Factors and Mechanisms Affecting Arsenic Migration in Cultivated Soils Irrigated with Contained Arsenic Brackish Groundwater.

Contained arsenic (As) and unsafe brackish groundwater irrigation can lead to serious As pollution and increase the ecological risk in cultivated soils. However, little is known about how Fe oxides and microbes affect As migration during soil irrigation processes involving arsenic-contaminated brackish groundwater. In this study, the samples (porewater and soil) were collected through the dynamic soil column experiments to explore the As migration process and its effect factors during soil irrigation.

Evaluation of water environmental capacity in a northern river-reservoir continuum using environmental fluid dynamics code.

The hydrodynamics, water temperature, and water quality model for the Dan River and Renzhuang Reservoir continuum were developed using field monitoring data and the Environmental Fluid Dynamics Code (EFDC). An in-situ water discharge experiment enabled the calculation of water propagation time using a simulated flood progression method and the hydrodynamics module of EFDC. Based on these model results, degradation coefficients for chemical oxygen demand, biochemical oxygen demand, nitrogen (N), phosphorus (P), fluoride, arsenic were determined, revealing significantly higher values when the wetland barrage was opening.

Contrasting effects of arsenic on mycorrhizal-mediated silicon and phosphorus uptake by rice.

Silicon (Si) and arbuscular mycorrhizal fungi (AMF) increase plant resistance to various environmental stresses, including heavy metal (and metalloid) toxicity. Although Si and AMF each independently enhance plant tolerance, the nature of their interactions and their combined impacts on nutrient uptake, especially in the context of toxic elements such as arsenic (As), remains to be elucidated. This study investigated AMF-mediated regulation of plant nutrient uptake under As stress using rice, a model Si-accumulating plant.

Dynamic transformation and leaching processes of nitrogen in a karst agricultural soil under simulated rainfall conditions.

Frequent exchange of surface water and groundwater in karst agricultural areas results in soil nutrient loss during rainfall and consequent deterioration of the aquatic environment. To understand nitrogen (N) transformation and leaching processes from karst soil during rainfall events, two typical N fertilizers were added to karst soil and consequently investigated the nitrogenous species using soil column experiments system. The contents of various N forms in the soil and leachate were analyzed, and the net nitrification and the N leaching rates were calculated.

Changing patterns of global nitrogen deposition driven by socio-economic development.

Advances in manufacturing and trade have reshaped global nitrogen deposition patterns, yet their dynamics and drivers remain unclear. Here, we compile a comprehensive global nitrogen deposition database spanning 1977-2021, aggregating 52,671 site-years of data from observation networks and published articles. This database show that global nitrogen deposition to land is 92.

C photosynthesis and hydraulics in grasses.

The anatomical reorganization required for C photosynthesis should also impact plant hydraulics. Most C plants possess large bundle sheath cells and high vein density, which should also lead to higher leaf capacitance and hydraulic conductance (K). Paradoxically, the C pathway reduces water demand and increases water use efficiency, creating a potential mismatch between supply capacity and demand in C plant water relations.

Tracking the Changes of DOM Composition, Transformation, and Cycling Mechanism Triggered by the Priming Effect: Insights from Incubation Experiments.

The priming effect (PE) is recognized as an important mechanism influencing organic matter transformation in aquatic systems. The land-ocean aquatic continuum (LOAC) has received large quantities of dissolved organic matter (DOM) from various sources, which is an ideal interface for PE research. Here, we investigated the PE process by utilizing such a coastal environment to explore the turnover of DOM in the LOAC system.

Assessing vegetation dynamics and human impacts in natural and urban areas of China: Insights from remote sensing data.

Vegetation changes and human activities in both natural and urban environments have played a crucial role in carbon cycling and sustainable development globally. However, there is an insufficient comparison in national vegetation changes across regions with varying intensities of human activities to those natural areas. Based on urban boundary and night-time light datasets, we have identified and extracted rural, urban-low activity, and urban-high activity areas within China.

Dominance of Plastic Emission in the High Arctic Aerosol in Light Spring.

Arctic haze has attracted considerable scientific interest for decades. However, limited studies have focused on the molecular composition of atmospheric particulate matter that contributes to Arctic haze. Our study collected atmospheric particles at Alert in the Canadian high Arctic from mid-February to early May 2000.

Carbon transfer from land to fluvial networks in a typical karst river-reservoir system.

Although terrestrial ecosystems have been widely recognized as an important atmospheric carbon (C) sink, the net C sink capacity may have been overestimated due to C loss through aquatic ecosystems, particularly in catchments with fragile landscapes and intense human disturbances. Here, we integrated the three primary pathways of aquatic C export, including C burial, gaseous C emissions, and downstream C export, into the terrestrial-aquatic C assessment within the Wujiang River basin (WRB) in Southwest China, a typical karst river-reservoir system with cascade reservoirs. The assessment reports a net landscape C sink of 12.

Revealing the mobilization and age of estuarine dissolved organic matter during floods using radiocarbon and molecular fingerprints.

Estuaries significantly affect the transport of dissolved organic matter (DOM) from land to ocean. While the transport and composition of estuarine DOM have been extensively studied, the direct link between DOM chemistry and its age remains unclear, limiting a comprehensive understanding of the dynamics and fate of estuarine DOM under severe conditions (e.g.

Seasonal variations and hydrological management regulate nutrient transport in cascade damming: Insights from carbon and nitrogen isotopes.

Reservoirs around the world have significantly altered the natural transport of nutrients in rivers. However, the specific effects of the cascade damming on the migration, transformation, and environmental consequences of these nutrients remain unclear. To address this knowledge gap, we analyzed spatiotemporal variations in water chemistry, nutrient concentrations, stable isotope of dissolved inorganic carbon (δC) and nitrate isotope (δN-NO) in seven cascade reservoirs along the Wujiang River, each characterized by different regulatory regimes.

