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The significance of intermittent streams in nutrient loss within forest ecosystems is becoming increasingly critical due to changes in precipitation patterns associated with global climate change. However, few studies have focused on nutrient export from intermittent streams. We conducted continuous sediment collection from intermittent streams from March 2022 to February 2023 to investigate the export pattern and mechanism of sediment-associated nitrogen (N) from intermittent streams of different forest types (composed forest of Castanopsis carlesii (Cas. carlesii) and Cunninghamia lanceolata (C. lanceolata) forests, compared to Cas. carlesii forests). We measured the N concentrations and calculated the export amounts of four common forms of N associated with sediments: total N (TN), dissolved N (DN), nitrate, and ammonia. Our results showed that (1) the annual average exports of TN, DN, nitrate, and ammonia associated with sediments from intermittent streams from both forest types were 273, 1.62, 0.26, and 0.84 kg ha-1, respectively; (2) N export was significantly higher in composite forests of Cas. carlesii and C. lanceolata, compared to Cas. carlesii forests; (3) stream sediment export amount positively affected N export both in composite forests and Cas. carlesii forests; and (4) N export was also controlled by rainfall amount and stream characteristics. Our study quantified sediment-associated N export from intermittent streams among different subtropical forest types, which will enhance our understanding of N dynamics associated with stream hydrological processes in subtropical forests.

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Climate change, a pressing global concern, poses significant challenges to agricultural systems worldwide. Among the myriad impacts of climate change, the cultivation of kiwifruit trees (Actinidia spp.) faces multifaceted challenges. In this review, we delve into the intricate effects of climate change on kiwifruit production, which span phenological shifts, distributional changes, physiological responses, and ecological interactions. Understanding these complexities is crucial for devising effective adaptation and mitigation strategies to safeguard kiwifruit production amidst climate variability. This review scrutinizes the influence of rising global temperatures, altered precipitation patterns, and a heightened frequency of extreme weather events on the regions where kiwifruits are cultivated. Additionally, it delves into the ramifications of changing climatic conditions on kiwifruit tree physiology, phenology, and susceptibility to pests and diseases. The economic and social repercussions of climate change on kiwifruit production, including yield losses, livelihood impacts, and market dynamics, are thoroughly examined. In response to these challenges, this review proposes tailored adaptation and mitigation strategies for kiwifruit cultivation. This includes breeding climate-resilient kiwifruit cultivars of the Actinidia species that could withstand drought and high temperatures. Additional measures would involve implementing sustainable farming practices like irrigation, mulching, rain shelters, and shade management, as well as conserving soil and water resources. Through an examination of the literature, this review showcases the existing innovative approaches for climate change adaptation in kiwifruit farming. It concludes with recommendations for future research directions aimed at promoting the sustainability and resilience of fruit production, particularly in the context of kiwifruit cultivation, amid a changing climate.

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Phosphate fertilizers are applied to the soil surface, especially in vineyards in production in subtropical regions. Nowadays, phosphorus (P) is not incorporated into the soil to avoid mechanical damage to the root system in orchards. However, over the years, successive surface P applications can increase the P content only in the topsoil, maintaining low P levels in the subsurface, which can reduce its use by grapevines. For this reason, there is a need to propose strategies to increase the P content in the soil profile of established orchards. The study aimed to evaluate the effect of management strategies to (i) increase the P content in the soil profile; (ii) enhance the grape production; and (iii) maintain the grape must composition. An experiment on the 'Pinot Noir' grape in full production was carried out over three crop seasons. The treatments were without P application (C), P on the soil surface without incorporation (SP), P incorporated at 20 cm (IP20), P incorporated at 40 cm (IP40), and twice the P dose incorporated at 40 cm (2IP40). The P concentration in leaves at flowering and veraison, P content in the soil, grape production and its components, and chemical parameters of the grape must (total soluble solids, total polyphenols, total titratable acidity, total anthocyanins, and pH) were evaluated. The P concentration in leaves did not differ among the P application modes. The application of P associated with soil mobilization, especially at 20 cm depth, increased grape production. The P application modes did not affect the values of the chemical parameters of the grape must except for the total anthocyanins, which had the highest values when the vines were subjected to 2IP40. Finally, the P application and incorporation into the soil profile was an efficient strategy for increasing the grape production in full production vineyards.

