Search Results (144)

Geochemical proxies in coastal sediments are widely applied to reconstruct past climatic and environmental changes, yet their sensitivity to climate versus localized depositional processes remains debated in dynamic land–sea interfaces. Here, we present major, trace, and rare earth element (REE) data from two Holocene sediment cores (QX01 and QX02) from the western coast of Bohai Bay to decouple provenance, weathering, and hydrodynamic controls. Provenance-sensitive trace element ratios (La/Sc and Th/Sc) and REE fractionation patterns indicate exceptional source stability dominated by the Yellow River and adjacent cratonic catchments throughout the Holocene, eliminating provenance shifts as a confounding variable. Since ~8 ka, an overarching upward increase in raw chemical index of alteration (CIA), accompanied by increasing Al/Si ratios and grain sizes, broadly aligned with the warm and humid Holocene Climate Optimum. Crucially, a highly significant linear relationship between grain size, Al/Si and CIA (R² > 0.78) demonstrates that raw CIA variations were decisively modulated by sea-level-driven hydrodynamic sorting during the Holocene transgression, which shifted the depositional setting from high-energy fluvial regimes to low-energy marine settings, preferentially trapping fine-grained, clay-hosted aluminosilicates with inherently high CIA values. During the late Holocene (~5 ka to present), stabilizing sea-level conditions shifted the raw records into an elevated plateau punctuated by high-frequency fluctuations and localized geochemical anomalies, reflecting a dynamic interface sensitive to episodic fluvial floods or tidal/storm reworking that periodically introduced coarser, quartz-rich detritus. The resulting sorting-corrected CIA_C removes the transgressive clay-trapping artifact and reveals a broad, subdued weathering plateau between ~8 ka and 4 ka BP, consisting with previous Chinese Loess Plateau weathering intensity. These findings highlight that in dynamic marginal-marine sinks, raw silicate weathering indices reflect physical sorting overprints, and hydrodynamic detrending is essential to extract genuine continental paleoclimate signals. Full article

In the Western Anti-Atlas, the stratiform copper mineralisations of the Tabia Member are distinctly hosted within sedimentary rocks, forming deposits comparable to the sediment-hosted stratabound copper (SSC) type. In Tizert, Ouarmdaz, and Talat n’Ouamane, the sandstones and clays host primary sulphides as disseminations and copper carbonates occurring as small continuous or lenticular beds, small geodes, and coatings on clay laminations. In Tiferki, the conglomerates are more mineralised; sulphides are represented by chalcopyrite and bornite, locally altered into chalcocite. Copper carbonates appear as malachite and azurite coating pebbles and deeply impregnate the granular matrix. From a sedimentological and sequence-stratigraphic perspective, the conglomeratic level at Tiferki represents a low-sea-level prism (LST) formed during a stage of maximum platform exposure allowing erosion products to accumulate at the base of the slope. By contrast, the silty–sandy complex known as the “Talat n’ Ouamane level” corresponds to a prograding sedimentary sequence (Highstand Systems Tract, HST) that developed after a relative regression where the platform was only partially exposed. In both cases, relative sea-level fall promoted the emergence of the hinterland and active erosion, supplying the depositional environment with coarse detrital during the maximum drops in sea level and sandy-to-micro-conglomeratic deposits during less pronounced regressions. This detrital supply probably brought copper in the form of grains and especially dissolved copper, which is largely deposited at the bottom of slopes and in marine environments where microbial communities contribute to the precipitation of copper. The selective distribution of sulphides within the Tabia Member shows that only the low-sea-level and high-sea-level prisms are enriched in stratiform copper, while the transgressive and maximum flooding systems tracts lack significant mineralisation. This suggests that sea-level variations played a controlling role in copper deposition. The regressive trend of the high sea-level suite continued until emergence, reflected by the invasion of the environment by red or ochre siltstones from the alluvial plain. The emergence at the transition from sandstones to dolomites, and the “Red Beds”-type mineralisation embedded in these subaerial facies, support the syngenetic origin of the sulphides in the Tabia Member. After this main emplacement of stratiform copper, the sulphides would have undergone remobilisation and alteration during a significant episode of vertical water escape that deformed the host facies and enhanced mineral concentration within permeable sandstones. Even the clays were delaminated and coated with a thin films of copper carbonates on their surfaces. In the Tamjout dolomites, carbonates are percolated by acidic solutions, contributing to the brecciation and silicification of the stromatolitic layers. Copper mineralisation accompanies this silicification and fills the karstification pockets. Full article

