This week’s publication highlights cover a wide range of issues related to soil carbon sequestration, forestation, carbon mineralization and enhanced weathering.
Soil Carbon Sequestration: Role of Fe Oxides and Polyphenol Oxidase Across Temperature and Cultivation Systems
Abstract
The “enzyme latch” and “Fe gate” mechanisms are crucial factors influencing soil carbon sequestration capacity, playing a key role in understanding the dynamic changes in soil organic carbon (SOC). However, there is a lack of research regarding polyphenol oxidase (PPO) activity and the concentration of iron oxides in paddy soils under varying incubating temperatures and cultivation practices. This study was conducted over three years in a double-cropping rice area in southern China, incorporating systematic soil sampling to measure PPO activity, Fe oxide concentration, and basic physicochemical properties. The results showed that temperature did not significantly affect either PPO activity or the concentration of Fe oxides. Additionally, compared to conventional management (CK), organic management led to a decrease in Fe oxides (Fe bound to organic matter, reactive Fe, and total free Fe) by 19.1%, 16.2%, and 13.7%, respectively (p < 0.05). At the same time, PPO activity did not show any significant changes. Our results indicated that short-term (5 weeks) incubation temperature did not affect PPO activity or Fe oxides, while organic farming decreased Fe oxides without influencing PPO activity. PPO activity increased with the length of the incubation period.
He, Y. et al. (2025) Soil Carbon Sequestration: Role of Fe Oxides and Polyphenol Oxidase Across Temperature and Cultivation Systems 14 (6) Plants.
Read the full paper here: Soil Carbon Sequestration: Role of Fe Oxides and Polyphenol Oxidase Across Temperature and Cultivation Systems I Plants.
Diminished Biophysical Cooling Benefits of Global Forestation under Rising Atmospheric CO2
Abstract
Forestation is a proposed solution for mitigating global warming through carbon sequestration. However, its biophysical effects through surface energy modulation, particularly under rising CO2 levels, is less understood. Here we investigate the biophysical effects of global potential forestation on near-surface air temperature (Ta) under increasing CO2 concentrations using a land-atmosphere coupled model with slab ocean module. Our findings reveal that, under current climate conditions, the biophysical effect of global full-potential forestation can reduce land surface Ta by 0.062 °C globally. However, this cooling benefit diminishes as CO2 rises. While elevated CO2 slightly alters evaporative local cooling via stomatal closure and adjustments in forestation-driven rainfall regimes, the dominant reduction stems from non-local mechanisms. Background climate shifts reorganize forestation-induced horizontal temperature advection, weakening remote cooling in the Northern Hemisphere. These findings highlight the necessity of incorporating dynamic forest management strategies to optimize mitigation potential under a changing climate.
Kan, F. et al. (2025) Diminished Biophysical Cooling Benefits of Global Forestation under Rising Atmospheric CO2 16 (4410) Nature Communications.
Read the full paper here: Diminished Biophysical Cooling Benefits of Global Forestation under Rising Atmospheric I Nature Communications.
Carbon Mineralization of Sulfate Wastes Containing Pb: Synchrotron Pb M3-Edge XANES Analysis of Simultaneous Heavy Metal and Carbon Sequestration
Abstract
Sulfate wastes are produced in large quantities and contain toxic heavy metals such as lead (Pb), posing environmental risks. Because of favorable solubility differences, these wastes can be repurposed for engineered carbon dioxide (CO2) sequestration. Understanding the fate and mobility of heavy metals during this process is important. This study focuses on Pb and the effect of zinc (Zn) on Pb in carbon mineralization. Synthesized gypsum was treated with a carbonate-rich solution at pH 11.5 to convert the sulfates to carbonates. Aqueous solutions and mineral solids were analyzed. Synchrotron-based micro-X-ray fluorescence and a novel application of Pb M3-edge X-ray absorption near-edge structure provided detailed insights into Pb distribution and mineral forms. Results showed significant reductions in aqueous Pb and Zn concentrations, indicating effective metal sequestration. Carbon mineralization transformed Pb from soluble anglesite (PbSO4) into insoluble cerussite (PbCO3) and hydrocerussite (Pb3(CO3)2(OH)2). Pb primarily precipitated onto calcium carbonate surfaces through surface-mediated precipitation reactions. While the presence of Zn modified crystallization dynamics, it did not impede Pb sequestration and potentially enhanced surface reactivity, facilitating greater Pb immobilization. These findings highlight carbon mineralization as a sustainable approach to immobilize toxic metals in sulfate wastes while advancing CO2 sequestration efforts.
