Traits estimated when grown alone may underestimate the competitive advantage and invasiveness of exotic species.

Functional differences between native and exotic species, estimated when species are grown alone or in mixtures, are often used to predict the invasion risk of exotic species. However, it remains elusive whether the functional differences estimated by the two methods and their ability to predict species invasiveness (e.g. high abundance) are consistent. We compiled data from two common garden experiments, in which specific leaf area, height, and aboveground biomass of 64 common native and exotic invasive species in China were estimated when grown individually (pot) or in mixtures (field). Exotic species accumulated higher aboveground biomass than natives, but only when grown in field mixtures. Moreover, aboveground biomass and functional distinctiveness estimated in mixtures were more predictive of species persistence and relative abundance in the field mixtures in the second year than those estimated when grown alone. These findings suggest that assessing species traits while grown alone may underestimate the competitive advantage for some exotic species, highlighting the importance of trait-by-environment interactions in shaping species invasion. Therefore, we propose that integrating multi-site or multi-year field surveys and manipulative experiments is required to best identify the key trait(s) and environment(s) that interactively shape species invasion and community dynamics.

Positive soil priming effects are the rule at a global scale.

Priming effects of soil organic matter decomposition are critical to determine carbon budget and turnover in soil. Yet, the overall direction and intensity of soil priming remains under debate. A second-order meta-analysis was performed with 9296-paired observations from 363 primary studies to determine the intensity and general direction of priming effects depending on the compound type, nutrient availability, and ecosystem type. We found that fresh carbon inputs induced positive priming effects (+37%) in 97% of paired observations. Labile compounds induced larger priming effects (+73%) than complex organic compounds (+33%). Nutrients (e.g., N, P) added with organic compounds reduced the intensity of priming effects compared to compounds without N and P, reflecting "nutrient mining from soil organic matter" as one of the main mechanisms of priming effects. Notably, tundra, lakebeds, wetlands, and volcanic soils showed much larger priming effects (+125%) compared to soils under forests, croplands, and grasslands (+24…+32%). Our findings highlight that positive priming effects are predominant in most soils at a global scale. Optimizing strategies to incorporate fresh organic matter and nutrients is urgently needed to offset the priming-induced accelerated organic carbon turnover and possible losses.

Direct antiglobulin (Coombs) test in HIV-positive Talaromycosis marneffei patients.

Talaromycosis marneffei (T.M) is the primary opportunistic infection of AIDS patients, and its morbidity and mortality are extremely high. To further clarify the disease characteristics of patients and provide a solid basis for in-depth exploration of their pathogenic mechanisms, we retrospectively summarized and analyzed their clinical data. We included all T.M patients tested for direct antiglobulin test (DAT) in the study. Interestingly, we found that AIDS-T.M patients had an extremely high rate of DAT positivity (92/127, 72.44%). In univariate analysis, a positive DAT was associated with blood culture of TM (P = .021), hypoproteinemia (P = .001), anemia (P = .001), thrombocytopenia (P = .003), sepsis (P = .007), and Sequential Organ Failure Assessment (SOFA) (P = .001). Hypoproteinemia, anemia, SOFA, APTT > 32.6 s, and AST > 40 U/l were studied by logistic regression. Logistic regression revealed that SOFA (OR = 1.311, P = .043), hypoproteinemia (OR = 0.308, P = .021), and anemia (OR = 0.19, P = .044) were associated with positive DAT. Positive DAT was associated with severe disease manifestations such as sepsis, and the DAT test is crucial in patients with fungemia.

Talaromycosis marneffei (T.M) is the primary opportunistic infection of AIDS patients and causes high morbidity and mortality. AIDS-T.M patients who were positive for direct antiglobulin test had higher manifestations of inflammation, abnormal liver function, coagulation dysfunction, and hematologic abnormalities.

Neuregulin 4 Attenuates Podocyte Injury and Proteinuria in Part by Activating AMPK/mTOR-Mediated Autophagy in Mice.