Satellite-based remote sensing has become an essential tool for territorial monitoring and environmental analysis, particularly in the context of extreme events. The European Union’s Copernicus Programme provides open-access satellite data that support near-real-time environmental assessment. Among its missions, the Sentinel-2 satellites, equipped with the Multispectral Instrument (MSI), offer high spatial and spectral resolution through 13 spectral bands, enabling the detection and monitoring of water quality parameters in inland and coastal water bodies. In early May 2024, intense rainfall events in Rio Grande do Sul, southern Brazil, triggered one of the most severe flooding episodes recorded in the region over the past 40 years. The objective of this study is to assess the environmental impacts of this event by mapping the flooded areas and analysing changes in water quality using Sentinel-2 imagery. Sentinel-2 Level-1C (Top-of-Atmosphere) products were processed using the Copernicus Browser to evaluate variations in coloured dissolved organic matter (CDOM) and dissolved organic carbon (DOC). Temporal analysis based on true-colour composite images allowed the observation of a significant increase in water extent over a seven-day period. Temporal comparison of Sentinel-2 images acquired before, during, and after the flood consistently showed a progressive expansion of inundated areas, accompanied by spatially coherent increases in satellite-derived CDOM and DOC indicators during the flood peak, followed by a partial decrease after flood recession. Although no simultaneous field measurements were available for quantitative validation, the observed spatial–temporal patterns consistently indicate flood-induced deterioration of water quality. Elevated CDOM and DOC levels are commonly associated with increased organic matter inputs and may have implications for water availability and suitability for human and animal consumption. Given the expected increase in the frequency and intensity of extreme weather events driven by climate change, this study highlights the importance of satellite-based remote sensing for rapid environmental monitoring. The Sentinel satellite constellation demonstrates strong potential for near-real-time assessment, offering timely information and broad spatial coverage to support environmental management and decision-making. Full article

In modern Jewish thought in Eastern Europe, the biblical narratives of the Flood (Mabul) and Noah’s Ark took on new symbolic meanings. Although these narratives had long occupied a place in religious interpretation and storytelling, they gained renewed significance in the nineteenth and early twentieth centuries, especially in Yiddish literature and modern Jewish intellectual discourse. This article examines how the Flood transformed from a biblical episode into a modern symbol through which Jewish writers, historians, and synagogue painters conceived of disaster, revolution, exile, and the fragile continuity of communal existence. In Yiddish literature, the Flood became a metaphor for pogroms, political upheaval, and social collapse, expressing a profound sense of historical instability and collective disorientation. By contrast, Noah’s Ark came to symbolize an uncertain refuge whose ability to preserve Jewish life was repeatedly questioned. In synagogue painting, however, representations of Noah’s Ark and the Flood softened these catastrophic meanings, transforming them into images of suspended survival and fragile continuity amidst ongoing historical turmoil. By examining literary and visual responses together, this article argues that modern Jewish culture in Eastern Europe reinterpreted biblical imagery as a means of coping with uncertainty, vulnerability, and the ongoing struggle for communal survival. Full article

