Yanan Shen

Ocean anoxia played a key role in the end-Permian mass extinction, the most severe biotic crisis in Earth’s history, yet reconstructions of oxygenation through this event have lacked a focus on deep-water oxygen loss. Thallium isotopes, which track deep-ocean oxygenation via manganese oxide burial, offer a potential solution but have only been applied to siliciclastic sections, limiting spatial and temporal coverage. Here, we present a combined carbonate-shale Tl isotope record, spanning four geographically distant regions and providing a near-continuous record of global-scale redox change during the extinction interval. Both lithologies record deep-marine anoxia beginning 1 million years before the extinction, demonstrating that carbonate- and shale-hosted Tl isotopes preserve consistent redox signals. Late Permian oxygen depletion likely remained largely constrained to the deep ocean and was distinct from the shelf- and slope-depth euxinia of the Early Triassic that was coupled with climate warming and central to the loss of animal diversity.

The genesis of Archean continental crust through partial melting of hydrous mafic protolith is widely acknowledged, yet the origin of the mafic protolith remains highly contentious. Silicon isotopes and quadruple sulfur isotopes serve as particularly powerful tools in this regard, as they directly trace the source nature of the felsic continent. Here, we integrate whole-rock silicon and sulfur isotopic data of Neoarchean granitoids from the North China Craton to constrain the origin and pathway of their protoliths. These granitoids exhibit non-zero Δ³³S (0.01‰ to - 0.24‰) and elevated δ³⁰Si ( - 0.09‰ to -0.05‰), requiring a supracrustal source and contrasting with the previously reported mantle-like zircon δ¹⁸O. Global compilation shows that granitoids formed after 3800 Ma uniformly contain enriched δ³⁰Si and non-zero Δ³³S, implying that most, if not all Archean continental crusts were derived from partial melting of supracrustal sources rather than unaltered mafic cumulates.

The genesis of Archean continental crust through partial melting of hydrous mafic protolith is widely acknowledged, yet the origin of the mafic protolith remains highly contentious. One view favors supracrustal basalts delivered to melting depth by crustal recycling, whereas others posit unaltered, mantle-derived gabbro emplaced by mantle plume to the lower crust level. Silicon isotopes and quadruple sulfur isotopes serve as particularly powerful tools in this regard, as they directly trace the source nature of the felsic continent. Here, we integrate whole-rock silicon and sulfur isotopic data of Neoarchean granitoids from the North China Craton to constrain the origin and pathway of their protoliths. These granitoids exhibit non-chondritic Δ³³S (− 0.06‰) and elevated δ³⁰Si (− 0.09‰ to − 0.05‰), requiring a supracrustal source and contrasting with the previously reported mantle-like zircon δ ¹⁸ O. Global compilation shows that granitoids formed after 3800 Ma uniformly contains enriched δ³⁰Si and non-zero Δ³³S, implying that most, if not all Archean continental crusts were derived from partial melting of supracrustal sources rather than unaltered mafic cumulates.

The observation of mass-independent sulfur isotope fractionations (S-MIF) in Archean–Paleoproterozoic rocks has been instrumental in constraining oxygen levels on early Earth. The S-MIF effect, experimentally demonstrated to result from photochemical reactions, has now been observed in coal combustion, expanding our understanding of this phenomenon. Our study reveals that the negative Δ ³³ S anomalies produced by coal combustion are consistent with similar anomalies observed in present-day sulfate aerosols in Beijing, China, and the black crust sulfates formed on building stones, monument walls, and sculptures in Europe that contribute to carbonate stone deterioration and cultural heritage damage. This finding provides independent evidence for a critical role of atmospheric sulfate from coal combustion in maintaining isotopic balance and offers an effective method for tracing sulfate aerosol sources. These insights are vital for developing more effective regulatory policies to control air pollution and protect public health. Given that coal energy production remains a significant issue in climate science, accurately mapping the global distribution of its by-products is imperative.

Climate changes are known to have been a key regulator of the biodiversity in Earth's history. However, the dry‐humid degrees and alternating patterns throughout the Phanerozoic remain largely unconstrained. In this study, we report high contents (2.4 ± 3.8 mg N kg⁻¹) and ¹⁷O anomalies (11.0 ± 7.4‰) of nitrate (NO₃⁻) in the early Cambrian black shale from South China, likely caused by atmospheric NO₃⁻ intrusion under dry climates that followed tectonic uplift. By developing new methods to quantify aridity indices (AI, 0.06 ± 0.08) in combination with observational data with paleoclimate models, we reconstructed the historical AI variations. Our analyses revealed three significant dry‐to‐humid transitions which include Cambrian‐Ordovician to Silurian‐Permian, Permian‐Triassic boundary to middle Triassic‐early Jurassic, and Jurassic‐Paleogene to Neogene. This study quantitatively unlocked the Phanerozoic climate changes in South China, offering important evidence for understanding the co‐evolution of ecological and climatic systems in Earth's history.