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The adverse effects of intensified cropland practices on soil quality and biodiversity become especially evident in India, where nearly 60% of land is dedicated to cultivation, and almost 30% of soil is already degraded. Intensive agricultural practice significantly contributes to soil degradation, highlighting the crucial need for effective countermeasures to support sustainable development goals. A long-term experiment, established in the semi-arid Nimar Valley (India) in 2007, monitors the effect of organic and conventional management on the plant-soil system in a Vertisol. The focus of our study was to assess how organic and conventional farming systems affect biological and chemical soil quality indicators. Additionally, we followed the community structure of the soil microbiome throughout the vegetation phase under soya or cotton cultivation in the year 2019. We found that organic farming enhanced soil organic carbon and nitrogen content, increased microbial abundance and activity, and fostered distinct microbial communities associated with traits in nutrient mineralization. In contrast, conventional farming enhanced the abundance of bacteria involved in ammonium oxidation suggesting high nitrification and subsequent nitrogen losses with regular mineral fertilization. Our findings underscore the value of adopting organic farming approaches in semi-arid subtropical regions to rectify soil quality and minimize nitrogen losses.

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There is limited information regarding spatial and seasonal variations of atmospheric microplastics (MPs) and factors influencing MPs at the intersection of tropical and subtropical regions. A one-year study was conducted at sites in a high-population-density village (HPDV) and a low-population-density village (LPDV) in Taiwan to investigate the characteristics and influencing factors of airborne MPs. The predominant shapes, sizes, and polymer compositions of MPs were fragments, 3 to 25 and 26-50 µm, and polyamide at both sites. Seasonal variation in MP morphologies was not significant. Average MP concentrations were 2.20 ±â€¯2.97 particles/m3 and 1.92 ±â€¯2.35 particles/m3 at the HPDV and LPDV sites, respectively, and did not differ significantly. Higher concentrations and smaller sizes of MPs were found during the summer at both sites, while the predominant wind direction was southerly or southwesterly. In samples with temperatures exceeding 25 °C, the temperature was positively associated with MP concentrations at both the HPDV and LPDV sites. These results reflect that temperature influences the variations in the concentrations and sizes of MPs at our study site. Future research should consider the adverse risks of MP inhalation during the hot season. Moreover, when sites with different population densities and levels of human activity are closed, MP concentrations will not differ significantly between these areas since airflow can transport these particles from high-population-density areas into low-population-density areas in a short time.

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Forests, the largest terrestrial carbon sinks, play an important role in carbon sequestration and climate change mitigation. Although forest attributes and environmental factors have been shown to impact aboveground biomass, their influence on biomass stocks in species-rich forests in southern China, a biodiversity hotspot, has rarely been investigated. In this study, we characterized the effects of environmental factors, forest structure, and species diversity on aboveground biomass stocks of 30 plots (1 ha each) in natural forests located within seven nature reserves distributed across subtropical and marginal tropical zones in Guangxi, China. Our results indicate that forest aboveground biomass stocks in this region are lower than those in mature tropical and subtropical forests in other regions. Furthermore, we found that aboveground biomass was positively correlated with stand age, mean annual precipitation, elevation, structural attributes and species richness, although not with species evenness. When we compared stands with the same basal area, we found that aboveground biomass stock was higher in communities with a higher coefficient of variation of diameter at breast height. These findings highlight the importance of maintaining forest structural diversity and species richness to promote aboveground biomass accumulation and reveal the potential impacts of precipitation changes resulting from climate warming on the ecosystem services of subtropical and northern tropical forests in China. Notably, many natural forests in southern China are not fully stocked. Therefore, their continued growth will increase their carbon storage over time.

