From holocene to anthropogenic impact: Surpassing coral's pH up-regulation capacity under ocean acidification

Corals' regulation of internal calcifying fluid (CF or cf) chemistry is crucial for their extraordinary calcification capacity, endowing them with a certain ability to cope with environmental changes such as anthropogenic ocean acidification (OA) and warming. However, it remains unclear whether the impacts of these changes on corals have substantially surpassed their regulation capacity, particularly in comparison to the CF chemistry responses to natural climate variability with minor or no human perturbation. In this study, we reconstructed the pH, dissolved inorganic carbon, and carbonate ion concentrations in coral CF (pH(cf), DICcf, and [CO32-](cf)) during the Mid- to Late-Holocene, by analyzing the skeletal delta B-11 and B/Ca of 80 Porites spp. from eastern Hainan Island in the South China Sea (SCS). Our records indicate considerable inter-colony variations in CF chemistry, with maximum disparities reaching 0.18 units for pH(cf) and 1664 mu mol/kg for DICcf. With this in mind, we found no clear responses of coral DICcf to the climate fluctuations during the past similar to 5500 years, nor evident differences in pH(cf) and [CO32-](cf) across pre-industrial natural epochs. However, pH(cf) and [CO32-](cf) of modern corals have significantly declined compared to fossil corals. Further analyzes compiling global data on Porites spp. also confirm this pronounced pH(cf) decrease in modern corals, suggesting the limitations of pantropical corals to counteract OA by up-regulating pH(cf). Importantly, these fossil and modern corals reveal a clear long-term pH(cf) descending trend parallel to atmospheric CO2 changes, supporting the reliability of coral delta B-11 in recording long-term changes in seawater pH (pH(sw))

Molecular characteristics of organic matters in PM 2.5 associated with upregulation of respiratory virus infection<i> in</i><i> vitro</i>

The extent to which organic matters (OM) in PM 2.5 affect virus infections and the key organic molecules involved in this process remain unclear. Herein, this study utilized ultra-high resolution mass spectrometry coupled with in vitro experiments to identify the organic molecules associated with respiratory virus infection for the first time. Water-soluble organic matters (WSOM) and water-insoluble organic matters (WIOM) were separated from PM 2.5 samples collected at the urban area of Guangzhou, China. Their molecular compositions were analyzed using Fourier transform ion cyclotron resonance mass spectrometry. Subsequently, in vitro experiments were conducted to explore the impact of WSOM and WIOM exposure on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pseudo-virus infection in A549 cells. Results revealed that WSOM and WIOM respectively promoted 1.7 to 2.1-fold and 1.9 to 3.5-fold upregulation of SARS-CoV-2 pseudo-virus infection in a concentration- dependent manner (at 25 to 100 mu g mL-1) compared to the virus-only control group. Partial least squares model analysis indicated that the increased virus infection was likely related to phthalate ester and nitro-aromatic molecules in WSOM, as well as LipidC molecules with aliphatic and olefinic structures in WIOM. Interestingly, the molecules responsible for upregulating SARS-CoV-2 receptor angiotensin-converting enzyme 2 ( ACE2 ) expression and virus infection differed. Thus, it was concluded that ACE2 upregulation alone may not fully elucidate the mechanisms underlying increased susceptibility to virus infection. The findings highlight the critical importance of aromatic and lipid molecules found in OM in relation to respiratory virus infection

A new calcite reference material for <i>in situ</i> oxygen isotope analysis using secondary ion mass spectrometry: development and application constraints

