Stable Carbon Isotope Measurements from 200+ Day Lab Incubations of Soil Samples Collected in 2019 and 2024 Across (National Ecological Observatory Network (NEON) Sites in the Continental US, Alaska, and Hawaii

The dynamics of soil organic matter decomposition are known to vary across climate, landscape, and depth. These processes may be illuminated by measuring the stable carbon isotopes of both the source (soil organic matter) and output (respired carbon dioxide from microbial respiration). Thus, roughly 300 soil samples were incubated in glass jars for 200+ days. The headspace was sampled on a roughly bi-weekly schedule, and CO2 concentration and delta13C (carbon isotope ratio) were measured. Data were corrected for leaks, and certain data points were dropped and gap filled due to technical issues with instrumentation. Cumulative delta13C was calculated and reported. Soils were collected in 2019 and 2024 from 30 National Ecological Observatory Network sites across the continental US, Alaska, and Hawaii. Soil was sampled to 30 cm and homogenized, then wet sieved to 2mm, adjusted to field capacity, and placed in either 1 pt or 1 qt jars (2019 and 2024, respectively). Headspace measured via trace gas analyzer.