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The present study investigates the temporal effects of flaxseed supplementation on boar semen quality, antioxidant status, and in-vivo fertility under high-temperature humidity index (THI) conditions in a sub-tropical climate. Twelve Hampshire crossbreed boars were randomly assigned to control and treatment groups, with the treatment group receiving flaxseed oil supplementation. Semen samples were collected and analyzed for semen quality parameters, sperm kinematics, and antioxidant status. Fertility outcomes were assessed through in-vivo mating trials. Flaxseed supplementation resulted in time dependent significant improvements in semen volume, sperm concentration, total and progressive sperm motility, sperm quality parameters, and antioxidant status. Fertility outcomes, including farrowing rates and litter sizes, were also enhanced in the flaxseed-supplemented group. These findings highlight the potential of flaxseed supplementation to improve boar fertility under high ambient stress conditions, with implications for optimizing reproductive performance in swine production systems.

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Secondary forests represent a significant proportion of global forest cover, with over 70% of forests in East Asia classified as regenerating. While succession has been studied extensively in temperate systems, trajectories of subtropical succession remain poorly characterized in highly disturbed, urban-adjacent forests. Investigating the additive beta diversity components of turnover and nestedness may reveal community assembly mechanisms driving secondary succession. The present study investigates plant community assembly along a successional gradient from 7 to 70 years following the onset of succession in secondary subtropical forests in Hong Kong, China. Plant survey data for 28 plots were analysed, generating additive Simpsons turnover and nestedness beta diversity metrics. Dissimilarity matrices were generated and modelled as a function of environmental matrices including forest plant community age (years following onset of secondary succession), inter-community distance (metres), and soil moisture saturation (%) across three elevational bands using generalized dissimilarity models. Nonmetric multidimensional scaling of plant communities was conducted with Bray-Curtis dissimilarity matrices. Inter-community distance and successional age differentially influenced plant species turnover between lowland and Montane forest types. Models of nestedness found that plot age and soil moisture saturation were significant drivers of nestedness patterns in plant communities across elevational classes. Turnover represented a higher proportion of Sorensen beta diversity than nestedness, while ANOSIM found significant differentiation between plant communities at different successional stages. Turnover patterns suggest a deterministic model of community assembly, with strong patterns of species replacement between communities at fine spatial scales and successional stages, as well as clear compositional shifts between lowland and montane forest types. NMDS analysis and functional compositional assessments suggested a transition from early successional communities with a high proportion of shrub species, to later successional communities with a higher proportion of tree species, with an increase in species turnover with greater age dissimilarity.

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Lakes play a crucial role in the nitrogen (N) cycle, and eutrophication disrupts the balance of the nitrogen cycle within lakes, including both the N removal process and the N supplement process. However, the mechanisms by which different nutrient levels affect seasonal nitrogen variations in the water columns are not clear, especially for long-term and large- scale studies. In this study, we used 206 independent spatial samples from a total of 108 subtropical shallow lakes from four surveys in the middle and lower reaches of the Yangtze River, as well as time-case study data from Lake Taihu and Lake Donghu of up to 23 and 14 years, respectively, to analyze the changes in summer TN compared to spring (delta TN). Delta TN was significantly negatively correlated with initial spring TN concentrations, with similar trends observed in both space and time. Furthermore, the slopes of spring TN vs. delta TN varied little across lakes in both time and space, suggesting a consistent relationship between initial spring TN and summer TN changes. When initial TN or TN: TP ratio was low, N fixation by algae played a significant role in compensating for summer N removal, thus mitigating summer N reductions; when TN was high or TN: TP ratio was high, ammonia stress reduced the compensatory effect of algae and denitrification played a significant role in summer N removal, thus increasing summer N reductions. Our study suggested that no matter what the initial conditions are, lakes tend to evolve towards a common nutrient status through biological regulation.

