Earth and Environmental Sciences

• Assessing drought impacts on canopy activity and growth improves die-off forecasts. • Vegetation indices and radial growth were measured in 45 die-off hotspots in Spain. • Hotter droughts were more frequent during the 21st century triggering die-off. • Drought constrained canopy activity and growth, which were more coupled in dry sites. • Severe reductions in greenness and growth occurred 6 years before die-off started. Decoding the long-term impacts of hotter droughts on canopy activity and growth provides information to forecast forest die-off leading to mortality hotspots. However, remotely sensed information often lacks field-based validation including long-term assessments of tree radial growth in those hotspots. To relieve this deficiency, we investigated climate data, canopy activity (NDVI, EVI) and radial growth in 45 die-off hotspots sampled across Spain and affecting six conifers (silver fir, Scots pine, Aleppo pine, maritime pine, stone pine, and Spanish juniper), and four broadleaves (European beech, pedunculate oak, downy oak, and holm oak). Hotter droughts, characterized by elevated evaporative water demand, are becoming more frequent in the study sites during the 21st century. Such warming and aridification started in the late 1990s and early 2000s and triggered several die-off hotspots, whose onset dates peaked in 1992, 2005, 2012, and 2017. In those sites, hotter droughts caused abrupt declines in canopy activity and radial growth. Year-to-year growth variability was more sensitive to drought than canopy greenness, and wetter sites showed the most negative growth trends. Drought constrained canopy activity and growth, which were more coupled in dry sites. The year of the strongest greenness loss and growth predated the observed die-off onset by six years, while abrupt growth reductions coincided with species-specific severe droughts such as 1986 (silver fir) or 2005 (Mediterranean pines). Both abrupt greenness loss and grow reductions were more common in recent years in drier sites as warming leads to more aridity. Forest mortality risk involves both site aridity and hotter-drought severity with tree-ring series representing promising data to forecast hotspot emergence.

Abstract. The China Meteorological Administration Global Forecast System (CMA-GFS) v4.0 model was upgraded to a higher resolution of 0.125° in May 2023. To be compatible with its fine resolution, the parameterization scheme of orographic gravity wave drag (OGWD) in CAM-GFS is revised herein by accounting for the nonhydrostatic effect (NHE) on the wave momentum flux of subgrid-scale orographic gravity waves. The performance of the revised OGWD scheme is then evaluated for the 10 d medium-range forecast in December 2023. Results show that the revised OGWD scheme can better capture the large-scale circulation in the Northern Hemisphere (NH), particularly in the high latitudes. The easterly (westerly) wind biases in the NH polar stratosphere (troposphere) are decreased. The underestimation of East Asia subtropical jet is also alleviated. Quantitative evaluation shows that the revised OGWD scheme reduces both the mean bias and root mean square error of 500 hPa geopotential height in the NH after the 6th forecast day, reaching 11.59 % and 5.06 %, respectively, by day 10. The decrease of easterly biases in the polar stratosphere is owing to the weakening of stratospheric zonal OGWD by the NHE. For the decrease of westerly biases in the NH polar troposphere, it is due to the fact that the enhanced stratospheric winds suppress the upward propagation of Rossby waves into the stratosphere, resulting in greater convergence of Eliassen-Palm flux in the mid-upper troposphere.

Abstract. We present an analysis of long-term trends in surface ozone (O3) across Ireland, with specific focus on the Mace Head atmospheric research station, representative of Northern hemispheric background atmospheric conditions. Surface O3 dataset was characterised using advanced trajectory analysis and seasonal decomposition, revealing distinct seasonal and spatial patterns. Findings show a significant rising trend in surface O3 at Irish urban sites over the past two decades but without a similar trend at coastal sites. Highest O3 levels and exceedances were observed at remote coastal sites, which are less susceptible to influence from local and easterly emissions but heavily influenced by transboundary pollution and stratospheric intrusion. At Mace Head, springtime O3 levels exhibit a declining trend, whereas wintertime levels show a rising trend. Focussing on the clean sector, the springtime decline remains significant, but without corresponding clean sector rising wintertime trends, implying the rising winter trends occur in response to declining local, United Kingdom (UK) and European emissions. Advanced modelling tools are used to quantify O3 source contributions, elucidating key drivers behind the observed changes. Characteristic springtime O3 maxima at Mace Head are predominantly attributed to stratospheric transport, hemispheric and long-range transport and lightning NOx. The complementary trend and sectoral observational analysis reveal a decline in total spring-time concentrations, with a more rapid decline in exceedances from the UK and continental sector. This research highlights the importance of seasonal factors in air quality management across Ireland, emphasising the need for a multi-faceted approach to control O3 levels and reduce exceedances through global and regional emission reductions.

