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Selenium (Se) is an essential element for humans, playing a critical role in the functioning of the immune system. The global prevalence of dietary Se deficiency is a significant public health concern, largely attributed to the low levels of Se present in crops. The sufficient Se in plants and humans is determined by the presence of stable Se sources in the soil. The Leizhou Peninsula is an important agricultural region in China, but the concentration and spatial distribution of Se in its soils remain unclear. To address this issue, we analyzed Se concentration data from 3333 soil samples collected at the depth of 0–20 cm from the Leizhou Peninsula, covering an area of 13,225 km2. The results indicate that the mean soil Se concentration was 0.50 mg kg−1, with Se-enriched soils being widely distributed. This provides prospects for the development of Se-enriched crops. Using random forest (RF) modeling and correlation analysis, the clay minerals (Fe–Al oxides), chemical index of alteration (CIA), and soil organic carbon (SOC) have been identified as the principal determinants of Se distribution in soil. During the weathering processes of the basalts, Fe–Al oxides serve as a crucial factor in Se accumulation in the red soils. Furthermore, the tropical climate further contributes to increasing the degree of weathering and the proportion of clay minerals and SOC in the soil. Atmospheric deposition derived from marine and precipitation is another important factor that promotes Se flux into soils. In conclusion, the distribution pattern of Se is jointly determined by the weathering process of basalt and climatic conditions. The results of the geographically weighted regression (GWR) analysis revealed that SOC, Al2O3, TFe2O3 and CIA change spatially and exhibit a spatial non-stationarity relationship with Se. This study offers a theoretical foundation and practical guidance for the sustainable development of Se-enriched agriculture and similar climate settings worldwide. [ABSTRACT FROM AUTHOR]

Leizhou Peninsula, a main crop producing area in South China, is majorly restricted by drought in terms of economic development because most of the rivers in this region are unbranched and the capacity of engineering regulation and storage is insufficient. In this paper, the standardized precipitation and evapotranspiration index (SPEI) at different time scales was calculated to analyze the variation characteristics of meteorological drought in the Leizhou Peninsula and to explore the influence of precipitation, temperature and teleconnection factors on the drought in the Leizhou Peninsula. The results show that: ①The frequency of annual drought in the Leizhou Peninsula is close to 20%, and the northern part shows a significant trend of wetting, while the southern part shows no significant trend of wetting. The northern part is more extreme drought-prone.②Precipitation and temperature are significantly correlated with SPEI, with a stronger correlation between precipitation and drought.③There is a significant negative correlation between the ocean Nino index (ONI) and the SPEI of the following year, indicating that ENSO is closely related to drought, and there is a difference in the impact on drought when the eastern and central ENSO warm events occur. The research results can provide references for the Leizhou Peninsula Irrigation District project to be implemented soon.

Copyright of Pearl River is the property of Pearl River Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Grasping the genetic structure ofmarine fish populations is vital for comprehending species connectivity patterns and determining the appropriate spatiotemporal scales for conservation management strategies. Here, we analyzed the population genetics of the Orangefin Ponyfish (Photopectoralis bindus Valenciennes, 1835) by examining a portion of the gene coding for the mitochondrial cytochrome c oxidase subunit I. The aim was to evaluate the haplotype pattern, genetic structure, demographic history, as well as the influence of ecological connectivity through the Qiongzhou Strait on the distribution patterns of this species in the northern South China Sea and the Beibu Gulf. In total, 257 specimens yielded only 13 haplotypes, with the predominant haplotype present at all sampling locations. The analysis revealed a "star-like" haplotype pattern, indicating low levels of both haplotype and nucleotide diversity. Additionally, a small but significant genetic structure was observed between the coastal regions flanking the Leizhou Peninsula. These patterns in the haplotype network and genetic structure may be significantly influenced by contemporary currents, particularly through the connectivity of the Qiongzhou Strait. Tajima's D and Fu's Fs demonstrated pronouncedly negative values, along with a unimodal mismatch distribution, suggested a recent demographic expansion of Photopectoralis bindus during the late Pleistocene, likely influenced by fluctuations in sea levels. [ABSTRACT FROM AUTHOR]

The distribution characteristics of size-fractionated Chlorophyll a (Chl-a) and the environmental factors were studied in the coastal area of the Leizhou Peninsula in January 2022. The result showed that Chl-a ranged from 0.39 to 4.78 mg/m³ (averaging 1.21 mg/m³ ) at the surface and 0.43 to 2.78 mg/m³ (averaging 1.04 mg/m³) at the bottom layer, respectively. The spatial distribution of Chl-a concentration was associated with salinity. High Chl-a concentration was observed in the eastern part of the Leizhou Peninsula characterized by lower salinity, and low Chl-a concentration in Qiongzhou Strait with higher salinity. Nanophytoplankton (2-20 µm) was the dominant contributor, accounting for 61.3% and 63.7% of the total Chl-a at the surface and bottom layer, respectively. Both microphytoplankton (>20 µm) and nanophytoplankton displayed increased Chl-a with the increase in total Chl-a. Salinity, nutrients and temperature appear to influence the phytoplankton size structure in the coastal area of the Leizhou Peninsula. Additionally, the regulation of nutrient varied among phytoplankton of different sizes. This study contributed to our understanding of coastal ecosystem processes and has potential implications for coastal management and monitoring efforts. [ABSTRACT FROM AUTHOR]

