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Leaf wax molecular and isotopic ratios are generally considered robust isotopic pale-ohydrologic proxies. Here we evaluate the proxy value of the molecular distributions and hydrogen isotopic compositions of long chain n-alkanes (δDalk ) in surface peats collected from peatlands across a range of annual air temperatures from 1 to 15°C and a range of annual mean precipitation from 720 to 2070 mm in the monsoonal region of China. The alkane ratios (ACL and CPI) and δDalk values show relatively large variations in multiple samples from a single site, highlighting the complexity of these ratios at a small spatial scale. In the montane Zoigê peatland, the apparent fractiona-tion between precipitation and δDalk is more positive than in the other six sites, which is possibly an effect of the higher conductivity of the water in this high elevation site (3500 m a.s.l.). At a larger spatial scale, the site-averaged CPI ratios and the δDalk values of n-C29 and n-C31 alkanes show significant correlation with the air temperature and precipitation. These results support the application of the CPI ratio and the δDalk ratios of n-C29 and n-C31 alkanes as sensitive paleohydrologic proxies on millennial and larger timescales. [ABSTRACT FROM AUTHOR]

Globally, forest ecosystems, especially subtropical forests, play a central role in biogeochemical cycles and climate regulation, demonstrating their irreplaceable function. The subtropical region of China, characterized by its unique forest ecosystem, complex terrain, climate heterogeneity, diverse vegetation types, and frequent human activities, underscores the importance of the in-depth study of its net primary productivity (NPP). This paper employs the eddy covariance–light use efficiency (EC-LUE) model to quantitatively estimate the gross primary productivity (GPP) of this region from 2001 to 2018, followed by an estimation of the actual net primary productivity (ANPP) using the carbon use efficiency (CUE). The results showed that over these 18 years, the annual average ANPP was 677.17 gC m−2 a−1, exhibiting an overall increasing trend, particularly in mountainous areas, reserves, and the cultivated lands of the northeastern plains, whereas a significant decrease was observed around the urban agglomerations on the southeast coast. Furthermore, the Thornthwaite memorial model was applied to calculate the potential net primary productivity (PNPP), and diverse scenarios were set to quantitatively evaluate the impact of climate change and human activities on the vegetation productivity in the study area. It was found that in areas where the ANPP increased, both human activities and climate change jointly influenced ANPP dynamics; in areas with a decreased ANPP, the impact of human activities was particularly significant. Additionally, the heterogeneous distribution of ANPP across different altitudinal gradients and the driving effects of various climatic factors were analyzed. Finally, a partial correlation analysis was used to examine the relationships between the temperature, precipitation, and ANPP. This study indicated that temperature and precipitation have a substantial impact on the growth and distribution of vegetation in the region, yet the extent of this influence shows considerable variation among different areas. This provides a robust scientific basis for further research and understanding of the carbon dynamics of subtropical forest ecosystems and their role in the global carbon cycle. [ABSTRACT FROM AUTHOR]

Critical Zone Science (CZS) explores the deep evolution of landscapes from the base of the groundwater or the saprolite‐rock interface to the top of vegetation, the zone that supports all terrestrial life. Here we propose a framework for CZS to evolve further as a discipline, building on 1st generation CZOs in natural systems and 2nd generation CZOs in human‐modified systems, to incorporate human behaviour for more holistic understanding in a 3rd generation of CZOs. This concept was tested in the China‐UK CZO programme (2016–2020) that established four CZOs across China on different lithologies. Beyond conventional CZO insights into soil resources, biogeochemical cycling and hydrology across scales, surveys of farmers and local government officials led to insights into human‐environment interactions and key pressures affecting the socio‐economic livelihoods of local farmers. These learnings combined with the CZS data identified knowledge exchange (KE) opportunities to unravel diverse factors within the Land‐Water‐Food Nexus, that could directly improve local livelihoods and environmental conditions, such as reduction in fertilizer use, contributing toward Sustainable Development Goals (SDGs) and environmental policies. Through two‐way local KE, the local cultural context and socio‐economic considerations were more readily apparent alongside the environmental rationale for policy and local action to improve the sustainability of farming practices. Seeking solutions to understand and remediate CZ degradation caused by human‐decision making requires the co‐design of CZS that foregrounds human behavior and the opinions of those living in human modified CZOs. We show how a new transdisciplinary CZO approach for sustainable Earth futures can improve alignment of research with the practical needs of communities in stressed environments and their governments, supporting social‐ecological and planetary health research agendas and improving capacity to achieve SDGs. Plain Language Summary: Critical Zone Science (CZS) explores how landscapes evolve from below the Earth's surface to the top of trees, supporting life on Earth. CZS was established by studying pristine landscapes, with little or no human modification of the land, water and soil. These pristine natural systems are rare in our modern world. In this paper, we have proposed a new approach to CZS for studying the human‐modified landscapes that dominate our world. To help explain why this is needed, we have re‐drawn a diagram explaining how the critical zone works to show the role of humans. We also give examples of research in three regions of China where we learned from local farmers living in our study areas, to improve our scientific understanding and to try to align our research process to address the biggest pressures affecting their lives. This new approach to CZS can help focus research to directly support local people and improve our ability to achieve the United Nations Sustainable Development Goals. Key Points: Integrating local knowledge with critical zone science can improve interpretation of scientific findings and delivery of Sustainable Development GoalsThird generation science can improve alignment of research with the practical needs of communities and governmentsA new conceptual diagram for human‐modified critical zones is produced to illustrate transdisciplinary Critical Zone Observatories for sustainable Earth futures [ABSTRACT FROM AUTHOR]

As an essential unconventional natural gas resource, China's coalbed methane resources are only commercially exploited in a few areas, such as the Qinshui Basin and the Ordos. The rise of coalbed methane bioengineering makes it possible to realize the conversion and utilization of carbon dioxide through microbial action and the carbon cycle. According to the metabolic behavior of the underground microbial community, if the coal reservoir is modified, it may stimulate the microorganism to continuously produce biomethane to prolong the production life of depleted coalbed methane wells. This paper systematically discusses the microbial response to promoting microbial metabolism by nutrients (microbial stimulation), introducing exogenous microorganisms or domestication of in situ microorganisms (microbial enhancement), pretreating coal to change its physical or chemical properties to improve bioavailability, and improving environmental conditions. However, many problems must be solved before commercialization. The whole coal reservoir is regarded as a giant anaerobic fermentation system. Some issues still need to be solved during the implementation of coalbed methane bioengineering. Firstly, the metabolic mechanism of methanogenic microorganisms should be clarified. Secondly, it is urgent to study the optimization of high-efficiency hydrolysis bacteria and nutrient solutions in coal seams. Finally, the research on the underground microbial community ecosystem and biogeochemical cycle mechanism must be improved. The study provides a unique theory for the sustainable development of unconventional natural gas resources. Furthermore, it provides a scientific basis for realizing the carbon dioxide reuse and carbon element cycle in coalbed methane reservoirs. [ABSTRACT FROM AUTHOR]

Arsenic (As) contamination of groundwater is a global public health problem. Microorganisms have a great effect on the migration and transformation of arsenic. Studying the effect of microbial community structure and function on arsenic release in the groundwater environment of the riverbank filtration zone has important theoretical and practical significance. In this paper, in-situ monitoring technology and molecular biology technology were used to study the microbial community in the process of river water infiltration in the Shenyang Huangjia water source, China. The results showed that the structure, diversity and abundance of the microbial community in groundwater were closely related to the arsenic content. Proteobacteria was the dominant phylum in groundwater of the study area, and Acinetobacter, Pseudomonas, Sulfuritalea, Sphingomonas and Hydrogenophaga etc. were the main dominant bacterial genera. In addition to reducing and oxidizing arsenic, these functional microorganisms also actively participated in the biogeochemical cycle of elements such as iron, manganese, nitrogen and sulfur. There was a significant correlation between dominant bacteria and environmental factors. Fe/Mn had a significant positive correlation with As, which brought potential danger to the water supply in high iron and manganese areas. [ABSTRACT FROM AUTHOR]

Phosphate‐solubilizing microbes (PSMs) drive the biogeochemical cycling of phosphorus (P) and hold promise for sustainable agriculture. However, their global distribution, overall diversity and application potential remain unknown. Here, we present the first synthesis of their biogeography, diversity and utility, employing data from 399 papers published between 1981 and 2017, the results of a nationwide field survey in China consisting of 367 soil samples, and a genetic analysis of 12986 genome‐sequenced prokaryotic strains. We show that at continental to global scales, the population density of PSMs in environmental samples is correlated with total P rather than pH. Remarkably, positive relationships exist between the population density of soil PSMs and available P, nitrate‐nitrogen and dissolved organic carbon in soil, reflecting functional couplings between PSMs and microbes driving biogeochemical cycles of nitrogen and carbon. More than 2704 strains affiliated with at least nine archaeal, 88 fungal and 336 bacterial species were reported as PSMs. Only 2.59% of these strains have been tested for their efficiencies in improving crop growth or yield under field conditions, providing evidence that PSMs are more likely to exert positive effects on wheat growing in alkaline P‐deficient soils. Our systematic genetic analysis reveals five promising PSM genera deserving much more attention. [ABSTRACT FROM AUTHOR]