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We conducted in a common garden experiment to explore the differences in soil enzyme activity, stoichiometry, and their influencing factors among a secondary Castanopsis carlesii forest, 10-year-old C. carlesii plantation, and Cunninghamia lanceolata plantation. The results showed that compared to the secondary forest, the soil organic carbon, total nitrogen, and dissolved organic carbon significantly decreased by 42.6%, 47.4%, and 60.9% in C. carlesii plantation, and by 42.9%, 36.7%, and 61.1% in C. lanceolata plantation. Soil microbial biomass C, microbial biomass N (MBN), and microbial biomass phosphorus decreased significantly by 40.6%, 35.5%, and 45.9% in C. carlesii plantation, and by 53.7%、56.4%, and 61.7% in C. lanceolata plantation. Compared to the secondary forest, soil enzymes activities in C. carlesii plantation did not change significantly, but in C. lanceolata plantation, the activities of ß-1,4-glucosidase and cellobiohydrolase significantly decreased by 51.2% and 59.8%, ß-N-acetyl glucosaminidase and acid phosphatase decreased significantly by 41.0% and 29.8%, and enzymatic C:N acquisition ratio and enzymatic C:P acquisition ratio significantly decreased by 11.3% and 7.7%, respectively. Results of redundancy analysis indicated that MBN and NO3--N were the primary factors influencing soil enzyme activity and enzymic stoichiometry. Collectively, there were significant differences in soil enzyme activity and microbial nutrient demands among different forest stands. Compared to secondary forests, the establishment of C. lanceolata plantations would intensify nutrient competition between plants and microbes, and exacerbate the N and P limitations for microbes.

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BACKGROUND AND AIMS: Subtropical China is dominated by evergreen broad-leaved forests (EBLFs) and is acknowledged as a critical region for its high floristic richness and endemism. Understanding of evolutionary mechanisms of such global biodiversity hotspots comes almost exclusively from long-lived tree species. Herbaceous plants represent critical biodiversity components in forests, however, the diversification history of understory herbs in subtropical EBLFs remain poorly understood. Here, we investigated the phylogeographic patterns and demographic history of Oreocharis auricula, a widespread perennial herb endemic to the EBLFs of subtropical China. METHODS: Both cpDNA sequences and single-copy nuclear genes were used to investigate the genetic variation among 657 individuals from 68 populations. Evidences from molecular dating, demographic history construction, and species distribution modeling were also combined to infer the phylogeography and evolutionary history of O. auricula. KEY RESULTS: Strong phylogeographic signals have been congruently observed using nuclear and plastid DNA markers, with the diversification patterns generally consistent with the recognized floristic subdivisions of subtropical China. Notably, we revealed an important phylogeographic barrier along the Nanling mountain range, which is also around a climatic transition at 24-26°N latitude in subtropical China, separating the south monsoon subtropical EBLFs from the mid-subtropical EBLFs. Demographic expansion and significant niche divergence were detected among the extant lineages, which may have diverged during the early Pleistocene. CONCLUSIONS: The inherent characteristics of understory herbs with limited dispersal and short generation time intensify the genetic divergence response of O. auricula to abiotic forces, contributing to the profound phylogeographic imprints of mountains and climate in such herbaceous flora. To further substantiate the generality of the identified patterns, it is paramount to extend phylogeographic investigations to other understory herbaceous taxa in subtropical China. These results have expanded our understanding of the diversification processes of subtropical forests in China.

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BACKGROUND AND AIMS: Species delimitation can be challenging when analysing recently diverged species, especially those taxonomically synonymised due to morphological similarities. We aimed to untangle the relationships between two grassland species, Petunia guarapuavensis and Petunia scheideana, exploring the dynamics of fast divergence and addressing their species delimitation. METHODS: We used a low-coverage genome sequencing and population genomic approach to distinguish species and populations between P. guarapuavensis and P. scheideana. Our analysis focused on detecting structuration, hybridisation/introgression, and phylogenetic patterns. We employed demographic models to support species delimitation while exploring potential phylogeographic barriers influencing gene flow. KEY RESULTS: Our findings indicated differentiation between the two species and revealed another lineage, which was phylogenetically distinct from the others and had no evidence of gene flow with them. The presence of a river acted as a phylogeographic barrier, limiting gene flow and allowing for structuration between closely related lineages. The optimal species delimitation scenario involved secondary contact between well-established lineages. CONCLUSIONS: The rapid divergence observed in these Petunia species explains the lack of significant morphological differences, as floral diagnostic traits in species sharing the pollinators tend to evolve more slowly. This study highlights the complexity of species delimitation in recently diverged groups and emphasises the importance of genomic approaches in understanding evolutionary relationships and speciation dynamics.

