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.

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.

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).

Dynamic changes, cycling and downward fate of dissolved carbon and nitrogen photosynthetically-derived from glaciers in upper Indus river basin.

Glaciers play key roles in capturing, storing, and transforming global carbon and nitrogen, thereby contributing markedly to their cycles. However, an integrated mechanistic approach is still lacking regarding glacier's primary producers (PP), in terms of stable dissolved inorganic carbon isotope (δC-DIC) and its relationship with dissolved carbon and nitrogen transformation d ynamic changes/cycling. Here, we sampled waters from glaciers, streams, tributaries, and the Indus River (IR) mainstream in the Upper IR Basin, Western Himalaya.

Biogeochemical process governing cadmium availability in sediments of typical coastal wetlands driven by drying-wetting alternation.

Fluctuations in water levels within coastal wetlands can significantly affect cadmium (Cd) cycling and behavior in sediments. Understanding the effects of drying-wetting cycles on Cd availability and binding mechanisms is crucial. However, information regarding this subject remains limited.

Global distribution and drivers of relative contributions among soil nitrogen sources to terrestrial plants.

Soil extractable nitrate, ammonium, and organic nitrogen (N) are essential N sources supporting primary productivity and regulating species composition of terrestrial plants. However, it remains unclear how plants utilize these N sources and how surface-earth environments regulate plant N utilization. Here, we establish a framework to analyze observational data of natural N isotopes in plants and soils globally, we quantify fractional contributions of soil nitrate (f), ammonium (f), and organic N (f) to plant-used N in soils.

Tracing phosphorus sources in the river-lake system using the oxygen isotope of phosphate.

The biogeochemical cycling of phosphorus (P) in river-lake systems presents significant challenges in tracing P sources, highlighting the importance of effective traceability approaches for formulating targeted management measures to mitigate lake eutrophication. In this study, we used the oxygen isotope of phosphate (δO) as a tracer in the river-lake systems, establishing a tracing pathway from potential end-members, through inflow rivers, and eventually to the lake. Taking Dianshan Lake and its main inflow rivers as the study area, we measured δO values of potential end-members, including domestic sewage treatment plant effluents, industrial effluents from phosphorus-related enterprises (printing and dyeing, electroplating, plastics, etc.

Microbial regulation on refractory dissolved organic matter in inland waters.

The production of refractory dissolved organic matter (RDOM) is complex and closely related to microbial consortia in aquatic ecosystems; however, it is still unclear how microorganisms regulate the production of RDOM and its molecular composition in inland waters. Therefore, we conducted a large-scale survey of inland waters and analyzed the optical and mass spectrometric characteristics of DOM, the microbial community and functional genes, as well as related environmental parameters, to understand the abovementioned issues. Here, the RDOM production was found mainly regulated by microbial (e.

Comprehensive source identification of heavy metals in atmospheric particulate matter in a megacity: A case study of Hangzhou.

Megacities face significant pollution challenges, particularly the elevated levels of heavy metals (HMs) in particulate matter (PM). Despite the advent of interdisciplinary and advanced methods for HM source analysis, integrating and applying these approaches to identify HM sources in PM remains a hurdle. This study employs a year-long daily sampling dataset for PM and PM to examine the patterns of HM concentrations under hazy, clean, and rainy conditions in Hangzhou City, aiming to pinpoint the primary sources of HMs in PM.

Organic matter composition and stability in estuarine wetlands depending on soil salinity.

Coastal wetlands are key players in mitigating global climate change by sequestering soil organic matter. Soil organic matter consists of less stable particulate organic matter (POM) and more stable mineral-associated organic matter (MAOM). The distribution and drivers of MAOM and POM in coastal wetlands have received little attention, despite the processes and mechanisms differ from that in the upland soils.

Peatland Wildfires Enhance Nitrogen-Containing Organic Compounds in Marine Aerosols over the Western Pacific.

Peatland wildfires contribute significantly to the atmospheric release of light-absorbing organic carbon, often referred to as brown carbon. In this study, we examine the presence of nitrogen-containing organic compounds (NOCs) within marine aerosols across the Western Pacific Ocean, which are influenced by peatland fires from Southeast Asia. Employing ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in electrospray ionization (ESI) positive mode, we discovered that NOCs are predominantly composed of reduced nitrogenous bases, including CHN+ and CHON+ groups.

Significant accrual of soil organic carbon through long-term rice cultivation in paddy fields in China.