Air pollution exposure is closely linked to population age and socioeconomic status. Population aging and imbalance in regional economy are thus anticipated to have important implications on ozone (O₃)‐related health impacts. Here we provide a driver analysis for O₃ mortality burden due to respiratory disease in China over 2013–2050 driven by population aging and regional inequity. Unexpectedly, we find that population aging is estimated to result in dramatic rises in annual O₃ mortality burden in China; by 56, 101–137, and 298–485 thousand over the periods 2013–2020, 2020–2030, and 2030–2050, respectively. This reflects the exponential rise in baseline mortality rates with increasing age. The aging‐induced mortality burden rise in 2030–2050 is surprisingly large, as it is comparable to the net national mortality burden due to O₃ exposure in 2030 (359–399 thousand yr⁻¹). The health impacts of O₃ pollution, shown as mortality burden per capita, are inequitably distributed, with more severe effects in less developed provinces than their developed counterparts by 23.1% and 21.5% in 2019 and 2030, respectively. However, the regional inequity in O₃ mortality burden is expected to be mitigated in 2050. This temporal variation reflects evolving demographic dividend characterized by a larger proportion of younger individuals in developed regions. These findings are critical for targeted improvement of healthcare services to ensure the sustainability of social development.

Data‐driven methods have been extensively applied to predict atmospheric compositions. Here, we explore the capability of a deep learning (DL) model to make ozone (O₃) predictions across continents in China, the United States (US) and Europe. The DL model was trained and validated with surface O₃ observations in China and the US in 2015–2018. The DL model was applied to predict hourly surface O₃ over three continents in 2015–2022. Compared to baseline simulations using GEOS‐Chem (GC) model, our analysis exhibits mean biases of 2.6 and 4.8 μg/m³ with correlation coefficients of 0.94 and 0.93 (DL); and mean biases of 3.7 and 5.4 μg/m³ with correlation coefficients of 0.95 and 0.92 (GC) in Europe in 2015–2018 and 2019–2022, respectively. The comparable performances between DL and GC indicate the potential of DL to make reliable predictions over spatial and temporal domains where a wealth of local observations for training is not available.

Urban air pollution continues to pose a significant health threat, despite regulations to control emissions. Here we present a comparative analysis of urban ozone (O₃) responses to nitrogen oxide (NO_x) changes in China and the United States (US) over 2015–2020 by integrating various data‐ and model‐based methods. The data‐based deep learning (DL) model exhibited good performance in simulating urban air quality: the correlation coefficients (R) of O₃ daily variabilities with respect to independent O₃ observations are 0.88 and 0.79 over N. China, 0.87 and 0.90 over S. China, and 0.87 and 0.49 over E. United States by the DL and GEOS‐Chem chemical transport models, respectively. Furthermore, the data‐based methods suggest volatile organic compound (VOC)‐limited regimes in urban areas over northern inland China and transitional regimes over eastern US urban areas; in contrast, GEOS‐Chem model suggests strong NO_x‐limited regimes. Sensitivity analysis indicates that the inconsistent O₃ responses are partially caused by the inaccurate representation of O₃ precursor concentrations at the locations of urban air quality stations in the simulations, while the data‐based methods are driven by the variabilities in local O₃ precursor concentrations and meteorological conditions. The O₃ responses to NO_x changes reported here provide a better understanding of urban O₃ pollution; for example, reductions in NO_x emissions are suggested to have resulted in an increase in surface O₃ by approximately 7 ppb in the Sichuan Basin in 2014–2020.

The Cryogenian Sturtian and Marinoan Snowball Earth glaciations bracket a nonglacial interval during which Demosponge and green-algal biomarkers first appear. To understand the relationships between environmental perturbations and early animal evolution, we measured sulfur and mercury isotopes from the Datangpo Formation from South China. Hg enrichment with positive Δ ¹⁹⁹ Hg excursion suggests enhanced volcanism, potentially due to depressurization of terrestrial magma chambers during deglaciation. A thick stratigraphic interval of negative Δ ³³ S _py indicates that the nonglacial interlude was characterized by low but rising sulfate levels. Model results reveal a mechanism to produce the Δ ³³ S anomalies down to −0.284‰ through Rayleigh distillation. We propose that extreme temperatures and anoxia contributed to the apparent delay in green algal production in the aftermath of the Sturtian glaciation and the subsequent reoxygenation of the iron-rich and sulfate-depleted ocean paved the way for evolution of animals.