Mineral carbonation, which precipitates dissolved carbon dioxide (CO2) as carbonate minerals in basaltic groundwater environments, is a potential technique for negative emissions. The Leizhou Peninsula in southwest Guangdong province has extensive basalt, indicating a promising potential for CO2 storage through rapid mineralization. However, understanding of the basic geological setting, potential, and mechanisms of CO2 mineralization in the basalts of the Leizhou Peninsula is still limited. The mineralization processes associated with CO2 storage at two candidate sites in the area are investigated in this paper: Yongshi Farm and Tianyang Basin (of the dried maar lake). Petrography, rock geochemistry, basalt petrophysical properties, and groundwater hydrochemistry analyses are included in the study. Numerical simulation is used to examine the reaction process and its effects. The results show that basalts in the study areas mainly comprise plagioclase, pyroxene, and Fe–Ti oxides, revealing a total volume fraction exceeding 85%. Additionally, small amounts of quartz and fayalite are available, with volume fractions of 5.1% and 1.0%, respectively. The basalts are rich in divalent metal cations, which can form carbonate minerals, with an average of approximately 6.2 moles of metal cations per 1 kg of rock. The groundwater samples have a pH of 7.5–8.2 and are dominated by the Mg–Ca–HCO3 type. The basalts demonstrate a porosity range of 10.9% to 28.8%, with over 70% of interconnected pores. A 20-year geochemical simulation revealed that CO2 injection dissolves primary minerals, including anorthite, albite, and diopside, while CO2 mineralization dissolves precipitation secondary minerals, such as calcite, siderite, and dolomite. Furthermore, a substantial rise in pH from 7.6 to 10.6 is observed in the vicinity of the injected well, accompanied by a slight reduction in porosity from 20% to 19.8%. Additionally, 36.8% of the injected CO2 underwent complete mineralization within five years, revealing an increasing percentage of 66.1% if the experimental period is extended to 20 years. The presence of abundant divalent metal cations in basalts and water-bearing permeable rocks in the Leizhou Peninsula supports the potential for mineral carbonation in basalts, as indicated by the geochemical simulation results. Additional research is necessary to identify the factors that influence the CO2 mineralization, storage, and sensitivity analysis of basalt in the Leizhou Peninsula. [ABSTRACT FROM AUTHOR]

This study examined the differences in rainfall characteristics and possible mechanisms behind such differences for two typhoons, Nesat (1117) and Kalmaegi (1415), which followed similar paths over the Leizhou Peninsula (LP). Utilizing data from conventional meteorological stations, regional automated weather stations, radar observations, and ERA5 reanalysis, the present study analyzed the distinct patterns of rainfall induced by these typhoons. The results showed that the total rainfall and maximum rainfall of Typhoon Nesat were 1.5 and 2.4 times higher than those of Typhoon Kalmaegi, respectively. The total rainfall of Typhoon Nesat included both rainfall from the typhoon circulation and the typhoon trough, while Typhoon Kalmaegi only had rainfall from the typhoon circulation. The major reasons for such differences were as follows: after the landfall of Typhoon Nesat, the South Asian High and the Subtropical High broke into the eastern and western parts, resulting in a strong high-level divergence over the LP area, and the southwesterly and southeasterly currents converged into the southerly at the low level. Meanwhile, the frontal area facilitated the intrusion of cold air from 850 hPa and below into the typhoon trough of Typhoon Nesat, and the baroclinic effect intensified convection. After the weakening of the typhoon circulation, the low-level convergence in the LP area strengthened again, which in turn created favorable conditions for rainfall and led to the intensification of rainfall in the typhoon trough. By contrast, after Typhoon Kalmaegi made landfall, the LP region was affected by the enhancement and southward movement of the South Asian High and the Subtropical High, and the low-level convergence in the LP area quickly changed to divergence after the weakening of the typhoon circulation. The downward airflow inhibited the development of convection, resulting in minimal rainfall formation in the typhoon trough. Moreover, it was also found that the topography of the LP affected the location of typhoon rainfall centers, which were usually identified on the windward slopes southeast of the LP's three peaks. These results may facilitate the forecasting and diagnosis of typhoon rainfall affecting the LP. [ABSTRACT FROM AUTHOR]

Copyright of New Architecture is the property of New Architecture Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To elucidate the spatial patterns of understory species in fragmented forests adjacent to human settlements, we examined the spatial distribution and intraspecific correlations of three dominant species Mallotus philippensis, Dasymashalon trichophorum, and Psychotria rubra by employing point pattern analysis, which were the top three in terms of importance value in the shrub layer of Fengshui forest in Leizhou Peninsula, Guangdong. The results showed that all the three species were mainly aggregated at the scale of 0-25 m, especially for young trees. The degree of aggregation gradually diminished with increasing age class. The spatial distribution patterns of three species were predominantly influenced by habitat heterogeneity, negative density dependence, and dispersal limitation. They showed positive association among different age classes, especially between young trees and middle age trees and between young trees and adult trees. Therefore, in the ecological restoration process of Leizhou Peninsula, M. philippensis, D. trichophorum, and P. rubra should be planted in clusters at a small scale within the range of 0-25 m, with the degree of clusters depending on plant morphology. For larger scales, a dispersed cultivation approach was advocated. [ABSTRACT FROM AUTHOR]

Quaternary volcanic rocks are widely distributed in the Leizhou Peninsula, but the age of volcanic formation remains controversial. This study used the high-precision laser stepwise heating 40Ar/39Ar method to date the age of volcanic samples from the midwest of the Leizhou Peninsula, and two volcanic cycles were determined by combining the contact relationship with the neighboring strata. Volcanic rocks of the first cycle (Ⅰ) occur as interlayers in the Zhanjiang Formation, only seen in Borehole ZKC12, and the lithology is olivine tholeiite; volcanic rocks of the second cycle (Ⅱ) are the most widely distributed in the study area, unconformably overlaying on the Zhanjiang Formation, with 40Ar/39Ar ages ranging from 2.02 to 0.88 Ma, indicating that they were erupted from the early stage of the early Pleistocene to the end of the early Pleistocene. On the combination of contact relationship with surrounding strata, the second cycle can be further divided into four eruption stages. The first eruption stage (Ⅱ1) has the largest scale and the most extensive area, forming two eruption centers with 40Ar/39Ar age of 2.02±0.03 Ma. The second eruption stage (Ⅱ2) centers in the areas of Guokailing and Beicha with 40Ar/39Ar ages of 1.77±0.03 Ma and 1.70±0.03 Ma, respectively. The eruptional center of the third eruption stage (Ⅱ3) lies at Huoju Farm, and the age of 40Ar/39Ar is 1.51±0.07 Ma. The lithology of the fourth eruption stage (Ⅱ4) is dominated by basaltic lava of overflow phase formed by fissure eruption, and the 40Ar/39Ar age is 0.88±0.14 Ma. The volcanic activity is obviously controlled by NE-trending and NW-trending basement faults. These results provide reliable age data to constrain Leizhou Peninsula’s forming age, eruption periods, and the law of volcanic activity.

Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although the water environment has certain self-purification capability, the natural balance is disrupted, leading to water quality deterioration when the discharge load of wastewater exceeds a certain threshold. This problem implies the urgency of evaluating marine environmental capacity as a necessary parameter for marine sustainable development of marine ecosystems. Through principal component analysis (PCA), clustering, and other methods, we analyzed the average concentration and fluxes of land-sourced pollutants and determined the pollution level around the Leizhou Peninsula. Combined with the Delft3D hydrodynamic numerical model, tidal hydrodynamic forces and pollutants migration and diffusion were calculated. Based on in-situ measured data, the model was validated. The sharing rate method was used to calculate the marine environmental capacity in Zhanjiang Bay and analyzed their impact on seawater eutrophication. The results showed that: (1) The average concentrations of chemical oxygen demand (COD), ammonia nitrogen (NH4+), total nitrogen (TN), and total phosphorus (TP) around Leizhou Peninsula were 22.56 mg/L, 0.69 mg/L, 6.69 mg/L, and 0.69 mg/L, respectively. (2) Six areas (Area A-F) can be divided into, based on the discharge of land-sourced pollutants into the sea area. According to the results of PCA, clustering, and other methods, the average concentration and fluxes of land-sourced pollutants in Area B (i.e. Zhanjiang Bay) were very high. (3) The environmental capacity of Zhanjiang Bay was calculated through Delft3D numerical simulation, and it was found that the COD and TN environmental capacity of 6 sewage outlets exceeded the standard, while the TP environmental capacity of 3 sewage outlets exceeded the standard. (4) According to the statistical research result, most of the Zhanjiang Bay waters has been restricted by nitrogen for over a decade. Therefore, we speculate that although TN environmental capacity exceeds the standard, its impact on eutrophication in Zhanjiang Bay is still limited to a certain extent.

Atmospheric visibility changes in areas near the coast have complex, non-linear and local characteristics. With few near-coastal meteorological observation stations, it has been difficult for fine forecasting operations. In this paper, a multi-station GRU model, a single-station GRU model and a stepwise regression forecast model for 1 h valid, short-impending forecast of near-coastal visibility for the Leizhou Peninsula were constructed, tested and evaluated using a GRU neural network with the national basic meteorological station of Zhanjiang and its surrounding upstream and downstream observations. The results show that compared with the traditional stepwise regression method, the GRU neural network can better identify the spatiotemporal meteorological characteristics of upstream and downstream visibility changes, and the mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2) scores of the multi-station GRU model are significantly better than those of the multiple stepwise regression model. Model structure is crucial to the effectiveness of short-range visibility forecasting, and the introduction of upstream and downstream meteorological features into the visibility short-impending forecasting model can significantly improve the forecasting effectiveness. The multistation GRU model decreased MAE and RMSE by 36% and 29%, respectively, and improved R2 by 30%, compared with the single-station GRU model in a typical case, indicating that the multi-station GRU neural network model has obvious advantages for visibility forecasting and provides a new idea for refining short-impending forecast of near-coastal visibility. [ABSTRACT FROM AUTHOR]

Understanding the effects of land use on soil structure and nutrients is important for soil and water conservation in an ecologically fragile zone. This study was carried out to examine the variability of physicochemical properties in three different land use types: abandoned land (AL), eucalyptus plantation (EP), and road lawn (RL) sites at soil depths of 0–10 and 10–20 cm in the Leizhou Peninsula, a tropical coastal ecologically fragile zone of South China. Soil physicochemical property patterns exhibited extremely significant differences among the three land uses (p < 0.001) at both soil depths. Soil nutrients, natural water content, and total porosity, from high to low, in the different land use types were RL, AL, and EP, while the bulk density, from high to low, was EP, AL, and RL. Soil total nitrogen, total phosphorus, total potassium, available potassium, exchangeable calcium, exchangeable magnesium, and natural water content exhibited significant differences (p < 0.05) among the three land use types at soil depths of 0–10 and 10–20 cm, while no significant changes were detected regarding soil organic carbon, available phosphorus, and total porosity. The correlation between physical and chemical properties at the 10–20 cm depth (R = 0.97, p < 0.001) was closer and more significant than that at the 0–10 cm depth (R = 0.95, p < 0.01). Overuse of land (EP) without a rest in the ecologically fragile zone leads to soil erosion and compaction. Compared with natural restoration (abandoned land), artificial restoration (road lawn) can improve soil nutrient and water status more quickly, but cannot modify the soil organic carbon and porosity in the short term. [ABSTRACT FROM AUTHOR]

Understanding past long-term vegetation responses to regional or even global climate change and forcing mechanisms is essential to future climate change projections. However, due to the lack of long-term terrestrial sedimentary records, there are few studies focusing on vegetation changes in tropical southern China since the last glacial period, especially from the perspective of peat n -alkane records. Here, we have presented a peat core record from the Xialu peatland in the northern Leizhou Peninsula, and n -alkanes were investigated in conjunction with multiple proxy indicators. Our results showed that the organic matter sources were mainly a mixture of aquatic and terrestrial vegetation, with terrestrial vegetation accounting for most of the bulk organic matter composition. From ∼44.1 to 29 cal kyr BP, the organic matter source was mainly dominated by terrestrial vegetation, which corresponds to warm and humid conditions. From 29 to 14 cal kyr BP, the input of the terrestrial vegetation was reduced, the aquatic vegetation input increased, implying cool and dry conditions. From 14 to 9.3 cal kyr BP, the climate gradually became warmer and wetter, and terrestrial vegetation dominated in this area. Overall, the climatic conditions from the Xialu peatland were generally consistent with other records from adjacent areas. Our results suggest that, during the Last Glacial Maximum (LGM), a substantial drop in regional and global sea levels may have been the main cause of drought in tropical southern China on orbital timescales. Meanwhile, several climatic fluctuations on millennial timescales could have been influenced by the variability of the North Atlantic Meridional Overturning Circulation (AMOC) and migration of the Intertropical Convergence Zone (ITCZ). [Display omitted] • n -alkanes were investigated together with multiple proxy indicators. • Terrestrial vegetation accounted for most of the bulk organic matter. • Vegetation changes are mainly regulated by sea level change on orbital timescales. • AMOC and ITCZ affect vegetation and environmental changes on millennial timescales. [ABSTRACT FROM AUTHOR]