Silver is a highly toxic element for marine organisms. However, its controlling factor in marine sediments remains largely unknown, limiting our understanding of its biogeochemical cycling. Based on a sediment core from the Vietnam upwelling area in the South China Sea, it is found that Ag is significantly enriched in sediments of this area (as high as 0.39 μg/g), and it shows a very similar geochemical behavior to Ca and Sr. Our study supports the theory that Ag could be a marine paleo‐productivity indicator. Burial of Ag over the past 3,200 years shows an abrupt increase at around 1850 CE, in concordance with the global atmospheric CO2 record. It is hypothesized that elevated CO2 and global warming enhance marine productivity in the Vietnam coastal upwelling area, favoring the burial of Ag. Human‐induced global warming thus significantly impacts its biogeochemical cycling. Plain Language Summary: Cycling of elements in Earth systems is fundamental to Earth vitality. Examining biogeochemical cycling of elements is thus important in geoscience research. Global warming in recent time has exerted significant impact on the cycles of some elements, including carbon (C), nitrogen (N), and phosphorus (P). This imposes challenges to the integrity and security of Earth ecosystems. However, little is known about some other bio‐active elements. For example, silver (Ag) is highly toxic to marine organisms, but its occurrence, distribution, and fate under a warming background is largely unknown. We analyzed a marine core from the South China Sea, Western Pacific. It was found that concentrations of Ag in the sediments were pretty high, and its burial rate showed an abrupt increase at around 1850 CE. This is probably associated with increased marine productivity as Earth warmed. This study advances our understanding of the Ag cycle. Key Points: High concentrations of and significant variations in Ag were found in marine sedimentsAg in marine sediments is a marker for ocean paleoproductivityGlobal warming favors the burial of Ag in oceans [ABSTRACT FROM AUTHOR]

As one of the important elements of controlling the redox system within the hyporheic and hypolentic zone, sulfur is involved in a series of complex biogeochemical processes such as carbon cycle, water acidification, formation of iron and manganese minerals, redox processes of trace metal elements and a series of important ecological processes. Previous studies on biogeochemistry of the hyporheic and hypolentic zones mostly concentrated on nutrients of nitrogen and phosphorus, heavy metals and other pollutants. Systematic study of biogeochemical behavior of sulfur and its main controlling factors within the lake hypolentic zone is very urgent and important. In this paper, a typical desert plateau lake, Dakebo Lake in northwestern China, was taken for example within which redox zonation and biogeochemical characteristics of sulfur affected by hydrodynamic conditions were studied based on not only traditional hydrochemical analysis, but also environmental isotope evidence. In the lake hypolentic zone of the study area, due to the different hydrodynamic conditions, vertical profile of sulfur species and environmental parameters differ at the two sites of the lake (western side and center). Reduction of sulfate, deposition and oxidation of sulfide, dissolution and precipitation of sulfur-bearing minerals occurred are responded well to Eh, dissolved oxygen, pH, organic carbon and microorganism according to which the lake hypolentic zone can be divided into reduced zone containing H2S, reduced zone containing no H2S, transition zone and oxidized zone. The results of this study provide valuable insights for understanding sulfur conversion processes and sulfur biogeochemical zonation within a lake hypolentic zone in an extreme plateau arid environment and for protecting the lake-wetland ecosystem in arid and semiarid regions. [ABSTRACT FROM AUTHOR]

Understory small trees and shrubs play a crucial role in the biogeochemical cycles in forest ecosystems. However, their biomass in northeastern China is still uncertain and has been heavily disregarded due to the limited number of available allometric equations. For this study, 782 plants from 33 species obtained by the destructive method were used to develop species-specific and generalized aboveground allometric biomass equations based on collar diameter (D) and height (H) using weighted nonlinear seemingly unrelated regression. Each biomass component was shown to be well predicted by D alone, with R2 adj. values mostly greater than 0.80. The majority of species performed better in the models for wood and aboveground biomass when H was included as D2H. Furthermore, generalized equations for the two components showed a comparatively large coefficient of variation but comparable Bias to species-specific equations, especially for small trees. It is recommended to estimate biomass using generalized equations for mixed species only when species-specific equations are unavailable at a given site. However, in the event when precision is not the primary concern, generalized equations are also suggested. The developed equations will help to improve the accuracy of biomass assessment of understory woody plants in northeastern China forest ecosystems. [ABSTRACT FROM AUTHOR]

Leaf senescence have shed light on its contribution to the recovery of nutrients and signaling of the transition from the active to the dormant stage in winter. The manner by which climatic and edaphic factors and plant phylogeny affect the senescent leaf economics spectrum (more mineral elements included) of different growth habits along elevational gradients in mountain ecosystems is highly uncertain. To fill this knowledge gap, we examined 15 representative subalpine forest species' senescent leaf functional traits (i.e., specific leaf area [SLA], leaf dry matter content [DMC], pH, carbon [C], nitrogen [N], phosphorus [P], potassium [K], calcium [Ca], sodium [Na], magnesium [Mg], manganese [Mn], aluminum [Al], iron [Fe], C:N, N:P, and C:P ratios) to determine the senescent leaf economics spectrum along elevational gradients in the Hengduan Mountains, China. Our results demonstrate that all the functional traits of senescent leaf showed strong correlations with one another, and K was observed as the hub for the leaf economics spectrum. Irrespective of the difference among growth habits (arbor vs. shrub), leaf habits (deciduous vs. evergreen), and leaf types (broad vs. needle), the variations in the two‐dimensional spectrum of the senescent leaf trait exhibited uniformly positive associations with elevation, primarily attributed to climatic drivers. However, the modulation of the senescent leaf economics spectrum by soil properties and plant phylogeny was surprisingly modest. Collectively, our results revealed that the resource trade‐off of senescent leaf showed a trend from acquisition to conservation along elevational gradients, which could broaden the plant economics spectrum to include senescent leaf. [ABSTRACT FROM AUTHOR]

Viruses, as the most prolific entities on Earth, constitute significant ecological groups within freshwater lakes, exerting pivotal ecological roles. In this study, we selected Chaohu Lake, a representative eutrophic freshwater lake in China, as our research site to explore the community distribution, driving mechanisms, and potential ecological functions of diverse viral communities, the intricate virus–host interaction systems, and the overarching influence of viruses on global biogeochemical cycling. [ABSTRACT FROM AUTHOR]

Bathyarchaeia (formerly Bathyarchaeota) is a group of highly abundant archaeal communities that play important roles in global biogeochemical cycling. Bathyarchaeia is predominantly found in sediments and hot springs. However, their presence in arable soils is relatively limited. In this study, we aimed to investigate the spatial distributions and diversity of Bathyarchaeia in paddy soils across eastern China, which is a major rice production region. The relative abundance of Bathyarchaeia among total archaea ranged from 3 to 68% in paddy soils, and Bathy-6 was the dominant subgroup among the Bathyarchaeia (70–80% of all sequences). Bathyarchaeia showed higher migration ability and wider niche width based on the neutral and null model simulations. Bathy-6 was primarily assembled by deterministic processes. Soil pH and C/N ratio were identified as key factors influencing the Bathyarchaeia composition, whereas C/N ratio and mean annual temperature influenced the relative abundance of Bathyarchaeia. Network analysis showed that specific Bathyarchaeia taxa occupied keystone positions in the archaeal community and co-occurred with some methanogenic archaea, including Methanosarcina and Methanobacteria, and ammonia-oxidizing archaea belonging to Nitrososphaeria. This study provides important insights into the biogeography and niche differentiation of Bathyarchaeia particularly in paddy soil ecosystems. [ABSTRACT FROM AUTHOR]

Multifaceted regime shifts of Earth's surface are ongoing dramatically and – in turn – considerably alter the global carbon budget, energy balance and biogeochemical cycles. Sustainably managing terrestrial ecosystems necessitates a deeper comprehension of the diverse and dynamic nature of multicomponent information within these environments. However, comprehensive records of global-scale fractional vegetation and soil information that encompass these structural and functional complexities remain limited. Here, we provide a globally comprehensive record of monthly vegetation and soil fractions during the period 2001–2022 using a spatiotemporally adaptive spectral mixture analysis framework. This product is designed to continuously represent Earth's terrestrial surface as a percentage of five physically meaningful vegetation and soil endmembers, including photosynthetic vegetation (PV), nonphotosynthetic vegetation (NPV), bare soil (BS), ice or snow (IS) and dark surface (DA), with high accuracy and low uncertainty compared to the previous vegetation index and vegetation continuous-field product as well as traditional fully constrained linear spectral mixture models. We also adopt nonparametric seasonal Mann–Kendall tested fractional dynamics to identify shifts based on interactive changes in these fractions. Our results – superior to previous portrayals of the greening planet – not only report a + 9.35 × 10 5 km 2 change in photosynthetic vegetation, but also explore decreases in nonphotosynthetic vegetation (- 2.19 × 10 5 km 2), bare soil (- 5.14 × 10 5 km 2) and dark surfaces (- 2.27 × 10 5 km 2). In addition, interactive changes in these fractions yield multifaceted regime shifts with important implications, such as a simultaneous increase in PV and NPV in central and southwestern China during afforestation activities, an increase in PV in cropland of China and India due to intensive agricultural development, a decrease in PV and an increase in BS in tropical zones resulting from deforestation. These advantages emphasize that our dataset provides locally relevant information on multifaceted regime shifts at the required scale, enabling scalable modeling and effective governance of future terrestrial ecosystems. The data about five fractional surface vegetation and soil components are available in the Science Data Bank (10.57760/sciencedb.13287, Sun and Sun, 2023). [ABSTRACT FROM AUTHOR]

