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Soils are the foundation of all terrestrial ecosystems1. However, unlike for plants and animals, a global assessment of hotspots for soil nature conservation is still lacking2. This hampers our ability to establish nature conservation priorities for the multiple dimensions that support the soil system: from soil biodiversity to ecosystem services. Here, to identify global hotspots for soil nature conservation, we performed a global field survey that includes observations of biodiversity (archaea, bacteria, fungi, protists and invertebrates) and functions (critical for six ecosystem services) in 615 composite samples of topsoil from a standardized survey in all continents. We found that each of the different ecological dimensions of soils-that is, species richness (alpha diversity, measured as amplicon sequence variants), community dissimilarity and ecosystem services-peaked in contrasting regions of the planet, and were associated with different environmental factors. Temperate ecosystems showed the highest species richness, whereas community dissimilarity peaked in the tropics, and colder high-latitudinal ecosystems were identified as hotspots of ecosystem services. These findings highlight the complexities that are involved in simultaneously protecting multiple ecological dimensions of soil. We further show that most of these hotspots are not adequately covered by protected areas (more than 70%), and are vulnerable in the context of several scenarios of global change. Our global estimation of priorities for soil nature conservation highlights the importance of accounting for the multidimensionality of soil biodiversity and ecosystem services to conserve soils for future generations.
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Biodiversidade , Conservação dos Recursos Naturais , Mapeamento Geográfico , Microbiologia do Solo , Solo , Animais , Conservação dos Recursos Naturais/métodos , Solo/parasitologia , Invertebrados , ArchaeaRESUMO
Deforestation poses a global threat to biodiversity and its capacity to deliver ecosystem services. Yet, the impacts of deforestation on soil biodiversity and its associated ecosystem services remain virtually unknown. We generated a global dataset including 696 paired-site observations to investigate how native forest conversion to other land uses affects soil properties, biodiversity, and functions associated with the delivery of multiple ecosystem services. The conversion of native forests to plantations, grasslands, and croplands resulted in higher bacterial diversity and more homogeneous fungal communities dominated by pathogens and with a lower abundance of symbionts. Such conversions also resulted in significant reductions in carbon storage, nutrient cycling, and soil functional rates related to organic matter decomposition. Responses of the microbial community to deforestation, including bacterial and fungal diversity and fungal guilds, were predominantly regulated by changes in soil pH and total phosphorus. Moreover, we found that soil fungal diversity and functioning in warmer and wetter native forests is especially vulnerable to deforestation. Our work highlights that the loss of native forests to managed ecosystems poses a major global threat to the biodiversity and functioning of soils and their capacity to deliver ecosystem services.
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Ecossistema , Microbiota , Solo/química , Conservação dos Recursos Naturais , Biodiversidade , Florestas , Bactérias , Microbiologia do SoloRESUMO
Microbes inhabiting deep soil layers are known to be different from their counterpart in topsoil yet remain under investigation in terms of their structure, function, and how their diversity is shaped. The microbiome of deep soils (>1 m) is expected to be relatively stable and highly independent from climatic conditions. Much less is known, however, on how these microbial communities vary along climate gradients. Here, we used amplicon sequencing to investigate bacteria, archaea, and fungi along fifteen 18-m depth profiles at 20-50-cm intervals across contrasting aridity conditions in semi-arid forest ecosystems of China's Loess Plateau. Our results showed that bacterial and fungal α diversity and bacterial and archaeal community similarity declined dramatically in topsoil and remained relatively stable in deep soil. Nevertheless, deep soil microbiome still showed the functional potential of N cycling, plant-derived organic matter degradation, resource exchange, and water coordination. The deep soil microbiome had closer taxa-taxa and bacteria-fungi associations and more influence of dispersal limitation than topsoil microbiome. Geographic distance was more influential in deep soil bacteria and archaea than in topsoil. We further showed that aridity was negatively correlated with deep-soil archaeal and fungal richness, archaeal community similarity, relative abundance of plant saprotroph, and bacteria-fungi associations, but increased the relative abundance of aerobic ammonia oxidation, manganese oxidation, and arbuscular mycorrhizal in the deep soils. Root depth, complexity, soil volumetric moisture, and clay play bridging roles in the indirect effects of aridity on microbes in deep soils. Our work indicates that, even microbial communities and nutrient cycling in deep soil are susceptible to changes in water availability, with consequences for understanding the sustainability of dryland ecosystems and the whole-soil in response to aridification. Moreover, we propose that neglecting soil depth may underestimate the role of soil moisture in dryland ecosystems under future climate scenarios.