Colorful dissolved organic matter (CDOM) is an optically important active substance in marine habitats that feature significant biochemical conservatism. Additionally, CDOM is an important tracer and indicator of pollution status in marine water masses. In this study, we use sampling data collected in September 2020 and May 2021 from the marine areas around the Leizhou Peninsula. This information is combined with the Delft 3D numerical simulation analysis to carry out a study on the relationship between the ag (355) in the marine areas and to determine the regional marine pollution levels. The results show that (1) the nearshore areas of the Leizhou Peninsula in spring and autumn are mainly lightly polluted. Compared with the same period in history, the pollution level has significantly decreased, and the ag (355), DIN, and DIP concentrations show a trend of high near the shore and low far from shore. The peak concentrations are mainly in the Zhanjiang Bay, Qiongzhou Strait, Wailuo Port, Liusha Port and Guangxi Tieshan Port. (2) ag (355) can be used as an indicator to characterize the degree of water pollution in the nearshore waters of the Leizhou Peninsula. In spring, the ag (355) interval of [0.115, 0.200] m−1, [0.201, 0.245] m−1 and [0.246, 0.484] m−1 can be considered clean, lightly polluted, and moderately polluted water, respectively. In autumn, the ag (355) interval of [0.180, 0.275] m−1, [0.276, 0.478] m−1, [0.479, 0.642] m−1, [0.643, 0.921] m−1 can be considered clean, lightly polluted, moderately polluted and heavily polluted water, respectively. (3) The response models between the ag (355) and pollutant dispersion trends were constructed in the Zhanjiang Bay and Tieshan Port. The RMSEs of the ag (355) validation points in the models were lower than 0.12 mg/L, and the MAPEs were lower than 30 %, the pollution traceability of CDOM is verified.

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Mudflats play a vital role in maintaining the dynamic balance between sea and land. To understand the characteristics, sources, and pollution risks of six heavy metals (As, Cd, Cr, Cu, Hg, and Pb) in the coastal mudflats on the Leizhou Peninsula, 257 surface sediment samples were studied using mathematical statistics, correlation analysis, and factor analysis. The results show that the overall concentrations of these heavy metals are low although there are several high abnormal points in the local areas. The strong correlation between these heavy metals indicates that the sources of some of the metals are similar, yet their elemental combinations in different cities (counties) varied. According to the calculated enrichment factor (EF), anthropogenic activity-induced heavy metals were determined in order of decreasing influence: As, Cd, Pb, Cr, Cu, and Hg. The low EF values of Hg indicate that it does not present as a contaminant in the study area, while low values of Cr and Cu from the Lianjiang City suggest that these two metals were also attributed to natural sources. The presence of As, Cd, Cr, Cu, and Pb from the remaining cities (counties) should be influenced by anthropogenic activities. The overall potential ecological risk index indicates that the ecological risks posed by the six analyzed heavy metals to the Leizhou Peninsula mudflats, in order of decreasing risk, are Cd, As, Hg, Pb, Cu, and Cr. It is noteworthy that only Cd in Lianjiang City demonstrated substantial ecological risk. Other examined heavy metals in other cities of the study area showed slight ecological risk. [ABSTRACT FROM AUTHOR]

Effective vegetation restoration plays an important role in maintaining and improving soil nutrients and can promote the fixation of soil organic carbon (SOC) and its fractions in degraded soil areas. To understand the influence of Eucalyptus plantation on SOC and its fractions in severely degraded soil in Leizhou Peninsula, China, vegetation restoration with Eucalyptus (RE: Eucalyptus–shrub ES, Eucalyptus–grass EG, and Eucalyptus–Dicranopteris ED) was chosen as the research object, and natural vegetation restoration without Eucalyptus (RNE: shrub S, grass G, and Dicranopteris D) nearby was used as the control group. SOC and its fractions in different vegetation types were compared and analyzed after sample plot surveys and sample determination, and the driving forces of SOC and its fractions were discussed. SOC, dissolved organic carbon (DOC), microbial biomass carbon (MBC), easily oxidized organic carbon (EOC), and particulate organic carbon (POC) in RE were significantly different from those in RNE, increasing by 194.4%, 36.3%, 111.0%, 141.6%, and 289.9%, respectively. The order of SOC, EOC, DOC, MBC, and POC content in RE was ES > EG > ED. SOC and its fractions were positively correlated with leaf litter cover and biomass, and soil organic matter. SOC, total nitrogen, available nitrogen, total phosphorus, available phosphorus, and enzyme activities were negatively correlated with microbial diversity but were not significantly correlated with soil bulk density and microbial richness. Structural equation modeling analysis results showed that soil enzyme activity was a direct driving force of SOC and its fractions. The input of carbon sources from leaf litter and soil properties were indirect factors that affected SOC and its fractions by affecting microbial characteristics and enzyme activities. Thus, planting Eucalyptus in harsh environments, where natural restoration is difficult, can be an effective measure for early vegetation restoration. [ABSTRACT FROM AUTHOR]

In the present research, a comparative analysis of and a sensitivity test study on a typical local rainstorm in Leizhou Peninsula were conducted using the ERA5 reanalysis data and real data. The results show that the local rainstorm was caused by a thunderstorm cell. The ERA5 data as the data of the initial field can better simulate with high resolution the local rainstorm process, precipitation center, and main precipitation period. The sensitivity test reveals that the key of the local rainstorm over Leizhou Peninsula is the water vapor in the atmosphere. Reduced soil moisture leads to an increase in sensible heat flux and a decrease in latent heat flux. Increased soil moisture leads to an increase in latent heat flux and a decrease in sensible heat flux, but the sum of latent heat flux and sensible heat flux basically remain the same as those in the reference experiment. The local rainstorm is still triggered, so the soil moisture cannot determine whether the local rainstorm is triggered or not. It is only triggered by the magnitude of the sensible heat flux in advance or behind the local rainstorm. Leizhou Peninsula is surrounded by the sea on three sides and the underlying surface is not uniformly heated, so the land serves as a heat source. Together, these factors play a decisive role in triggering the local rainstorm over Leizhou Peninsula. [ABSTRACT FROM AUTHOR]