Fluvial superfloods are geomorphologically significant episodes due to their enormous energy and extremely low recurrence in the geological record. Their rarity is particularly notable in areas far from the major continental glacial masses. Hydraulic constrictions in the Lower Ebro River gorges caused the accumulation of fluvial deposits, as floodwaters from the Ebro River were forced upstream into the tributary valleys of the Móra Basin. The most illustrative example is the Comte Creek, where two depositional units of different ages show upstream flood accumulations (extending up to ~4 km) with very high-energy sedimentary structures, followed by downstream reworking during backflow. Two-dimensional hydraulic simulations indicate that peak discharges reaching 385,000 m³·s⁻¹, with water depths of approximately 28 m in the confluence area, would have been required to transport sediments to the observed outcrop positions. Luminescence dating of the slackwater deposits indicates that the formative processes occurred during the latest Middle Pleistocene or the Last Interglacial (Eemian). Full article

An aeolian event and a fluvial episode affected Gale crater, Mars, prior to 3.6 billion years ago. Both were short-lived and catastrophic. The same two events also modified the Southern Highlands of the red planet during the same time interval. We show that events in Gale crater were a part of those that modified vast areas of the southern hemisphere of Mars. As such, the patterns documented in Gale crater are consistent with reshaping of large portions of Mars by short-lived catastrophic events by wind and water, although data from other regions are needed to establish this on a planetary scale. The study is based on data collected by the Curiosity rover during the past 14 years. The aeolian event that excavated Gale crater was lithologically controlled. It formed two distinct morphological provinces with two contrasting rock types. One was the cone-shaped ancestral Aeolis Mons, informally known as Mt. Sharp, that consists of sandstone, siltstone, and mudstone. The other was the nearly flat hollowed margin, the ancestral crater floor, that was initially covered by loose pebbles, cobbles, and boulders which were reworked and lithified to a conglomeratic rock unit later. Commonly reported Martian aeolian erosion rates cannot account for the abrasion and transport of 39,000 km³ of sediments out of Gale crater. This conclusion is supported by little modification of Gale crater during the past 3.6 billion years by ordinary winds. Our evaluation indicates that the excavation of Gale crater took place by a powerful aeolian perturbation that resembled a sand-blasting operation. It was short-lived, had extremely high erosion rates, and occurred during a cold and dry climate. The fluvial episode followed the aeolian event. The study of its sedimentary record indicates that it began with intense precipitation-driven great floods that eroded the ancestral Mt. Sharp, carved large canyons on its slope, and reworked gravels of the ancestral crater floor into giant bedforms. Flood waters also formed a deep lake that experienced one rise and one fall of lake-level and had a dynamic storm-driven sedimentation. The fluvial episode was also short-lived and indicates catastrophic actions of water during a warm and wet climate. As such, this study suggests that the extensive reshaping of the red planet during the Late Noachian period, including formation of valley networks, occurrence of hundreds of crater lakes, and excavation of numerous craters, were also due to short-lived, intense, climate-related perturbations by powerful wind and water rather than by ordinary, slow rate, long-duration processes. Another implication of the study is for the mineralogical evolution of Martian sedimentary rocks. It indicates that the Late Noachian period may have been mostly cold and dry, similar to the modern Mars. Its low water/rock ratio and cold temperatures halted chemical weathering that resulted in preservation of highly unstable minerals such as olivine and pyroxene. The fluvial perturbation with its high water/rock ratio was not long and/or warm enough to alter or significantly affect the mineralogy by weathering at the source region, or during the transport, or at the depositional site. Full article

Leptospirosis is an emerging zoonotic infectious disease in the adventure traveler with recreational freshwater exposure. We describe three cases of probable leptospirosis acquired during whitewater rafting trips in rural Ecuador. Rafting took place following periods of heavy rainfall and flooding of rivers, which are well documented risk factors for leptospirosis. Two of our patients presented to our rapid assessment clinic with acute febrile illness after travel to a region with a confirmed leptospirosis outbreak, while the third patient presented four weeks after a convalescent episode of acute febrile jaundice during a dramatic rise in reported leptospirosis cases in Ecuador. Delayed turnaround times for confirmatory microbiologic diagnostics in leptospirosis challenge its management and necessitate provisional clinical diagnosis and empiric antimicrobials based on compatible clinical symptoms, biochemical abnormalities, exposure history, and known outbreak epidemiology. We herein situate the presentations of our patients within the broader literature by reviewing the clinical, diagnostic, therapeutic, and prognostic considerations when caring for leptospirosis patients. Leptospirosis should be considered in the differential diagnosis of all patients presenting with acute febrile illness following adventure travel with freshwater exposure, and empiric treatment should be considered given the absence of readily available confirmatory microbiologic testing. Full article