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Bactérias , Microbiota , Bactérias/metabolismo , Archaea , Solo/química , Água/metabolismo , Microbiologia do SoloRESUMO
Plant-soil biodiversity interactions are fundamental for the functioning of terrestrial ecosystems. Yet, the existence of a set of globally distributed topsoil microbial and small invertebrate organisms consistently associated with land plants (i.e., their consistent soil-borne microbiome), together with the environmental preferences and functional capabilities of these organisms, remains unknown. We conducted a standardized field survey under 150 species of land plants, including 58 species of bryophytes and 92 of vascular plants, across 124 locations from all continents. We found that, despite the immense biodiversity of soil organisms, the land plants evaluated only shared a small fraction (less than 1%) of all microbial and invertebrate taxa that were present across contrasting climatic and soil conditions and vegetation types. These consistent taxa were dominated by generalist decomposers and phagotrophs and their presence was positively correlated with the abundance of functional genes linked to mineralization. Finally, we showed that crossing environmental thresholds in aridity (aridity index of 0.65, i.e., the transition from mesic to dry ecosystems), soil pH (5.5; i.e., the transition from acidic to strongly acidic soils), and carbon (less than 2%, the lower limit of fertile soils) can result in drastic disruptions in the associations between land plants and soil organisms, with potential implications for the delivery of soil ecosystem processes under ongoing global environmental change.
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Embriófitas , Microbiota , Microbiologia do Solo , Biodiversidade , Solo/químicaRESUMO
Foliar assimilation of elemental mercury (Hg0) from the atmosphere plays a critical role in the global Hg biogeochemical cycle, leading to atmospheric Hg removal and soil Hg insertion. Recent studies have estimated global foliar Hg assimilation; however, large uncertainties remained due to coarse accounting of observed foliar Hg concentrations, posing a substantial challenge in constraining the global Hg budget. Here, we integrated a comprehensive observation database of foliar Hg concentrations and machine learning algorithms to predict the first spatial distribution of foliar Hg concentrations on a global scale, contributing to the first estimate of global Hg pools in foliage. The global average of foliar Hg concentrations was estimated to be 24.0 ng g-1 (7.5-56.5 ng g-1), and the global total in foliar Hg pools reached 4561.3 Mg (1455.2-9062.8 Mg). The spatial distribution showed the hotspots in tropical regions, including the Amazon, Central Africa, and Southeast Asia. A range of 2268.5-2727.0 Mg yr-1 was estimated for annual foliar Hg assimilation accounting for the perennial continuous assimilation by evergreen vegetation foliage. The first spatial maps of foliar Hg concentrations and Hg pools may aid in understanding the global biogeochemical cycling of Hg, especially in the context of climate change and global vegetation greening.
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Mercury, a neurotoxic substance, circulates globally, significantly stored in soils through atmospheric deposition and plant decay. Despite being deposited, mercury can be remobilized and released into the atmosphere and water, enhancing its global cycle. Recent research suggests that climate warming may amplify the remobilization of soil mercury, facilitating its incorporation into food webs that humans exploit. However, the potential geospatial feedback of soil mercury levels in response to warming remains unclear. By leveraging up-to-date soil measurements and observation-driven models, we determined the amount of mercury stored in global 0-100 cm soils to be 4.3 Tg (interquartile range: 2.5-6.3 Tg). Furthermore, our analysis indicates that warming likely aggravates global soil mercury levels, particularly in many temperate areas in East Asia, North Europe, and North America (>20 ng g-1 increase by 2100) due to warming-induced vegetation greening. Critically, observation-driven models raise the possibility that implementing ambitious mercury-emission-control schemes alone may be insufficient to counterbalance the positive feedback of soil mercury concentration, while process-based biogeochemical modeling demonstrates consistent patterns that reinforce this concern. These findings hold broad implications; for example, such feedback may catalyze mercury remobilization in land-ocean continuums and exacerbate human risks, stressing the necessity for continued reductions in greenhouse gas and mercury emissions.