In this study, we investigate the effect of neuregulin 4 (NRG4) on podocyte damage in a mouse model of diabetic nephropathy (DN) and we elucidate the underlying molecular mechanisms. In vivo experiments were conducted using a C57BL/6 mouse model of DN to determine the effect of NRG4 on proteinuria and podocyte injury, and in vitro experiments were performed with conditionally immortalized mouse podocytes treated with high glucose and NRG4 to assess the protective effects of NRG4 on podocyte injury. Autophagy-related protein levels and related signaling pathways were evaluated both in vivo and in vitro. The involvement of the adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway was detected using chloroquine or AMPK inhibitors. The results showed that the AMPK/mTOR pathway was involved in the protective roles of NRG4 against high glucose-mediated podocyte injury. Also, NRG4 significantly decreased albuminuria in DN mice. PAS staining indicated that NRG4 mitigated glomerular volume and mesangium expansion in DN mice. Consistently, western blot and RT-PCR analyses confirmed that NRG4 decreased the expression of pro-fibrotic molecules in the glomeruli of DN mice. The immunofluorescence results showed that NRG4 retained expression of podocin and nephrin, whereas transmission electron microscopy revealed that NRG4 alleviated podocyte injury. In DN mice, NRG4 decreased podocyte apoptosis and increased expression of nephrin and podocin, while decreasing the expression of desmin and HIF1α. Overall, NRG4 improved albuminuria, glomerulosclerosis, glomerulomegaly, and hypoxia in DN mice. The in vitro experiments showed that NRG4 inhibited HG-induced podocyte injury and apoptosis. Furthermore, autophagy of the glomeruli decreased in DN mice, but reactivated following NRG4 intervention. NRG4 intervention was found to partially activate autophagy via the AMPK/mTOR signaling pathway. Consequently, when the AMPK/mTOR pathway was suppressed or autophagy was inhibited, the beneficial effects of NRG4 intervention on podocyte injury were diminished. These results indicate that NRG4 intervention attenuates podocyte injury and apoptosis by promoting autophagy in the kidneys of DN mice, in part, by activating the AMPK/mTOR signaling pathway.

Colonization ability and uniformity of resources and environmental factors determine biological homogenization of soil protists in human land-use systems.

Humans have substantially transformed the global land surface, resulting in the decline in variation in biotic communities across scales, a phenomenon known as "biological homogenization." However, different biota are affected by biological homogenization to varying degrees, but this variation and the underlying mechanisms remain little studied, particularly in soil systems. To address this topic, we used metabarcoding to investigate the biogeography of soil protists and their prey/hosts (prokaryotes, fungi, and meso- and macrofauna) in three human land-use ecosystem types (farmlands, residential areas, and parks) and natural forest ecosystems across subtropical and temperate regions in China. Our results showed that the degree of community homogenization largely differed between taxa and functional groups of soil protists, and was strongly and positively linked to their colonization ability of human land-use systems. Removal analysis showed that the introduction of widespread, generalist taxa (OTUs, operational taxonomic units) rather than the loss of narrow-ranged, specialist OTUs was the major cause of biological homogenization. This increase in generalist OTUs seemingly alleviated the negative impact of land use on specialist taxa, but carried the risk of losing functional diversity. Finally, homogenization of prey/host biota and environmental conditions were also important drivers of biological homogenization in human land-use systems, with their importance being more pronounced in phagotrophic than parasitic and phototrophic protists. Overall, our study showed that the variation in biological homogenization strongly depends on the colonization ability of taxa in human land-use systems, but is also affected by the homogenization of resources and environmental conditions. Importantly, biological homogenization is not the major cause of the decline in the diversity of soil protists, and conservation and study efforts should target at taxa highly sensitive to local extinction, such as parasites.

Mineralization and microbial utilization of poly(lactic acid) microplastic in soil.

