Climate change is rapidly redefining the biogeochemical dynamics of our planet, particularly in relation to soil organic carbon (SOC) storage and loss. We aim to isolate confounding elements and elucidate the principal mechanisms underpinning SOC dynamics under diverse environmental scenarios: warming (ambient, +1.5°C, and +2.5°C), and nutrient (nitrogen and phosphorus) and carbon addition treatments. Samples were collected from a low-latitude soil warming experiment where warming commenced in 2010 (Whitehall Forest, Athens, Georgia). Under laboratory conditions, we incubated soil samples (22 days) at their respective field temperatures at the time of sample collection. 

Core aspects of the soil carbon cycle, including particulate (and mineral-associated) organic carbon, microbial biomass carbon, and microbial necromass carbon, as well as critical processes such as soil microbial respiration and enzyme kinetics were examined. Our systematic evaluations helped separate the direct and indirect effects of warming (e.g., the inherent and apparent temperature sensitivity of SOC formation and loss). Our findings indicate that warming has a minor influence on soil carbon storage in substrate-limited ecosystems. However, as carbon and nutrient inputs increase, soil carbon loss accelerates. This study sheds light on the delicate balance between underlying mechanisms that control SOC dynamics in the face of climate change, emphasizing the nuanced interdependence of temperature, substrate resource availability, and soil carbon dynamics.