The study of aeolian deposition in China is very important for paleoclimate and paleoenvironment. In order to deeply understand the current status and development trend of Chinese aeolian deposition research in recent years, we used Web of Science as the data source and 932 research papers from 2000 to 2023 as the research object, and adopted the bibliometric analysis method, utilizing tools such as CiteSpace and Biblioshiny, to carry out the co-citation analysis, keyword analysis and collaboration analysis. The bibliometric analysis was used to analyze co-citation, keyword analysis and collaboration analysis. It is found that: Research output in the field of wind-dust accumulation shows an overall upward trend, particularly over the past decade; the research hotspots focus on the sources, deposition environments, driving factors and environmental significance of wind-dust accumulation in different regions, and the characteristic and prominent directions are monsoon climate evolution, climate variability and monsoon-drought environment, etc.; in terms of international collaboration and impact, the leading countries in publication volume within this field are China, the United States, and Japan; The main research institutions are Chinese Academy of Sciences, the University of Chinese Academy of Sciences, Lanzhou University, etc. In the future, it is necessary to strengthen the research on the controversy over the provenance and chronological differences, and to deepen the research on the transport dynamics and mechanism, so as to make greater contributions to the environmental evolution and the evolution of human civilization.
The Yellow River Estuary, situated in a land-sea transition zone, is highly sensitive to environmental changes. Understanding the sedimentary environmental characteristics is crucial for exploring regional climate-environmental evolution and supporting high-quality development. Through analyses of AMS14C dating, lithology, particle size, magnetic susceptibility, TOC/TN, and other proxies on the Kenli borehole from the Yellow River estuary, the sedimentary environmental characteristics of this region have been reconstructed since the Holocene. The results indicate that the KL core spans the past 9.28 ka, revealing five distinct stages in the Holocene sedimentary environment of the Yellow River Estuary. From approximately 9.28 to 8.15 cal ka BP: Sediments exhibited coarser grain size, higher magnetic susceptibility, and higher TOC/TN ratios, indicating intense terrigenous input within a deltaic depositional environment dominated by fluvial processes. From approximately 8.15 to 7.37 cal ka BP: Grain size became finer and TOC/TN ratios decreased, suggesting an increased input of warm-humid aquatic organic matter. During this period, the area transitioned to a littoral sedimentary environment. From approximately 7.37 to 3.19 cal ka BP: Terrigenous sedimentation gradually increased, marked by frequent grain size fluctuations, declining magnetic susceptibility, and mixed organic matter sources. This reflects the onset of a transition to a terrestrial sedimentary environment. From approximately 3.19 to 0.82 cal ka BP: Persistent terrigenous sedimentation occurred alongside stable grain size and rising magnetic susceptibility. These changes indicate a cooling climate and intensified human activity. From approximately 0.82 cal ka BP to present: Uniform lithology, low organic matter content, and high magnetic susceptibility point to the establishment of a relatively stable terrigenous sedimentary system. This study elucidates the environmental evolution of the Yellow River estuary under the combined influences of natural processes and human activities. These findings have significant implications for predicting future regional environmental changes.
Chronological Study is of Great Significance in Exploring Environmental Changes in the Salawusu River Basin. This study utilized single-grain optically stimulated luminescence (OSL) dating techniques to determine the ages of quartz and potassium feldspar minerals from surface sediment samples collected in the Salawusu River. For the two collected samples, the quartz and potassium feldspar mineral fractions were separated. The equivalent dose (De) of the quartz was measured using the single-aliquot regenerative-dose (SAR) procedure. The De of the potassium feldspar was measured using the post-infrared infrared stimulated luminescence (pIRIR) procedure with a two-step infrared excitation protocol. The test results indicate that: (1) The quartz OSL signals from the tested samples were very weak, making quartz unsuitable for OSL dating of fluvial sediments from this location. (2) The pIRIR170 protocol was applied to measure the De of potassium feldspar in the two modern samples (SCH-QT-M01 and LJB-MR-01). Most recycling ratios fell between 0.9 and 1.1, and recuperation was generally less than 10%, indicating the reliability of the measurement procedure. (3) The anomalous fading rates (g-values) for the IRSL50 signals of the two samples were 1.88±0.11 and 1.79±0.17, respectively. The anomalous fading rates for the pIRIR170 signals were 0.18 ± 0.07 and 0.19 ± 0.15, respectively, indicating that anomalous fading of the potassium feldspar pIRIR170 signal is negligible. (4) The Minimum Age Model (MAM) ages obtained from the potassium feldspar pIRIR170 signals for the two river surface sediment samples were 90 ± 20 years and 50±10 years, respectively. This indicates that the surface sediments of the Salawusu River primarily consist of mixed accumulations deposited over the last century by processes including flowing water and wind. Considering the associated errors, these results demonstrate that the single-grain potassium feldspar pIRIR170 technique is suitable for dating fluvial sediments in the Salawusu River.