The Wadi Al-Ahsaba watershed is an arid to semi-arid catchment situated in southwestern Saudi Arabia, characterized by intermittent surface flow, high evaporation and low rainfall, and a dam reservoir built for flood control. The work aims to assess hydrological and anthropogenic controls on surface and groundwater quality, pollution status, and human health risks using an integrated approach of hydrogeochemical analysis, multivariable statistics, and water quality and contamination indices. A total of 21 water samples (15 surface water, 6 groundwater) were analyzed for general chemistry, major ions, and trace elements. Hydrogeochemical analysis and principal component analysis (PCA) were implemented to differentiate the geogenic from anthropogenic control on water quality. The pollution status and associated risk were evaluated using water quality index (WQI), contamination degree (Cd), Hazard Quotient (HQ), and Hazard Index (HI). Results suggest limited surface–groundwater interaction, with surface water dominated by Ca–Mg–HCO₃ facies, indicating recent recharge and limited water–rock interaction, whereas groundwater exhibits mixed Ca–Mg–Cl and Ca–Na–Cl–SO₄ types, revealing longer residence time and water–rock interaction. Nitrate (9.5–109 mg/L) and TDS (522–1003 mg/L) exceeded drinking water standards in 90% and 95% of tested samples, respectively, and WQI ranged from 43 to 134, reflecting excellent to poor water. High non-carcinogenic risk from nitrate was observed, especially for infants. The study concluded that the geogenic processes (water–rock interaction, evaporation, and mineral dissolution) control the general chemistry of tested water, while anthropogenic input from wastewater and agriculture input are likely contributors to nitrate contamination. The study contributes to the understanding of arid wadi-dam systems by revealing how limited recharge, hydrological connectivity, and episodic flow control contaminant transport and persistence, underscoring the critical role of integrated hydrological analysis and land use management in safeguarding freshwater resources in arid environments. Full article

The 2019 Mississippi River floods were among the most severe in recent U.S. history, impacting 11 states and driven by multiple tributary flood events rather than a single episode. This study focuses on the Lower Mississippi River Basin in Mississippi, examining how flood frequency interacts with land ownership patterns to influence agricultural losses in the Yazoo–Mississippi Delta. Using Sentinel-2 imagery within Google Earth Engine, land use and land cover were classified with a random forest algorithm, followed by change detection and a flood recurrence–persistence modeling framework to map and characterize inundation. Results indicate that mid-year floods (April–July) caused the greatest crop losses, particularly in soybeans (4475 ha), cotton (501 ha), and corn (546 ha). Most impacts were associated with short-duration, low-recurrence floods, which affected many structures (1812) and extensive agricultural areas due to their broad spatial reach. Small agricultural parcels (≤48 ha) experienced the highest proportional exposure across flood zones, while medium and large parcels showed comparatively lower vulnerability. These findings highlight the importance of targeted resilience and mitigation strategies that account for flood frequency, land use, and land ownership patterns across the Delta. Full article

