The effect of extreme temperatures on soil organic matter decomposition from Atlantic oak forest ecosystems.(ISCIENCE-D-21-01516R1)

This paper focuses on the soil organic matter, SOM, sensitivity to extreme temperatures and intends to relate it to soil organic matter properties which could be attached to the recalcitrance and lability of the organic substrates. The soil samples were collected in oak forests ecosystems in Ireland (Samples DC, G and K) and UK (Samples ROG, BW and NF) and represents the organic matter from different soil horizons: LF samples from the soil surface; the mineral soil under, M samples; and in the case of the samples from Ireland, an intermediate H layer in between LF and M horizons (H samples). SOM thermal properties were provided by simultaneous thermogravimetry (TG) and differential scanning calorimetry (DSC) (TG-DSC) in an attempt of parametrizing SOM recalcitrance by the red-ox state. This is connected to the response of the soil samples to increasing and decreasing temperatures, measured by calorimetry as the heat rate of SOM decomposition. The calorimeter used is a model TAM III that allows the direct monitoring of the heat rates at different temperatures. The simultaneous TG-DSC gave the different soil thermal fractions of the samples and their heat of combustion, QSOM, values, connected to the degree of reduction of organic substrates by well-known principles. Here we attach the raw tabulated data from the TG-DSC measurements for all the samples used in this work as supplementary material S1. They are Excel files with columns representing, from left to right, time in seconds, temperature in Celsius degrees, the heat released in mW and the weight lost in mg. TAM III allows us to design a calorimetric heat wave and to monitor the heat rate from the soil samples at increasing temperatures from 20 ºC to 30, 40, 50 and 60 ºC, and to decreasing temperatures from 60ºC to 40 and 20 ºC. By this procedure we can compare which samples resist or do not resist the heat wave and to link it to their red-ox state by different statistical analysis. All the raw tabulated data from the calorimetric design with TAM III are provided here too, together with their baselines, as supplementary material S2. The Excel files show the heat flow rate in watts and joules at the different temperatures of the measurement. The files S2a are the data from UK LF samples, S2b the ones from UK Mineral samples, S2c are the calorimetric data from Irish LF samples, S2d the Irish H samples, and S2e the Irish M samples. Samples S2f and S2g are the baselines with the empty ampoules used in the calorimetric measurements, detailed for every experiment in the first folder of the Excel files. All the details dealing with the samples are explained in the paper.本研究聚焦于土壤有机质（Soil Organic Matter, SOM）对极端温度的敏感性，旨在将其与土壤有机质属性相关联，而这些属性可归因于有机底物的难降解性与易降解性。土壤样品采集自爱尔兰（样品DC、G与K）及英国（样品ROG、BW与NF）的栎林生态系统，涵盖不同土壤发生层的有机质：土壤表层的LF样品、下层矿质土壤M样品；针对爱尔兰的样品，还包含LF与M层之间的过渡H层样品（H样品）。 土壤有机质的热性质通过同步热重-差示扫描量热法（Simultaneous Thermogravimetry, TG）与差示扫描量热法（Differential Scanning Calorimetry, DSC），即TG-DSC技术获取，以期通过氧化还原状态对土壤有机质的难降解性进行参数化。该方法关联了土壤样品对升降温过程的响应——该响应通过量热法测得的土壤有机质分解热速率得以表征。本次实验所用量热仪为TAM III型，可直接监测不同温度下的热速率。 同步TG-DSC分析可得到样品的不同土壤热组分及其燃烧热QSOM数值，该数值与基于公认原理得出的有机底物还原程度相关。本文将本研究中所有样品的TG-DSC测量原始制表数据作为补充材料S1附后。该数据为Excel文件，列项从左至右依次为：时间（秒）、温度（摄氏度）、释放热量（毫瓦）以及失重质量（毫克）。 TAM III型量热仪支持设计量热热波实验，并可监测土壤样品在20℃升温至30℃、40℃、50℃及60℃，再从60℃降温至40℃、20℃过程中的热速率。通过该实验流程，可对比不同样品的耐热性差异，并通过多种统计分析将其与氧化还原状态相关联。本文同时附带来自TAM III量热实验的全部原始制表数据及其基线数据，作为补充材料S2。该Excel文件展示了不同测量温度下的热流速率（瓦与焦耳）。其中，S2a为英国LF样品的数据集，S2b为英国矿质土壤样品的数据集，S2c为爱尔兰LF样品的量热数据，S2d为爱尔兰H层样品的数据集，S2e为爱尔兰M层样品的数据集；S2f与S2g为量热实验所用空白安瓿瓶的基线数据，Excel文件的首个文件夹中详细标注了每一次实验的相关细节。 所有与样品相关的详细信息均已在正文中说明。