A mixed forested/ agricultural area within Brandenburg’s lower Spree catchment, northeast Germany. This study examines the potential of managed aquifer recharge (MAR) to stabilize groundwater and connected surface water resources affected by climatic and anthropogenic impacts by reducing declines and overall variability. Utilizing an integrated surface water-groundwater model, the suitability of selected topographic basins was assessed in terms of their ability to recharge the underlying aquifer with surplus discharge water from local streams. After analyzing the aquifer’s response to increased groundwater recharge, the feedback of connected surface waters to the rise in groundwater levels was quantified and discussed in the context of regional adaptation strategies. (1) It was determined that MAR operates efficiently with temporal surplus stream-discharge volumes to induce a significant increase in groundwater recharge and a resulting rise in the groundwater table of up to 2 m. (2) Selected topographic natural small basins were verified as efficient locations to recharge an unconfined aquifer via percolation and may be applied in greater number to strengthen the regional aquifer system. (3) The increase in groundwater levels over longer distances (> 900 m) enables the stabilization of the base flow of connected surface waters and strengthens water related ecosystems via an increase in flow volume by up to 15%. • Development of a surface-water-groundwater model to assess MAR effects in topographic basins on local groundwater resources. • A applied surplus stream discharges from nearby small streams resulted in a substantial increase in groundwater recharge. • The temporally shifted increase in base flow stabilized connected surface water bodies and buffered hydrologic droughts. • The concept of MAR was verified to be applicable in a regional context of the younger Pleistocene landscape of NE-Europe.

Abstract Sustainable groundwater management of coastal aquifers is challenging due to saltwater intrusion, climate change, and diverse societal preferences. This requires approaches that are both scientifically rigorous and socially legitimate. This study introduces a stakeholder-informed simulation–optimization framework, which directly integrates collaborative modeling with stakeholders into the core formulation of the simulation optimization problem, unlike traditional approaches that treat participation as a separate or post hoc step. Applied to the Pearl Harbor aquifer in Hawaiʻi, the modeling team and water managers co-designed the simulation optimization decision variables, objectives, constraints, and scenario analysis, ensuring that research output would inform real-world decision-making. More specifically, the integration embedded management settings and goals, societal values, and ecological thresholds in the simulation optimization to co-define feasible solutions, thereby enhancing model credibility, legitimacy, and salience. Results show that projected climate change under a dry scenario with sea-level rise could reduce sustainable groundwater withdrawal by up to 46% by mid-century due to saltwater intrusion. The stakeholder-informed simulation optimization mitigates these impacts, improving freshwater availability by up to 30% compared to non-optimized approaches. Combining optimization with nature-based solutions like watershed restoration through forest protection and corridor development provides synergistic benefits, adding up to 10% more sustainable yield. The framework also quantifies key policy trade-offs, such as the balance between maximizing withdrawal and maintaining spring discharge for ecological and cultural uses. By operationalizing stakeholder knowledge within the simulation optimization framework, this work offers a transferable collaborative modeling framework for advancing groundwater sustainability in coastal regions worldwide.