The current carbon dioxide (CO2) evolution-based standard method for determining biodegradable microplastics (MPs) degradation neglects its priming effect on soil organic matter decomposition, which misestimates their biodegradability. Here, a 13C natural abundance method was used to estimate the mineralization of poly(lactic acid) (PLA) MP in various agricultural soils, and to trace its utilization in different microbial groups. In alkaline soils, the PLA-derived CO2 emissions increased with increasing soil carbon/nitrogen (C/N) ratios, and the mineralization of PLA MP concentrations ranged from 3-33 %, whereas the CO2 evolution method probably over- or under-estimated the mineralization of PLA in alkaline soils with different soil C/N ratios. Low PLA mineralization (1-5 %) were found in the acidic soil, and the standard method largely overestimated the mineralization of PLA MP by 1.3- to 3.3-fold. Moreover, the hydrolysate of PLA MP was preferentially assimilated by Gram-negative bacteria, but Gram-positive bacterial decomposition mainly contributed to the release of PLA-derived CO2 at low MP concentrations (≤ 1 %). Overall, the 13C natural abundance method appears to be suitable for tracking the mineralization and microbial utilization of biodegradable PLA in soils, and the PLA-derived C is mainly assimilated and decomposed by bacterial groups.

Permafrost carbon cycle and its dynamics on the Tibetan Plateau.

Our knowledge on permafrost carbon (C) cycle is crucial for understanding its feedback to climate warming and developing nature-based solutions for mitigating climate change. To understand the characteristics of permafrost C cycle on the Tibetan Plateau, the largest alpine permafrost region around the world, we summarized recent advances including the stocks and fluxes of permafrost C and their responses to thawing, and depicted permafrost C dynamics within this century. We find that this alpine permafrost region stores approximately 14.1 Pg (1 Pg=1015 g) of soil organic C (SOC) in the top 3 m. Both substantial gaseous emissions and lateral C transport occur across this permafrost region. Moreover, the mobilization of frozen C is expedited by permafrost thaw, especially by the formation of thermokarst landscapes, which could release significant amounts of C into the atmosphere and surrounding water bodies. This alpine permafrost region nevertheless remains an important C sink, and its capacity to sequester C will continue to increase by 2100. For future perspectives, we would suggest developing long-term in situ observation networks of C stocks and fluxes with improved temporal and spatial coverage, and exploring the mechanisms underlying the response of ecosystem C cycle to permafrost thaw. In addition, it is essential to improve the projection of permafrost C dynamics through in-depth model-data fusion on the Tibetan Plateau.

Global turnover of soil mineral-associated and particulate organic carbon.

Soil organic carbon (SOC) persistence is predominantly governed by mineral protection, consequently, soil mineral-associated (MAOC) and particulate organic carbon (POC) turnovers have different impacts on the vulnerability of SOC to climate change. Here, we generate the global MAOC and POC maps using 8341 observations and then infer the turnover times of MAOC and POC by a data-model integration approach. Global MAOC and POC storages are 975 964 987 Pg C (mean with 5% and 95% quantiles) and 330 323 337 Pg C, while global mean MAOC and POC turnover times are 129 45 383 yr and 23 5 82 yr in the top meter, respectively. Climate warming-induced acceleration of MAOC and POC decomposition is greater in subsoil than that in topsoil. Overall, the global atlas of MAOC and POC turnover, together with the global distributions of MAOC and POC stocks, provide a benchmark for Earth system models to diagnose SOC-climate change feedback.

Contrasting impacts of fertilization on topsoil and subsoil greenhouse gas fluxes in a thinned Chinese fir plantation.