The oxygen isotopic microanalysis of calcite is essential for obtaining high spatial resolution data linked to microstructures, a challenge for conventional techniques. This analysis, however, relies heavily on matrix-matched reference materials, of which only a few calcite standards are available. In this study, an inorganically precipitated calcite vein sample (WS-1) was evaluated through 225 SIMS oxygen isotope analyses and was found to have a homogeneous isotopic composition, with an external reproducibility <= 0.21 parts per thousand (1 sigma), suggesting its potential as a SIMS reference material. The precise delta 18OVPDB value, determined via traditional gas-source IRMS, was -16.52 +/- 0.13 parts per thousand (1SD). Matrix effects were assessed using various carbonates, including abiotic aragonite (VS001/1-A), three abiotic calcites (NBS18, Cal-1, WS-1), and a high-Mg calcite (gorgonian coral). The results revealed negligible matrix effects between abiotic aragonite and calcites but significant differences between calcites and high-Mg calcite, likely due to Mg content or differences in biogenic crystal morphology and trace organic composition. This study demonstrates the utility of in situ oxygen isotopic microanalysis for calcite but emphasizes the need for caution when analyzing high-Mg calcitic skeletons

Modulating interfacial electron transfer in hydrothermal carbon/ humboldtine to achieve superior heterogeneous Fenton reactivity and H2O2 utilization efficiency

The strategic enhancement of interfacial electron transfer dynamics between carbon and iron, coupled with the improvement of H2O2 ' s effective decomposition, is imperative for achieving significant progress in the field of iron-carbon-based heterogeneous Fenton catalysis. This study prepared a novel Fenton catalyst, namely hydrothermal carbon/humboldtine (HTC/Hum), where Fe(III) was totally reduced to Fe(II) during catalyst preparation process due to the highly effective electron transfer between carbon and iron. Consequently, HTC/Hum exhibits exceptional Fenton catalytic performance, which would achieve 100 % degradation of Bisphenol A (BPA) within 5 min, outperforming conventional carbon-iron materials by increasing BPA degradation and H2O2 utilization efficiency by 230-400 and 18-24 times, respectively. Density functional theory (DFT) calculations also indicated that the energy barrier for HO center dot escaped from HTC/Hum is significantly lower than the conventional catalysts. Xray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and electrochemical analysis all demonstrated that the electron transfer from carbon to iron also occurred continuously in the HTC/Hum system during the Fenton reaction, facilitated by electrons from defects and persistent free radicals in HTC, promoting the redox cycle of Fe(III)/Fe(II). This study presents a novel strategy enhancing electron transfer and H2O2 utilization, with promising applications in environmental remediation

Combustion-related isoprene contributes substantially to the formation of wintertime secondary organic aerosols

Isoprene is a key reactive organic gas involved in organic aerosol formation. While biogenic isoprene from terrestrial plants has been extensively studied and is recognized as a major contributor to secondary organic aerosol (SOA), high levels of observed SOA, especially in winter, cannot be fully explained by biogenic isoprene alone. In this study, we developed a comprehensive bottom-up emission inventory for isoprene, incorporating both biogenic and combustion sources and modeling their contributions to SOA in China from 2000 to 2016. Combustion-related isoprene emissions from open biomass burning and residential fuel combustion were estimated at 52.0 (39.1-65.7) Gg in 2000, declining to 14.8 (10.6-19.0) Gg by 2016. Open biomass burning contributes similar to 40% of combustion-related isoprene emissions. Though, annually, combustion-related isoprene emissions were much smaller than the biogenic emissions, they did account for 32%-80% of total isoprene emissions in many north and west provinces in the colder months in 2016, and were even higher during the early 2000s owing to more biofuel-burning emissions. Model simulation results indicated that combustion-related isoprene could contribute 25%-40% of winter SOA in northern regions. Wintertime isoprene-derived SOA levels declined since 2000, corresponding with decreased combustion-related isoprene emissions; however, the extent of this decline varied regionally due to the influence of other precursors like nitrogen oxides (NOx). In the northeast region with high NOx levels, while combustion-related isoprene emissions decreased by >80% from 2000 to 2016, isoprene-derived SOA declined by only similar to 20%. These findings highlight the previously underappreciated contributions of combustion-related isoprene to observed high wintertime isoprene-derived SOA levels

Microstructure and trace element occurrence in molybdenite (MoS2) from the Dexing ore field: Implications for the differential enrichment of rhenium