Abstract The Kasaï River Basin (KRB), the largest tributary system of the Congo Basin, is undergoing rapid land-use transformation driven by population growth and expanding economic activities. However, existing global and regional land-cover products do not fully capture this highly heterogeneous, smallholder-dominated landscape or its temporal dynamics. Here, we develop a regionally calibrated 30 m resolution land-cover dataset for the KRB for 2017–2024 by combining 3,734 reference observations across five classes (urban, water, forest, savanna/grassland, cropland) with a random forest classifier trained on multi-source Earth observation datasets encoded as embeddings by Google’s AlphaEarth Foundations. The resulting classification achieves 96–100% accuracy for urban and water classes and 74–87% for forest, savanna/grassland, and cropland classes, substantially outperforming current global products (30–65%). This improvement results from using a large region-specific training dataset and a modeling strategy designed to capture land surface phenology; this enhances the detection of inter-annual dynamics in rotational and intermittent smallholder agriculture, characteristic for many tropical regions such as the KRB. We estimate that in 2024 cropland covered 16.2% of the KRB, while forest and savanna/grassland occupied 41.1% and 41.5%, respectively—values that contrast sharply with those from existing products, which report cropland extents of only 0.1–4.7%. Transition analysis further reveals that over 53,128 km² of forest and grassland in the KRB have been converted to cropland between 2017 and 2024. These results highlight the need for regionally calibrated land-cover products in heterogeneous tropical landscapes. By resolving the systematic biases present in existing global products, the dataset produced here provides an accurate, high-resolution benchmark that underpins environmental modeling, food security analysis, and land-use decision-making in the KRB and other tropical regions.

Hydroxymethyl hydroperoxide (HMHP, HOCH2OOH) is one of the most abundant organic peroxides (POs) in the atmosphere. Owing to its extremely high solubility, HMHP readily partitions into cloudwater and aerosol liquid water, where it hydrolyzes to hydrogen peroxide (H2O2) and formaldehyde (HCHO). However, previous studies were conducted in dilute solutions and did not adequately account for the high-salinity characteristic of deliquesced aerosol particles. Here, we systematically investigate the combined effects of pH (0–6), temperature (277–313 K), ionic strength (0–10 M), and ion identity (NH4+, Na+, SO42–, and Cl–) on the hydrolysis kinetics of HMHP. For the first time, a parametrization formula describing the dependence of the hydrolysis rate constant on ionic strength is established, demonstrating that ionic strength exerts only a limited influence on HMHP hydrolysis. However, it is found that in highly concentrated ammonium salt solutions, HMHP undergoes a previously unrecognized NH3-driven reaction pathway. This new pathway competes with hydrolysis, accelerating the apparent transformation rate of HMHP by more than an order of magnitude while significantly reducing the yield of H2O2 and HCHO. Our findings highlight that future atmospheric chemical models should fully account for the NH3-driven pathway in aqueous-phase reactions of POs, thereby enabling a more accurate assessment of the role of POs in atmospheric oxidant cycling and secondary particulate matter formation.

As global photovoltaic (PV) deployment accelerates, PV systems, as a new land-atmosphere interface, significantly alter local thermal environments. However, the mechanisms driving the resulting surface cool island effect remain unclear. Utilizing multisource remote sensing data, this study quantifies global surface changes and cooling induced by PV installation through causal inference. Results show that PV installation leads to an 8.4% reduction in vegetation cover (-0.043) and a 4.82% decrease in surface albedo. Surface temperature decreases significantly, by 0.17 °C in daytime LST and 0.05 °C at night. Grassland and cropland cooling show significant seasonal variation, stronger in winter and weaker in summer; conversely, bare land maintains a stable cooling effect year-round. Causal inference reveals that the cool island effect is driven by two pathways: energy retention from reduced evapotranspiration and energy removal through photovoltaic conversion. In summer, the PV energy removal pathway is suppressed, while the stronger evapotranspiration pathway further weakens the cool island effect in photovoltaic areas relative to natural backgrounds; the opposite occurs in winter. These pathways, modulated by vegetation and climate, explain seasonal variations in the cool island effect. This study highlights the impacts of PV installation on surface energy balance, supporting synergies in carbon reduction, cooling, and ecological sustainability.