Globally, forest soils are considered as important sources and sinks of greenhouse gases (GHGs). However, most studies on forest soil GHG fluxes are confined to the topsoils (above 20 cm soil depths), with only very limited information being available regarding these fluxes in the subsoils (below 20 cm soil depths), especially in managed forests. This limits deeper understanding of the relative contributions of different soil depths to GHG fluxes and global warming potential (GWP). Here, we used a concentration gradient-based method to comprehensively investigate the effects of thinning intensity (15% vs. 35%) and nutrient addition (no fertilizer vs. NPK fertilizers) on soil GHG fluxes from the 0-40 cm soil layers at 10 cm depth intervals in a Chinese fir (Cunninghamia lanceolata) plantation. Results showed that forest soils were the sources of CO2 and N2O, but the sinks of CH4. Soil GHG fluxes decreased with increasing soil depth, with the 0-20 cm soil layers identified as the dominant producers of CO2 and N2O and consumers of CH4. Thinning intensity did not significantly affect soil GHG fluxes. However, fertilization significantly increased CO2 and N2O emissions and CH4 uptake at 0-20 cm soil layers, but decreased them at 20-40 cm soil layers. This is because fertilization alleviated microbial N limitation and decreased water filled pore space (WFPS) in topsoils, while it increased WFPS in subsoils, ultimately suggesting that soil WFPS and N availability (especially NH4+-N) were the predominant regulators of GHG fluxes along soil profiles. Generally, there were positive interactive effects of thinning and fertilization on soil GHG fluxes. Moreover, the 35% thinning intensity without fertilization had the lowest GWP among all treatments. Overall, our results suggest that fertilization may not only cause depth-dependent effects on GHG fluxes within soil profiles, but also impede efforts to mitigate climate change by promoting GHG emissions in managed forest plantations.

Whole-soil warming leads to substantial soil carbon emission in an alpine grassland.

The sensitivity of soil organic carbon (SOC) decomposition in seasonally frozen soils, such as alpine ecosystems, to climate warming is a major uncertainty in global carbon cycling. Here we measure soil CO2 emission during four years (2018-2021) from the whole-soil warming experiment (4 °C for the top 1 m) in an alpine grassland ecosystem. We find that whole-soil warming stimulates total and SOC-derived CO2 efflux by 26% and 37%, respectively, but has a minor effect on root-derived CO2 efflux. Moreover, experimental warming only promotes total soil CO2 efflux by 7-8% on average in the meta-analysis across all grasslands or alpine grasslands globally (none of these experiments were whole-soil warming). We show that whole-soil warming has a much stronger effect on soil carbon emission in the alpine grassland ecosystem than what was reported in previous warming experiments, most of which only heat surface soils.

Increase in HIV reservoir and T cell immune response after CoronaVac vaccination in people living with HIV.

Introduction: CoronaVac, an inactivated vaccine developed by Sinovac Life Sciences, has been widely used for protection against Coronavirus Disease 2019 (COVID-19). This study investigates its effect on the HIV reservoir and T cell repertoires in people living with HIV (PLWHs). Methods: Blood samples were collected from fifteen PLWHs who were administered at least two doses of CoronaVac between April 2021 and February 2022. The levels of cell-associated HIV RNA (CA HIV RNA) and HIV DNA, as well as the T cell receptor (TCR) repertoire profiles, TCR clustering and TCRß annotation, were studied. Results: A significant increase was observed in CA HIV RNA at 2 weeks (431.5 ± 164.2 copies/106 cells, P = 0.039) and 12 weeks (330.2 ± 105.9 copies/106 cells, P = 0.019) after the second dose, when compared to the baseline (0 weeks) (73.6 ± 23.7 copies/106 cells). Various diversity indices of the TCRß repertoire, including Shannon index, Pielou's evenness index, and Hvj Index, revealed a slight increase (P < 0.05) following CoronaVac vaccination. The proportion of overlapping TCRß clonotypes increased from baseline (31.9 %) to 2 weeks (32.5 %) and 12 weeks (40.4 %) after the second dose. We also found that the breadth and depth of COVID-19-specific T cells increased from baseline (0.003 and 0.0035) to 12 weeks (0.0066 and 0.0058) post the second dose. Conclusions: Our study demonstrated an initial increase in HIV reservoir and TCR repertoire diversity, as well as an expansion in the depth and breadth of COVID-19-specific T-cell clones among CoronaVac-vaccinated PLWHs. These findings provide important insights into the effects of COVID-19 vaccination in PLWHs.

Identification of an IGHV3-53-Encoded RBD-Targeting Cross-Neutralizing Antibody from an Early COVID-19 Convalescent.