Hu, J. et al. (2025) Carbon Mineralization of Sulfate Wastes Containing Pb: Synchrotron Pb M3-Edge XANES Analysis of Simultaneous Heavy Metal and Carbon Sequestration. 59 (14) Environmental Science & Technology
Read the full paper here: Carbon Mineralization of Sulfate Wastes Containing Pb: Synchrotron Pb M3-Edge XANES Analysis of Simultaneous Heavy Metal and Carbon Sequestration I Environmental Science & Technology.
Towards Net-Zero: Coupling Carbon Mineralization with Seasonal Energy Storage in Integrated Energy Systems Planning
Abstract
As climate change accelerates, alongside rising energy demands and intermittent renewable resources, integrated energy systems urgently require strategies that achieve deep carbon reductions while maximizing energy utilization. This study proposes an innovative low-carbon planning model that integrates advanced carbon mineralization technology with trans-seasonal thermal storage, enhancing both environmental and economic outcomes in integrated energy systems, by constructing a novel carbon reduction model that couples carbon capture power plants with power-to-gas conversion and mineralization processes, captured carbon dioxide is repurposed into stabilized carbonates and natural gas, thereby significantly enhancing carbon utilization. A seasonal thermal storage system based on underground caverns was constructed to utilize the thermal energy generated from the aforementioned carbon conversion reactions and power plant flue gases. By accounting for ambient temperature and static storage losses, the introduced cavern thermal storage model accurately simulates changes in stored thermal energy, effectively enhancing energy utilization efficiency and mitigating seasonal load fluctuations. Building on these foundations, a two-layer planning model was developed to integrate the proposed full-chain carbon reduction scheme, encompassing carbon capture, reutilization, waste heat recovery, and thermal storage. Simulation results of the regional energy system show that the methodology improves carbon utilization by 22.7 % and energy efficiency by 3.81 %, demonstrating the potential of the planning scheme to promote the transition of the energy system to net-zero carbon emissions.
Zhang, J. et al. (2025) Towards Net-Zero: Coupling Carbon Mineralization with Seasonal Energy Storage in Integrated Energy Systems Planning 393 (126065) Applied Energy.
Read the full paper here: Towards Net-Zero: Coupling Carbon Mineralization with Seasonal Energy Storage in Integrated Energy Systems Planning I Applied Energy.
Soil Cation Storage as a Key Control on the Timescales of Carbon Dioxide removal through Enhanced Weathering
Abstract
Significant interest and capital are currently being channeled into techniques for durable carbon dioxide removal (CDR) from Earth’s atmosphere. A particular class of these approaches — referred to as enhanced weathering (EW) — seeks to modify the surface alkalinity budget to store CO2 as dissolved inorganic carbon species. Here, we use SCEPTER — a reaction-transport code designed to simulate EW in managed lands — to evaluate the throughput and storage timescales of anthropogenic alkalinity in agricultural soils. Through a series of alkalinity flux simulations, we explore the main controls on cation storage and export from surface soils in key U.S. agricultural regions. We find that lag times between alkalinity modification and climate-relevant CDR can span anywhere from years to many decades locally but can aggregate to shorter timescales depending on deployment region. Background soil cation exchange capacity, agronomic target pH, and fluid infiltration all impact the timescales of CDR relative to the timing of alkalinity input. There is likely scope for optimization of weathering-driven alkalinity transport through variation in land management practice. However, shifting management practices to reduce lag times will likely decrease total CDR from weathering and lead to non-optimal nutrient use efficiencies and soil nitrous oxide (N2O) fluxes. Although CDR lag times will be more of an issue in some regions than others, these results have significant implications for the technoeconomics of EW and the integration of EW into voluntary carbon markets, as there may often be a large temporal disconnect between deployment of EW and climate-relevant CDR.
Kanzaki, Y. et al. (2024) Soil Cation Storage as a Key Control on the Timescales of Carbon Dioxide Removal through Enhanced Weathering ESS Open Archive.
Read the full paper here: Soil Cation Storage as a Key Control on the Timescales of Carbon Dioxide Removal through Enhanced Weathering I ESS Open Archive.