It is crucial to comprehend how fertilization and cultivation management alter the composition of dissolved organic carbon (DOC) and microbial communities to regulate the biogeochemical cycling of soil nutrients and mitigate adverse impacts on soil–water quality. Based on 15 years of long-term field trials conducted in purple soil on farmland with a slope of 15° in southwestern China, the following five treatments were examined: CK (no fertilizer was applied), T1 (NPK plus organic manure and downslope cultivation), T2 (NPK and downslope cultivation), T3 (1.5-fold NPK and downslope cultivation), and T4 (NPK and contour cultivation). Soil samples were obtained from summer maize at two soil depths (0–10 and 10–20 cm) and from rhizospheric soil, and the changes in the DOC content, UV–visible (UV–Vis) absorptivity, and phospholipid fatty acids (PLFAs) were assessed. Our results revealed a significant change in the DOC content following fertilization, especially in T1, as it was 136.0%, 179.4%, and 132.2% higher, respectively, than that in CK at the 0–10 and 10–20 cm depths and rhizospheric soil. Fertilization decreased the UV–Vis absorptivity variables of DOC (i.e., SUVA254, SUVA260, SUVA400, SUVA465, SUVA665, and C:C ratio) and raised the E4:E6 ratio (fulvic acid to humic acid in DOC), regardless of T2 and T3 at the 10–20 cm depth and in the rhizospheric soil compared with those in CK, respectively. Fertilization significantly increased the total PLFA content and selected microbial groups relative to CK. Among the treatments, T1 significantly increased the total PLFA content by 50.6%, 59.0%, and 46.2%, respectively, relative to CK, at the 0–10 and 10–20 cm depths and in the rhizospheric soil. The microbial community structure in contour cultivation (T4) was significantly greater than in downslope cultivation (T2). Random forest analysis (RFA) revealed that SOC and DOC were likely the primary variables for regulating the total PLFAs in the examined soil. Partial least squares path modeling (PLS-PM) further indicated that the DOC content and the ratio of E4:E6 among DOC compositions had greater effects on the soil microbial community structure in the examined soil. These observations suggested that long-term fertilization and cultivation management are effective approaches to regulating the soil microbial community structure by altering the composition of DOC in sloping farmland. [ABSTRACT FROM AUTHOR]

A portable electrochemical system based on rGO/AuNPs/Nafion was constructed for selenium (IV) field determination in coastal seawater of the North Yellow Sea, East China Sea and South China Sea. This system demonstrated a low determination limit (0.03 μg/L), a wide linear range of concentration (0.1–30 μg/L), exceptional reproducibility and repeatability, and excellent selectivity. Each individual, entire test could be accomplished within 8 min. In Yantai Sishili Bay, the Se (IV) concentrations ranged from 0.16–3.59 μg/L (average 1.43 μg/L). In Shengshan Island, the Se (IV) concentrations ranged from 0.20–5.18 μg/L (average 2.06 μg/L). In Zhelin Bay, the Se (IV) concentrations ranged from 0.87–4.87 μg/L (average 3.13 μg/L). The average concentrations of Se (IV) in surface seawater showcased an increasing trend from the north to the south of China, suggesting Zhelin Bay > Shengshan Island > Sishili Bay. The system develops a new, competitive method for water quality assessment, and contributes to the accurate study of the biogeochemical cycles of selenium. [ABSTRACT FROM AUTHOR]

Global management of wetlands to suppress greenhouse gas (GHG) emissions, facilitate carbon (C) sequestration, and reduce atmospheric CO2 concentrations while simultaneously promoting agricultural gains is paramount. However, studies that relate variability in CO2 and CH4 emissions at large spatial scales are limited. We investigated three-year emissions of soil CO2 and CH4 from the primary wetland types of the Liaohe Delta, China, by focusing on a total wetland area of 3287 km2. One percent is Suaeda salsa, 24% is Phragmites australis, and 75% is rice. While S. salsa wetlands are under somewhat natural tidal influence, P. australis and rice are managed hydrologically for paper and food, respectively. Total C emissions from CO2 and CH4 from these wetland soils were 2.9 Tg C/year, ranging from 2.5 to 3.3 Tg C/year depending on the year assessed. Primary emissions were from CO2 (~98%). Photosynthetic uptake of CO2 would mitigate most of the soil CO2 emissions, but CH4 emissions would persist. Overall, CH4 fluxes were high when soil temperatures were >18°C and pore water salinity <18 PSU. CH4 emissions from rice habitat alone in the Liaohe Delta represent 0.2% of CH4 carbon emissions globally from rice. With such a large area and interannual sensitivity in soil GHG fluxes, management practices in the Delta and similar wetlands around the world have the potential not only to influence local C budgeting, but also to influence global biogeochemical cycling. [ABSTRACT FROM AUTHOR]

The green vegetation fraction Fg, which represents the horizontal density of live vegetation, is an important parameter for the study of global energy, carbon, hydrological, and biogeochemical cycling. A common method of calculating Fg is to create a simple linear mixing model between two NDVI endmembers: bare soil NDVI, , and full vegetation NDVI, . However, many uncertainties exist for the determination of these parameters at large scales. The present study investigates how and determination can impact Fg calculations for all of China, based on different land-cover datasets, hyperspectral data, and soil type classification maps. The results show the following: 1) The regional ChinaCover dataset, with higher accuracy and more detailed classification, is preferable for calculating Fg in China, compared with the most commonly used MOD12Q1 dataset, although it would not lead to too much difference in values. 2) The soil NDVI from Hyperion datasets shows that soils have highly variable NDVI values (0.006-0.2), and 79.36% of the area studied has a much larger NDVI value than the commonly used value of 0.05. Therefore, the dynamic values with different soil types are much better for Fg calculation than the invariant value (0.05), which would yield a significant overestimation of Fg, especially for areas with low vegetation coverage. 3) A high-quality Fg dataset for China from 2000 to 2010 was established with and parameters based on MOD13Q1 250-m NDVI data. [ABSTRACT FROM AUTHOR]

Nitrogen isotope (δ15N) analysis has been used to evaluate depositional redox conditions in well-preserved sedimentary systems; however, fewer N-isotope studies have been performed to reconstruct the redox conditions in lacustrine shales. In this paper, we report the δ15N data from the Upper Triassic Chang 7 Shale of the Ordos Basin, North China. Sedimentary δ15N values are significantly higher in the Chang 7 3 and the lower part of the Chang 7 2 submembers (Zone A; average = 9.4 ± 1.3‰) than in the upper part of the Chang 7 2 and the Chang 7 1 submembers (Zone B; average = 5.4 ± 1.5‰). Previous geochemical measurements (i.e., U and TOC/P) of both zones show wide redox variation, however, the average values of these redox proxies are relatively higher in Zone A than those of Zone B. Combined with lithological aspects of the Chang 7 Shale, our study suggest that Zone A was mainly deposited under suboxic bottom water conditions, whereas Zone B deposits accumulated within an oxygenated water column. Stable organic carbon isotopes (δ13C org) and total nitrogen (TN) values of the two zones display little variation that could be attributed to changing organic matter sources and/or post-depositional alteration of δ15N. Thus, we suggest that variations in δ15N throughout the Chang 7 Shale primarily reflect differences in depositional redox conditions and δ15N values of the shale that can provide important details regarding the depositional history of unconventional resource plays. • Provide the first δ15N records of the Chang 7 Shale, Ordos Basin. • Differences in δ15N are primarily influenced by water column redox conditions. • Organic-rich intervals accumulated under suboxic conditions. • Tectonic events drove redox changes during deposition. [ABSTRACT FROM AUTHOR]

• We summarized and discussed about antimony pollution in water environment and its sources. • Research on toxicity of antimony was documented. • Occurrence and biogeochemistry of antimony in water environment were discussed. Antimony, the compounds of which exhibit toxicity, finds extensive usage in industrial processes for flame retardants, plastics, batteries, electronic components, and mechanical bearings. Consequently, mining and industrial activities contribute to the continuous migration of antimony into aquatic environments, influencing the Earth's biogeochemical cycle. Given China's status as the primary global exporter of antimony, the country confronts the challenge of water pollution arising from intensive antimony mining operations. This paper focuses on the latest advances in research concerning antimony toxicity, identifies potential sources of antimony water pollution, and explores its migration pathways and biogeochemistry. Moreover, the study provides estimations of antimony quantities in different compartments. Finally, we discuss the prospects for enhancing our comprehension of antimony's biogeochemical behavior. [ABSTRACT FROM AUTHOR]

Aims: The anthropogenic nitrogen (N) input has considerable consequences on soil microbial biomass, which is critical for biogeochemical cycling. As prevalent grassland management, mowing may reduce soil N storage, enhance plant biodiversity and soil microbial carbon (C) availability, all of which are important regulators of soil microbial biomass. However, convincing data is still scarce about how mowing affects soil microbial biomass under N enrichment. Methods: The interactive effects of N addition (0 – 50 g N m−2 yr−1) and mowing (unmown vs. mown) on soil microbial biomass C (MBC) were measured by manipulating 6 years' N addition experiment in Inner Mongolia grassland of China. Results: Mowing increased soil inorganic N concentration, available Cu2+ concentration, plant aboveground net primary production (ANPP), species richness, Shannon-Wiener biodiversity and ratio of fungal to bacterial biomass, and decreased soil available Mn2+ concentration under N enrichment. Mowing also significantly reduced the dominance of Leymus chinensis. While mowing did not affect the soil MBC compared with that in only N added plots. The soil MBC was positively regulated by plant species richness and biodiversity, while was negatively regulated by ANPP, soil inorganic N, available Cu2+ and Mn2+ concentration in mown plots. Conclusions: The results highlight that mowing cannot mitigate the negative effects of N enrichment on soil MBC. The soil, plant and microbial properties play important roles in regulating the response of soil MBC to mowing in N-enriched soil. This work improves the mechanistic understanding of the linkages between plant community and soil microbial C cycling. [ABSTRACT FROM AUTHOR]

