation temperatures (21–229 °C) were calculated from the O-isotope composition of chalcedony (+19.6 to +25.5‰), quartz (+18.1 to +22.3‰), and amethyst (+18.2 to +21.5‰). The cold-water monophase fluid inclusions revealed in amethyst crystals suggest that the mineralizing fluids have low temperatures (<100 °C) and low salinity. Magnetite grains in host rock, together with goethite inclusions identified within the amethyst crystals, point to a change in redox conditions and the presence of iron in the agate-forming fluids, which entered the quartz lattice during crystallization and influenced the formation of the violet color. Full article

Improving the remote sensing frameworks related to land cover mapping is necessary to make informed policy, development, planning, and natural resource management decisions. These efforts are especially important in tropical countries where technical capacity is limited. Land cover legend specification is a critical first step when mapping land cover, with consequences for its subsequent use and interpretation of results. We integrated the temporal metrics of SAR (Synthetic Aperture Radar) and multispectral data (Sentinel-1 and Sentienel-2) with visual pixel classifications and field surveys using five machine learning algorithms that apply different statistical methods to assess the prediction and mapping of two different land cover legends at a high spatial resolution (10 m) in a tropical region with seasonal flooding. The evaluated legends were CORINE (Coordination of Information on the Environment) and ECOSO, a legend that we defined based on the ecological and socio-economic conditions of the study area. Compared with previous studies, we obtained high accuracies for land cover modeling (kappa = 0.82) and land cover mapping (kappa = 0.76) when using ECOSO. We also found that the CORINE legend generated lower accuracies than the ECOSO legend (kappa = 0.79 for land cover modeling and kappa = 0.61 for the land cover mapping). Although CORINE was developed for European environments, it is the official land cover legend of Colombia, a South American country with tropical ecosystems not found in Europe. Therefore, some of the CORINE classes have ambiguous definitions for the study area, explaining the lower accuracy of its modeling and mapping. We used free and open-access data and software in this research; thus, our methods can be applied in other tropical regions. Full article

This article presents a stakeholders’ mapping exercise in 2017 and 2018 in the Oyapock watershed. Ninety-two maps were obtained covering almost the entire watershed. Results show that roads are becoming a more significant spatial reference to people, apart from the population minority living along the river. This latter polarizes itself into Brazilian colonization down and midstream, legal farmers on the Brazilian side, illegal gold diggers on the French Guiana side, and an Amerindian demographic growth upstream, both at the expense of the historical Saramaka/Creole area. Recent roads sticking each bank of the Oyapock River to their hinterland, Brazil, and France, respectively, like rubber bands, are separating them slowly, despite the bridge, primarily useless for now. Full article

Space exploration and extraterrestrial civilization have fascinated humankind since the earliest days of human history. It was only in the last century that humankind finally began taking significant steps towards these goals by sending astronauts into space, landing on the moon, and building the International Space Station. However, space voyage is very challenging and dangerous, and astronauts are under constant space radiation and microgravity. It has been shown that astronauts are at a high risk of developing a broad range of diseases/disorders. Thus, it is critical to develop a rapid and effective assay to monitor astronauts’ health in space. In this study, gene expression and correlation patterns were analyzed for 10 astronauts (8 male and 2 female) using the publicly available microarray dataset E-GEOD-74708. We identified 218 differentially expressed genes between In-flight and Pre-flight and noticed that space travel decreased genome regulation and gene correlations across the entire genome, as well as individual signaling pathways. Furthermore, we systematically developed a shortlist of 32 genes that could be used to monitor astronauts’ health during space travel. Further studies, including microgravity experiments, are warranted to optimize and validate the proposed assay. Full article