Abstract In this study, daytime F‐region irregularities were observed at low latitudes during the main phase of the 12 November 2025 strong magnetic storm, causing intense very high frequency radar echoes ranging hundreds of kilometers in altitude. They were generated mainly at the F‐region topside, associated with significant plasma density enhancement possibly driven by storm‐time electric field polarity transition from eastward to westward, or meridional wind. The enhanced plasma density could provide favorable downward density gradient for generating the daytime irregularities via gradient drift instability at F‐region topside under westward storm‐time electric field. The irregularities occurred over a large zonal region spanning thousands of kilometers. The study provides new possibility of low‐latitude F‐region irregularities different from the major irregularity types over low latitudes, which could be the first report of its kind at this region.

Sea-level rise (SLR) and saltwater intrusion are driving large-scale ecosystem retreat along economically valuable coasts. However, it remains unclear how human interventions influence climate-driven processes, especially in rural areas. Sea-level-driven land use change is typically modelled as a binary response, where human-dominated uplands convert to wetlands instantaneously or else are protected indefinitely. Here we use 38 years of satellite observations across the mid-Atlantic SLR hotspot to show that marsh encroachment is nearly twice as fast, and 1.4–6.8 times more frequent, on agricultural land than forestland. Field measurements indicate that local interventions have slowed the loss of agricultural land on private property to rates far lower than SLR; however, our results suggest that, at the regional scale, agriculture accelerates the impacts of saltwater intrusion. These results imply a unique scale-dependent impact of humans on coastal management and extend our understanding of humans as principal agents of change, even in rural landscapes. As sea levels rise, coastal ecosystems and economies are threatened by saltwater intrusion and wetland encroachment. These effects are accelerated by coastal agriculture, highlighting the importance of local management interventions.

• Coupled ICESat-2 and optical bathymetry yields precise long-term storage estimates. • Ebinur Lake water storage fluctuated dramatically, but there is a trend toward stabilization. • Quantitative analysis reveals decreased river inflow drives overall water storage decline. Quantitative monitoring of lake water storage in arid regions is essential for effective management of regional water resources, and can also elucidate the impacts of ecological degradation on lake water storage. This study investigates changes in water storage in Ebinur Lake, Xinjiang, from 2011 to 2024 using field–measured water depth data and multi–sensor satellite remote sensing data, including optical (Landsat-5/7/8, Sentinel-2, and MODIS) and LiDAR (ICESat-2) data. After preprocessing the satellite images acquired on different dates, including radiometric and atmospheric correction, maps of lake area and reconstructed water depth patterns were generated, and water storage was calculated. Finally, the driving factors influencing changes in water storage over time are examined. The results indicate that Ebinur Lake underwent three distinct phases: “expansion (2011–2017), shrinkage (2018–2023), and brief recovery (2024)”. Interannual and warm-season monthly variations were notably pronounced, with the coefficient of variation fluctuating between 4.10% and 52.10%. The lake area reached a maximum of 865.99 km 2 and a minimum of 58.23 km 2 . The reconstructed water depth pattern of the lake is relatively homogeneous and predominantly shallow, with the central area being deeper and the edges being shallower. Overall, the lake exhibits a shallow-basin morphology during the study period. The water storage ranges from 1.26 × 10 8 m 3 to 10.49 × 10 8 m 3 , showing an annual average decline of 2.31%. The water storage of Ebinur Lake is influenced by factors such as river inflow, atmospheric precipitation, ambient temperature, evapotranspiration, and human activities, with river inflow being the key driving factor behind the variation in water storage.