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Organic carbon (C) and CO2 pools are closely interactive in aquatic environments. While there are strong indications linking freshwater CO2 to dissolved organic matter (DOM), the specific mechanisms underlying their common pathways remain unclear. Here, we present an extensive investigation from 20 subtropical lakes in China, establishing a comprehensive conceptual framework for identifying CO2 drivers and retrieving CO2 magnitude through co-trajectories of DOM evolution. Based on this framework, we show that lake CO2 during wet period is constrained by a combination of biogeochemical processes, while photo-mineralization of activated aromatic compounds fuels CO2 during dry period. We clearly determine that biological degradation of DOM governs temporal variations in CO2 rather than terrestrial C inputs within the subtropical lakes. Specifically, our results identify a shared route for the uptake of atmospheric polycyclic aromatic compounds and CO2 by lakes. Using machine learning, in-lake CO2 levels are well modelled through DOM signaling regardless of varying CO2 mechanisms. This study unravels the mechanistic underpinnings of causal links between lake CO2 and DOM, with important implications for understanding obscure aquatic CO2 drivers amidst the ongoing impacts of global climate change.

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In the transition from pelagic larva to benthic adult, larvae likely encounter a diverse assemblage of resident invertebrates in their habitat, which may also compete for space during post-settlement periods. Fouling fauna in rocky and seagrass habitats on Inhaca Island, southern Mozambique, was evaluated over 4 months in each of two seasons on oyster collectors fixed at 2 cm above the bottom. As expected, two species of oysters recruited to tiles: the rock oyster Saccostrea cucullata in rocky habitats and the pearl oyster, Pinctada capensis in seagrass habitats. The composition and density of other fouling fauna varied among habitats, location, seasons and surfaces and depending on the duration of the deployment. In seagrass habitats, oysters and barnacles were generally less abundant, allowing other taxa to have higher relative abundance, while higher density of individuals was recorded in rocky habitat. Barnacles dominate among fouling fauna on collectors in both habitats. Despite evidence consistent with negative interactions between oysters and barnacles, the effects of other fouling fauna on oyster abundance appear modest up to 4 months after tiles are placed. Overall, the results help improve our general understanding of the environmental processes that affect the colonisation of intertidal invertebrates, particularly in the southwestern Indian Ocean.

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BACKGROUND AND AIM: The present study aimed to evaluate and compare the overall and breed-specific seasonal breeding patterns, fertility rates, cyclicity, and follicular dynamics of Arab, Thoroughbred, and Percheron mares under the subtropical conditions of Pakistan. MATERIALS AND METHODS: A retrospective analysis of climatic data and breeding records of eleven breeding studs spanning four years (2020-2023) was made to find out the overall seasonality in the breeding pattern of mares. Fifty mares of each breed (n = 150 in total) were scanned by ultrasonography for a calendar year to find the cyclicity pattern and follicular dynamics (follicular growth rate, size of ovulatory follicle, and days from estrus till ovulation). RESULTS AND DISCUSSION: The statistical analysis of breeding records demonstrated a clear pattern of seasonal breeding (p< 0.05). The highest monthly foalings were noted in March (247 ± 45.37), and overall breeding activities peaked in Spring season (p< 0.05). Breed-specific results of Arab, Thoroughbred, and Percheron mares revealed that Arab mares maintained stable breeding activity throughout the year, with the highest activity in spring and peak conception rate in winter (56.25% ± 32.78; p > 0.05). Thoroughbred mares experienced significant seasonal declines from spring to winter with a peak conception rate in winter (63.89% ± 27.37, p > 0.05). Percherons showed the most pronounced seasonal effects, especially with a high fall conception rate (73.04% ± 19.61) and a sharp decrease in winter breeding metrics (p< 0.05). Furthermore, Thoroughbred and Percheron mares displayed the most pronounced seasonal effects on the percentage of cyclic mares 77.3% and 56% in winters (p< 0.05). Moreover, the follicular dynamics of the three breeds also exhibited significant differences (p< 0.05). CONCLUSION: The current study concludes that seasonal and breed-specific variability exists among the reproductive parameters of Arab, Thoroughbred, and Percheron mares in subtropics, necessitating breed-specific reproductive management measures to maximize mare breeding efficiency.