As most of the outcropping and shallow mineral deposits have been found, new technology is imperative to finding the hidden critical mineral deposits required to transition to renewable energy. One such new technique, called ambient seismic noise tomography, has shown promise in recent years as a low-cost, low environmental impact method that can image under cover and at depth. Wireless and compact nodal seismic technology has been instrumental to enable industry applications of ambient noise tomography, but these devices are designed for the active seismic reflection method and do not have the required sensitivity at low frequencies for ambient noise tomography, and real-time data transmission in remote locations requires significant infrastructure to be installed. In this paper, we show the development and testing of the Geode—a real-time seismic node purpose-built by Fleet Space Technologies for ambient seismic noise tomography on exploration scales. We discuss the key differences between current nodal technology and the Geode and show results of a field trial where the performance of the Geode is compared with a commercially popular nodal geophone. The use of a 2 Hz high sensitivity geophone and low noise digitiser results in an instrument noise floor that is more than 30 dB lower below 5 Hz than nodes that are commonly used in the industry. The increased sensitivity results in signal-to-noise ratios in the cross-correlation functions in the field trial that are more than double that of commercially available nodal geophone at low frequencies. When considering the full bandwidth of retrievable correlations in our study, using the Geode would reduce the required recording time from 75 h to 32 h to achieve an average signal-to-noise ratio in the cross-correlation functions of 10. We also discuss the integration of a real-time direct-to-satellite Internet of Things (DtS-IoT) modem in the Geode, which, together with edge processing of seismic data directly on the Geode, enables us to image the subsurface in real-time. During the field trial, the Geodes successfully transmitted more than 90% of the available preprocessed data packets. The Geode is compact enough so that several devices can be carried and installed by one field technician, whilst the array of stations do not require a base station to transmit data to the cloud for further processing. We believe this is the future of passive seismic surveys and will result in faster and more dynamic seismic imaging capabilities analogous to the medical imaging community, increasing the pace at which new mineral deposits are discovered. Full article

In this article, we describe in detail three seismic measurement campaigns based on refraction methods that we conducted at different sites in Bavaria, Germany. The measured data is published as an open data set. The particularity of this data set lies in its available ground truth information about each measurement site. Acquiring seismic data from sites with ground truth information is important for validation of seismic inversion algorithms. Since near-surface seismic field data with ground truth information is rather limited, we anticipate this data set to be a valuable contribution to the research community. For the measurements, three sites have been selected: (1) a gravel pit with a ground water layer, (2) a site above a highway tunnel and (3) a surface over underground tubes. The measurements have been conducted using line arrays of geophones, the Geode Seismograph from Geometrics Inc. and hammer strikes as seismic source. To obtain inversion results a travel time tomography based on first-arrivals within the software SeisImager is used. The inversion results show that we are able to image the ground water layer in the gravel pit, the highway tunnel and partly features of underground tubes. Furthermore, the results coincide with available ground truth information about the measurement sites. This paper summarizes the measurement campaigns and the respective data sets obtained through these campaigns. The data have been published by the authors as an open data set under the license CC BY 4.0 on figshare to make it available to the research community for validation of seismic data processing and inversion techniques. Full article

Human beings are an active component of every terrestrial ecosystem on Earth. Although our local impact on the evolution of these ecosystems has been undeniable and extensively documented, it remains unclear precisely how our activities are altering them, in part because ecosystems are dynamic systems structured by complex, non-linear feedback processes and cascading effects. We argue that it is only by studying human–environment interactions over timescales that greatly exceed the lifespan of any individual human (i.e., the deep past or longue durée), we can hope to fully understand such processes and their implications. In this article, we identify some of the key challenges faced in integrating long-term datasets with those of other areas of sustainability science, and suggest some useful ways forward. Specifically, we (a) highlight the potential of the historical sciences for sustainability science, (b) stress the need to integrate theoretical frameworks wherein humans are seen as inherently entangled with the environment, and (c) propose formal computational modelling as the ideal platform to overcome the challenges of transdisciplinary work across large, and multiple, geographical and temporal scales. Our goal is to provide a manifesto for an integrated scientific approach to the study of socio-ecological systems over the long term. Full article

We performed an extensive optical and chemical analysis of a single Keokuk geode using electron microscopy (SEM) with energy dispersive X-ray (EDX) spectroscopy that revealed an extraordinary array of minerals and multiple, complex cycles of mineralization. We identified at least 15 minerals including 5 that, to our knowledge, have not been reported in previous studies of these geodes. Along with bitumen we have described the occurrence of REE’s, and other unidentified phases containing metals such as chromium, nickel, molybdenum, tin, copper, zinc, and lead. Additionally, preliminary thin-section analysis reveals the occurrence of the tentatively identified minerals zircon, rutile, and xenotime as well as grains containing gold and silver within the chalcedony shell. The presence of these potentially economically valuable minerals warrants further investigation into the micro-minerology of Keokuk geodes. Our SEM/EDX analysis reveals an array of complex mineral assemblages, intergrowths, and inclusions that help chronologically link multiple stages of paragenesis occurring in different locations within the geode. Consequently, morphology and intricate microstructures provide a window into the extreme complexity of mineral crystallization. The majority of micro-minerals we have observed correspond with the later stages of geode paragenesis, thus providing a detailed record of the secondary mineralization processes which occurred over thousands to millions of years. Full article