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With the increasing amount of renewable energy produced, many governments and industries are pushing for the installation of battery energy storage system (BESS) solutions. Thermal batteries are systems that store heat made from various energy sources, and can be used to produce electricity upon demand. These systems are easily scalable and can be installed in cities, homes and remote locations. Thermochemical energy storage (TCES) uses the enthalpy of a chemical reaction to store and release heat through endothermic and exothermic processes, respectively. CaCO3 has been identified as an ideal TCES material as it is cheap and abundant, but maximising long-term cyclability is key to ensure battery longevity. This article investigates the addition of CaSiO3, CaTiO3 and CaZrO3 to CaCO3 in a 1 : 1 ratio to ascertain the reaction properties and cyclic capacity over time. Cycling longevity and thermodynamic properties were determined using simultaneous differential scanning calorimetry and thermogravimetric analysis (DSC-TGA) along with the Sieverts technique, and their reaction pathway studied by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The low cost of the CaCO3-CaSiO3 material of $1.8 USD per kW hth suggests that if a suitable particle refinement agent were to be employed to ensure cycling longevity this material would be an excellent TCES material. Despite the CO2 cycling capacity of the CaCO3-CaZrO3 system only reducing by 16 wt% over 100 cycles, the cost of ZrO2 brings the materials cost to $30.9 USD per kW hth, making this material currently unsuitable for application. The CaCO3-CaTiO3 system showed only a 17% drop in total CO2 uptake over 100 cycles, although the cost was $11.1 USD per kW hth.
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Ultrafine KAl(OH)2CO3 dry powder (UDWP), as a novel high-temperature-resistant ultrafine dry powder fire extinguishing agent, has garnered significant attention in the field of aviation fire protection. However, its development has been hindered by its hydrophilicity, which leads to hygroscopicity, and its tendency for re-ignition due to oil deposition. Therefore, this study employs perfluorodecyltrimethoxysilane (PFDTMS) to modify the surface of UDWP, resulting in hydrophobic and oleophobic M-UDWP. The thermal stability and hydrophobicity of M-UDWP ensure its long-term stable storage in aircraft equipment compartments, thereby reducing aircraft maintenance costs. Additionally, its oleophobicity provides excellent anti-re-ignition performance, protecting aircraft power compartments from secondary fire damage. Energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses indicate that the PFDTMS modifier was successfully grafted onto KAl(OH)2CO3. Furthermore, M-UDWP exhibits a three-stage thermal decomposition process. The first-stage decomposition can be regarded as a single-step reaction, and the calculated kinetic parameters provide accurate predictions. Thermogravimetric analysis-Fourier transform infrared spectroscopy-mass spectrometry (TG-FTIR-MS) results reveal that M-UDWP significantly produces H2O and CO2 during thermal decomposition, which is one of its core fire extinguishing mechanisms. For the combustion of #RP-3 and #RP-5 aviation kerosene, commonly found in aircraft engine nacelles, the extinguishing times required by M-UDWP are 243 ms and 224 ms, respectively, with minimum extinguishing concentrations (MEC) of 25.9 g/m3 and 23.4 g/m3, respectively. The study of M-UDWP's thermal stability aids in understanding its storage stability under high-temperature conditions and its fire extinguishing mechanisms in fire zones. Moreover, the research findings suggest that M-UDWP has the potential to replace Halon 1301 in aircraft engine nacelles.
