Can we detect changes in high-latitude soil respiration over decadal time scales?

Abstract

Soil respiration (RS), the soil surface CO~2~ flux, is the second-largest terrestrial carbon flux, but because of its high variability and the inaccessibility of the soil medium it remains one of the least well-constrained parts of the terrestrial carbon cycle. If the carbon stored in high-latitude ecosystems is being mobilized by climate changes (whether by increasing temperature, changing precipitation, altered disturbance regimes, etc.) we may be able to detect RS changes in the now forty-year record of RS chamber measurements. We searched the published literature and found 194 RS observations from 1964 to 2008 at high latitudes, and paired their known measurement locations with a global climate data set spanning the time period. Linear regression was used to examine the effects of various parameters on RS. The data showed a strong temporal trend, with RS measurements increasing ~4%/yr after the effects of mean annual temperature and moisture had been accounted for. Precipitation anomaly (the deviation of precipitation from the mean 1961-1990 value) was positively correlated with RS, while temperature anomaly was, surprisingly, negatively correlated with it. The small size of the data set limits its inferential power; nonetheless, our results suggest that high-latitude RS is changing due to climate and disturbance changes