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Tropical and subtropical evergreen broadleaved forests (TEFs) contribute more than one-third of terrestrial gross primary productivity (GPP). However, the continental-scale leaf phenology-photosynthesis nexus over TEFs is still poorly understood to date. This knowledge gap hinders most light use efficiency (LUE) models from accurately simulating the GPP seasonality in TEFs. Leaf age is the crucial plant trait to link the dynamics of leaf phenology with GPP seasonality. Thus, here we incorporated the seasonal leaf area index of different leaf age cohorts into a widely used LUE model (i.e., EC-LUE) and proposed a novel leaf age-dependent LUE model (denoted as LA-LUE model). At the site level, the LA-LUE model (average R2 = .59, average root-mean-square error [RMSE] = 1.23 gC m-2 day-1) performs better than the EC-LUE model in simulating the GPP seasonality across the nine TEFs sites (average R2 = .18; average RMSE = 1.87 gC m-2 day-1). At the continental scale, the monthly GPP estimates from the LA-LUE model are consistent with FLUXCOM GPP data (R2 = .80; average RMSE = 1.74 gC m-2 day-1), and satellite-based GPP data retrieved from the global Orbiting Carbon Observatory-2 (OCO-2) based solar-induced chlorophyll fluorescence (SIF) product (GOSIF) (R2 = .64; average RMSE = 1.90 gC m-2 day-1) and the reconstructed TROPOspheric Monitoring Instrument SIF dataset using machine learning algorithms (RTSIF) (R2 = .78; average RMSE = 1.88 gC m-2 day-1). Typically, the estimated monthly GPP not only successfully represents the unimodal GPP seasonality near the Tropics of Cancer and Capricorn, but also captures well the bimodal GPP seasonality near the Equator. Overall, this study for the first time integrates the leaf age information into the satellite-based LUE model and provides a feasible implementation for mapping the continental-scale GPP seasonality over the entire TEFs.

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Introduction: In recent years, nitrogen deposition has constantly continued to rise globally. However, the impact of nitrogen deposition on the soil physicochemical properties and microbial community structure in northern Guangxi is still unclear. Methods: Along these lines, in this work, to investigate the impact of atmospheric nitrogen deposition on soil nutrient status and bacterial community in subtropical regions, four different nitrogen treatments (CK: 0 gN m-2 a-1, II: 50 gN m-2 a-1, III: 100 gN m-2 a-1, IV: 150 gNm- 2 a-1) were established. The focus was on analyzing the soil physical and chemical properties, as well as bacterial community characteristics across varying nitrogen application levels. Results and discussion: From the acquired results, it was demonstrated that nitrogen application led to a significant decrease in soil pH. Compared with CK, the pH of treatment IV decreased by 4.23%, which corresponded to an increase in soil organic carbon and total nitrogen. Moreover, compared with CK, the soil organic carbon of treatment IV increased by 9.28%, and the total nitrogen of treatment IV increased by 19.69%. However, no significant impact on the available nitrogen and phosphorus was detected. The bacterial diversity index first increased and then decreased with the increase of the nitrogen application level. The dominant phylum in the soil was Acidobacteria (34.63-40.67%), Proteobacteria, and Chloroflexi. Interestingly, the abundance of Acidobacteria notably increased with higher nitrogen application levels, particularly evident in the IV treatment group where it surpassed the control group. Considering that nitrogen addition first changes soil nutrients and then lowers soil pH, the abundance of certain oligotrophic bacteria like Acidobacteria can be caused, which showed a first decreasing and then increasing trend. On the contrary, eutrophic bacteria, such as Actinobacteria and Proteobacteria, displayed a decline. From the redundancy analysis, it was highlighted that total nitrogen and pH were the primary driving forces affecting the bacterial community composition.