Background: Microbes constitute almost the entire biological community in subsurface groundwater and play an important role in ecological evolution and global biogeochemical cycles. Ecological baseline as a fundamental reference with less human interference has been investigated in surface ecosystems such as soils, rivers, and ocean, but the existence of groundwater microbial ecological baseline (GMEB) is still an open question so far. Results: Based on high-throughput sequencing information derived from national monitoring of 733 newly constructed wells, we find that bacterial communities in pristine groundwater exhibit a significant lateral diversity gradient and gradually approach the topsoil microbial latitudinal diversity gradient with decreasing burial depth of phreatic water. Among 74 phyla dominated by Proteobacteria in groundwater, Patescibacteria act as keystone taxa that harmonize microbes in shallower aquifers and accelerate decline in bacterial diversity with increasing well-depth. Decreasing habitat niche breadth with increasing well-depth suggests a general change in the relationship among key microbes from closer cooperation in shallow to stronger competition in deep groundwater. Unlike surface-water microbes, microbial communities in pristine groundwater are predominantly shaped by deterministic processes, potentially associated with nutrient sequestration under dark and anoxic environments in aquifers. Conclusions: By unveiling the biogeographic patterns and mechanisms controlling the community assembly of microbes in pristine groundwater throughout China, we firstly confirm the existence of GMEB in shallower aquifers and propose Groundwater Microbial Community Index (GMCI) to evaluate anthropogenic impact, which highlights the importance of GMEB in groundwater water security and health diagnosis. ALYCGLN5KzhFnoJfDo9dQR Video Abstract [ABSTRACT FROM AUTHOR]

Introduction: Soil microbial communities are critical in regulating grassland biogeochemical cycles and ecosystem functions, but the mechanisms of how environmental factors affect changes in the structural composition and diversity of soil microbial communities in different grassland soil types is not fully understood in northwest Liaoning, China. Methods: We investigated the characteristics and drivers of bacterial and fungal communities in 4 grassland soil types with 11 sites across this region using highthroughput Illumina sequencing. Results and Discussion: Actinobacteria and Ascomycota were the dominant phyla of bacterial and fungal communities, respectively, but their relative abundances were not significantly different among different grassland soil types. The abundance, number of OTUs, number of species and diversity of both bacterial and fungal communities in warm and temperate ecotone soil were the highest, while the warm-temperate shrub soil had the lowest microbial diversity. Besides, environmental factors were not significantly correlated with soil bacterial Alpha diversity index. However, there was a highly significant negative correlation between soil pH and Shannon index of fungal communities, and a highly significant positive correlation between plant cover and Chao1 index as well as Observed species of fungal communities. Analysis of similarities showed that the structural composition of microbial communities differed significantly among different grassland soil types. Meanwhile, the microbial community structure of temperate steppe-sandy soil was significantly different from that of other grassland soil types. Redundancy analysis revealed that soil total nitrogen content, pH and conductivity were important influencing factors causing changes in soil bacterial communities, while soil organic carbon, total nitrogen content and conductivity mainly drove the differentiation of soil fungal communities. In addition, the degree of connection in the soil bacterial network of grassland was much higher than that in the fungal network and soil bacterial and fungal communities were inconsistently limited by environmental factors. Our results showed that the microbial community structure, composition and diversity of different grassland soil types in northwest Liaoning differed significantly and were significantly influenced by environmental factors. Microbial community structure and the observation of soil total nitrogen and organic carbon content can predict the health changes of grassland ecosystems to a certain extent. [ABSTRACT FROM AUTHOR]

Forest litter is an important guarantee for maintaining forest soil fertility and circulating material in forest ecosystems. The input of litter plays an important role in soil organic matter formation and biogeochemical cycles in forest ecosystems. However, the production and elements concentrations of Juniperus przewalskii (JP) litter in the Qilian Mountains are still unknown. In this study, we investigated the production of needle, branch and bark, cone, and impurity litters. We determined the concentrations and fluxes of major (K, Mg, Al, and Fe) and trace (Na, Mn, Zn, Cr, Ni, Cu, Pb, Co, Cd, and Ag) elements in needle litter of JP from September 2020 to August 2021. The results showed that the annual litter production was 4040.74 ± 495.96 kg ha−1 a−1. Needle and cone litters were the main components of the total litter production. The major elements (MEs) and trace elements (TEs) fluxes of litter were consistent with the litter production trend. The concentrations and fluxes of MEs and TEs in needle litter decreased in the order: K > Mg > Al > Fe > Na > Mn > Zn > Cr > Ni > Cu > Pb > Co > Cd > Ag. These results have important implications for understanding the migration processes of MEs and TEs in forest ecosystems of the Qilian Mountains. [ABSTRACT FROM AUTHOR]

Nitrogen (N) and phosphorus (P) are key elements essential for plant growth and development. Due to fertilizer application, rapid urbanization, and fossil fuel combustion, nitrogen deposition has reached relatively high levels in China. However, there is still uncertainty regarding the response of N:P stoichiometry in plants and soil to N deposition across different ecosystems. Therefore, a meta-analysis was conducted using 845 observations from 75 studies to evaluate the response of plant and soil N and P concentrations and N to P ratios across various ecosystems to N addition. The analysis revealed that N concentration and N:P stoichiometry in plants and soil increased under N addition, while P concentration in plants and soil decreased on average. Furthermore, the magnitude of these responses was related to the N input rate and experimental duration. Finally, the effects of N addition on N concentration, P concentration, and N:P in terrestrial ecosystems would alter their allocation patterns, depending on relevant climate factors such as mean annual temperature and mean annual precipitation. This study highlights the ecological impact of N addition on the biogeochemical cycling of major elements (N and P) in terrestrial ecosystems in China. These findings are necessary for improving our understanding of the characteristics of plant ecological stoichiometry and helping to plan measures for increasing N deposition. [ABSTRACT FROM AUTHOR]

Ecosystem C:N:P stoichiometry has implications for biogeochemical cycles and ecosystem functioning. However, variations in ecosystem stoichiometry along a forest succession chronosequence and the underlying mechanisms remain unclear. We quantified the C:N:P stoichiometry of different plant organs (leaves, branches, stems and roots), and different ecosystem components (plant community, litter and soil) at four successional stages of a mixed broadleaved–Korean pine (Pinus koraiensis) forest in northeast China. The C:N:P stoichiometry of plant organs and the plant community varied significantly along the succession chronosequence, with variation mainly driven by changes in tree size and plant diversity. The C:N:P stoichiometry in litter and soil did not change with succession. Furthermore, most allometric exponents of C-N-P scaling relationships did not differ among plant organs and ecosystem components and were equal to 1, indicating strong conservatism of the C-N-P stoichiometry scaling relationship in this ecosystem. Our findings highlight the conservative isometric allocation strategies of elements among different organs and ecosystem components during forest succession. Further, they help improve our understanding of the underlying mechanisms for variations in C:N:P stoichiometry from the plant organ level to the ecosystem level. [ABSTRACT FROM AUTHOR]

Globally, the loss of forest vegetation is a significant concern due to the crucial roles that forests play in the Earth's system, including the provision of ecosystem services, participation in biogeochemical cycles, and support for human well-being. Forests are especially critical in mountains environments, where deforestation can lead to accelerated biodiversity loss, soil erosion, flooding, and reduced agricultural productivity, as well as increased poverty rates. In response to these problems, China has implemented a series of ecological restoration programs aimed at restoring forests. However, there is a lack of knowledge as to whether the forest cover is increasing or decreasing, as well as the relative roles played by natural and human factors in forest change. Here, we aim to address these issues by analyzing the pattern and process of the forest changes in Guizhou province, a typical mountainous karst area with a fragile environment in southwestern China, between 1980 and 2018, and evaluating the extent to which these forest changes were influenced by natural and anthropogenic driving forces. Using a temporal sequence of satellite images and a Markov model, we found that the forest cover increased by 468 km2, and that over 33% of the cropland in Guizhou province was converted into forest between 1980 and 2018, with the most significant increases in the forest cover occurring in Qiandongnan. Through correlation analyses and generalized linear model (GLM) regression, we demonstrate that management factors exerted a more significant positive impact on the forest cover than climate change. While the mean annual precipitation and temperature were mostly stable during the period studied, the effects of population and gross domestic product (GDP) on the forest changes weakened, and the influence of land-use change markedly increased. These findings provide valuable information for resource managers engaging in forest protection, deforestation prevention, and ecological restoration in similar regions. [ABSTRACT FROM AUTHOR]

Aims: Ecological stoichiometry plays an important role in biogeochemical cycles and ecosystem functions. However, we know little of fine-root stoichiometry responses to nitrogen (N) addition and whether the responses are similar to those of leaves. Methods: We conducted a field experiment to explore the effects of N addition on carbon: N: phosphorus (C:N:P) stoichiometric ratios and homeostasis in green leaves, fine roots and soil as well as the regulatory effects of plant and soil stoichiometric ratios on forest growth in poplar plantations on the eastern Chinese coast. Results: We found that N addition increased soil organic C (SOC), soil available N and P, and soil N:P and decreased soil C:N. We also found that N addition increased leaf C and N, N:P and C:P of green leaves and fine roots, while it decreased fine root C and P as well as green leaf and fine root C:N. The consistent responses of green leaf and fine root stoichiometry to N addition were attributed to stoichiometric homeostasis. That diameter at breast height (DBH) and fine root biomass (FRB) growth contradicted C:N:P stoichiometry appeared to be because of their different nutrient uptake and utilization efficiencies. Conclusions: The C:N:P stoichiometry of green leaves and fine roots was generally consistent in response to N addition. These findings contribute to our understanding of the biogeochemical cycles of plantation ecosystems and provide basic data for plantation cultivation and management. [ABSTRACT FROM AUTHOR]