Since November 2021, Omicron has emerged as the dominant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, and its sublineages continue to appear one after another, significantly reducing the effectiveness of existing therapeutic neutralizing antibodies (NAbs). It is urgent to develop effective NAbs against circulating Omicron variants. Here, we isolated receptor binding domain (RBD)-specific single memory B cells via flow cytometry from a COVID-19 convalescent. The antibody variable region genes of the heavy chain (VHs) and light chain (VLs) were amplified and cloned into expression vectors. After antibody expression, ELISA screening and neutralizing activity detection, we obtained an IGHV3-53-encoded RBD-targeting cross-neutralizing antibody D6, whose VL originated from the IGKV1-9*01 germlines. D6 could potently neutralize circulating Omicron variants (BA.1, BA.2, BA.4/5 and BF.7), with IC50 values of less than 0.04 µg/mL, and the neutralizing ability against XBB was reduced but still effective. The KD values of D6 binding with RBD of the prototype and BA.1 were both less than 1.0 × 10-12 M. The protein structure of the D6-RBD model indicates that D6 interacts with the RBD external subdomain and belongs to the RBD-1 community. The sufficient contact and deep interaction of D6 HCDR3 and LCDR3 with RBD may be the crucial reason for its cross-neutralizing activity. The sorting and analysis of mAb D6 will provide important information for the development of anti-COVID-19 reagents.

Reconciling carbon quality with availability predicts temperature sensitivity of global soil carbon mineralization.

Soil organic carbon (SOC) mineralization is a key component of the global carbon cycle. Its temperature sensitivity Q10 (which is defined as the factor of change in mineralization with a 10 °C temperature increase) is crucial for understanding the carbon cycle-climate change feedback but remains uncertain. Here, we demonstrate the universal control of carbon quality-availability tradeoffs on Q10. When carbon availability is not limited, Q10 is controlled by carbon quality; otherwise, substrate availability controls Q10. A model driven by such quality-availability tradeoffs explains 97% of the spatiotemporal variability of Q10 in incubations of soils across the globe and predicts a global Q10 of 2.1 ± 0.4 (mean ± one SD) with higher Q10 in northern high-latitude regions. We further reveal that global Q10 is predominantly governed by the mineralization of high-quality carbon. The work provides a foundation for predicting SOC dynamics under climate and land use changes which may alter soil carbon quality and availability.

Anti-N-methyl-D-aspartate Receptor Encephalitis in People Living with HIV: Case Report and Literature Review.

With the increase in the number of cases of autoimmune encephalitis (AE), the cerebrospinal fluid (CSF) of people living with HIV (PLWH) showing abnormal behavior, cognitive impairment or abnormal movements should be actively screened for the antibody panel of AE. Early recognition and treatment can prevent severe seizures or coma and markedly improve the prognosis of patients. The first-line immunotherapy for AE includes intravenous methylprednisolone and immunoglobulin. However, whether long-time immunosuppressive maintenance therapy is needed is debated. For PLWH, immunosuppressive therapy and even steroids could be more challenging. Here, we review and summarize the clinical characteristics often reported cases and report one case from our center to improve the diagnosis and treatment of anti-N-methyl-D-aspartate receptor encephalitis in PLWH.

Distinct Lipidomic Profiles between People Living with HIV Treated with E/C/F/TAF or B/F/TAF: An Open-Label Prospective Cohort Study.