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Tumor-specific activatable long-wavelength (LW) photosensitizers (PSs) show promise in overcoming the limitations of traditional photodynamic therapy (PDT), such as systemic phototoxicity and shallow tissue penetration. However, their insufficient LW light absorption and low singlet oxygen quantum yield (Φ 1O2) usually require high laser power density to produce thermal energy and synergistically enhance PDT. The strong photothermal radiation causing acute pain significantly reduces patient compliance and hinders the broader clinical application of LW PDT. Through the exciton dynamics dissection strategy, we have developed a series of pH-activatable cyanine-based LW PSs (LET-R, R = H, Cl, Br, I), among which the activated LET-I exhibits strong light absorption at 808â nm and a remarkable 3.2-fold enhancement in Φ 1O2 compared to indocyanine green. Transient spectroscopic analysis and theoretical calculations confirmed its significantly promoted intersystem crossing and simultaneously enhanced LW fluorescence emission characteristics. These features enable the activatable fluorescence and photoacoustic dual-modal imaging-escorted complete photodynamic eradication of tumors by the folic acid (FA)-modified LET-I probe (LET-I-FA), under the ultralow 808â nm laser power density (0.2â W cm-2) for irradiation, without the need for photothermal energy synergy. This research presents a novel strategy of dissecting exciton dynamics to screen activatable LW PSs for traceable PDT.
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Microbial communities play critical roles in fixing carbon from the atmosphere and fixing it in the soils. However, the large-scale variations and drivers of these microbial communities remain poorly understood. Here, we conducted a large-scale survey across China and found that soil autotrophic organisms are critical for explaining CO2 fluxes from the atmosphere to soils. In particular, we showed that large-scale variations in CO2 fixation rates are highly correlated to those in autotrophic bacteria and phototrophic protists. Paddy soils, supporting a larger proportion of obligate bacterial and protist autotrophs, display four-fold of CO2 fixation rates over upland and forest soils. Precipitation and pH, together with key ecological clusters of autotrophic microbes, also played important roles in controlling CO2 fixation. Our work provides a novel quantification on the contribution of terrestrial autotrophic microbes to soil CO2 fixation processes at a large scale, with implications for global carbon regulation under climate change.
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Dióxido de Carbono , Solo , Solo/química , Microbiologia do Solo , Processos Autotróficos/fisiologia , Carbono , BactériasRESUMO
Microbial residues contribute to the long-term stabilization of carbon in the entire soil profile, helping to regulate the climate of the planet; however, how sensitive these residues are to climatic seasonality remains virtually unknown, especially for deep soils across environmental gradients. Here, we investigated the changes of microbial residues along soil profiles (0-100 cm) from 44 typical ecosystems with a wide range of climates (~3100 km transects across China). Our results showed that microbial residues account for a larger portion of soil carbon in deeper (60-100 cm) vs. shallower (0-30 and 30-60 cm) soils. Moreover, we find that climate especially challenges the accumulation of microbial residues in deep soils, while soil properties and climate share their roles in controlling the residue accumulation in surface soils. Climatic seasonality, including positive correlations with summer precipitation and maximum monthly precipitation, as well as negative correlations with temperature annual range, are important factors explaining microbial residue accumulation in deep soils across China. In particular, summer precipitation is the key regulator of microbial-driven carbon stability in deep soils, which has 37.2% of relative independent effects on deep-soil microbial residue accumulation. Our work provides novel insights into the importance of climatic seasonality in driving the stabilization of microbial residues in deep soils, challenging the idea that deep soils as long-term carbon reservoirs can buffer climate change.