Abstract Intensifying climate extremes under future scenarios are expected to exacerbate soil erosion, with widespread impacts on food security, water quality, and ecosystem stability. These shifts may compromise the effectiveness of soil and water conservation measures, particularly in erosion-prone regions of the Ethiopian Highlands. However, evidence remains limited on how CMIP6 climate projections influence sediment yield and the performance of best management practices (BMPs). This study assessed the impacts of climate change on sediment yield and evaluated BMP effectiveness under CMIP6 scenarios (SSP245 and SSP585) using the Soil and Water Assessment Tool (SWAT) in the Beressa watershed, Ethiopia. Model performance was strong, with R² values of 0.83 and 0.88 and NSE values of 0.78 and 0.85 for streamflow during calibration and validation, respectively. For sediment, R² and NSE values were 0.73 and 0.69 during calibration, and 0.75 and 0.68 during validation. Extreme rainfall events accounted for nearly half of the interannual variability in sediment yield. Projections indicate increased sediment yield and expansion of hotspot areas under future scenarios. Terracing reduced sediment yield by 48–51%, conservation agriculture by 30–33%, and contour farming by ~20%, while combined practices achieved up to 60% reduction. Terracing and combined BMPs markedly expanded areas below the tolerable soil loss threshold (11 Mg ha⁻¹ yr⁻¹), increasing stable zones by 48–61% across climate scenarios. In years dominated by extreme rainfall, soil and water conservation measures experience reduced efficiency and increased maintenance demands, with associated resource and cost implications. These findings highlight the need for climate-resilient, integrated land management strategies to sustain ecosystem services in the Ethiopian Highlands.

Abstract The Kelvin‐Helmholtz instability (KHI) mediates the viscous‐like solar‐terrestrial interaction by generating magnetopause surface waves that quickly become non‐linear. Basic theory predicts the locally most‐unstable linear wave dominates. However, Kelvin‐Helmholtz is a broad, convective instability that also amplifies waves originating upstream. We address this conundrum by applying dynamic mode decomposition to a Gorgon global magnetohydrodynamic simulation of the KHI. While distinct modes quickly grow at points along the magnetopause, signaling local generation, their energy continues to slowly grow downtail. Thus, a superposition is present along the magnetopause, where the dominant mode is not always the locally fastest‐growing. Each mode's wavelength elongates downtail, correlating with the boundary layer flow speed due to the accelerating advective flow around the magnetosphere Doppler shifting the fixed‐frequency waves. This may explain why longer wavelengths are observed in the tail than theory predicts and motivates further exploration of tangential inhomogeneities in basic Kelvin‐Helmholtz theory.

Abstract Paddy crop water requirements (CWR) in Malaysia’s key granary regions are projected to rise significantly under future climate scenarios, posing increased risks of water stress for rice production. This study assesses CWR in Kedah and Kelantan by applying LARS-WG to generate local climate data from three global climate models (BCC CSM1.1, CSIRO-MK3.6, HadGEM2-ES) under two representative concentration pathways (RCP 4.5 and RCP 8.5). The models underwent calibration with climate data from 1985 to 2021 and CROPWAT was used to forecast CWR between 2021 and 2100. The study reveals a clear difference in how climate change affects the two planting seasons. The off-season (S1) remains the most water-demanding period in terms of total volume, with requirements reaching 732.9 mm in Kelantan. However, the main season (S2) shows a more dramatic shift, experiencing a higher percentage increase compared to its historical baseline. This indicates that while S1 consumes more water overall, S2 is experiencing a more rapid intensification of water demand, making it increasingly vulnerable to future climate warming. Baseline CWR ranged from 523–659 mm across Kedah and Kelantan. By 2100, CWR is projected to increase under RCP 8.5 to 560–736 mm, with Kelantan experiencing the highest increases. Percentage increases under RCP 8.5 range from 6.9–11.8%, while under RCP 4.5 the increase is 3–7%. The region of Kelantan will face the highest temperature rise under RCP 8.5 with HadGEM2-ES because of more intense local warming patterns. The research results show that climate-smart water management systems need urgent implementation when they combine modified planting periods with enhanced irrigation methods and drought-tolerant rice breeds. Looking ahead, adaptation planning should bring together insights from climate science, hydrology, agronomy, and social systems to ensure sustainable rice production into the future.