Microbes depolymerize soil organic matter to supply themselves with carbon (C), and nutrients such as nitrogen (N) and phosphorus (P). In this way, microbial resource limitations play an important role in characterizing the biogeochemical cycle dynamics of the ecosystem. However, the effect of warming on microbial resource limitations, especially in resource-poor subsoils, remains unclear. Therefore, this study aimed to examine the effects of warming (+ 5 °C above ambient) on microbial resource limitation and explored their relationships with soil physicochemical properties and microbial community structure in topsoil (0–10 cm) and subsoil (40–60 cm) in a Chinese fir (Cunninghamia lanceolata) plantation in southern China. Microbial resource limitation with warming treatment was assessed via vector analysis of soil extracellular enzymatic stoichiometry after two years. We found warming aggravated microbial C limitation in the topsoil but alleviated microbial C limitation in the subsoil, while it shifted the relative nutrient limitation from P limitation to N limitation in the subsoil. Soil microbial C limitation was explained by soil properties (specifically, ammonium nitrogen) in the topsoil while by microbial community composition in the subsoil based on variance partition analysis. The soil microbial nutrient limitation was explained by soil properties in the topsoil and subsoil. The decrease in actinomycetes abundance in the warming treatment may have led to a decreased microbial C limitation in the subsoil. Our study highlighted the differences in warming effects between the topsoil and subsoil. We argue that the microbial resource demand of the subsoil should be further implemented in the study of soil biogeochemistry to improve the prediction of the impact of climate warming on soil C dynamics. [ABSTRACT FROM AUTHOR]

The end‐Permian mass extinction is thought to have greatly altered biogeochemical cycles. The absence of chert and dominance of claystone in low‐latitude pelagic deep‐sea sedimentary sequences of Early Triassic Panthalassa (the deep‐sea chert gap) has been believed to record radiolarian die‐off and consequent decline in biogenic silica production. However, recent studies showed that the upper portion of the deep‐sea chert gap has sedimentation rates higher than bedded chert, meaning that increased clastic inputs, rather than decreased biogenic silica inputs, resulted in the anomalous lithology. In this study, we focus on the Akkamori‐2 section, which preserves a rare sedimentary sequence spanning a large part of the lower portion of the claystone of the deep‐sea chert gap. We obtained conodont fossils that allow correlation with sections in South China that have numerous dated tuffs. By projecting the dates of the tuffs to our measured sections, we show that sedimentation rates of the lower portion of the deep‐sea chert gap is also higher than bedded chert. Hence, most of the deep‐sea chert gap was formed under increased clastic inputs, which likely records disturbance in the terrestrial landscape, probably aridification and/or increased seasonality in arid areas, that lead to elevated dust flux to the pelagic ocean. On the other hand, the idea that the deep‐sea chert gap records lingering effects of the mass extinction event on radiolarians cannot explain the high sedimentation rates of the deep‐sea chert gap. This previously favored scenario needs to be reconsidered, taking into account the burial efficiency of biogenic silica in the Early Triassic ocean, and also effects of increased clay deposition on preservation of radiolarians. [ABSTRACT FROM AUTHOR]

The Cretaceous Era has always been a focus of geologic and palaeoenvironmental studies. Previous researchers believed that the impact of the global carbon cycle represents significant short-term global biogeochemical fluctuations, leading to the formation of a large number of organic rich sediments in the marine environment. During the Turonian, a large number of organic-rich oil shales were deposited in the lakes of the Songliao Basin in the Qingshankou Formation. How the depositional environment affected the formation of oil shales in continental lakes and the characteristics of these oil shales remain controversial. In this paper, through sampling of Qingshankou Formation strata, various testing methods are used to provide a variety of new data to study the characteristics of oil shales and palaeoenvironment evolution history in the Songliao Basin. The research of the sediments in the Qingshankou Formation in the Fuyu oilfield, Songliao Basin, via result analysis revealed that the oil shales possess an excellent oil-generation potential with moderate-high total organic carbon (TOC) levels (0.58–9.43%), high hydrogen index (HI) values (265–959 mg hydrocarbons (HC)/g TOC), high extractable organic matter (EOM) levels (2.50–6.96 mg/g TOC) and high hydrocarbon fractions (48–89%). The sources of the organic matter were mainly zooplankton, red algae and higher plants (including marine organisms). The aqueous palaeoenvironment of the Qingshankou Formation was a saline water environment with a high sulfate concentration, which promoted an increase in nutrients and stratification of the water density in the lake basin. Oxygen consumption in the bottom water layer promoted the accumulation and burial of high-abundance organic matter, thus forming the high-quality oil shales in the Qingshankou Formation. The global carbon cycle, warm-humid palaeoclimate, dynamic local biogeochemical cycling and relative passive tectonism were the most likely reasons for the TOC increase and negative δ13Corg deviation. [ABSTRACT FROM AUTHOR]

A rich of global land use/land cover (LULC) products exist, such as DISCover, FORM-GLC30, CCI_LC, MCD12Q1, etc. These products play an extremely important role in the study of the earth’s biochemical cycles and climate change simulations. However, these LULC products vary in spatial and temporal scale. Scale conversion is one of the effective means to solve this difference, which can realize the spatial matching between different LULC products and complete the effective integration of LULC products with other geographic element products. Due to data acquisition limitations, this study adopted China as a case study for examining the accuracy of upscaling of five LULC products, FORM-GLC30, GLC_FCS30, CCI_LC, MCD12Q1, and CNLUC. The original resolution of FORM-GLC30 and GLC_FCS30 is 30 m, and that of CCI_LC, MCD12Q1, and CNLUCC is 300 m, 500 m, and 1 km, respectively. There are four different upscaling methods of grid center, maximum area, maximum aggregation, and nearest neighbor to amplify the resolution to 1 ∼ 8 km. Within the upscaling experiment, using area change index and Shannon index to assess accuracy of LULC Product upscaling. The results showed that: (1) the rank of the upscaling methods according to upscaling accuracy was nearest neighbor > grid center > maximum area > maximum aggregation. (2) The most suitable scales for upscaling of FORM-GLC30, GLC_FCS30, CCI_LC, MCD12Q1, and CNLUCC are 2 km, 2 km∼6 km, 2 km∼5 km, 2 km, and 3 km∼5 km, respectively. (3) The CNLUCC dataset in China was shown to be suitable for conducting relevant long-term time-series research due to its long time span, high data accuracy, and relatively higher accuracy when upscaled. [ABSTRACT FROM AUTHOR]

Rivers carry large amounts of freshwater and terrestrial material into shelf seas, which is an important part of the global water and biogeochemical cycles. The earth system model or climate model is an important instrument for simulating and projecting the global water cycle and climate change, in which tides however are commonly removed. For a better understanding of the potential effect of the absence of tides in the simulation of the water cycle, this study compared the results of a regional model with and without considering tides, and evaluated the effect of tides on the behavior of three major rivers (i.e., the Yellow, Yalujiang, and Changjiang rivers) water in the eastern shelf seas of China from the perspectives of transport pathways, timescales, and water concentration. The results showed that the tides induced more dispersed transport for the water of the Yellow and Yalujiang rivers, but more concentrated transport for the Changjiang River water. The effect of tides on the transit areas of the Yellow, Yalujiang, and Changjiang rivers was 13 %, 40 %, and 21 %, respectively. The annual mean water age and transit time of the three rivers in the model with tides were several (∼ 2–10) times higher than those in the no-tide model, suggesting that tides dramatically slow the river water transport and export rate over the shelf. By slowing the river water export, tides induced a three-fold increase in river water concentration and a decrease in shelf seawater salinity by > 1. Moreover, the effect of tides on river behavior was stronger in relatively enclosed seas (i.e., the Bohai and Yellow seas) than in relatively open seas (i.e., the East China Sea). The change in the shelf currents induced by tides is the main cause of the difference in the river water behavior between the two model runs. Tides can increase bottom stress and thus weaken shelf currents and decrease the water transport timescales. The improvement in tidal parameterization in the no-tide model in the simulation of river water behavior was very limited. Given the important role of river runoff on the global water cycle and the effect of changes in river water behavior on ocean carbon cycling, it is important to include the tidal effect in earth system models to improve their projection accuracy. [ABSTRACT FROM AUTHOR]

Phosphorus is an essential macronutrient that plays a crucial role in the regulation of the biological productivity and biogeochemical cycling of other biogenic elements. As a large tidal wetland dominated by reeds in Liaoning province, China, the Shuangtai estuary wetland is a unique ecosystem class. To better understand the spatial and temporal distributions of total phosphorus (TP) in the sediments of the Shuangtai estuary wetland during the period of reed growth, eight sampling sites were established within the wetland, approximately 11 to 24 km from Liaohe River. These sites were sampled once a month at multiple sediment depth intervals between April and October in 2018 and 2019, periods of time that corresponded with the reed growth period. An alkali fusion method was used to determine TP in the sediment samples. The results show that sediment TP content of wetland sediments ranged from 0.001 to 0.781 mg/kg, and decreases from southwest to northeast with the increase in sediment depth. The TP content reaches the maximum corresponding to the fastest growth stage of the reeds (June and July), while the minimum occurs in October (i.e., the maturity stage of reeds). The variation law of TP in cross-sectional sediment in the wetland is that the deeper the sediments are, the lower the content; its maximum content occurs in surface soil. The TP content of each site tends to be stable with increasing depth and has a regularly dynamic seasonal variation with the growth of reeds. [ABSTRACT FROM AUTHOR]

