In mid-July 2021, a quasi-stationary extratropical cyclone over parts of western Germany and eastern Belgium led to unprecedented sustained widespread precipitation, nearly doubling climatological monthly rainfall amounts in less than 72 h. This resulted in extreme flooding in many of the Eifel-Ardennes low mountain range river catchments with loss of lives, and substantial damage and destruction. Despite many reconstructions of the event, open issues on the underlying physical mechanisms remain. In a numerical laboratory approach based on a 52-member spatially and temporally consistent high-resolution hindcast reconstruction of the event with the integrated hydrological surface-subsurface model ParFlow, this study shows the prognostic capabilities of ParFlow and further explores the physical mechanisms of the event. Within the range of the ensemble, ParFlow simulations can reproduce the timing and the order of magnitude of the flood event without additional calibration or tuning. What stands out is the large and effective buffer capacity of the soil. In the simulations, the upper soil in the highly affected Ahr, Erft, and Kyll river catchments are able to buffer between about one third to half of the precipitation that does not contribute immediately to the streamflow response and leading eventually to widespread, very high soil moisture saturation levels. In case of the Vesdre river catchment, due to its initially higher soil water saturation levels, the buffering capacity is lower; hence more precipitation is transferred into discharge.
Terrestrial ecosystems, account for approximately 31% of the global land area and play a significant role in the biogeochemical cycling of toxic elements. Previous studies have explored the spatial patterns, effects, and drivers of toxic elements along urban gradients, agricultural lands, grasslands, and mining sites. However, the elevational patterns of toxic elements in montane ecosystems and the underlying drivers remain largely unknown. Atmospheric deposition is a crucial pathway through which toxic elements accumulate along terrestrial elevational gradients. The accumulation of toxic elements exhibited seasonal variability along elevational gradients, with higher deposition occurring in summer and winter. Approximately 46.77% of toxic elements (e.g. Hg) exhibited increasing trends with elevation, while 22.58% demonstrated decreasing patterns (Ba, Co). Furthermore, 8.06% displayed hump-shaped distributions (Ag), and 22.58% showed no distinct patterns (As and Zn). The accumulation of these elements is influenced by several key factors, including atmospheric deposition (26.56%), anthropogenic activities (14.11%), and precipitation (10.37%) primarily via wet deposition of atmospheric pollutants. The accumulation of toxic elements threatens terrestrial biodiversity by disrupting food chains, altering community structures, and causing individual mortality. These disruptions also pose risks to human health through contaminated food sources and food webs, potentially leading to health issues like cancer, organ damage, and reproductive challenges. This review offers key insights into the factors affecting the accumulation and distribution of toxic elements along elevation gradients. It also lays the groundwork for further study on how toxic elements impact ecosystem functions, which is crucial for protecting biodiversity under climate change.
Considering the increase in demand for rare earth elements (REEs) and their accumulation in soil ecosystems, it is crucial to understand their toxicity. However, the impact of lanthanum, yttrium and cerium oxides (La2O3, Y2O3 and CeO2, respectively) on soil organisms remains insufficiently studied. This study aims to unravel the effects of La2O3, Y2O3 and CeO2 nanoparticles (NPs) and their corresponding bulk forms (0, 156, 313, 625, 1250 and 2500 mg/kg) on the terrestrial species Enchytraeus crypticus. The effects on survival, reproduction (21 days (d)), avoidance behavior (2 d) and DNA integrity (2 and 7 d) of E. crypticus were evaluated. No significant effects on survival were observed. For La2O3, the bulk form affected more endpoints than the NPs, inducing avoidance behavior (1250 mg/kg) and DNA damage (1250 mg/kg- 2 d; 2500 mg/kg- 7 d). The Y2O3 NPs demonstrated higher toxicity than the bulk form: decreased reproduction (>= 1250 mg/kg); induced avoidance behavior (>= 625 mg/kg) and DNA damage (>= 156 mg/kg- 2 d; 2500 mg/kg- 7 d). For CeO2, both forms exhibited similar toxicity, decreasing reproduction (625 mg/kg for bulk and 2500 mg/kg for NPs) and inducing DNA damage at all tested concentrations for both forms. REEs oxides toxicity was influenced by the REEs type and concentration, exposure time and material form, suggesting different modes of action. This study highlights the distinct responses of E. crypticus after exposure to REEs oxides and shows that REEs exposure may differently affect soil organisms, emphasizing the importance of risk assessment.