This paper develops a Business Resilience Index (BRI) that measures county-level resilience to natural disasters at a county-quarter frequency for the United States over 2014–2024. The index integrates high-frequency labor market outcomes from the Quarterly Census of Employment and Wages with flood insurance policy information from FEMA, disaster damages from the NOAA Storm Events Database, and social and health determinants from County Health Rankings. Starting from a broad candidate set, we apply an interpretable feature-screening pipeline to retain 79 variables and then use principal component analysis to extract four orthogonal structural dimensions of resilience: market scale, socioeconomic resilience, urban density risk, and industrial economy profile. We construct a domain-weighted strategic index and benchmark it against data-driven and equal-weight alternatives, showing that county rankings are highly stable across weighting schemes. To evaluate whether the BRI aligns with recovery behavior under acute shocks, we implement a matched difference-in-differences event study around two major flood episodes—Texas in 2015Q2 and North Carolina in 2018Q3. Conditional on exposure intensity and matched comparability, higher pre-event BRI counties exhibit earlier stabilization and a stronger post-event employment path relative to lower BRI counties, with differences in magnitude and timing across cases. Overall, the BRI provides an interpretable, high-frequency baseline for identifying capacity constraints that may slow recovery and for supporting preparedness targeting and post-disaster monitoring. Full article

Warm rain events occur when moist air masses containing elevated precipitable water produce high rainfall rates capable of generating local flash floods. Catalonia, located on the northeastern Mediterranean coast of the Iberian Peninsula, is regularly affected by such episodes: approximately 70% of daily precipitation events exceeding 10 mm with fewer than ten cloud-to-ground lightning flashes can be classified as warm rain. The current research aimed to identify the meteorological conditions most conducive to heavy warm rain episodes in Catalonia. These cases are commonly associated with flash flood episodes in the study region. We utilized rain gauges, lightning data, radar, and model fields, combined with radio sounding profiles. First, we identified and characterized warm rain cases, and second, we have selected some relevant cases to characterize the phenomenon. These events occur predominantly along the Catalan coast during the warm season, typically following the passage of a cold front, and are associated with shallow convective clouds producing little or no lightning. However, the key determining factor is a characteristic vertical thermodynamic profile: a moist and saturated lower troposphere with high precipitable water beneath a low- to mid-level thermal inversion, and weak instability concentrated near the surface. Furthermore, local wind convergence plays a principal role in the rainfall pattern. Full article

This study analyses two wetlands within the Medina del Campo groundwater body (Duero River Basin, Spain) to reconstruct flood patterns and quantify the hydrological volumes involved in episodic inundation. We integrate Sentinel satellite imagery (2015–2024), targeted field campaigns (2024–2025), and preliminary water-balance assessments (2015–2022). Calculations were constrained to the inundated cells of each wetland bed to reduce spatial heterogeneity issues. For Laguna de los Lavajares, an initial standing water depth was assumed to estimate infiltration losses more accurately. We discuss the primary sources of uncertainty—particularly the representation of atmospheric losses as evaporation versus evapotranspiration—and recommend computing water balances for wet, average, and dry years to capture interannual variability. Key findings include the identification of distinct hydroperiods for each wetland, the dominant role of infiltration in the water balance of Laguna de los Lavajares, and the critical influence of vegetation-driven evapotranspiration in Laguna Redonda. Full article

The northeast monsoon prevailing over southeastern China in late seasons, generally from October to March, frequently generates water level anomalies upstream of the Taiwan Strait (TWS) that reach the coastal waters of Guangdong in South China, and, with compounding astronomical high tides, elevate coastal flood risk over the region. The risk of coastal flooding or sea inundation is further heightened when monsoon forcing co-occurs with storm surge brought by late-season tropical cyclones (TCs). This study integrates tide gauge observations from Hong Kong (HK) and its vicinity together with Delft3D Flexible Mesh simulations to diagnose a tide-modulated anomaly wave mechanism. Observations show that anomalies originating in or near TWS arrive in HK with station-dependent phasing. These water level anomalies exhibit a characteristic ~6 h periodicity west of the Taiwan Shoal, and display peaks that systematically align with the astronomical high tide. Time–frequency analysis reveals a wave period transformation from ~12 h north of Dongshandao over the coast of southeastern China to ~6 h west of the Taiwan Shoal. We test the hypothesis that wind-forced water anomalies generated in or near TWS undergo shoal-modulated nonlinear tide–wind interaction and tidal-current advection that transform their dominant period and phase-lock them to the tide, producing four anomaly peaks per day downstream and station-dependent phasing in HK. Hindcasts of the November 2024 monsoon episode reproduce the observed timing, periodicity, and spatial transition, while constituent experiments demonstrate that semi-diurnal forcing entering via the TWS is the primary driver of the ~6 h signal, with the Taiwan Shoal acting as the modulation locus. Accurate water level forecasts for the Guangdong coast, therefore, need to incorporate upstream wind forcing over the TWS and bathymetric controls around the Taiwan Shoal, with practical implications for compound flood risk during spring tides and co-occurring monsoon and/or TC events. Full article