Rhenium (Re), a critical metal of significant importance to national security and military strategies, has garnered extensive attention in recent years. Most of the world's rhenium is extracted from molybdenite in porphyry deposits. As the primary host-mineral of Re, molybdenite (MoS2) is a layered sulfide mineral featuring two hexagonally coordinated sulfur layers enclosing a molybdenum layer. Molybdenite, a mineral commonly found in hydrothermal ore deposits, is similar to other layered minerals in that it exhibits polytypism. Nevertheless, the nanoscale distribution and enrichment mechanisms of rhenium (Re) within molybdenite remain largely enigmatic. This research utilizes high-resolution transmission electron microscopy (HRTEM), in combination with the nanobeam techniques, to explore the occurrence and variable enrichment of rhenium (Re) in molybdenite extracted from the Fujiawu and Tongchang deposits within the Dexing ore field, eastern China, where notably diverse average rhenium contents are observed. The molybdenite polytypes identified in the Dexing ore field encompass 2H1 and 2H1 + 3R, whereas those from Fujiawu are categorized as 2H1 and 2Hd, and those from Tongchang as 2H1, 3R and 2Hd and 3Rd. The disordered molybdenite from the Dexing ore field formed under non-equilibrium conditions, with molybdenite from Fujiawu displaying a higher degree of orderliness compared to that from Tongchang. Rhenium is found adsorbed on the surface of molybdenite from the Dexing ore field in the form of Re-S complexes. By comparing the trace element compositions and microstructures of molybdenite from the Fujiawu and Tongchang deposits, we ascribe the differential enrichment of Re predominantly to the microstructures of molybdenite, the impurity content of ore-forming fluids, the rates of cooling and crystallization during molybdenite formation

Formation of carbonatite-related giant rare earth element deposits by liquid immiscibility

The occurrence of sulfate and fluoride minerals in carbonatite-hosted rare earth element (REE) deposits suggests that sulfur and fluorine play important roles in REE mineralization. However, their influence on the partitioning behavior of REEs during the immiscibility process remains poorly understood. This study performed partitioning experiments to explore the impact of sulfur and fluorine on the liquid immiscibility between carbonatitic melt and alkaline silicate melt at 1000-1200 degrees C and 0.5-2.2 GPa. Surprisingly, the experimental results indicate that the addition of sulfur and fluorine does not significantly change the partition coefficients of trace elements between carbonatitic melt and silicate melt. The key factor determining REE partitioning is the structural difference between the two immiscible melts, which can be characterized by the non-bridging oxygen per tetrahedrally coordinated cation of the silicate melt (NBO/T). Partition coefficients tend to decrease as NBO/T increases. Importantly, REE, SO3, and F exhibit similar behaviors, making sulfate and fluoride minerals useful indicators for exploring carbonatite-hosted REE deposits. Additionally, we used rhyolite-MELTS software to simulate crystallization differentiation and liquid immiscibility in alkaline silicate melts. Modeling results show that the initial CO2 content of silicate melt determines the degree of crystallization at which liquid immiscibility occurs. Lower initial CO2 content enhances the enrichment of REEs in the immiscible carbonatitic melt

Identification of Hydroxylated Chlorinated Paraffins in Human Serum and Their Potential Metabolic Pathways

Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) are frequently detected in humans. However, information regarding their metabolites is still very limited. Herein, target analysis and halogenation-guided nontarget and suspect screening were conducted on serum samples using UHPLC-Orbitrap-HRMS. The median concentrations of SCCPs and MCCPs were 7.76 and 4.31 ng/mL, respectively. A series of hydroxylated chlorinated paraffins (OH-CPs) were tentatively identified with an estimated average concentration of 1.80 ng/mL, which was approximately 9.9% of the total SCCPs and MCCPs. A chlorine distribution shift was observed from chlorinated paraffins (CPs) dominated by Cl6 and Cl7 to OH-CPs dominated by Cl5, Cl6, and Cl4. In human liver cytochrome P450 (CYP) enzyme incubation assays, the CPs in commercial mixtures were mainly metabolized into OH-CPs with various carbon lengths and chlorine substituents. The results obtained from human serum and in vitro experiments suggested the oxidative metabolism of SCCPs and MCCPs in humans. The metabolic pathways were then comprehensively explored using a CP monomer (1,1,1,3,10,11-hexachloroundecane) incubated with the same CYP enzymes, demonstrating that CPs can be metabolized through successive oxidative dechlorination and direct hydroxylation, with subsequent oxidation to carboxylic acids. Further studies should focus on the long-term toxicity of OH-CPs

