Accurate predictions of soil C feedbacks to climate change depend on an improved understanding of responses of soil C pools and C use by soil microbial groups. We assessed soil and microbial C in a 7‐year manipulation of CO 2 and warming in a semi‐arid grassland. Continuous field isotopic labelling under elevated CO 2 further allowed us to study the dynamics of the existing C (Old C) in soil and microbes as affected by warming...

Temporal variation in soil nitrogen (N) availability affects growth of grassland communities that differ in their use and reuse of N. In a 7‐year‐long climate change experiment in a semi‐arid grassland, the temporal stability of plant biomass production varied with plant N turnover (reliance on externally acquired N relative to internally recycled N). Species with high N turnover were less stable in time compared to species wi...

Terrestrial plant and soil respiration, or ecosystem respiration (R eco ), represents a major CO 2 flux in the global carbon cycle. However, there is disagreement in how R eco will respond to future global changes, such as elevated atmosphere CO 2 and warming. To address this, we synthesized six years (2007–2012) of R eco data from the Prairie Heating And CO 2 Enrichment ( PHACE ) experiment. We applied a semi‐mechanistic temp...

Net ecosystem productivity ( NEP ) was measured on shortgrass steppe ( SGS ) vegetation at the USDA C entral P lains E xperimental R ange in northeastern C olorado from 2001 to 2003. Large year‐to‐year differences were observed in annual NEP , with >95% of the net carbon uptake occurring during M ay and J une. Low precipitation during the 2002 A pril to J une time period greatly reduced annual net carbon uptake. Large precipit...