Abstract This study examines the duration, intensity, and frequency of compound hot and dry extremes (CHDEs) in Senegal, together with their time of emergence (ToE), using daily temperature and precipitation from ten NASA Earth Exchange Global Daily Downscaled Projections-Coupled Model Intercomparison Project Phase 6 (NEX-GDDP-CMIP6) models under three Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, and SSP5-8.5). Observations from the Climate Hazards Group Infrared Temperature with Stations (CHIRTS) dataset for temperature and the Climate Hazards Group InfraRed Precipitation with Stations (CHIRPS) dataset for precipitation are used for historical evaluation . The multi-model ensemble reproduces spatial and temporal CHDE patterns reasonably well, though duration and intensity are underestimated in northern Senegal and frequency is overestimated in the northwest coastal zone. Projections indicate substantial increases across all scenarios, with the largest changes under SSP5-8.5, where duration may lengthen by over six days, intensity may exceed historical baseline by 8°C, and frequency may reach 10-14 events by 2100. The ToE analysis shows that under SSP5-8.5, CHDE intensity and frequency may emerge from historical variability as early as 2025, much earlier than under SSP1-2.6. The early and widespread emergence of CHDEs, particularly in the northern and coastal regions, emphasizes the urgent need for robust adaptation strategies and rapid emission reductions. These findings offer crucial insights for climate risk management and can inform national planning efforts to mitigate the escalating threats of compound climate extremes.

Dissimilatory nitrate reduction to ammonium (DNRA), essential for nitrogen retention in ecosystems, is traditionally considered a strictly anaerobic process. Challenging this, emerging evidence revealed robust DNRA activity under aerobic conditions, yet the underlying mechanisms remain elusive. In this study, we elucidate the molecular basis of oxygen-tolerant DNRA driven by sulfide oxidation in a Mycobacterium-dominated system. Under fully aerobic conditions (dissolved oxygen >3 mg/L), this system converted 1.4–4.5 mmol of nitrate to ammonium per 100 mmol of sulfide oxidized, with efficiency increasing at higher sulfide loads. Transcriptomic analysis revealed strong upregulation of DNRA genes (narGHI, nirBD) in Mycobacterium in response to elevated sulfide. In contrast to canonical DNRA organisms, which rely on the oxygen-sensitive transcription factor Fnr, Mycobacterium lacks the fnr gene and instead uses the nitrite-responsive NarL to drive DNRA gene expression irrespective of oxygen availability. Structural and molecular-dynamics analysis of Mycobacterium NarGHI complex─initiating enzyme of DNRA─reveals an evolutionarily adapted, distinctly narrowed, and highly hydrophobic substrate channel. This confined architecture protects the catalytic site from oxidative damage by raising the O2 diffusion free-energy barrier and enhancing nitrate-specific induced-fit recognition. Our findings reveal metabolic plasticity of microbial nitrogen cycling, imply convergent evolutionary strategies for oxygen tolerance in other classically anaerobic pathways, and offer key practical insights for optimizing nitrogen management in both sustainable agriculture and wastewater treatment.

• A dual-interpretation stacking method for base models and features was proposed. • Fusion of in-situ and satellite hyperspectral highlighted response to available HMs. • The stacking method has high explanatory for spatial variability of available HMs. • Adsorption and electron transition caused spectral response of available HMs. Machine learning (ML) models predicting the geospatial variability of soil heavy metals (HMs) often face monotonicity constraints and limited interpretability. Here, based on the satellite-borne hyperspectral combined with competitive adaptive reweighted sampling (CARS) and stepwise linear regression (SLR) models to reconstruct in-situ hyperspectral features, we proposed an interpretable stacking framework. In this framework, the Bayesian optimization was used to tune the hyperparameters of random forest (RF), gradient boosting decision tree (GBDT), extreme gradient boosting (XGBoost), and categorical boosting (CatBoost), while partial least squares (PLS) served as the meta-model to predict available HMs (As, Cu, Ni, Zn) concentrations, and the SHapley additive explanations (SHAP) analysis quantified the prediction mechanisms of the stacking model and the contribution of characteristic bands. The results demonstrated that the stacking method significantly outperformed individual ML models (R 2 > 0.8). Spatial mapping of the stacking model indicated that Ni, Cu, and Zn exhibit relatively higher concentrations in the northern and eastern regions. Furthermore, the SHAP analysis indicated GBDT and XGBoost contributed the most (more than 30%) to predictions, followed by CatBoost (20%–30%) and RF (less than 20%). And the short-wave infrared band (1205–2500 nm) influenced As and Cu, while the visible light band (846–1088 nm) affected Ni and Zn. Moreover, the path analysis of the structural equation model (SEM) revealed that soil properties influence the spectral response mechanisms of available HMs by affecting the carbonate index (CAI) and soil organic matter (SOM). Overall, this study provides a dual interpretability stacking framework of both base models and hyperspectral features, offering new perspectives for enhancing productivity in agricultural remote sensing.