Paddy fields serve as significant reservoirs of soil organic carbon (SOC) and their potential for terrestrial carbon (C) sequestration is closely associated with changes in SOC pools. However, there has been a dearth of comprehensive studies quantifying changes in SOC pools following extended periods of rice cultivation across a broad geographical scale. Using 104 rice paddy sampling sites that have been in continuous cultivation since the 1980s across China, we studied the changes in topsoil (0-20 cm) labile organic C (LOC I), semi-labile organic C (LOC II), recalcitrant organic C (ROC), and total SOC.

Microbial contribution estimated by clumped isotopologues (CHD and CHD) characteristics in a CO enhanced coal bed methane reservoir.

Carbon capture and storage (CCS) of CO is a key technology for substantially mitigating global greenhouse gas emissions. Determining the biogeochemical processes in host rocks after CO injection informs the viability of carbon storage as a long-term sink for CO, the complexity of reservoir CH cycling, as well as the direct and indirect environmental impacts of this strategy. The doubly substituted ('clumped') isotopologues of methane (CHD and CHD) provide novel insights into methane origins and post-generation processing.

Dominant contribution of combustion-related ammonium during haze pollution in Beijing.

Aerosol ammonium (NH), mainly produced from the reactions of ammonia (NH) with acids in the atmosphere, has significant impacts on air pollution, radiative forcing, and human health. Understanding the source and formation mechanism of NH can provide scientific insights into air quality improvements. However, the sources of NH in urban areas are not well understood, and few studies focus on NH/NH at different heights within the atmospheric boundary layer, which hinders a comprehensive understanding of aerosol NH.

Stepwise degradation of organic matters driven by microbial interactions in China΄s coastal wetlands: Evidence from carbon isotope analysis.

The microbial "unseen majority" as drivers of carbon cycle represent a significant source of uncertain climate change. To comprehend the resilience of life forms on Earth to climate change, it is crucial to incorporate knowledge of intricate microbial interactions and their impact to carbon transformation. Combined with carbon stable isotope analysis and high-throughput sequencing technology, the underlying mechanism of microbial interactions for organic carbon degradation has been elucidated.

Microbial Necromass, Lignin, and Glycoproteins for Determining and Optimizing Blue Carbon Formation.

Coastal wetlands contribute to the mitigation of climate change through the sequestration of "blue carbon". Microbial necromass, lignin, and glycoproteins (i.e.

Silicon fractionations in coastal wetland sediments: Implications for biogeochemical silicon cycling.

Coastal wetland sediment is important reservoir for silicon (Si), and plays an essential role in controlling its biogeochemical cycling. However, little is known about Si fractionations and the associated factors driving their transformations in coastal wetland sediments. In this study, we applied an optimized sequential Si extraction method to separate six sub-fractions of non-crystalline Si (Si) in sediments from two coastal wetlands, including Si in dissolved silicate (Si), Si in the adsorbed silicate (Si), Si bound to organic matter (Si), Si occluded in pedogenic oxides and hydroxides (Si), Si in biogenic amorphous silica (Si), and Si in pedogenic amorphous silica (Si).

Multiple Sulfur Isotopic Evidence for Sulfate Formation in Haze Pollution.

The mechanism of sulfate formation during winter haze events in North China remains largely elusive. In this study, the multiple sulfur isotopic composition of sulfate in different grain-size aerosol fractions collected seasonally from sampling sites in rural, suburban, urban, industrial, and coastal areas of North China are used to constrain the mechanism of SO oxidation at different levels of air pollution. The ΔS values of sulfate in aerosols show an obvious seasonal variation, except for those samples collected in the rural area.

Unraveling the factors influencing CO emissions from hydroelectric reservoirs in karst and non-karst regions: A comparative analysis.

Carbon migration, transformation, and emissions as CO in reservoir and lake systems have been extensively studied. However, uncertainties persist regarding carbon cycling variations in both karst and non-karst regions within large thermal stratified river-reservoir systems. To address this knowledge gap, we combined measurements of water chemistry, isotopic compositions (δC), partial pressure of CO (pCO), and CO fluxes (F) to elucidate the differences, control mechanisms, and environmental effects of various carbon biogeochemical processes in the Hongjiadu reservoir (HJD, karst reservoir) and Shangyoujiang reservoir (SYJ, non-karst reservoir), Yangtze River basin, China.

Machine Learning Predicts the Methane Clumped Isotopologue (CHD) Distributions Constrain Biogeochemical Processes and Estimates the Potential Budget.

Methane (CH) is a matter of environmental concern; however, global methane isotopologue data remain inadequate. This is due to the challenges posed by high-resolution testing technology and the need for larger sample volumes. Here, worldwide methane clumped isotope databases ( = 465) were compiled.