In recent years, frequent flood disasters have posed significant threats to human life and property. From 28 July to 1 August 2023, a basin-wide extreme flood occurred in the Haihe River Basin (23.7 flood). The Gravity Recovery and Climate Experiment satellite can effectively detect the spatiotemporal characteristics of terrestrial water storage anomalies (TWSA) and has been widely used in flood disaster monitoring. However, flood events usually occur on a submonthly scale. This study first utilizes near-real-time precipitation data to illustrate the evolution of the 23.7 extreme flood. We then reconstruct daily TWSA to improve the issues of coarse temporal resolution and data latency and further calculate wetness index (WI) to explore its flood warning. In addition, we analyze soil moisture storage anomalies to provide a comprehensive understanding of flood mechanisms. The study also compares the 2023 floods to a severe flood event in 2021. Results indicate that reconstructed daily TWSA increases by 143.43 mm in 6 days during the 23.7 flood, highlighting the high sensitivity of our approach to extreme events. Moreover, compared to daily runoff data, the WI consistently exceeds warning thresholds 2-3 days in advance, demonstrating the flood warning capability. The flood event 2021 is characterized by long duration and large precipitation extremes, whereas the 2023 flood affects a wider area. This study provides a reference for using daily TWSA to monitor short-term flood events and evaluate the flood warning potential of WI, aiming to enhance near-real-time flood monitoring and support flood prevention and damage mitigation efforts.
To protect agro-systems and food security, study on the effect of microplastics and heavy metals on edible plants is of great significance. Existing studies mostly used virgin microplastics to evaluate their effects on plants, effects of naturally aged microplastics and their combined effects with heavy metals are rarely explored. In this study, single and combined effect of polyethylene microplastics (PE, both virgin and naturally aged) and cadmium (Cd) on pakchoi under seedling and mature stages were analyzed from perspectives of growth inhibition, oxidative damage, nutrition content and soil enzyme activities. Results showed that inhibiting effects of naturally aged PE (PEa) on the growth of pakchoi were stronger than virgin PE (PEv), whereas co-contamination of PEa and Cd was less toxic than that of PEv and Cd. The co-contamination of PE and Cd could inhibit pakchoi dry biomass by over 85 %. Both single and combined contamination of PE and Cd promoted soil fluorescein diacetate hydrolase (FDA)
Many evidences have shown that both atmospheric and soil droughts can constrain vegetation growth and further threaten its ability to sequester carbon. However, the trigger thresholds of vegetation production loss under different atmospheric and soil drought conditions are still unknown. In this study, we proposed a Copula and Bayesian equations-based framework to investigate trigger thresholds of various vegetation production losses under different atmospheric and soil drought conditions. The trigger thresholds dynamics and their possible causes were also investigated. To achieve this goal, we first simulated the gross primary production, soil moisture, and vapor pressure deficit over China during 1961-2018 using an individual-based, spatially explicit dynamic global vegetation model. The main drivers of the dynamic change in trigger thresholds were then explored by Random Forest model. We found that soil drought caused greater stress on gross primary production loss than atmospheric drought, with a larger impact area and higher probability of damage. In terms of spatial distribution, the risk probability of gross primary production loss was higher in eastern China than in western China, and the drought trigger threshold was also smaller in eastern China. In addition, the trigger thresholds for atmospheric and soil drought in most regions exhibited a decreasing trend from 1961 to 2018, while the CO2 fertilization enhanced the drought tolerance of vegetation. The reduction in CO2 fertilization effect slowed down the downward trend of trigger threshold for soil drought, while the increase in temperature exacerbated the downward trend of trigger threshold for atmospheric drought. This study highlighted the larger effect of soil drought on vegetation production loss than atmospheric drought and implied that climate change can modulate
As terrestrial resources and energy become increasingly scarce and advancements in deep space exploration technology progress, numerous countries have initiated plans for deep space missions targeting celestial bodies such as the Moon, Mars, and asteroids. Securing a leading position in deep space exploration technology is critical, and ensuring the successful completion of these missions is of paramount importance. This paper reviews the timelines, objectives, and associated geotechnical and engineering challenges of recent deep space exploration missions from various countries. Extraterrestrial geotechnical materials exist in unique environments characterized by special gravity, temperature, radiation, and atmospheric conditions, and are subject to disturbances such as meteoroid impacts. These factors contribute to significant differences from terrestrial geotechnical materials. Based on a thorough literature review, this paper investigates the transformation of geomechanical properties of extraterrestrial geological materials due to the distinctive environmental conditions, referred to as the four unique characteristics and one disturbance, and their distinct formation processes. Considering current deep space mission plans, the paper summarizes the geotechnical challenges and research advancements addressing specific mission requirements. These include unmanned exploration and in-situ mechanical testing, construction of extreme environment test platforms, the mechanical properties of geotechnical materials under extreme conditions, the interaction between engineering equipment and geotechnical materials, and the in-situ utilization of extraterrestrial geotechnical resources. The goal is to support the successful execution of China's deep space exploration missions and to promote the development of geomechanics towards extraterrestrial geomechanics.