Water-floating solar photovoltaics (FPV) add to renewable energy capacity building without additional land requirements. We quantify the environmental impacts of FPV on inland water bodies with a focus on greenhouse gas (GHG) emissions and water consumption. We harmonize and compare all existing peer-reviewed life cycle assessments on FPV and add two case studies. We consider the full life cycle of FPV, including future (prospective) material recycling options, as well as changes in water evaporation and aquatic GHG emissions at the FPV location. On average, we computed an overall GHG footprint of 36 gCO2 kWh–1, similar to ground-based PV. Biogenic aquatic GHG emissions at the FPV location are expected to contribute a relatively minor share (1%–8%) to the GHG footprint of the FPV systems. Water savings due to prevented evaporation are much higher than the FPV systems’ water consumption. Collectively, our findings support the continued development and deployment of FPV technology to aid the transition toward renewable energy supply.

Abstract. This article, the ninth in the series, presents kinetic and photochemical data sheets evaluated by the International Union of Pure and Applied Chemistry (IUPAC) Task Group on Atmospheric Chemical Kinetic Data Evaluation. It covers an extension of the gas phase and photochemical reactions of halogenated alkanes, alkenes, and oxygenated organic compounds implemented on the IUPAC website since 2008. The article consists of a summary table of the recommended kinetic parameters for the evaluated reactions, and a supplement containing the data sheets providing information upon which the recommendations are made.

Study Region: Urban road catchment areas with shallow-water drainage systems, where grate inlet clogging by floating debris frequently exacerbates flooding. Study Focus: This study employs a coupled Volume of Fluid-Discrete Element Method (VOF-DEM) model, validated by physical experiments, to simulate the transport and clogging behavior of three typical urban debris types—foam (300 kg/m³), leaves (1000 kg/m³), and plastic bags (1500 kg/m³)—under shallow-water drainage conditions. The objective is to investigate how material-specific properties (density and morphology) govern clogging dynamics and drainage performance. New Hydrological Insights for the Region: Results reveal that density governs movement patterns: low-density foam floats and migrates widely with minimal direct clogging; near-water-density leaves suspend and accumulate at grate gaps and corners; high-density plastic bags rapidly settle and cover the grate surface, reducing effective flow area. Morphology synergizes with density to enhance clogging stability. Clogging reduces drainage efficiency, with an average water level backwater of 3.2 mm and flow velocity reduction of 0–15.4%, showing spatial heterogeneity. This study establishes a multi-scale framework linking material properties to hydraulic response, providing quantitative references for anti-clogging grate design, targeted maintenance, and risk assessment of stormwater inlets in the study region. • VOF-DEM model examines float body traits' effect on clogging and drainage. • Low/high-density debris reduce flow via suspension or surface coverage. • Clogging impact varies spatially, most severe near outlets with water rise.