Insights into chemoautotrophic traits of a prevalent bacterial phylum CSP1-3, herein .

Candidate bacterial phylum CSP1-3 has not been cultivated and is poorly understood. Here, we analyzed 112 CSP1-3 metagenome-assembled genomes and showed they are likely facultative anaerobes, with 3 of 5 families encoding autotrophy through the reductive glycine pathway (RGP), Wood-Ljungdahl pathway (WLP) or Calvin-Benson-Bassham (CBB), with hydrogen or sulfide as electron donors. Chemoautotrophic enrichments from hot spring sediments and fluorescence hybridization revealed enrichment of six CSP1-3 genera, and both transcribed genes and DNA-stable isotope probing were consistent with proposed chemoautotrophic metabolisms.

Soil nitrogen biogeochemistry and hydrological characteristics shape the nitrate levels in a river.

The high levels of nitrate (NO) in the surface water have contributed to eutrophication and other eco-environmental damages worldwide. Although the excessive NO concentrations in rivers were often attributed to anthropogenic activities, some undisturbed or slightly disturbed rivers also had high NO levels. This study utilized multi-pronged approaches (i.

Keystone taxa drive the synchronous production of methane and refractory dissolved organic matter in inland waters.

The production of both methane (CH) and refractory dissolved organic matter (RDOM) depends on microbial consortia in inland waters, and it is unclear yet the link of these two processes and the underlying microbial regulation mechanisms. Therefore, a large-scale survey was conducted in China's inland waters, with the measurement of CH concentrations, DOM chemical composition, microbial community composition, and relative environmental parameters mainly by chromatographic, optical, mass spectrometric, and high-throughput sequencing analyses, to clarify the abovementioned questions. Here, we found a synchronous production of CH and RDOM linked by microbial consortia in inland waters.

Mineral states and sequestration processes involving soil biogenic components in various soils and desert sands of Inner Mongolia.

Soil biogenic components are subject to continuous sequestration, and export from soils into the surrounding air and water environments. However, the processes involving the stability or lability of their mineral states remain still unclear. To assess these issues, we have measured various biogenic components in a number of agricultural, forest, grassland, and deep soils, as well as desert sands from Inner Mongolia, both in the solid state and liquid extracts.

Impact of Hydrothermal Fluids on Hydrocarbon Generation and Solid Bitumen Formation in the Kongdian Formation, Huanghua Depression, China.

Hydrothermal fluid plays a crucial role in the generation and migration of hydrocarbons within sedimentary basins. Herein, we employed bulk analysis and high-resolution mass spectrometry techniques to investigate the transformation dynamics from source rock to hydrocarbons under conditions influenced by magmatic activities in the Kongdian Formation, Huanghua Depression, China. The results revealed that hydrocarbon generation in the Ek shale of the study area was significantly influenced by abnormal heating from hydrothermal fluids.

IPCC Emission Factor Overestimates NO Emissions from Agricultural Ditches.

Agricultural ditches emit disproportionate amounts of nitrous oxide (NO), but their contributions to regional or global NO emissions remain unclear due to limited data. The Intergovernmental Panel on Climate Change (IPCC) recommends using emission factors (EFs) to estimate indirect NO emission, but the EF for ditches (EF) is categorized as groundwater, which potentially introduces a significant bias. This study conducted a regional-scale campaign in the North China Plain, one of the world's most intensive agricultural regions, and calculated the EF values from agricultural ditches by the concentration method (NO-N/NO-N).

Evaluating the role of recalcitrant dissolved organic matter in bacterial community dynamics in urbanized freshwater ecosystems.

Dissolved organic matter (DOM) and recalcitrant dissolved organic matter (RDOM) play distinct roles in shaping microbial communities. However, characterizing these roles is difficult, especially in ecosystems subjected to varying degrees of anthropogenic influence. This study investigated the molecular compositions and ecological impacts of DOM and RDOM in the Fen River, Shanxi Taiyuan, comparing pristine upstream regions with highly urbanized downstream areas.

Effects of nanoplastics on the growth, transcription, and metabolism of rice (Oryza sativa L.) and synergistic effects in the presence of iron plaque and humic acid.

Nanoplastics (NPs) can adversely affect living organisms. However, the uptake of NPs by plants and the physiological and molecular mechanisms underlying NP-mediated plant growth remain unclear, particularly in the presence of iron minerals and humic acid (HA). In this study, we investigated NP accumulation in rice (Oryza sativa L.

Impacts of altitudinal ecohydrological dynamic changes on water balance under warming climate in a watershed of the Qilian Mountains, China.

In alpine areas of northwest China, one of the major concerns is the rapid warming and stimulated vegetation growth consume more water and reduce available water for downstream oasis development. Investigating the response of these ecohydrological dynamics to climate change is thus crucial, but is also challenging because of tremendous variability of vegetation, hydrology, and climate in elevation and complex interactions between them. Here, we performed numerical simulations in a mountainous watershed covering a range of contrasting climatic conditions and vegetation characteristics representative of the Qilian Mountains, China.

A portable fluorescence sensing system for timely onsite perfluorooctane sulfonate detection based on an aggregate induced emission fluorescence sensor.

Perfluorooctane sulfonate (PFOS), a ubiquitous persistent organic pollutant, has aroused growing concern due to its adverse effects on human health. Timely onsite monitoring of PFOS in heavily contaminated areas is crucial for effective pollution management and prevention of its spread. However, relevant PFOS detection methods have rarely been reported.