Apatite low-temperature thermochronology constraints on the Cenozoic differential uplift/denudation of the Ke'eryin lithium ore field in western China: Implications for lithium exploration

The Ke'eryin pegmatite-type lithium ore field is a major lithium concentration area in the Songpan-Garze fold belt, western China. However, there is a notable spatial variability in lithium mineralization, with the northeastern and southeastern regions showing higher mineralization intensity than the western and northern parts. Previous studies suggest that this difference is likely related to the development of a Cenozoic thrust fault, the Ke'eryin thrust fault (KEYF), which traverses the eastern and southern parts of the ore field. However, direct chronological evidence is lacking. This study employs apatite fission track thermochronology on three representative deposits located in the northeastern, southeastern, and western regions of the Ke'eryin ore field, offering insights into differential uplift/denudation. The integration of regional tectonic evolution, apatite fission track age data, and thermal modelling results reveals that the Ke'eryin ore field has underwent two primary phases of rapid cooling after its formation: initially from the Late Jurassic to the Cretaceous, and subsequently from the Early Miocene to the present. The initial rapid cooling phase is mainly attributed to the LhasaQiangtang collision, whereas the subsequent phase is connected to significant fault activity and regional river incision due to the India-Asia continental collision. Apatite fission track age data and thermal modelling results indicate that differential uplift/denudation between the eastern and western Ke'eryin ore field primarily took place during the Late Miocene of the Cenozoic. The development of the thrust fault, which has been constrained to have initiated since 12 Ma, has led to the denudation of lithium deposits in the hanging wall (the western and northern parts of the Ke'eryin ore field), whereas those in the footwall (the eastern part) remain relatively well preserved. Based on these characteristics, this study recommends focusing exploration efforts for pegmatite-type lithium resources in the footwall regions, particularly in exploration gaps that are away from river valleys between large and super-large deposits. Additionally, in the entire Songpan-Garze fold belt, there is significant pegmatite-type lithium exploration potential in the high elevation, arid, and less topographically relieved western regions

Impacts of anthropogenic disturbances on antibiotic resistomes in biological soil crusts on the Qinghai-Tibetan Plateau

Biological soil crusts (BSCs) are the main landscape on the Qinghai-Tibetan Plateau and an ecological indicator of human disturbance. Information about antibiotic resistomes in BSCs on the Qinghai-Tibetan Plateau can provide baseline for the risk assessment and management of resistomes and yet to be explored. This work investigated the profiles and geographic patterns of antibiotic resistomes in BSCs along the Lhasa River and their response to anthropogenic activities for the first time. Various antibiotic resistance genes (ARGs) were widely distributed in BSCs, but had relatively lower detection frequency and abundance comparing to soils from human disturbed sites. ARGs profiles in BSCs were separated by altitude from 3860 to 3880 m, possibly attributing to the difference in anthropogenic activities. Above 3860 m, resistomes exhibited lower abundance including total ARGs, aadA, blaSFO and tnpA-04 owing to the rare human activities; at human disturbed sites with altitude <3860 m, the detection frequency and relative abundance of tetG02, oprJ, qacEdelta1-01, and ARGs with the mechanism of efflux pump were higher and viewed as potential indicators of human activities. Anthropogenic activities potentially promoted the horizontal gene transfer of ARGs in BSCs at human disturbed sites from co-occurrence network analysis. Our findings provided fundamental information of antibiotic resistomes in BSCs on the Qinghai-Tibetan Plateau, and unraveled possible mechanisms of human disturbance in shaping antibiotic resistomes