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Flavonoids play an important role in forming wine grapes and wine quality characteristics. The flavonoids of three winter red wine grapes, Yeniang No. 2 (YN2), Marselan (Mar), and Guipu No. 6 (GP6), were analyzed by ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QQQ-MS). Furthermore, the flavonoids in GP6 grapevines using two types of training systems, namely, trellis (T) and espaliers (E), were also compared in this study. Overall, 196 flavonoid metabolites, including 96 flavones, 38 flavonols, 19 flavanones, 18 polyphenols, 15 anthocyanins, 7 isoflavones, and 3 proanthocyanidins, were identified. The flavonoid profiles were remarkably different among these three grape varieties, while they did not change much in the GP6 managed on trellis and espaliers. Grape varieties with different genetic backgrounds have their own unique flavonoid profiles. Compared with Mar-T, isoflavones and flavonols presented higher contents in GP6-T and YN2-T, which mainly contain glycitein, genistin, calycosin, kaempferide, isotrifoliin, and ayanin. The anthocyanin content was significantly higher in YN2-T than in the other two varieties. YN2 and GP6-T present a more stable color, with significantly more acetylated diglucosides and methylated anthocyanins in YN2-T and GP6-T than in Mar-T. Notably, GP6 had more varied flavonoids and the better characteristics to its flavonoid profile out of these three varieties, due to it containing a higher number of anthocyanins, flavone, and flavonols and the greatest number of different flavonoid metabolites (DFMs), with higher contents than YN2 and Mar. Compared with the trellis training system, the espaliers training system increased the content of flavonoids detected in GP6 grape berries; however, the composition of flavonoids strictly depends on the grape variety.

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Although seagrass meadows are intense carbon sinks, information on the regional variability in seagrass blue carbon stocks and carbon sequestration remains limited. We estimated the organic carbon (Corg) stocks and carbon accumulation rates (CAR) of seven seagrass meadows along the subtropical coast of China's Zhanjiang City and analyzed the driving factors of variability in sediment Corg stocks in three seagrass meadows. Results showed that most Corg (99.83 %) was stored in the sediments, and the contribution of living biomass was minor. The average Corg stocks of living biomass and sediments across all sites were 0.04 ± 0.01 and 42.03 ± 25.07 Mg C ha-1, respectively, which were significantly lower than the world average (2.52 ± 0.48 and 194.2 Mg C ha-1). The sediment Corg stocks of the upper 1 m ranged from 24.26 to 157.12 Mg C ha-1 with substantial variability among sites: Liusha Bay (64.93 ± 22.31 Mg C ha-1) > Donghai Island (33.8 ± 10.65 Mg C ha-1) > Dongshen Ferry (27.35 ± 4.15 Mg C ha-1). The average sediment CAR was 53.47 g C m-2 yr-1, and the total CAR of 864.18 ha seagrass meadows was 260.76 ± 4.86 Mg C yr-1 in these studied sites. Physicochemical factors, such as high moisture content, salinity, CaCO3 content, and low dry bulk density, jointly inhibited the mineralization rate of Corg in sediments. Our study provides data from understudied regions to a growing dataset on seagrass carbon stocks and sequestration rates and highlights the significance of local and regional differences in seagrass blue carbon storage to accurately assess the climate change mitigation potential of seagrass ecosystems.

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In recent years, as the abundance of residual mulch film (RMF) in agricultural soil continues to increase, whether the adsorption capacity of its surface affects the migration of heavy metals is a topic of current interest for scholars. Herein, this study investigated the distribution of RMF abundance and metal concentration in different soil layers of 75 plastic-mulching croplands in subtropical China; meanwhile, we also explored the associations of RMF characteristics with metal concentration. The results showed that land type, film mulching amount, and film mulching time were the main factors affecting RMF abundance, distribution, and particle size composition. The highest abundance of RMF was found in the garden soils (910 n·kg-1) with more than 15 years mulching period and more than 19.5 kg hm-2 of annual mulch amount. The lowest abundance of RMF was occurred in the group of field and conservation agricultural land (237 n·kg-1). Moreover, the concentrations of metals in soil, especially Cd, Cr, Cu, and Pb, were closely related to the extent of RMF contamination in the soil environment. In the 0-10 cm and 10-20 cm soil layers, microplastic abundance exhibited a negative correlation with Cr and Cu concentrations and a positive correlation with Pb concentration. Based on the above findings, it is demonstrated that RMF significantly influences the mobility of metals in soil via adsorption processes, with potential synergistic effects between RMF and heavy metals posing a heightened risk to the soil environment.

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