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Abstract As the second common type of volcanic vent on Earth, maar-diatreme volcanoes and their post-eruptive lacustrine sediments are a main focus of volcanology, palaeolimnology, palaeoclimatology and palaeontology. A number of maar-type volcanoes have been found in Leizhou Peninsula, South China, but little is known about their eruption processes and detailed stratigraphy of the post-eruptive sediments. We present a combined geophysical and geological analysis to study the eruptive history and post-eruptive sediment stratigraphy of a large maar, the elliptical (1.8 × 3.0 km2) Jiudouyang (JDY) maar. The lacustrine stratigraphy revealed by drilling cores shows that the JDY maar lake has three major stages of evolution: (i) deep-lake sedimentary environment characterized by high autochthonous diatom productivity; (ii) shallow lake to swamp with very low water levels, characterized by a high total organic carbon (TOC) and abundant wood fragments; and, (iii) intermittent shallow lake and alluvial deposits composed of clay minerals and sand. The electrical resistivity tomography (ERT) values and lithological features are highly consistent, which clearly reveal the presence of ca. 50 m thick lacustrine sediments, directly underlain by a ca. 70 m thick basaltic lava rather than diatreme breccia in the crater. This infill sequence implies an alternation of eruption style from phreatomagmatic to Strombolian and/or lava flow, due to high magma flux and ascent rate of the Hainan Plume during the middle Pleistocene. The ERT data also reveal the initial phreatomagmatic crater floor at ca. 120 m depth. The initial crater had a large diameter/depth ratio (ca. 17), with an elongated shape (major axis to minor axis = 0.6), implying possible lateral vent migration during the eruption. A significant erosion under tropical weathering condition during the last few hundred thousand years, accounted for the large size of the maar crater. The study provides insights into the eruptive history and post-eruptive evolution of a large maar, as well as the spatial distribution of the lacustrine sediments.

Amphioctopus aegina is an important fishery resource in the coastal waters of China. In the present study, the genetic diversity and population genetic structure among four populations of A. aegina throughout its distributional range in China were assessed using the mitochondrial cytochrome oxidase 1 (COI) sequences. The results revealed a generally low genetic diversity (Hd: 0.2842-0.6670; Pi: 0.0007-0.0015) in A. aegina populations. The neighbor-joining (NJ) phylogenetic tree and the haplotype networks, as well as the results of the molecular variance (AMOVA) analyses, indicated a shallow phylogeographic structure among the four populations. However, pairwise FST statistics and genetic distance analyses revealed significant (p<0.01) genetic differentiation among Qinzhou and the rest three populations of Zhanjiang, Huizhou, and Dongshan. The demographic history analyses indicated a population expansion in A. aegina, and the role of Leizhou peninsula isolation in shaping the population differentiation. These results would largely enhance our understanding of the genetic structure and hence promote the scientific management of A. aegina fishery resources in coastal waters of China. [ABSTRACT FROM AUTHOR]

This paper explores the adaptive design of historic villages and dwellings in response to the typhoon climate of the Leizhou Peninsula. A field investigation involving 917 historic villages was conducted. The physical features of the villages were superimposed with the visualized spatial trajectories of the cyclones. Case studies were also adopted to reveal their windproofing mechanisms. The results show that villages are safeguarded through systematic approaches. First, planting windbreaks with appropriate densities and locations was a first line of defence. Second, dwellings were arranged to form a dense-alley pattern, through which the windward faces were reduced and rapid drainage was achieved. Third, the courtyard layout, strengthened exterior walls, and a set of roof protection technologies were applied to increase the stability and integrity of the building. Traditional wisdom was identified in that villages and dwellings were built with the philosophy of reducing the possibility of a disaster in an ordinary windstorm situation through appropriate rather than excessive windproof construction to achieve a balance between survival and development under resource constraints. This knowledge complements the traditional technologies of wind protection developed in other regions of the world and has modern significance for building climate-adaptive and environmentally friendly settlements and buildings. [ABSTRACT FROM AUTHOR]

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Total organic carbon (TOC), total nitrogen (TN) and multi-biomarker indexes were analyzed for two sediment cores from the eastern coastal area of the Beibu Gulf (core 45, AMS 14C dated) and Qiongzhou Strait (core 29), South China Sea. The results showed that the TOC and TN content of the samples studied were 0.32–0.62% and 0.02–0.07%, respectively. The hydrocarbons in offshore sediments of Leizhou Peninsula were consisted of biogenic hydrocarbons and petrogenic hydrocarbons. The Core 29 sediments contain more terrigenous organic matter than that of sediments in core 45 due to the difference in hydrodynamic conditions. The composition and distribution of various lipid biomarkers indicate the presence of petrogenic hydrocarbons in the sediments of the whole profile of two sediment cores. There are multiple natural sources of hydrocarbons that could potentially contribute to the petroleum background through oil seeps and erosion of carbon-rich rock outcrops or bitumen deposits. Deep sourced hydrocarbon inputs from the submarine hydrocarbon seepage cannot be excluded. Further study is needed to resolve the specific sources for the petrogenic hydrocarbons and may be significant to petroleum exploration in the study area.