As significant source of greenhouse gases, urban river has wide ranges of N2O and CH4 emission rates because of various environmental conditions and different monitoring methods. A typical unban river, the Wei River in Xinxiang City, was selected to monitor the emission rates of N2O and CH4 at the river water—air interface in spring. Both the floating static chamber method and the diffusion model method were applied to conduct the experiment, and comparison between their results was carried out. The influences of water quality and other environmental factors on the emission rates were also analyzed. The results showed that the Wei River behaved as continued source of N2O and CH4, and both the concentrations and the emission rates of N2O were significantly related to nitrate (P<0.01), ammonia (P<0.01), dissolved organic carbon (P<0.01) and redox potential (P<0.05), and the air temperature and dissolved inorganic carbon were only related to N2O emission rates (P<0.05). The concentrations of CH4 were significantly correlated to dissolved organic carbon (P<0.01) and redox potential (P<0.05), while CH4 emission rates were significantly correlated to water temperature (P<0.01) and redox potential (P<0.01). The average daily emission rates of N2O and CH4 obtained by the diffusion model method were 59.15% and 68% of those measured using the floating static chamber method, respectively. Moreover, the emission rates of the gases calculated from the two methods were significantly correlated (P<0.01), demonstrating that the diffusion model method is suitable for shallow and slow urban rivers. The daily average emission rates obtained by the diffusion model method were 59.15% (N2O) and 68.74% (CH4) of the static box method, respectively, reflecting that the contribution of CH4 bubbling emission in the Wei River was low in spring, while N2O may have a higher bubbling emission flux.
As an important ecological barrier in the Yellow River Basin and a key hub of the Eastern Route of the South-to-North Water Diversion Project, the sediment organic carbon distribution in Dongping Lake is of great significance to the regional carbon cycle and water quality security. This study analyzed 74 surface sediment samples from Dongping Lake for total organic carbon (TOC), total carbon (TC), total nitrogen (TN), and grain size, to explore the spatial distribution characteristics, sources, and influencing factors of organic carbon in the lake. The results showed that the organic carbon mass fraction in the surface sediments of Dongping Lake ranged from 0.31% to 6.56%, with an average of 2.42%, exhibiting a decreasing trend from west to east. The w(TOC)/w(N) ratio ranged from 6.03 to 11.54, with an average of 7.44, indicating that the main source of organic matter in Dongping Lake is endogenous organic matter, mainly from aquatic plants and algae. The distribution of surface organic matter in Dongping Lake shows obvious spatial differences, and its sedimentation process is mainly affected by human activities, grain size, and the underwater topography of the lake, showing a decreasing trend from west to east. The research results can provide a scientific basis for the management of the carbon pool and ecological protection of Dongping Lake.