INTRODUCTION: Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF) has been increasingly replaced by bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in the treatment of human immunodeficiency virus (HIV) owing to its more favorable pharmacokinetics and fewer drug-drug interactions. However, the effect of this switch on plasma lipids and lipidomic profiles remains poorly characterized. METHODS: HIV infected patients on an E/C/F/TAF regimen were recruited into the study and followed up every 12 weeks. Participants were divided into E/C/F/TAF and B/F/TAF groups depending on whether they were switched to B/F/TAF during follow-up. Clinical information and blood samples were collected at 0, 12, and 24 weeks, and lipidomic analysis was performed using liquid chromatography mass spectrometry. RESULTS: No significant differences were observed between the groups at baseline. At week 24, patients switched to B/F/TAF had lower triglyceride [mmol/L; 1.23 (0.62) versus 2.03 (0.75), P = 0.001] and very low-density lipoprotein cholesterol [mmol/L; 0.64 (0.26) versus 0.84 (0.32), P = 0.037) compared with patients who continued E/C/F/TAF therapy. Small decrease from baseline in Framingham general cardiovascular risk score (FRS) was observed in the B/F/TAF arm [week (W) 0: 2.59 (1.57) versus W24: 2.18 (1.01), P = 0.043]. Lipidomic analysis indicated that E/C/F/TAF treatment increased the levels of several diglycerides (DGs), triacylglycerols (TAGs), and lyso-phosphatidylcholines (LPCs), whereas switching to B/F/TAF led to increased sphingolipids and glycerophospholipids. After adjusting for demographic and clinical parameters, only DG (16:0/18:2), DG (18:2/22:6), DG (18:3/18:2), DG (20:5/18:2), TAG (18:3/18:2/21:5), TAG (20:5/18:2/22:6), and LPC (22:6) were found to be significantly associated with FRS (regression coefficient of 0.17-6.02, P < 0.05). Most of these FRS associate lipid species were significantly elevated in individuals treated with E/C/F/TAF instead of individuals treated with B/F/TAF. CONCLUSION: E/C/F/TAF promotes the accumulation of lipid species closely associated with cardiovascular disease (CVD) risk among people living with HIV, whereas B/F/TAF has a decreased impact on CVD-related lipid profile and is associated with lower CVD risk. A graphical abstract is available with this article. TRIAL REGISTRATION: ClinicalTrials.gov; identifier, NCT06019273.

Rhizosphere priming promotes plant nitrogen acquisition by microbial necromass recycling.

Nitrogen availability in the rhizosphere relies on root-microorganism interactions, where root exudates trigger soil organic matter (SOM) decomposition through the rhizosphere priming effect (RPE). Though microbial necromass contribute significantly to organically bound soil nitrogen (N), the role of RPEs in regulating necromass recycling and plant nitrogen acquisition has received limited attention. We used 15N natural abundance as a proxy for necromass-N since necromass is enriched in 15N compared to other soil-N forms. We combined studies using the same experimental design for continuous 13CO2 labelling of various plant species and the same soil type, but considering top- and subsoil. RPE were quantified as difference in SOM-decomposition between planted and unplanted soils. Results showed higher plant N uptake as RPEs increased. The positive relationship between 15N-enrichment of shoots and roots and RPEs indicated an enhanced necromass-N turnover by RPE. Moreover, our data revealed that RPEs were saturated with increasing carbon (C) input via rhizodeposition in topsoil. In subsoil, RPEs increased linearly within a small range of C input indicating a strong effect of root-released C on decomposition rates in deeper soil horizons. Overall, this study confirmed the functional importance of rhizosphere C input for plant N acquisition through enhanced necromass turnover by RPEs.

Improved soil moisture, nutrients, and economic benefits using plastic mulchs in balsa-based agroforestry systems.

The manufacture of wind turbine blades generally uses balsa wood as the base materials, and it is crucial to explore new regions for cultivating balsa trees to achieve carbon neutrality in the future. Xishuangbanna may be China's only area with a tropical climate suitable for the large-scale planting of balsa trees. The present study investigated the key soil elements influencing the growth of balsa plantations and the effects of different cultivation practices on soil environments and economic benefits in Xishuangbanna, China. We found that the height of balsa stems after growing 4 years reached 5.8 m; the increment of diameter at breast height (DBH) reached 27.7 cm and volume of balsa stems reached 196.0 m3 ha-1 in Xishuangbanna of China. It is of the utmost importance to improve the contents of soil exchangeable magnesium (Mg) and available phosphorus (P) for the growth of balsa trees, and exchangeable aluminium (Al) inhibited the growth of balsa trees. The practice of plastic film mulching not only improved soil moisture in the 40‒100-cm soil layer in the dry season and in the 0-60-cm soil layer in the rainy season but also enhanced soil nitrate nitrogen when compared with no plastic-mulching practice in balsa plantations. The comprehensive economic benefits of balsa/coriander/ginger/taro plantations were significantly improved by implementing plastic film mulching, as compared to balsa plantations. We conclude that balsa tree can be cultivated in Xishuangbanna, China, and its successful cultivation provides opportunities for China's wind power development.