Reservoirs and dams are essential infrastructure in water management; thus, information of their surface water area (SWA), water surface elevation (WSE), and reservoir water storage change (RWSC) is crucial for understanding their properties and interactions in hydrological and biogeochemical cycles. However, knowledge of these reservoir characteristics is scarce or inconsistent at the national scale. Here, we introduce comprehensive reservoir datasets of 338 reservoirs in China, with a total of 470.6 km 3 storage capacity (50 % Chinese reservoir storage capacity). Given the scarcity of publicly available gauged observations and operational applications of satellites for hydrological cycles, we utilize multiple satellite altimetry missions (SARAL/AltiKa, Sentinel-3A and Sentinel-3B, CroySat-2, Jason-3, and ICESat-2) and imagery data from Landsat and Sentinel-2 to produce a comprehensive reservoir dataset on the WSE, SWA, and RWSC during 2010–2021. Validation against gauged measurements of 93 reservoirs demonstrates the relatively high accuracy and reliability of our remotely sensed datasets. (1) Across gauge comparisons of RWSC, the median statistics of the Pearson correlation coefficient (CC), normalized root mean square error (NRMSE), and root mean square error (RMSE) are 0.89, 11 %, and 0.021 km 3 , with a total of 91 % validated reservoirs (83 of 91) having good RMSE from 0.002 to 0.31 km 3 and NRMSE values smaller than 20 %. (2) Comparisons of WSE retracked by six satellite altimeters and gauges show good agreement. Specifically, the percentages of reservoirs having good and moderate RMSE values smaller than 1.0 m for CryoSat-2 (validated in 30 reservoirs), SARAL/AltiKa (9), Sentinel-3A (34), Sentinel-3B (25), Jason-3 (11), and ICESat-2 (26) are 77 %, 75 %, 79 %, 87 %, 81 %, and 82 %, respectively. By taking advantages of six satellite altimeters, we are able to densify WSE observations across spatiotemporal scales. Statistically, around 96 % of validated reservoirs (71 of 74) have RMSE values below 1.0 m, while 57 % of reservoirs (42 of 74) have good data quality with RMSE values below 0.6 m. Overall, our study fills such a data gap with regard to comprehensive reservoir information in China and provides strong support for many aspects such as hydrological processes, water resources, and other studies. The dataset is publicly available on Zenodo at https://doi.org/10.5281/zenodo.7251283 (Shen et al., 2021). [ABSTRACT FROM AUTHOR]

As the boundary interface between the atmosphere and ocean, the sea-surface microlayer (SML) plays a significant role in the biogeochemical cycles of dissolved organic matter (DOM) and macronutrients in marine environments. In our study, the optical properties of DOM were compared between the sub-surface water (SSW) and the SML during spring, summer and winter in the East China Sea (ECS) and the Yellow Sea (YS). In addition, photoexposure experiments were designed to compare photochemical degradation processes of DOM between the SML and the SSW. Chromophoric DOM (CDOM), fluorescent DOM, dissolved organic carbon, chlorophyll a (Chl a), picoplankton, nutrients and bacteria were frequently enriched in the SML. The enrichment factors (EFs) of tryptophan-like component 4 were significantly higher than other fluorescence components; the longer wavelength absorption values of CDOM showed higher EFs in the SML, and a more significant relationship between CDOM and Chl a in the SML, indicating that autochthonous DOM was more strongly enriched in the SML than the terrestrial DOM. Higher EFs were generally observed in the SML in the off-shore regions than in the coastal regions, and CDOM in the SML was photobleached more after relatively strong irradiation, as also indicated by the lower percentages of humic-like DOM and lower specific UV absorbance values (SUVA 254) in the SML than the SSW. Compared to the SSW, the elevated nutrients may stimulate phytoplankton growth, biological activity and then production of abundant fresh autochthonous DOM in the SML. Our results revealed a new enrichment model for exploring the air–sea interface environment, which can explain the more autochthonous properties of DOM in the SML than the SSW. [ABSTRACT FROM AUTHOR]

China ranks in the highest position for nitrogen (N) fertilizer consumption in the world. Although N fertilizer use has greatly contributed to the China's food production, this has also caused an unprecedented alteration in the biogeochemical cycles and endangered terrestrial and aquatic ecosystems. Existing use of N fertilizers in China, as shown by digital maps, is usually coarse in resolution and intermittently covered with a biased gridded dataset. Here, we have reconstructed a historical, annual N fertilizer use dataset in China and resampled it to 5km×5km resolution, covering the period from 1952 to 2018 by integrating improved cropland maps. Results showed that most of the N input was directly applied as N-only fertilizer, while the contribution from compound fertilizers has ranged between 16 % and 24 % since 1980. The national total N fertilizer input increased from 0.06 Tg N yr -1 (0.05 g N m -2 yr -1) in 1952 to 31.15 Tg N yr -1 (18.83 g N m -2 yr -1) in 2014 and then decreased to 28.31 Tg N yr -1 (17.06 g N m -2 yr -1) in 2018. Despite the total N input decreasing by 9.1 % (2.84 Tg N yr -1) from 2014 to 2018, the N input from compound fertilizers has increased by 6 % (0.43 Tg N yr -1) during the corresponding period. The previous Food and Agriculture Organization (FAO) data-based N fertilizer products in China overestimated N use in low cropland coverage areas but underestimated N use in high cropland coverage areas. However, our newly reconstructed data have not only corrected the existing biases and improved the spatial distribution but have also shown that vegetable and other crops (e.g., orchards), but not grain crops, are the most intensively fertilized crops in China, implying the importance of quantifying greenhouse gas (GHG) emissions from these croplands. We argue that the reconstructed, spatially explicit N fertilizer use data in this study are expected to contribute to better understanding of biogeochemical cycles, including the simulations of GHG emissions and food production in China. The spatially explicit N fertilizer use and the crop-specific N fertilizer use datasets are available via an open data repository (10.6084/m9.figshare.21371469.v1; Yu, 2022). [ABSTRACT FROM AUTHOR]

As the responsive soil properties, soil microbial fractions and enzymatic activities are often recommended for assessing soil environment. Different flora, silvicultural practices, and anthropogenic activities regulate essential ecosystem processes. They could substantially affect biological properties, nutrient budgets, and biogeochemical cycles at local and regional scales. This study examined how different forest compositions influenced by various anthropogenic activities (land use change, over-exploitation, species translocation) affect soil microbial properties and enzymatic activities, as well as the effects of soil chemical properties on these patterns in important sub-tropical forest ecosystems in Southern China. The research was conducted at Lutou forest research station, located in Yueyang, Hunan Province, China. Soil samples were collected at 0–10, 10–20, and 20–40 cm depths from natural broadleaved forest (NBF), coniferous monoculture plantations (CPF), and mixed forest stand. CPF stands are directly affected by human interference and frequent harvesting practices, whereas mixed forest and NBF stands are naturally grown forests with minimal human interference. Enzymes continually play a positive role in preserving soil health. The results showed that the interaction effect of forest type and soil depth significantly influenced urease, sucrase, and protease activity (all p < 0.001); however, no clear patterns were observed. Soil microbial carbon (MBC) and soil microbial nitrogen (MBN) were remarkably higher in 0–10 cm in mixed forest and NBF stand compared to CPF stand. For the upper soil layer, soil organic carbon (SOC) was higher in mixed forest, whereas, for the remaining two layers, it was observed to be highest in NBF. Moreover, the microbial quotient (MBC/SOC) was considerably higher in NBF forest in all soil layers than in mixed forest and CPF stand. Soil organic carbon (SOC) and soil total nitrogen (TN) had a strong positive relationship with MBC compared to MBN. Our study contributes toward an enhanced understanding of soil enzymatic responses and microbial soil dynamics' biological patterns, controls, and activities in different rural forest ecosystems. [ABSTRACT FROM AUTHOR]

Foliar stable nitrogen (N) isotopes (δ15N) generally reflect N availability to plants and have been used to infer about changes thereof. However, previous studies of temporal trends in foliar δ15N have ignored the influence of confounding factors, leading to uncertainties on its indication to N availability. In this study, we measured foliar δ15N of 1811 herbarium specimens from 12 plant species collected in southern China forests from 1920 to 2010. We explored how changes in atmospheric CO2, N deposition and global warming have affected foliar δ15N and N concentrations ([N]) and identified whether N availability decreased in southern China. Across all species, foliar δ15N significantly decreased by 0.82‰ over the study period. However, foliar [N] did not decrease significantly, implying N homeostasis in forest trees in the region. The spatiotemporal patterns of foliar δ15N were explained by mean annual temperature (MAT), atmospheric CO2 (PCO2), atmospheric N deposition, and foliar [N]. The spatiotemporal trends of foliar [N] were explained by MAT, temperature seasonality, PCO2, and N deposition. N deposition within the rates from 5.3 to 12.6 kg N ha−1 year−1 substantially contributed to the temporal decline in foliar δ15N. The decline in foliar δ15N was not accompanied by changes in foliar [N] and therefore does not necessarily reflect a decline in N availability. This is important to understand changes in N availability, which is essential to validate and parameterize biogeochemical cycles of N. [ABSTRACT FROM AUTHOR]

