Gaojun Li’s research while affiliated with Nanjing University and other places

Enhanced silicate weathering (ESW) is a geoengineering method aimed at accelerating carbon dioxide (CO2) removal (CDR) from atmosphere by increasing the weathering flux of silicate rocks and minerals. It has emerged as a promising strategy for CDR. Theoretical studies underscore ESW’s substantial potential for CDR and its diverse benefits for crops when applied to croplands. However, the well-known significant discrepancies in silicate weathering rates between laboratory and field conditions introduce uncertainty in CDR through ESW. By compiling data from recent literature, we calculated and compared CDR efficiency (t CO2 tsilicate−1 ha−1 y−1) observed in mesocosm experiments and field trials. The findings indicate that CDR efficiencies in field trials are comparable to or exceeding that observed in mesocosm experiments by 1–3 orders of magnitude, particularly evident with wollastonite application. The hierarchy of CDR efficiency among silicates suitable for ESW is ranked as follows: olivine ⩾ wollastonite > basalt > albite ⩾ anorthite. We suggest the potential role of biota, especially fungi, in contributing to higher CDR efficiencies observed in field trials compared to mesocosm experiments. We further emphasize introducing fungi known for their effectiveness in silicate weathering could potentially enhance CDR efficiency through ESW in croplands. But before implementing fungal-facilitated ESW, three key questions need addressing: (i) How does the community of introduced fungi evolve over time? (ii) What is the long-term trajectory of CDR efficiency following fungal introduction? and (iii) Could fungal introduction lead to organic matter oxidation, resulting in elevated CO2 emissions? These investigations are crucial for optimizing the efficiency and sustainability of fungal-facilitated ESW strategy.

Silicate weathering acts as a significant carbon sink and sustains ecosystems by supplying essential elements, thus shaping Earth's habitability. However, our understanding the evolution of silicate weathering rates remains incomplete, with most knowledge focusing on rate decreases at solution‐silicate interfaces, while reactivity at fungi‐weathered silicate interfaces is poorly understood. This study shows that the fungus Talaromyces flavus significantly enhances the dissolution of olivine and lizardite covered by Si‐rich layers up to 3.6 μm thick by one to two orders of magnitude compared to abiotic conditions. Initially, fungal hyphae create dissolution channels ∼10–65 nm deep, promoting element release from altered layers and underlying pristine minerals while oxidizing structural Fe(II). Over time, hyphae penetrate these altered layers, exposing and etching the underlying minerals. Our data suggest that fungal etching and penetration degrade the altered layers, leading to increased interdiffusion of weathering agents and released cations, thereby continuously driving silicate weathering.

The evolution of oxygen cycles on Earth’s surface has been regulated by the balance between molecular oxygen production and consumption. The Neoproterozoic–Paleozoic transition likely marks the second rise in atmospheric and oceanic oxygen levels, widely attributed to enhanced burial of organic carbon. However, it remains disputed how marine organic carbon production and burial respond to global environmental changes and whether these feedbacks trigger global oxygenation during this interval. Here, we report a large lithium isotopic and elemental dataset from marine mudstones spanning the upper Neoproterozoic to middle Cambrian [~660 million years ago (Ma) to 500 Ma]. These data indicate a dramatic increase in continental clay formation after ~525 Ma, likely linked to secular changes in global climate and compositions of the continental crust. Using a global biogeochemical model, we suggest that intensified continental weathering and clay delivery to the oceans could have notably increased the burial efficiency of organic carbon and facilitated greater oxygen accumulation in the earliest Paleozoic oceans.

The formation and evolution of the landscape of the Chinese Loess Plateau (CLP) is debated because of uncertainties regarding dust provenance. We present a quantitative estimation of dust source contributions to the CLP, based on more than 37,100 detrital zircon U-Pb ages, combined with mineral assemblages and isotope analyses. Our results reveal that the CLP was stepwise formed by ~8 million years (Ma) and is mainly composed of material from the Northeastern Qinghai-Tibetan Plateau, with stepwise shifts in relative contributions of different eolian silt sources occurring at ~2.6 Ma and 1.5 to 1.2 Ma. We infer that these changes were driven by stepwise global cooling, which induced aridification and enhanced silt production in glaciated-cold climate dust source regions, as well as dust ablation in the expanded arid regions. We propose that global cooling, rather than regional tectonic deformation, was the main driver of the formation and evolution of the CLP during late Cenozoic.

Plain Language Summary The provenance of silt‐sized particles in the Taklimakan Desert is critical for understanding aridification and climate dynamics in central Asia, as well as the production mechanism of dust—a key player in the global biogeochemical cycles of nutrient elements. Here, we measured the uranium‐strontium‐neodymium isotopes in silt‐sized particles from the Taklimakan Desert and the adjacent mountains to understand the source, production, and transport of dust in the region. The uranium isotopes record the timespan since particles were separated from the bedrock and are independent of bedrock composition. Our results indicate that the silt‐sized materials in the Taklimakan Desert are mainly sourced from the eastern Kunlun Shan, with partial contribution from the Pamir mountains. The isotopic evidence weakens the possibility that the Taklimakan Desert is a major source of the Chinese Loess Plateau. We found that besides mountainous (fluvial and glacial) processes, in‐situ desert processes (e.g., abrasion) produce a significant amount of the silts in the Taklimakan Desert and the aeolian dust flux from the Tarim Basin, which gets transported by the westerly jet and influences global ecosystems. These findings shed new light on dust production and transport in arid areas.