Primary activation of para-quinone methides by chiral phosphoric acid for enantioselective construction of tetraarylmethanes.

Demonstrated here is an asymmetric nucleophilic addition via primary activation of para-quinone methides (p-QMs) based on a chiral phosphoric acid catalytic system. In sharp contrast to previous CPA-based bifunctional activation processes that all required the nucleophiles to have an effective hydrogen bond donor unit (e.g., OH, NH), here no such unit is required in the nucleophile. N-protected indole nucleophiles were successfully utilized for the synthesis of chiral tetraarylmethanes with high efficiency and enantioselectivity under mild conditions. Therefore, this protocol significantly expanded the scope of asymmetric transformations of p-QMs.

Effects of whole-soil warming on CH4 and N2 O fluxes in an alpine grassland.

Global climate warming could affect the methane (CH4 ) and nitrous oxide (N2 O) fluxes between soils and the atmosphere, but how CH4 and N2 O fluxes respond to whole-soil warming is unclear. Here, we for the first time investigated the effects of whole-soil warming on CH4 and N2 O fluxes in an alpine grassland ecosystem on the Tibetan Plateau, and also studied the effects of experimental warming on CH4 and N2 O fluxes across terrestrial ecosystems through a global-scale meta-analysis. The whole-soil warming (0-100 cm, +4°C) significantly elevated soil N2 O emission by 101%, but had a minor effect on soil CH4 uptake. However, the meta-analysis revealed that experimental warming did not significantly alter CH4 and N2 O fluxes, and it may be that most field warming experiments could only heat the surface soils. Moreover, the warming-induced higher plant litter and available N in soils may be the main reason for the higher N2 O emission under whole-soil warming in the alpine grassland. We need to pay more attention to the long-term response of greenhouse gases (including CH4 and N2 O fluxes) from different soil depths to whole-soil warming over year-round, which could help us more accurately assess and predict the ecosystem-climate feedback under realistic warming scenarios in the future.

Independent and combined effects of microplastics pollution and drought on soil bacterial community.

Global terrestrial ecosystems are simultaneously threatened by multiple environmental pressures, with microplastics (MPs) pollution and drought possibly being the most pressing, both of which may have unanticipated effects on soil organisms. Here, we investigated the responses of diversity, composition and functions of soil bacterial community to MPs pollution (including two MPs types: polyethylene (PE) and polylactic acid (PLA); two MPs sizes: < 20 µm and <300 µm) and drought in microcosms. We found that only 20 µm PLA MPs significantly decreased soil bacterial diversity by 17.4 % and altered soil bacterial community composition, while PE MPs and 300 µm PLA MPs had no significant effects. The copiotrophic bacteria (i.e., Proteobacteria and Firmicutes) were enriched in the 20 µm PLA MPs pollution soils due to the enhanced dissolved organic carbon contents. Moreover, our results showed that the 20 µm PLA MPs also affected the potential phenotypes and functions of soil bacterial community, increasing the potentially pathogenic, stress-tolerant, containing mobile elements and forming biofilms phenotypes, and promoting membrane transport and signal transduction pathways. These results suggested that the effects of MPs on soil bacterial community varied depending on MPs types and sizes. However, drought significantly increased soil bacterial diversity by 10.3 % and affected soil bacterial community composition in the 20 µm PLA MPs pollution soils. We also found that drought inhibited the levels of potentially pathogenic, containing mobile elements and forming biofilms phenotypes in the 20 µm PLA MPs pollution soils. Taken together, these findings reveal that drought may alleviate the adverse effects of MPs pollution on soil bacterial community, which enhances our understanding of the interactive effects of multiple global change factors on agroecosystem functions.