Marine aerosol is one of the most important natural aerosols. It has a significant impact on marine climate change, biochemical cycling and marine ecosystems. Previous studies on marine aerosols, especially in the South China Sea, were carried out by satellite and shipborne measurements. The above methods have drawbacks, such as low temporal–spatial resolution and signal interference. However, lidar has high accuracy and high temporal–spatial resolution, so it is suitable for high-precision long-term observations. In this work, we obtain marine aerosol data using Mie Lidar in Sansha, an island in the South Chain Sea. Firstly, by comparing boundary layer height (BLH) between Sansha and Hefei, we found that Sansha's boundary layer height has significant differences with that of inland China. Secondly, we compare the aerosol extinction coefficients and their variation with height in Sansha and Hefei. Finally, we obtain hourly averaged aerosol optical depth at Sansha and explore its relation with weather. To analyze the AOD–weather relation, we select three meteorological factors (sea surface temperature, mean sea level pressure and 10 m u-component of wind) based on their feature importance, which is determined by random forest regression. We also analyze the relationship between AOD and the above meteorological factors in each season separately. The results show that there is a strong relation between the meteorological factors and AOD in spring and summer, while there is no clear correlation in fall and winter. These analyses can provide valid data for future researches on marine aerosols in the South China Sea. [ABSTRACT FROM AUTHOR]

At certain nutrient concentrations, shallow freshwater lakes are generally characterized by two contrasting ecological regimes with disparate patterns of biodiversity and biogeochemical cycles: a macrophyte-dominated regime (MDR) and a phytoplankton-dominated regime (PDR). To reveal ecological mechanisms that affect bacterioplankton along the regime shift, Illumina MiSeq sequencing of the 16S rRNA gene combined with a novel network clustering tool (Manta) were used to identify patterns of bacterioplankton community composition across the regime shift in Taihu Lake, China. Marked divergence in the composition and ecological assembly processes of bacterioplankton community was observed under the regime shift. The alpha diversity of the bacterioplankton community consistently and continuously decreased with the regime shift from MDR to PDR, while the beta diversity presents differently. Moreover, as the regime shifted from MDR to PDR, the contribution of deterministic processes (such as environmental selection) to the assembly of bacterioplankton community initially decreased and then increased again as regime shift from MDR to PDR, most likely as a consequence of differences in nutrient concentration. The topological properties, including modularity, transitivity and network diameter, of the bacterioplankton co-occurrence networks changed along the regime shift, and the co-occurrences among species changed in structure and were significantly shaped by the environmental variables along the regime transition from MDR to PDR. The divergent environmental state of the regimes with diverse nutritional status may be the most important factor that contributes to the dissimilarity of bacterioplankton community composition along the regime shift. [ABSTRACT FROM AUTHOR]

Aims: Although the influences of coastal embankments on soil physicochemical properties and carbon (C) and nitrogen (N) cycling have been widely reported, the mechanisms of their effects on soil microbial ecologies remain poorly understood. Thus, the aim of this study was to investigate the variations in the diversity and composition of soil bacterial and archaeal communities between natural and embanked saltmarshes, as well as the determinants that drive these variations. Methods: 16S rRNA gene sequence analysis was performed to assess the impacts of coastal embankments on the bacterial and archaeal communities of native Suaeda salsa, Phragmites australis, and invasive Spartina alterniflora saltmarshes on the east coast of China. Results: Embankments were found to significantly decrease the microbial diversity of S. alterniflora salt marsh, while increased the OTU richness of P. australis salt marsh. Embankments modified the compositions of soil bacterial and archaeal communities in both S. alterniflora and P. australis salt marshes. However, variations in the microbial diversity, richness, and community compositions between the native and embanked S. salsa salt marshes were insignificant. Conclusions: These results were possibly because the embankment significantly altered soil nutrient substrate levels (e.g., soil organic C and N) by variations in plant residues and soil physiochemical properties in S. alterniflora and P. australis saltmarshes, whereas the embankment had no observable changes in the soil nutrient substrate and plant residue in S. salsa saltmarsh. This study also elucidated the effects of coastal embankments on biogeochemical cycles, and highlighted their potential hazards to ecosystems. [ABSTRACT FROM AUTHOR]

Iron (Fe) is an important element for the terrestrial and marine ecosystems through its biogeochemical cycling on the Earth's surface. China has a long rice cultivation history, with extensive rice distribution across many types of paddy soils. Paddy soils are the largest anthropogenic wetlands on earth with critical roles in ecosystem functions. The periodic artificial submergence and drainage during paddy soil evolution result in significant changes in soil moisture regime and redox conditions from the natural soils, which facilitate the increase of Fe solubility and mobilization. However, there is a lack of systematic assessment on the magnitude of the migration and loss amount of Fe from paddy soils. In order to quantify the Fe loss and assess the dynamic evolution of Fe in the soils after rice cultivation, seven paddy soil chronosequences derived from different landscapes (bog, plain, terrace) and parent materials (acidic, neutral, calcareous) with cultivation history from 0 to 2,000 yr were studied. Results showed that the rates and trajectories of Fe evolution showed distinct patterns among the studied seven paddy soil chronosequences. However, net losses of Fe from 1 m soil depth occurred at all studied paddy soil chronosequences regardless of the original landscapes and parent materials. Fe in the paddy soils derived from the calcareous lacustrine sediments in the bog area showed a slight accumulation during the initial stage (50 yr) of paddy cultivation, with a loss rate of 0.026 kg m−2 yr−1 during the 50- to 500-yr time period. For the paddy soils developed on the calcareous marine sediments in the plain area, Fe evolution was dominated by the internal movement in soil profiles through coupled reducing-eluviation reactions in the surface horizons and oxidation-illuviation in the subsurface horizons within 1,000 yr of paddy cultivation, with an averaged net loss rate of 0.029 kg m−2 yr−1 during the 1,000- to 2,000-yr time period of rice cultivation. In contrast, Fe in the paddy soils derived from the acidic and neutral parent materials in the plain and terraced upland areas was rapidly lost during the initial stage of paddy cultivation, with a maximum loss rate of 1.106 kg m−2 yr−1, while the Fe loss rate decreased gradually with increasing paddy cultivation age. Soil pH, CaCO3, and organic matter contents of the original soils, the length of time of paddy cultivation, landscape types and positions, and changes in soil moisture regime and redox condition induced by artificial submergence and drainage were the main factors controlling the rates and trajectories of Fe loss during paddy soils evolution. The amount of Fe loss caused by rice cultivation at the national scale was estimated based on the data collected from this study and the literature. The Fe loss fluxes of paddy soils in China were about 46.4–195.7 Tg yr−1, and the amounts of Fe losses from paddy fields nationwide were about 5,121.5–9,412.2 Tg. Quantifying Fe loss from paddy fields is important to scientifically assess the impact of paddy cultivation on the Fe biogeochemical cycle. [ABSTRACT FROM AUTHOR]

A key scientific issue in the study of the Anthropocene is the determination of the corresponding stratigraphic marker in geological archives. The arid and semi-arid regions of Asia are the second largest dust source on Earth, and their release, transport and deposition of dust affect global climate change, as well as marine and terrestrial biogeochemical cycles. Over the past ∼2000 years, human activity has outpaced natural climatic variability as the dominant control of dust storms in northern China. Thus, exploring the potential of anthropogenic Asian dust as a marker of the Anthropocene and its impacts on lake ecosystems may contribute to an improved definition of the characteristics and timing of the Anthropocene. In this context, we measured spectrally-inferred chlorophyll a from the sediments of an undisturbed alpine lake in northern China, and compared the results with dust storm data from the same cores and with regional climatic records. Asian dust is a widely distributed, globally significant signal of human activity, and it is also well preserved in various geological archives; hence, we propose anthropogenic dust can be considered as a potential marker of the Anthropocene. Anthropogenic dust signals in stratigraphic records during the past ∼2000 years differ substantially from those during the early and middle Holocene, which demonstrates that, at least since ∼2000 years ago, human activity has exceeded the natural forcing of dust transport in northern China. We therefore propose that there are spatial and temporal differences in the onset of the Anthropocene, as defined by anthropogenic dust deposition, which is therefore time-transgressive. Our spectrally-inferred chlorophyll a record is consistent with dust storm activity over the past ∼2000 years (except since the 1950s), suggesting that anthropogenic dust storms were the dominant control on lake primary production. Prior to the 1950s the interactions of the East Asian summer monsoon (EASM), human activity, dust storms and lake ecosystems resulted in a shift from a pattern in which "human activity outpaced the EASM as the dominant control on the Earth surface system" to one in which, after the 1950s, "human activity became the dominant factor influencing the EASM and the Earth surface system". In the future this pattern may trend towards one in which there is the "sustainable development of humans and the environment". We suggest that, in order to better understand the interactions of human activity, climate and environment, future research on the Anthropocene should focus on its time-transgressive characteristics and regional differences, in addition to the "Great Acceleration". [ABSTRACT FROM AUTHOR]