Abstract The increase in shipping in the Canadian Arctic has significant impacts on Inuit coastal communities and their traditional way of life. Examples include the risk of chemical spills, underwater noise and ships’ hulls acting as vectors for non-indigenous species, all of which impact ecosystems and wildlife which Inuit rely on for health, food security and cultural sustainability. However, the number and types of ships travelling near communities and the associated risks remain poorly quantified, limiting effective management strategies. We use ship tracklines generated from Automatic Identification System (AIS) ship positions between 2013 and 2022 to calculate voyages within 20 km of 43 communities distributed throughout Northern Canada (north of 60° N and Hudson Bay). Over 10 years, voyages increased significantly by a factor of 1.7 (from 116 in 2013 to 317 in 2022), with the largest increases due to dry bulk, cargo and government/research vessels. This varies between communities, with 15 (35%) having shown little change or a small decrease in shipping, and 28 (65%) showing an increase. Six communities accounted for the majority of the overall increase. We examine these sites in detail, identifying drivers behind the voyage increases such as the proximity to mines, growing resupply needs, tourism expansion and increased navigability along transit routes close by due to the reduction in sea ice. Our results on the rate and drivers of change in ship traffic provide essential insights for local and regional governance of shipping impacts.

lacks canonical siderophore pathways but employs a noncanonical iron-acquisition strategy, which may contribute to enhanced iron availability under trace metal-limited conditions. These results provide experimental evidence that specific bacterial lineages closely associated with toxic dinoflagellates can promote their proliferation. Our findings highlight the ecological significance of dinoflagellate-associated core microbiota and offer new directions for microbiome-informed strategies in HAB monitoring and management.

Manganese (Mn) contamination of groundwater is widespread and poses a global challenge to ensuring access to safe drinking water. MnOx(s)-filter media is commonly employed in conventional household drinking water treatment systems for Mn(II)aq removal due to its cost-effectiveness. However, these treatment systems may struggle to consistently meet health-based standards under certain conditions, and water supply systems may also experience issues. Thus, we investigate whether conventional MnOx(s)-media can activate peroxymonosulfate (PMS) via advanced oxidation processes to enhance Mn(II)aq removal efficiency. Batch experiments demonstrated superior Mn(II)aq removal efficiency using the novel method compared to the conventional approach for a range of PMS concentrations, MnOx(s)-media types and dosages, and pH values. A PMS-activated MnOx(s)-coated sand system (MCS) exhibited greater Mn(II)aq removal potential than a PMS-activated natural Mn ore (NMO) system (PMS = 500 μM, 96.8% vs 30.0%). Results identified the involvement of adsorbed oxygen (Oads) and suggested the potential role of surface-reactive Mn species in the oxidation of Mn. Characterization of the reaction products revealed the formation of stable MnO2 precipitates. Both radical (i.e., •OH and SO4•–) and nonradical (i.e., 1O2 and electron transfer) pathways contributed to Mn(II)aq removal in the PMS-activated MnOx(s)-coated sand system, whereas removal in the PMS-activated NMO system is driven by a nonradical pathway. This study proposes a promising alternative for enhanced removal of Mn(II)aq from drinking water, especially in anoxic, reducing groundwater wells, and provides insight into the underlying mechanism of Mn(II)aq removal.

Floodplain and wetland sediments serve as critical interfaces between surface water and groundwater, where per- and polyfluoroalkyl substances (PFAS) in urban waterways can infiltrate, accumulate, and partition across solid, liquid, and air-water interfaces. We measured the spatial and vertical distributions of 40 PFAS in floodplain sediments in a Southern California urban watershed. We detected perfluorooctanesulfonic acid (PFOS) most frequently and at the highest concentrations. We performed desorption and sequential batch adsorption-desorption experiments to estimate PFOS in situ pore-water concentrations and to quantify hysteretic behavior during repeated cycles of adsorption and desorption. Estimated in situ PFOS pore-water concentrations in vadose zone sediments were more than twice (78 ng/L) those in recently measured surface water (<30 ng/L), which may reflect seasonal fluctuations in water-content-dependent partitioning and long-term trends in surface water. Our new method of employing mass-labeled PFOS in batch experiments presents direct comparisons of the adsorption of field-derived PFOS to that of PFOS introduced at discrete steps in the laboratory. Our results suggest two mechanisms governing hysteresis in PFOS solid-phase partitioning across distinct time scales: (1) rapid mass exchange at sediment surfaces influenced by the historical maximum aqueous concentration, and (2) rate-limited diffusion of PFOS in organic-rich sediments occurring over long time scales in the field but not in most laboratory batch experiments.