Due to the growing focus on daily hygiene practices, sodium dodecyl sulfate (SDS), a widely used surfactant, is increasingly found in domestic sewage and rainfall runoff. Upon entering the lake-terrestrial ecotone, SDS affects the composition, abundance, and functional capacity of soil bacterial communities due to its bacteriostatic properties. To investigate the effects of long-term discharge of sewage containing low concentrations of SDS on microorganisms in the lake-terrestrial ecotone, alterations in bacterial community structure, functional genes, and biomass were examined using a simulated continuous pollutant input. The results indicated the following: (1) The degradation rate of sodium dodecyl sulfate (SDS) by soil microorganisms in the lake-terrestrial ecotone under long-term and low concentrations of SDS stress ranged from 11 to 16 mg/kgd. (2) The effects of low concentrations and long-term SDS stress on bacterial community structure and gene function in the lake-terrestrial ecotone differed significantly from those of short-term pollution. The damage to microbial-promoted material cycling in the lake-terrestrial ecotone was more severe; however, the proliferation of pathogenic bacteria remained continuously suppressed. (3) Soil bacteria in the lake-terrestrial ecotone responded to the stress of long-term and low concentrations of SDS primarily by enhancing chemotaxis and tolerance.
This review explores the development and potential applications of space concrete, a critical material for future extraterrestrial construction. Space concrete, adapted to withstand the harsh conditions of outer space, such as extreme temperatures, vacuum, microgravity, and radiation, offers a sustainable solution for building habitats and infrastructure on celestial bodies like the Moon and Mars. Emphasizing the innovative approaches in formulating space concrete, including the use of lunar and Martian soil as aggregates and the exploration of alternative binders to traditional water-based cement, this review highlights the significance of in-situ resource utilization (ISRU) and 3D printing technologies in advancing extraterrestrial construction. Additionally, the current designs and applications of space concrete structures are discussed. By providing a detailed analysis of the challenges faced in space construction and the latest advancements in material and structural research, the review underlines the pivotal role of space concrete in supporting space exploration and long-term habitat.
The Arctic terrestrial ecosystems are undergoing rapid climate change, causing shifts in the dynamics of soil nitrogen (N), a pivotal but relatively underexplored component. To understand the impacts of climate change on soil labile N pools, we performed meta- and decision-tree analyses of 391 observations from 38 peer-reviewed publications across the Arctic, focusing on experimental warming and snow addition. Soil dissolved organic nitrogen (DON), ammonium (NH4+ ), and nitrate (NO3 ) pools under experimental warming exhibited overall standard mean differences (SMDs) ranging from -0.08 to 0.02, with no significance (P > 0.05); however, specific conditions led to significant changes. The key determinants of soil labile N responses to warming were experimental duration and mean annual summer temperature for DON; annual precipitation, soil moisture, and sampling timing for NH+4 ; and soil layer for NO3 . Snow addition significantly increased all labile N pools (overall SMD = 0.23-0.36; P < 0.05), influenced by factors such as sampling timing and vegetation type for DON; experimental duration and soil moisture for NH+4 ; and soil pH for NO3 . By consolidating and reprocessing datasets, we not only showed the overall responses of soil labile N pools to climate manipulation experiments in Arctic tundra ecosystems but also identified key determinants for changes in soil N pools among environmental and experimental variables. Our findings demonstrate that warming and snow-cover changes significantly affect soil labile N pools, highlighting how the unique environmental characteristics of different sites influence terrestrial N cycling and underscoring the complexity of Arctic N dynamics under climate change.