In the background of global warming,drought disasters occur frequently,bringing serious impacts on the natural ecosystem,human production and life and social & economic development.Therefore,it is of great significance to analyze and assess regional drought characteristics and study local drought mitigation and disaster reduction decisions and climate change.Based on the meteorological and hydrological data of 12 sites in Leizhou Peninsula from 1970 to 2019,this paper identifies and evaluates the drought events via standardised precipitation-evapotranspiration index (SPEI) and run theory,and analyzes the temporal and spatial variation characteristics of drought duration and intensity in Leizhou Peninsula in recent 50 years combined with curve fitting method,inverse distance weighted spatial interpolation,etc.The results show that:①The monthly SPEI index of the Leizhou Peninsula in recent 50 years showed a decreasing trend in fluctuation.On the time scale of the recent 50 years,it fluctuated with a period of about 10 years,which is related to the influence of ENSO.The SPEI is relatively high in cold event years,on the contrary,in warm event years,the SPEI is low and the drought is serious.②The greater the intensity of drought disaster in Leizhou Peninsula,the smaller the probability.③Due to regional difference,the spatial distribution of drought frequency,intensity and duration showed a gradually increase trend from the northeast to the southwest.④The regional difference of the occurrence frequency of drought of different grades showed that the frequency of moderate drought and above in the central and southern and northeastern regions of Leizhou Peninsula was higher than that in the central and northern regions.In addition,the drought in the southern part of Leizhou and Xuwen County was severe.⑤Droughts occur frequently in spring and winter.In spring and summer,the drought in the northeast and central-south part of the Leizhou Peninsula was more severe,the drought in autumn was more serious in the central-north part of the peninsula,and the drought in winter seriously affected the central-south part of the peninsula.

As the second common type of volcanic vent on Earth, maar-diatreme volcanoes and their post-eruptive lacustrine sediments are a main focus of volcanology, palaeolimnology, palaeoclimatology and palaeontology. A number of maar-type volcanoes have been found in Leizhou Peninsula, South China, but little is known about their eruption processes and detailed stratigraphy of the post-eruptive sediments. We present a combined geophysical and geological analysis to study the eruptive history and post-eruptive sediment stratigraphy of a large maar, the elliptical (1.8 × 3.0 km2) Jiudouyang (JDY) maar. The lacustrine stratigraphy revealed by drilling cores shows that the JDY maar lake has three major stages of evolution: (i) deep-lake sedimentary environment characterized by high autochthonous diatom productivity; (ii) shallow lake to swamp with very low water levels, characterized by a high total organic carbon (TOC) and abundant wood fragments; and, (iii) intermittent shallow lake and alluvial deposits composed of clay minerals and sand. The electrical resistivity tomography (ERT) values and lithological features are highly consistent, which clearly reveal the presence of ca. 50 m thick lacustrine sediments, directly underlain by a ca. 70 m thick basaltic lava rather than diatreme breccia in the crater. This infill sequence implies an alternation of eruption style from phreatomagmatic to Strombolian and/or lava flow, due to high magma flux and ascent rate of the Hainan Plume during the middle Pleistocene. The ERT data also reveal the initial phreatomagmatic crater floor at ca. 120 m depth. The initial crater had a large diameter/depth ratio (ca. 17), with an elongated shape (major axis to minor axis = 0.6), implying possible lateral vent migration during the eruption. A significant erosion under tropical weathering condition during the last few hundred thousand years, accounted for the large size of the maar crater. The study provides insights into the eruptive history and post-eruptive evolution of a large maar, as well as the spatial distribution of the lacustrine sediments. [ABSTRACT FROM AUTHOR]

Widely distributed wetlands in China play an important role in the global carbon cycle. However, the long-term response of wetland evolution and carbon storage in tropical southern China to climate change remains unclear. Here, we present a sediment core record from the Tiaoshu Wetland in the northern Leizhou Peninsula and multiple proxy indicators are investigated, with the aim of better understanding past vegetation and environmental changes. The following conclusions were drawn: (i) The organic matter deposited in the Tiaoshu Wetland was mainly derived from terrestrial C3 plants and aquatic plants growing in and/or around the catchment. The temporal variability in the relative proportions of organic matter contributed by various sources revealed paleoenvironmental changes in the study area, generally consistent with regional and global climate records. (ii) The peat formation pattern in the Tiaoshu Wetland is in contrast to some individual sites reported in subtropical China, suggesting that there may be different peat formation patterns in the tropical and subtropical regions of China, which may be closely related to specific hydrothermal conditions in different regions. In addition, by comparison with atmospheric CH 4 concentrations, our results suggest potential relationships between the evolution of wetlands in tropical China and global atmospheric CH 4 cycles. • Alternation between terrestrial and aquatic plants dominated the organic matter sources in the Tiaoshu Wetland. • Variations in organic matter sources reveal vegetation succession and a response to climate changes. • Peat formation patterns may differ between tropical and subtropical regions of China. [ABSTRACT FROM AUTHOR]

Microplastic is an emerging pollutant and a technical fossil in Anthropocene sediments. Typhoon frequency and intensity have increased due to climate change, which has a major effect on the distribution patterns of microplastics. It is still unknown, though, how the topography of the peninsula affects the reconstruction of the distribution of microplastic in typhoons. Due to frequent typhoons, the Leizhou Peninsula (LZP) in the north part of the South China Sea is an ideal place to study the impact of topographic variations on microplastic distribution during typhoon events. This study investigated microplastics ranging in size from 50 μm to 5 mm in sediment. Microscopic inspection and μ-FTIR tests were used to identify microplastic characteristics from offshore surface sediments before and after typhoons. The average microplastic abundance in offshore sediments decreased from 18 ± 17 items/kg to 15 ± 15 items/kg after typhoons. Results show that typhoons only increase the microplastic abundance in topographically protected areas along the northeast coast of LZP, with no significant difference observed in other regions. The influence of typhoon on the morphological characteristics of microplastics in sediments is more pronounced and widespread, as evidenced by a shift in the predominant shape of microplastics from fibers to fragments and a decrease in size accompanied by an increased abundance within the 100 μm–1 mm fraction. The color of microplastics remained similar before and after typhoons, and the polymer composition of microplastics became more uniform. The alteration of microplastic morphology may be attributed to the enhancement of wave intensity induced by typhoons. This study enhances the comprehension of typhoon-induced impacts on pollutant redistribution, specifically microplastics, thereby providing essential empirical evidence and theoretical foundations for pollution regulation. [Display omitted] • Typhoon increased microplastic (MP) abundance in topographically protected areas. • Impact of typhoon on MP morphology is more significant than other MP characteristics. • Typhoon changed the predominant MP shape from fibers to fragments. • Typhoon made MP smaller and more concentrated in 100 μm–1 mm fraction. • Redistribution of MP shapes may be primarily due to typhoon-induced wave enhancement. [ABSTRACT FROM AUTHOR]