Pasture ecosystems provide essential ecosystem services, yet poisonous plants create persistent veterinary and economic risks. We examined how hydroclimatic variability restructures the poisonous-plant assemblage across three Central Kazakhstan rangelands during an extremely dry year (2023) and an exceptionally wet year (2024). A total of 32 toxic vascular plant species were recorded. Xeromorphic pastures maintained a stable floristic core across years, whereas the wet year triggered recruitment of wet-associated poisonous taxa (hydrophytic/hygrophytic group) exclusively in the Nura River floodplain and increased species richness. Thus, interannual variability was controlled by hydrologically sensitive habitats rather than wholesale community turnover. The principal grazing hazard was associated with flood-related species (e.g., Cicuta virosa, Oenanthe aquatica) and persistent forage contaminants (Datura/Hyoscyamus, Lolium temulentum). These findings indicate that toxic-plant risk follows an asymmetric seasonal pattern: episodic post-flood hazard in floodplains combined with constant background risk in steppe pastures. Therefore, grazing management should integrate event-based monitoring of wet habitats with continuous forage-quality control. Full article

Palynological analysis of seventy-seven cutting samples from six boreholes in the Marañón Basin (northeastern Peru) has identified five distinct Neogene marine incursion events (ME-1 to ME-5), challenging existing models that depict them as short-lived episodes. The diverse palynological assemblages, comprising spores, pollen, freshwater algae, and critical marine indicators—including dinoflagellate cysts, foraminiferal test linings, and copepod eggs—reveal that these incursions were protracted and recurrent, each associated with a maximum flooding surface and bounded by intervals of continental sedimentation. The stratigraphic record shows the earliest event ME-1 (Aquitanian to Late Burdigalian, 23.03–17.7 Ma) identified across all studied wells. ME-2 (latest Burdigalian to Middle Langhian, 17.0–16.1 Ma) is also recorded basin-wide. ME-3 (latest Burdigalian to earliest Langhian 16.5–15.7 Ma) registered in two wells. ME-4 (Late Langhian to latest Serravallian, 14.6–11.62 Ma) registered in only two wells and ME-5 (Early Tortonian, 11.6–10 Ma) is documented exclusively in the southernmost well, culminating in Zanclean (~5.5–3.6 Ma) mangrove development. We interpret the ingress routes for ME-1 to ME-3 to be westward via the Marañón Portal or northward from the Caribbean, associating them with the Proto-Pebas and Pebas systems. In contrast, ME-4 would also be from Amazon trunk or Paraná Portal associated with the Pebas Phase, and ME-5 likely originated from the south through the Paraná Portal, linking it to the Acre Phase. These results demonstrate that Miocene marine incursions into western Amazonia were not brief episodes but represented prolonged periods of marine influence, facilitated by sustained subsidence in the Marañón retro-arc foreland basin. This history reveals a dynamic connectivity throughout the Neogene, with marine conditions acting as persistent biogeographic barriers that critically shaped the region’s Miocene biodiversity patterns. This refined chronology provides a comprehensive regional framework, significantly advancing our understanding of Amazonian paleogeography. Full article