The grain size characteristics of lake sediments serve as a critical proxy for reconstructing sedimentary dynamics and paleoenvironmental changes. However, traditional studies often rely on bulk grain size parameters, which may obscure signals from mixed depositional processes. This study focuses on the multi-modal grain size distribution of sediments from a 49-cm core (SSL core) collected at the center of the Thirty-Six Feet Lake, a small closed lake on Pingtan Island, Fujian Province, China. Using laser granulometry and log-normal distribution modeling, three distinct grain size components were identified: a dominant coarse-grained component (mode sizes of p1: 25~70 μm), a secondary fine-grained component (mode sizes of p2: 5~12 μm), and a minor ultra-fine component (mode sizes of p3: 0.6~1.5 μm). Unlike typical lake-center deposits in larger lakes, where fine-grained components dominate, the SSL core exhibits a "lakeshore-like" depositional pattern, with p1 accounting for 48.6%~70.9% of the total volume. This anomaly is attributed to the lake's small size (2.1 km2), shallow depth (mean 4~5 m), and proximity to the shore (0.37 km from the center), which enhance hydrodynamic intensity at the lake center, enabling coarse particles to be transported via saltation. The p2 component is deposited under weaker hydrodynamics through suspension. By deconvoluting multi-modal grain size components, this study demonstrates that separating depositional signals from mixed processes enhances the accuracy of environmental proxies. The findings underscore the necessity of considering lake morphology and hydrodynamic conditions when interpreting grain size data, particularly for small lakes. This work provides a theoretical framework for optimizing sedimentological proxies in paleoenvironmental reconstructions and highlights the unique sedimentary dynamics of small closed lakes.
Mudflat afforestation is an important measure to restore mangrove wetlands and improve blue carbon function in the coastal zone. Yet, the biomass, soil carbon sink capacity and influence of factors for the early stage of artificial mangroves still remain unclear. In this study, the artificially Laguncularia racemosa communities (planted for 3-5 years) in the estuary of Changsha Bay, Haifeng, Guangdong Province, was selected. The characteristics of mangrove communities in different forest ages and sections (near-land, transitional, and near-sea) was investigated and soil core samples from 0 to 100 cm in depth was collected. The growth status, biomass accumulation, and allocation characteristics of different organs of Laguncularia racemosa communities in different forest ages and sections, as well as the horizontal and vertical distribution patterns of soil carbon storage and their influencing factors were analyzed. The results showed that the growth status of Laguncularia racemosa communities deteriorated gradually with decreasing tidal height from land to sea. In the near-land section, Laguncularia racemosa accumulated biomass by inhibiting seedling emergence with RSD of -6 879 plants·hm⁻²·yr⁻¹ and rapidly increasing the diameter at breast height of initially planted trees with RDBH of 8.4 mm·yr⁻¹. In the near-sea section, Laguncularia racemosa maintained population stability and biomass accumulation by increasing the number of seedling propagules with RSD of 6 784 plants·hm⁻²·yr⁻¹. The proportion of annual increase in stem biomass of Laguncularia racemosa from sea to land increased from 26.58% to 41.91%, which enhanced intraspecific competitive advantage. The proportions of annual increase in root and leaf biomass of Laguncularia racemosa from land to sea increased from 32.93% and 5.69% to 40.15% and 16.16%, respectively, which increased resistance to wind and waves and survival rate. Due to the slow growth and metabolism of young mangrove plants at the early stage of restoration, soil carbon storage was less influenced by plant growth. The soil organic carbon density showed little variation horizontally, with an average value of 81.42±3.79 t·hm⁻², but decreased gradually with depth. It was significantly influenced by soil bulk density, organic carbon mass fraction, moisture content, nitrogen, phosphorus, and other soil physicochemical properties. As the increase of mangrove restoration process, the influence of plant growth on mangrove biomass and soil carbon storage will gradually increase.