Nitrogen, as the main bioactive element, plays an important role in biological productivity, ecosystem function, and biogeochemical processes in marine environment. In this study, seawater samples collected from China's Leizhou Peninsula coastal water (LZPCW) during dry, normal, and wet seasons in 2018 were explored to reveal the spatiotemporal variation, composition, and transport flux of dissolved inorganic nitrogen (DIN) linked to hydrographic condition. DIN concentration and speciation showed significantly seasonal variation (P < 0.01), and the concentration of DIN species was significantly higher in dry season than other seasons. The annual mean DIN concentration was 8.01 ± 5.79 μmol L−1. In addition, the N–NO 2 −, N–NO 3 − and N–NH 4 + were significantly different in the DIN bulk in different seasons. The largest fraction of DIN was N–NO 3 −, followed by N–NH 4 +, the lowest was N–NO 2 −, comprising up to 67.92 ± 23.20%, 23.90 ± 23.19% and 8.18 ± 8.19%, respectively. Besides, the Beibu Gulf was subjected to 7.28 × 1010 mol DIN annual flux through the Qiongzhou Strait. The annual transport fluxes of N–NO 2 −, N–NO 3 −, and N–NH 4 + accounted for 6.43%, 77.20% and 16.36%, respectively. The DIN concentration and coastal water flow led to the largest DIN flux transport in dry season. This study revealed that the coastal ocean currents, river plumes and human activities jointly drove the dynamic variations of N species in LZPCW. It provides a baseline data for studying the spatiotemporal effects of hydrographic condition on nitrogen distribution and transport flux in the LZPCW, which is implications for understanding nutrients dynamics and coastal water quality management in future. • Significant DIN variations were observed in spatiotemporal scale. • Beibu gulf was subjected to huge DIN flux by Qiongzhou Strait transport. • N–NH 4 +, N–NO 2 -, and N–NO 3 - accounted for 16.36%, 6.43%, 77.20% in annual DIN flux. • DIN concentration and coastal water flow lead to the largest DIN flux in dry season. • Coastal current and riverine input strongly impacted on the DIN variation. [ABSTRACT FROM AUTHOR]

Mangrove actinomycetia are considered one of the promising sources for discovering novel biologically active compounds. Traditional bioactivity- and/or taxonomy-based methods are inefficient and usually result in the re-discovery of known metabolites. Thus, improving selection efficiency among strain candidates is of interest especially in the early stage of the antibiotic discovery program. In this study, an integrated strategy of combining phylogenetic data and bioactivity tests with a metabolomics-based dereplication approach was applied to fast track the selection process. A total of 521 actinomycetial strains affiliated to 40 genera in 23 families were isolated from 13 different mangrove soil samples by the culture-dependent method. A total of 179 strains affiliated to 40 different genera with a unique colony morphology were selected to evaluate antibacterial activity against 12 indicator bacteria. Of the 179 tested isolates, 47 showed activities against at least one of the tested pathogens. Analysis of 23 out of 47 active isolates using UPLC-HRMS-PCA revealed six outliers. Further analysis using the OPLS-DA model identified five compounds from two outliers contributing to the bioactivity against drug-sensitive A. baumannii. Molecular networking was used to determine the relationship of significant metabolites in six outliers and to find their potentially new congeners. Finally, two Streptomyces strains (M22, H37) producing potentially new compounds were rapidly prioritized on the basis of their distinct chemistry profiles, dereplication results, and antibacterial activities, as well as taxonomical information. Two new trioxacarcins with keto-reduced trioxacarcinose B, gutingimycin B (16) and trioxacarcin G (20), together with known gutingimycin (12), were isolated from the scale-up fermentation broth of Streptomyces sp. M22. Our study demonstrated that metabolomics tools could greatly assist classic antibiotic discovery methods in strain prioritization to improve efficiency in discovering novel antibiotics from those highly productive and rich diversity ecosystems.

We developed a numerical model, RFLUX, which uses the heat tracer method for vertical groundwater flux estimation, and applied it to the Leizhou Peninsula, South China, to provide information to inform local groundwater resource utilization and management. The temperature–depth (TD) profiles of 24 boreholes, along with the observed ground surface temperature (GST) and surface air temperature (SAT) series in recent decades, were collected in this area. Underground TD data demonstrated the capacity to identify groundwater flow patterns, and local GST and SAT data demonstrated a strong correlation with each other over monthly, seasonal, and annual scales. In the RFLUX model, the average GST and SAT series were applied as an upper boundary condition, and a nonlinear initial condition was set using an analytical solution from the literature. The model results of selected TD profiles demonstrated that the annual vertical groundwater flux was about 0.15 m a−1, which tended to be overestimated if a linear initial condition was used. This model can be easily applied with minor modifications, considering its clear purpose and simplicity. [ABSTRACT FROM AUTHOR]

To elucidate the spatial patterns of understory species in fragmented forests adjacent to human settlements, we examined the spatial distribution and intraspecific correlations of three dominant species Mallotus philippensis , Dasymashalon trichophorum , and Psychotria rubra by employing point pattern analysis, which were the top three in terms of importance value in the shrub layer of Fengshui forest in Leizhou Peninsula, Guangdong. The results showed that all the three species were mainly aggregated at the scale of 0-25 m, especially for young trees. The degree of aggregation gradually diminished with increasing age class. The spatial distribution patterns of three species were predominantly influenced by habitat heterogeneity, negative density dependence, and dispersal limitation. They showed positive association among different age classes, especially between young trees and middle age trees and between young trees and adult trees. Therefore, in the ecological restoration process of Leizhou Peninsula, M. philippensis , D. trichophorum , and P. rubra should be planted in clusters at a small scale within the range of 0-25 m, with the degree of clusters depending on plant morphology. For larger scales, a dispersed cultivation approach was advocated.

