Heating effects on jack pine pyrogenic organic matter properties from a pyrocosm study in 2022

This dataset contains data associated with the preprint “Fire removes preexisting pyrogenic organic matter from the ecosystem through the mechanisms of both direct combustion and increasing mineralizability” (Luo et al., 2025b), which is the complementary study to the published paper “Reburning pyrogenic organic matter: a laboratory method for dosing dynamic heat fluxes from above” (Luo et al., 2025a). We designed a full-factorial experiment with different burial depths of jack pine (Pinus banksiana Lamb) pyrogenic organic matter (PyOM) (Surface, 1 cm, and 5 cm) and different heat-flux profiles (High, Low, and Control) to examine how subsequent fires affect the properties of preexisting PyOM. We measured total carbon (C), pH, dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and mineralized C (as CO₂-C, from a 12-week incubation).We found that high heat flux and/or surface placement resulted in substantial direct C losses through combustion. Intermediate heat exposure produced both combustion losses and increases in DOC and mineralizability, which may have complex long-term implications: an increased dissolved fraction of PyOM may promote downward transport into mineral soils and potentially contribute to deeper, longer-term C storage, but it may also make PyOM more susceptible to microbial decomposition. Under the lowest heat flux and deepest burial, most PyOM was retained, and changes in DOC and C mineralization were minimal. Finally, PyOM pH, an important chemical property, decreased under low-temperature heating but increased under higher temperatures.We uploaded pH data for all samples (“pH_of_all_samples.csv”); pH and temperature-related data (peak temperature and degree hours) for samples in High and Low heat-flux treatments (“pH_vs_peakT_and_degree_hours_only_for_heated_samples.csv”); total C data (“CN_pct_C_stock_C_loss_in_samples.csv”); DOC and DIC data (“doc_dic.csv”); and mineralized C (CO₂-C) data (“CO2-C_all_original.csv”). Additional details can be found in the Methods & Sampling section.All datasets uploaded to ESS-DIVE are clearly labeled, cleaned, and include both raw and derived data, ready for reuse in other analyses. All analysis code and raw datasets are also available on GitHub: https://github.com/MengmengLuo/Fire-removes-preexisting-pyrogenic-organic-matter-from-the-ecosystem.

本数据集关联于预印本《火通过直接燃烧与提升矿化性双重机制移除生态系统中原生热解有机质（pyrogenic organic matter, PyOM）》（Luo等，2025b），该研究是已发表论文《复燃热解有机质：一种调控上方动态热通量的实验室方法》（Luo等，2025a）的补充研究。本研究设置了完全析因实验，设置北美短叶松（Pinus banksiana Lamb）热解有机质（pyrogenic organic matter, PyOM）的不同埋藏深度（地表、1 cm、5 cm）以及不同热通量模式（高温、低温、对照组），以探究后续火烧如何影响原生PyOM的性质。我们测定了总碳（C）、pH值、溶解性有机碳（dissolved organic carbon, DOC）、溶解性无机碳（dissolved inorganic carbon, DIC）以及矿化碳（以12周培养过程中产生的CO₂-C计）。研究发现，高热通量和/或地表埋藏的PyOM会通过燃烧发生显著的直接碳损失。中等热暴露会同时引发燃烧碳损失，并提升DOC含量与矿化性，这可能带来复杂的长期影响：PyOM的溶解性组分占比提升可促进其向下运移至矿质土壤，或有助于深层长期碳固存，但也会使PyOM更易被微生物分解。在最低热通量与最深埋藏条件下，大部分PyOM得以保留，DOC与碳矿化的变化幅度极小。此外，作为重要化学性质的PyOM pH值，在低温加热时会下降，而在高温加热时则会上升。我们上传了所有样品的pH数据（"pH_of_all_samples.csv"）；高热通量与低热通量处理组样品的pH及温度相关数据（峰值温度与小时积温，"pH_vs_peakT_and_degree_hours_only_for_heated_samples.csv"）；总碳数据（"CN_pct_C_stock_C_loss_in_samples.csv"）；DOC与DIC数据（"doc_dic.csv"）；以及矿化碳（CO₂-C）数据（"CO2-C_all_original.csv"）。更多细节可参见方法与采样部分。上传至ESS-DIVE的所有数据集均已清晰标注与整理，包含原始数据与衍生数据，可直接复用至其他分析研究。所有分析代码与原始数据集也可在GitHub获取：https://github.com/MengmengLuo/Fire-removes-preexisting-pyrogenic-organic-matter-from-the-ecosystem。