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Carbono , Microbiologia do Solo , Solo , Carbono/análise , China , Mudança Climática , Ecossistema , Solo/químicaRESUMO
It remains unknown whether plastic-biodegrading macroinvertebrates generate microplastics (MPs) and nanoplastics (NPs) during the biodegradation of plastics. In this study, we utilized highly sensitive particle analyzers and pyrolyzer-gas chromatography mass spectrometry (Py-GCMS) to investigate the possibility of generating MPs and NPs in frass during the biodegradation of polystyrene (PS) and low-density polyethylene (LDPE) foams by mealworms (Tenebrio molitor larvae). We also developed a digestive biofragmentation model to predict and unveil the fragmentation process of ingested plastics. The mealworms removed 77.3% of ingested PS and 71.1% of ingested PE over a 6-week test period. Biodegradation of both polymers was verified by the increase in the δ13C signature of residual plastics, changes in molecular weights, and the formation of new oxidative functional groups. MPs accumulated in the frass due to biofragmentation, with residual PS and PE exhibiting the maximum percentage by number at 2.75 and 7.27 µm, respectively. Nevertheless, NPs were not detected using a laser light scattering sizer with a detection limit of 10 nm and Py-GCMS analysis. The digestive biofragmentation model predicted that the ingested PS and PE were progressively size-reduced and rapidly biodegraded, indicating the shorter half-life the smaller plastic particles have. This study allayed concerns regarding the accumulation of NPs by plastic-degrading mealworms and provided critical insights into the factors controlling MP and NP generation during macroinvertebrate-mediated plastic biodegradation.
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Poliestirenos , Tenebrio , Animais , Polietileno , Tenebrio/metabolismo , Plásticos , Larva/metabolismo , Biodegradação Ambiental , MicroplásticosRESUMO
Soil stores a large amount of mercury (Hg) that has adverse effects on human health and ecosystem safety. Significant uncertainties still exist in revealing environmental drivers of soil Hg accumulation and predicting global Hg distribution owing to the lack of field data from global standardized analyses. Here, we conducted a global standardized field survey and explored a holistic understanding of the multidimensional environmental drivers of Hg accumulation in global surface soils. Hg content in surface soils from our survey ranges from 3.8 to 618.2 µg kg-1 with an average of 74.0 µg kg-1 across the globe. Atmospheric Hg deposition, particularly vegetation-induced elemental Hg0 deposition, is the major source of surface soil Hg. Soil organic carbon serves as the major substrate for sequestering Hg in surface soils and is significantly influenced by agricultural management, litterfall, and elevation. For human activities, changing land-use could be a more important contributor than direct anthropogenic emissions. Our prediction of a new global Hg distribution highlights the hot spots (high Hg content) in East Asia, the Northern Hemispheric temperate/boreal regions, and tropical areas, while the cold spots (low Hg content) are in arid regions. The holistic understanding of multidimensional environmental drivers helps to predict the Hg distribution in global surface soils under a changing global environment.
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Mercúrio , Poluentes do Solo , Humanos , Mercúrio/análise , Solo/química , Ecossistema , Carbono , Monitoramento AmbientalRESUMO
Protist predation is a crucial biotic driver modulating bacterial populations and functional traits. Previous studies using pure cultures have demonstrated that bacteria with copper (Cu) resistance exhibited fitness advantages over Cu-sensitive bacteria under the pressure of protist predation. However, the impact of diverse natural communities of protist grazers on bacterial Cu resistance in natural environments remains unknown. Here, we characterized the communities of phagotrophic protists in long-term Cu-contaminated soils and deciphered their potential ecological impacts on bacterial Cu resistance. Long-term field Cu pollution increased the relative abundances of most of the phagotrophic lineages in Cercozoa and Amoebozoa but reduced the relative abundance of Ciliophora. After accounting for soil properties and Cu pollution, phagotrophs were consistently identified as the most important predictor of the Cu-resistant (CuR) bacterial community. Phagotrophs positively contributed to the abundance of a Cu resistance gene (copA) through influencing the cumulative relative abundance of Cu-resistant and -sensitive ecological clusters. Microcosm experiments further confirmed the promotion effect of protist predation on bacterial Cu resistance. Our results indicate that the selection by protist predation can have a strong impact on the CuR bacterial community, which broadens our understanding of the ecological function of soil phagotrophic protists.