Zhong, Z.; Yang S., and Duan, Y., 2018. Sustainable development of typhoon prone coastal areas based on SD model. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 754–769. Coconut Creek (Florida), ISSN 0749-0208. Sustainable development systems are a dynamic and complicated large systems, that can both be modestly destroyed and restrained by typhoon disasters. System dynamics can be used to study the problems of sustainable development. In this study, based on the theory of sustainable development and targeting typhoon disaster events in Leizhou Peninsula of China, we selected four subsystems (economy, population, environment, and water resource) using the background of typhoon disasters to empirically analyze the effectiveness and practicability of simulation models. Based on this, the restricting factors for sustainable development of the Leizhou Peninsula were assessed via scenario analysis. It was found that typhoon disasters introduced both benefits and harms to the economic development. The existing environmental protection investment did not meet the demands for social development, and the supply-demand contradiction of water resources remained severe. To promote sustainable development of the Leizhou Peninsula, the government has to adjust industrial structure, increase environmental investment, preserve water resources, and improve water quality. [ABSTRACT FROM AUTHOR]

The LeiZhou Peninsula is situated at the southern tip of mainland China with frequent tropical cyclone activity. Its special feature of large-scaled westward concaved coastline results in complex storm-induced hydrodynamic processes in a variety of spatial scales. Statistics show that the surge distributions in the east LeiZhou Peninsula are sensitive to the landfall location and moving direction of the storm tracks. This paper provides a detailed assessment to investigate the nearshore and coastal responses to different tropical cyclone behaviours in this region. A high-resolution integrally-coupled wave and circulation model (FVCOM-SWAVE) on a large-domain unstructured mesh containing the northern South China Sea is applied in this study. The model is validated by observed water level records during three typical typhoon events of Krovanh (2003), Kai-tak (2012) and Mujigae (2015). Induced by the right-handed cyclone wind rotation at the northern hemisphere, surges at ZhanJiang and NanDu perform as set-up processes when the storm lands to the south of the ZhanJiang Bay and as mixtures of slight set-up and medium set-down when the storm lands to the north of the ZhanJiang Bay. For set-up cases, the storm tracks with moving direction of WNW ( α  = 10° ∼ 30°) are more likely to cause heavy surges. Complex coastal morphology has great impacts on the surge distributions. For outer-bay coastlines, the area at the distance of 1 ×  RMW  ∼ 1.5 ×  RMW right to the cyclone track is most dangerous prone to high surge. For inner-bay areas, three high-risk regions—the NanSan Channel, the HuGuang branch of the ZhanJiang Bay and west coast of the LeiZhou Bay—are more likely to generate violent surges because of their westward narrowing-down configurations. Protected by a narrow entrance oriented to ESE, surge variations in the ZhanJiang Bay are less sensitive to the variations of landfall location and moving direction than that in the LeiZhou Bay. [ABSTRACT FROM AUTHOR]

With the emergence of the neologism ‘intangible cultural heritage’ in 2003 and the adoption of the Intangible Cultural Heritage Law of the People’sRepublic of China in 2011 various popular religious practices in China which used to be considered as feudal superstitions started to be recognized as examples of cultural heritage worthy of protection. If we examine the concept of religious diversity at a local level in contemporary China, the process of a ‘patrimonialization’ of popular religious practices that reflect the dynamic relationships which can be detected across diverse discourses, multiple stakeholders and cultural policies in different arenas could offer us a new perspective on religious practices to explore. In this article I offer an analysis, based on fieldwork conducted between 2013 and 2016 on the Leizhou Peninsula in southern China’s Guangdong Province, of the varying degrees of acceptance, accommodation and resistance prompted by the actualization of popular religious practices in this era of patrimonialization.

A triply-nested two-dimensional (2D) ocean circulation model along with observed sea level records are used to study tide-surge interaction along the east coast of the Leizhou Peninsula (LP) which is characterized by extensive mudflats, large tidal ranges and a complex coastline. The dependency of surge maxima on the water level and the phase of tide are respectively investigated using two statistical approaches. Results show that tide-surge interaction along the east coast of the LP is significant, where surges peak 3–6 h before or after the nearest high water. The triply-nested 2D ocean circulation model is used to quantify tide-surge interaction in this region and to investigate its physical cause. The largest amplitudes of tide-surge interaction are found in the shallow water region of the Leizhou Bay, with values up to 1 m during typhoon events. Numerical experiments reveal that nonlinear bottom friction is the main contributor to tide-surge interaction, while the contribution of the nonlinear advective effect can be neglected. The shallow water effect enhances the role of nonlinear bottom friction in determining tide-surge modulation, leaving the surge peaks usually occur on the rising or falling tide. It is also found that the relative contribution of local wind and remote wind is different depending on the storm track and storm intensity, which would finally affect the temporal and spatial distribution of tide-surge interaction during typhoon events. These findings confirm the importance of coupling storm surges and tides for the prediction of storm surge events in regions which are characterized by shallow water depths and large tidal ranges. [ABSTRACT FROM AUTHOR]

Here, we present a well-dated terrestrial charcoal chronology covering the interval ~ 41,000–7050 cal BP and identifying the millennial-scale variability in biomass burning for the tropical Leizhou Peninsula, south China. Our results show that changes in biomass burning closely followed regional temperature and precipitation variations on orbital timescales, i.e., more biomass burning occurred during the warm/wet Marine Isotope Stage (MIS) 3, and less biomass burning occurred during the cold/dry MIS 2. Superimposed on this general trend, our charcoal record shows millennial-scale variability in biomass burning corresponding to the rapid climate changes associated with Dansgaard–Oeschger (D–O) cycles, i.e., biomass burning increased during D–O warming events, whereas biomass burning decreased during intervals of rapid cooling terminated by Heinrich events. During the cooler/drier periods, low biomass burning can be explained by the decline of vegetation productivity, whereas the warmer/wetter periods are characterized by higher biomass burning related to increasing fuel availability. Therefore, climate control can be considered as the major forcing factor of biomass burning from 41,000–7050 cal BP on both orbital and millennial timescales in the northern Leizhou Peninsula. [ABSTRACT FROM AUTHOR]