Radiocarbon of soil CO2 efflux and soils with experimental soil warming and drying in lowland tropical forests in Panama

In 2019, we measured the Δ14C and δ13C of soil respired carbon dioxide (CO2) in Panamanian forests that are subject to either in situ experimental soil warming (4C above ambient temperature to 1.2 m depth) or in situ experimental drying (50% throughfall exclusion). The warming site and one drying site are both within the Barro Colorado Nature Monument in nearby and similar forests on similar soils, enabling direct comparison of warming and drying effects on soil CO2 efflux. A second drying experiment is on the northern side of the Panama Isthmus on infertile soils where mean annual precipitation is greater, representative of a broad geographic area of the tropics. Given the seasonality of these forests, we performed measurements at stages of the seasonal cycle for which we expected the largest variation in CO2 efflux between control and experimental plots based on previous studies – the wet season (October-December) and dry season (March/April) or dry-to-wet season transition (May). This dataset includes Δ14C and δ13C of in situ soil surface CO2 flux as well as CO2 flux rates, volumetric soil moisture, soil temperature, and calculated partitioning of the fraction of total soil respiration from heterotrophs vs roots at the time of isotope sampling in AllSites_SoilResp_14C_data.xlsx. This dataset also includes Δ14C and δ13C of bulk soil, density fractions, and CO2 respired during laboratory incubations in AllSites_bulk_soil14C.xlsx. Datafiles are also available in csv format.

2019年，我们对巴拿马境内两类实验森林的土壤呼吸释放的二氧化碳（CO₂）的Δ¹⁴C与δ¹³C值进行了测定。其中一类森林接受原位实验性土壤增温处理——较环境温度升高4℃，处理土层深度达1.2米；另一类则接受原位实验性干旱处理（throughfall exclusion，截留50%穿透降雨）。
增温样地与一处干旱样地均坐落于巴罗科罗拉多自然纪念物（Barro Colorado Nature Monument）范围内，二者毗邻且土壤类型相似，可直接对比增温与干旱对土壤CO₂排放的影响效应。第二处干旱实验设置于巴拿马地峡北侧的贫瘠土壤区域，该区域年平均降水量更高，能够代表热带地区大面积的同类生境。
鉴于这些森林的季节节律特征，我们基于前期研究结果，在预计对照样地与实验样地间CO₂排放差异最大的季节阶段开展测定：分别为湿季（10月—12月）、干季（3/4月）以及干湿季过渡阶段（5月）。
本数据集包含AllSites_SoilResp_14C_data.xlsx中记录的原位土壤表面CO₂通量的Δ¹⁴C、δ¹³C值，同时涵盖CO₂通量速率、体积土壤含水量、土壤温度，以及同位素采样时测定的总土壤呼吸中异养呼吸与根系呼吸占比的计算结果。此外，数据集还包含AllSites_bulk_soil14C.xlsx中记录的原状土壤、密度分级组分的Δ¹⁴C与δ¹³C值，以及实验室培养过程中释放的CO₂的同位素组成。所有数据文件均同步提供CSV格式版本。