Background: Soil microorganisms in the thawing permafrost play key roles in the maintenance of ecosystem function and regulation of biogeochemical cycles. However, our knowledge of patterns and drivers of permafrost microbial communities is limited in northeastern China. Therefore, we investigated the community structure of soil bacteria in the active, transition and permafrost layers based on 90 soil samples collected from 10 sites across the continuous permafrost region using high-throughput Illumina sequencing. Results: Proteobacteria (31.59%), Acidobacteria (18.63%), Bacteroidetes (9.74%), Chloroflexi (7.01%) and Actinobacteria (6.92%) were the predominant phyla of the bacterial community in all soil layers; however, the relative abundances of the dominant bacterial taxa varied with soil depth. The bacterial community alpha-diversity based on the Shannon index and the phylogenetic diversity index both decreased significantly with depth across the transition from active layer to permafrost layer. Nonmetric multidimensional scaling analysis and permutation multivariate analysis of variance revealed that microbial community structures were significantly different among layers. Redundancy analysis and Spearman's correlation analysis showed that soil properties differed between layers such as soil nutrient content, temperature and moisture mainly drove the differentiation of bacterial communities. Conclusions: Our results revealed significant differences in bacterial composition and diversity among soil layers. Our findings suggest that the heterogeneous environmental conditions between the three soil horizons had strong influences on microbial niche differentiation and further explained the variability of soil bacterial community structures. This effort to profile the vertical distribution of bacterial communities may enable better evaluations of changes in microbial dynamics in response to permafrost thaw, which would be beneficial to ecological conservation of permafrost ecosystems. [ABSTRACT FROM AUTHOR]

Ephemeral plants are a crucial vegetation component in temperate deserts of Central Asia, and play an important role in biogeochemical cycle and biodiversity maintenance in desert ecosystems. However, the nitrogen (N) and phosphorus (P) status and interrelations of leaf-root-soil of ephemeral plants remain unclear. A total of 194 leaf-root-soil samples of eight ephemeral species at 37 sites in the Gurbantunggut Desert, China were collected, and then the corresponding N and P concentrations, and the N:P ratio were measured. Results showed that soil parameters presented no significant difference among the eight species. The total soil N:P was only 0.116 (geomean), indicating limited soil N, while the available soil N:P (4.896, geomean) was significantly larger than the total N:P. The leaf N (averagely 30.995 mg g−1) and P (averagely 1.523 mg g−1) concentrations were 2.64–8.46 and 0.93–3.99 times higher than the root N (averagely 8.014 mg g−1) and P (averagely 0.802 mg g−1) concentrations, respectively. Thus, leaf N:P (averagely 21.499) was 1.410–2.957 times higher than root N:P (averagely 11.803). Meanwhile, significant interspecific differences existed in plant stoichiometric traits. At the across-species level, N content scaled as the 3/4-power of P content in both leaves and roots. Leaf and root N:P ratios were mainly influenced by P; however, the leaf-to-root N or P ratio was dominated by roots. Leaf and root N, P contents and N:P were generally unrelated to soil nutrients, and the former presented lower variation than the latter, indicating a strong stoichiometric homeostasis for ephemerals. These results demonstrate that regardless of soil nutrient supply capacity in this region, the fast-growing ephemeral plants have formed a specific leaf-root-soil stoichiometric relation and nutrient use strategy adapting to the extreme desert environment. [ABSTRACT FROM AUTHOR]

Dam construction is widespread, changing the hydrological and biogeochemical conditions and thereby the bacterial communities in the rivers of the earth. To date, knowledge is lacking about bacterial communities in cascade reservoirs. Here, we investigated the bacterial communities and potential functions of nine cascade hydropower reservoirs in 1290 km of the upper Mekong River (Lancang River in China). Along the reservoir cascade, the water temperature, rather than the presence of dams, was the main cause for the geographical patterns of bacterial community composition. Within a reservoir, significant spatial differences in sediment bacterial communities were observed between the tail, middle, and head of a reservoir. The differences in sediment properties resulted by flow velocity‐sieved sedimentation from the tail to head of a reservoir caused the spatial variation in sediment bacteria communities, forming potential hotspots for biogeochemical cycling in the middle of the reservoir. In contrast, unlike in deep lakes and deep single reservoirs, the bacterioplankton community composition had no distinctly layered features in the deep cascade reservoirs, because density‐induced underwater currents and convection resulting from hydropower production reduced the vertical hydro‐environmental gradients. This study provides a novel perspective on the processes affecting the distribution and function of bacterial communities in river‐reservoir cascades, and is a first step toward forecasting the consequences of microbially mediated biogeochemical cycling in existing and future reservoirs worldwide. [ABSTRACT FROM AUTHOR]

Soil microbes play a fundamental role in maintaining nutrient biogeochemical cycles. To understand the distribution of soil bacterial communities on grassland plateaus, high-throughput sequencing was used to compare bacterial communities in soils from swamp meadows (SM), alpine meadows (AM), alpine steppes (AS), and desert steppes (DS) at the eastern edge of the Qinghai–Tibetan Plateau (QTP) in China. We then compared response to nitrogen addition between SM and DS soils in microcosms. Bacterial α-diversity decreased from SM > AM > AS > DS. Variations in soil properties across grassland types was associated with different soil bacterial communities corresponding to bacterial species associated with nutrient cycles to those associated with degradation. Soil moisture, pH, and total phosphorus were the main drivers of these differences. Nitrogen addition decreased bacterial diversity but had inconsistent effects on soil bacterial communities in SM and DS, which may also indicate that different alpine grassland soil types have unique bacterial communities. Alpine grassland degradation significantly affects bacterial communities, and the response to nitrogen addition depends on the alpine grassland type. These results allow for better predictions of soil bacteria community-level responses to geochemical and environmental change in alpine areas. [ABSTRACT FROM AUTHOR]

Epiphytic bacteria on the surfaces of submerged macrophytes play important roles in the growth of the host plant, nutrient cycling, and the conversion of pollutants in aquatic systems. A knowledge of the epiphytic bacterial community structure could help us to understand these roles. In this study, the abundance, diversity, and functions of the epiphytic bacterial community of Myriophyllum spicatum collected from Baiyangdian Lake in June, August, and October 2019 were studied using quantitative PCR (qPCR), high-throughput sequencing, and the prediction of functions. An analysis using qPCR showed that the epiphytic bacteria were the most abundant in October and the least abundant in August. High-throughput sequencing revealed that Proteobacteria, Gammaproteobacteria, and Aeromonas were the dominant phylum, class, and genus in all the samples. The common analyses of operational taxonomic units (OTUs), NMDS, and LDA showed that the epiphytic bacterial communities were clustered together based on the seasons. The results of a canonical correlation analysis (CCA) showed that the key water quality index that affected the changes of epiphytic bacterial community of M. spicatum was the total phosphorus (TP). The changes in abundance of Gammaproteobacteria negatively correlated with the TP. Predictive results from FAPROTAX showed that the predominant biogeochemical cycle functions of the epiphytic bacterial community were chemoheterotrophy, nitrate reduction, and fermentation. These results suggest that the epiphytic bacterial community of M. spicatum from Baiyangdian Lake varies substantially with the seasons and environmental conditions. [ABSTRACT FROM AUTHOR]

Resource allocation, including biomass allocation and nutrient allocation between different organs in a plant, reflects the trade‐off in partitioning between above‐ground and below‐ground organs and the growth and adaptation strategies of plants in a changing environment. Although varied resource allocation patterns among different organs in different functional groups of terrestrial plants have been found, few studies have focused on freshwater ecosystems.In this study, to clarify biomass and nutrient allocation strategies and their responses to environmental factors, we collected and analysed 2,162 samples from 262 aquatic plant communities (including emergent plants, floating‐leaved plants and submerged plants) in various aquatic habitats in north‐eastern China.The results showed that the root/shoot (R/S) ratios of the three aquatic plant life‐forms were significantly different, and the trend showed that the ratio values for the three plant life‐forms occurred in the following order: emergent plants > floating‐leaved plants > submerged plants. There were obvious scaling relationships between above‐ground biomass, N (or P or N:P ratios) and below‐ground biomass, N (or P or N:P ratios), but their scaling exponents changed among different aquatic plant life‐forms. The allocation of biomass and nutrients between different organ responses to environmental factors was not consistent for the different life‐forms of aquatic plants. The partial least squares path model revealed that plant stoichiometric characteristics are important direct drivers of biomass production. Climate conditions, water properties and soil nutrients indirectly affect biomass through effects on plant stoichiometric characteristics.Synthesis. Our study demonstrates that global climate change may affect water properties and soil nutrients, influence plant stoichiometric characteristics and affect aquatic plant growth, further altering aquatic plant community structure and biogeochemical cycles. [ABSTRACT FROM AUTHOR]

The northern South China Sea is subject to an increasing influence of aerosol loading, particularly over the past decades owing to the fast economic growth of mainland China. To study the response of the coastal phytoplankton community to atmospheric deposition, we performed onboard microcosm experiments at various coastal regions of the northern South China Sea, including a river plume zone and the two major upwelling zones. We found that the addition of aerosol and rainwater significantly increased the micro‐phytoplankton size‐fraction by 2.3–5.4‐folds regardless of the type of preexisting nutrient limitation in the phytoplankton community. There were three types of distinct responses to the manipulation additions observed: positive, negligible, or even negative effects. A significant inhibition effect (27–74% decrease) in the Qiongdong upwelling zone could be attributed to elevated metal toxicity on the phytoplankton community seeding from the subsurface after it had been brought up to the surface due to an outcrop of the thermocline. While Prochlorococcus growth was uniformly inhibited by the additions, both positive and negative effects were observed for the remainder of the picoplankton community. P‐limited Synechococcus was stimulated by aerosol and rainwater additions (1.2–2.8‐folds increase), whereas N‐limited Synechococcus was inhibited (decreased by 9–28%). Our results suggest that coastal phytoplankton responses to atmospheric depositions are regulated by both the fertilizing effects of aerosol nutrients and the toxic effects of aerosol metals. Our findings highlight the critical role of atmospheric depositions on spatial change of phytoplankton biomass and community structure in the coastal ocean, which could greatly affect ecosystem dynamics and biogeochemical cycles of the shelf sea. [ABSTRACT FROM AUTHOR]