Fengshui ponds, a type of semi-enclosed static water body artificially excavated or modified, hold unique cultural significance in the Lingnan region. Heavy metal contamination in sediments of rural fengshui ponds (water ponds for geomantic purposes) is crucial for ecological security construction. This study focuses on a typical rural Fengshui pond in Guangdong Province, where water quality ecological restoration has been conducted in recent years. To evaluate the effectiveness of ecological restoration, sediment cores and surface samples were systematically collected. Concentrations of heavy metals (Cr, Mn, Co, Cu, Zn, As, Pb) were determined using ICP-MS. The pollution degree, ecological risk, and health risk were comprehensively assessed using the geo-accumulation index (Igeo), potential ecological risk index (RI), and human health risk assessment models, respectively. Pollution sources were explored via Pearson correlation analysis. The results indicated that concentrations of all measured heavy metals in the sediment cores were significantly higher than the continental crust background values, exhibiting an increasing trend from the bottom to the top layer. Significant positive correlations (r>0.500, P<0.001) among Zn, Mn, As, Co, Cu, and Pb suggested a common source. Analysis of surface sediments from designated restoration zones and untreated controls revealed that the average concentrations of Co, Cu, Zn, As, and Pb in the restoration zones significantly decreased over time, indicating that aquatic phytoremediation had effectively reduced the load of these target heavy metals. As and Pb were identified as the primary enriched pollutants, posing the highest ecological risks. Health risk assessment identified Cr, Mn, and As as the main contributing factors, with dermal contact being the dominant exposure pathway. Children faced higher health risks than adults. This study addresses a research gap in the evaluation of remediation effects in small-scale, culturally significant artificial water bodies, providing a scientific basis for using aquatic plant remediation technology to manage heavy metal pollution in Fengshui ponds, control pollution input and accumulation, and mitigate ecological risks
Continental red beds serve as crucial archives for paleoclimatic and paleoenvironmental data, facilitating analog studies of ancient environments and planetary geological evolution. Within these deposits, white spots are localized bleached reduction zones that typically appear as grayish-white to gray-green spheroidal, ellipsoidal, or banded structures. In biogeochemistry they preserve signatures of the early deep subsurface biosphere. In addition, their mineralogical and spectral characteristics have potential as indicators in the search for extraterrestrial life. Their genesis has long been debated, involving complex interactions among pore-fluid infiltration, organic matter degradation, and microbial processes. Despite this, the formation mechanism remains a subject of debate, necessitating further quantitative analysis and research. This study employed scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), to conduct a comparative analysis of the elemental and mineralogical compositions of the white patches and surrounding continental red-layer deposits.The XPS results indicate a slightly elevated Fe2+/Fe3+ ratio (~1.00) within the white spots, implying mildly reducing conditions and partial reduction-mobilization of Fe3+. Concurrent enrichment of Al is consistent with feldspar alteration and clay mineralization processes. SEM observations reveal widespread carbonate cementation, chloritization, and alteration of Cr-Fe-Ti-bearing heavy minerals within pore spaces and fractures, reflecting the penetration of acidic reducing fluids. These findings suggest that the formation of white spots resulted from coupled interactions between pore fluids and detrital heavy minerals, with microorganisms likely serving as catalytic agents in local reductive bleaching. The study provides mineralogical and redox evidence for understanding reduction-oxidation dynamics and potential subsurface microbial activity in continental sedimentary environments.
Driven by the dual demands of addressing international situations and enhancing the level of domestic social governance, political geography and its teaching practices have attracted extensive attention. However, the teaching of Political Geography in the stage of higher education still faces challenges such as outdated textbook knowledge, complex and difficult-to-understand concepts and theories for students, and limited integration with ideological and political education. Therefore, this paper puts forward three innovative teaching philosophies including promoting education by research, reasoning by example and integrating political geographical theories with political education in the curriculum. Guided by these new principles, this research has propelled innovations in teaching contents and pedagogical methodologies. Firstly, we enhance the up-to-dateness and comprehensiveness of teaching content by publishing academic papers related to disciplinary concepts and theories and incorporating them into course instruction. Secondly, we improve the comprehensibility and practical relevance of teaching contents through the introduction and analysis of concrete cases. Finally, we strengthen students' political literacy and patriotic commitment by organically integrating ideological and political education into the curriculum. Furthermore, this paper elaborates on the implementation pathways and examines the initial outcomes through the exemplary course "Territory Concept and the Territorial Trap Theory". The pedagogical framework proposed in this study not only enhances the effectiveness of political geography teaching and expands the curriculum system, but also provides new directions and actionable pathways for the reform and practice of higher education.