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Cobre , Solo , Cobre/farmacologia , Bactérias/genética , Microbiologia do SoloRESUMO
Methylmercury (MeHg) is a potent neurotoxin and has great adverse health impacts on humans. Organisms and sunlight-mediated demethylation are well-known detoxification pathways of MeHg, yet whether abiotic environmental components contribute to MeHg degradation remains poorly known. Here, we report that MeHg can be degraded by trivalent manganese (Mn(III)), a naturally occurring and widespread oxidant. We found that 28 ± 4% MeHg could be degraded by Mn(III) located on synthesized Mn dioxide (MnO2-x) surfaces during the reaction of 0.91 µg·L-1 MeHg and 5 g·L-1 mineral at an initial pH of 6.0 for 12 h in 10 mM NaNO3 at 25 °C. The presence of low-molecular-weight organic acids (e.g., oxalate and citrate) substantially enhances MeHg degradation by MnO2-x via the formation of soluble Mn(III)-ligand complexes, leading to the cleavage of the carbon-Hg bond. MeHg can also be degraded by reactions with Mn(III)-pyrophosphate complexes, with apparent degradation rate constants comparable to those by biotic and photolytic degradation. Thiol ligands (cysteine and glutathione) show negligible effects on MeHg demethylation by Mn(III). This research demonstrates potential roles of Mn(III) in degrading MeHg in natural environments, which may be further explored for remediating heavily polluted soils and engineered systems containing MeHg.
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Mercúrio , Compostos de Metilmercúrio , Humanos , Manganês/química , Compostos de Metilmercúrio/metabolismo , Oxidantes/química , CisteínaRESUMO
Telemetry data are the most important basis for ground operators to assess the status of satellites in orbit, and telemetry data-based anomaly detection has become a key tool to improve the reliability and safety of spacecrafts. Recent research on anomaly detection focuses on constructing a normal profile of telemetry data using deep learning methods. However, these methods cannot effectively capture the complex correlations between the various dimensions of telemetry data, and thus cannot accurately model the normal profile of telemetry data, resulting in poor anomaly detection performance. This paper presents CLPNM-AD, contrastive learning with prototype-based negative mixing for correlation anomaly detection. The CLPNM-AD framework first employs an augmentation process with random feature corruption to generate augmented samples. Following that, a consistency strategy is employed to capture the prototype of samples, and then prototype-based negative mixing contrastive learning is used to build a normal profile. Finally, a prototype-based anomaly score function is proposed for anomaly decision-making. Experimental results on public datasets and datasets from the actual scientific satellite mission show that CLPNM-AD outperforms the baseline methods, achieves up to 11.5% improvement based on the standard F1 score and is more robust against noise.
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Recombinant tissue-type plasminogen activator (rtPA) is the clot lysis drug approved for clinical use, and is characterised by a short half-life and substantial inactivation by plasminogen activator inhibitor-1 (PAI-1). We previously discovered that a tPA mutation (A419Y) at the protease domain led to enhanced fibrinolysis activity. In the present study, we studied the mechanism of such mutation in enhancing the proteolytic activity, and whether such enhancement persists in reteplase, an United States Food and Drug Administration-approved tPA truncated variant. We constructed and expressed a series of reteplase-based mutants, including rPAG (glycosylated rPA), rPAG -Y (with A419Y mutant at rPAG ), rPAG -A4 (tetra-alanine mutation at 37-loop of rPAG ), and rPAG -A4/Y (with both) and evaluated their plasminogen activation and PAI-1 resistance. Surface plasmon resonance analysis showed that the rPAG had fibrin affinity comparable to full-length tPA. Moreover, rPAG -Y had 8·5-fold higher plasminogen activation and stronger tolerance to PAI-1 compared to rPAG . We also found that the mutations containing tetra-alanine (rPAG -A4 and rPAG -A4/Y) had dramatically reduced plasminogen activation and impaired clot lysis. In a pulmonary embolism murine model, rPAG -Y displayed a more efficient thrombolytic effect than rPAG . These results identified a novel mutant reteplase variant of tPA with increased fibrinolytic activity, laying the foundation for the development of a new potent fibrinolytic agent.
