Spatial and temporal variability in soil CO 2–C emissions and relation to soil temperature at King George Island, maritime Antarctica

Abstract

Few studies have examined the effects of temperature on spatial and temporal trends in soil CO 2–C emissions in Antarctica. In this work, we present in situ measurements of CO 2–C emissions and assess their relation with soil temperature, using dynamic chambers. We found an exponential relation between CO 2 emissions and soil temperature, with the value of Q 10 being close to 2.1. Mean emission rates were as low as 0.026 and 0.072 g of CO 2–C m −2 h −1 for bare soil and soil covered with moss, respectively, and as high as 0.162 g of CO 2–C m −2 h −1 for soil covered with grass, Deschampsia antarctica Desv. (Poaceae). A spatial variability analysis conducted using a 60-point grid, for an area with mosses ( Sannionia uncianata) and D. antarctica, yielded a spherical semivariogram model for CO 2–C emissions with a range of 1 m. The results suggest that soil temperature is a controlling factor on temporal variations in soil CO 2–C emissions, although spatial variations appear to be more strongly related to the distribution of vegetation types.