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Tempo de Lise do Coágulo de Fibrina/métodos , Fibrinólise/efeitos dos fármacos , Fibrinolíticos/uso terapêutico , Ativador de Plasminogênio Tecidual/uso terapêutico , Animais , Fibrinolíticos/farmacologia , Humanos , Camundongos , Mutação Puntual , Proteínas Recombinantes/farmacologia , Proteínas Recombinantes/uso terapêutico , Ativador de Plasminogênio Tecidual/farmacologiaRESUMO
Warming is known to reduce soil carbon (C) stocks by promoting microbial respiration, which is associated with the decomposition of microbial residue carbon (MRC). However, the relative contribution of MRC to soil organic carbon (SOC) across temperature gradients is poorly understood. Here, we investigated the contribution of MRC to SOC along two independent elevation gradients of our model system (i.e., the Tibetan Plateau and Shennongjia Mountain in China). Our results showed that local temperature increases were negatively correlated with MRC and SOC. Further analyses revealed that rising temperature reduced SOC via decreasing MRC, which helps to explain future reductions in SOC under climate warming. Our findings demonstrate that climate warming has the potential to reduce C sequestration by increasing the decomposition of MRC, exacerbating the positive feedback between rising temperature and CO2 efflux. Our study also considered the influence of multiple environmental factors such as soil pH and moisture, which were more important in controlling SOC than microbial traits such as microbial life-style strategies and metabolic efficiency. Together, our work suggests an important mechanism underlying long-term soil C sequestration, which has important implications for the microbial-mediated C process in the face of global climate change.
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Carbono , Solo , Carbono/metabolismo , Dióxido de Carbono , Solo/química , Microbiologia do Solo , TemperaturaRESUMO
The Minamata Convention on Mercury calls for Hg control actions to protect the environment and human beings from the adverse impacts of Hg pollution. It aims at the entire life cycle of Hg. Existing studies on the Hg cycle in the global environmental-economic system have characterized the emission-to-impact pathway of Hg pollution. That is, Hg emissions/releases from the economic system can have adverse impacts on human health and ecosystems. However, current modeling of the Hg cycle is not fully looped. It ignores the feedback of Hg-related environmental impacts (including human health impacts and ecosystem impacts) to the economic system. This would impede the development of more comprehensive Hg control actions. By synthesizing recent information on Hg cycle modeling, this critical review found that Hg-related environmental impacts would have feedbacks to the economic system via the labor force and biodiversity loss. However, the interactions between Hg-related activities in the environmental and economic systems are not completely clear. The cascading effects of Hg-related environmental impacts to the economic system throughout global supply chains have not been revealed. Here, we emphasize the knowledge gaps and propose possible approaches for looping the Hg cycle in global environmental-economic system modeling. This progress is crucial for formulating more dynamic and flexible Hg control measures. It provides new perspectives for the implementation of the Minamata Convention on Mercury.
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Mercúrio , Ecossistema , Meio Ambiente , Monitoramento Ambiental , Poluição Ambiental , Humanos , Mercúrio/análise , Modelos TeóricosRESUMO
Bacterial metal detoxification mechanisms have been well studied for centuries in pure culture systems. However, profiling metal resistance determinants at the community level is still a challenge due to the lack of comprehensive and reliable quantification tools. Here, a novel high-throughput quantitative polymerase chain reaction (HT-qPCR) chip, termed the metal resistance gene (MRG) chip, has been developed for the quantification of genes involved in the homeostasis of 9 metals. The MRG chip contains 77 newly designed degenerate primer sets and 9 published primer sets covering 56 metal resistance genes. Computational evaluation of the taxonomic coverage indicated that the MRG chip had a broad coverage matching 2 kingdoms, 29 phyla, 64 classes, 130 orders, 226 families, and 382 genera. Temperature gradient PCR and HT-qPCR verified that 57 °C was the optimal annealing temperature, with amplification efficiencies of over 94% primer sets achieving 80-110%, with R2 > 0.993. Both computational evaluation and the melting curve analysis of HT-qPCR validated a high specificity. The MRG chip has been successfully applied to characterize the distribution of diverse metal resistance determinants in natural and human-related environments, confirming its wide scope of application. Collectively, the MRG chip is a powerful and efficient high-throughput quantification tool for exploring the microbial metal resistome.