Growing season net ecosystem CO2 exchange of two desert ecosystems with alkaline soils in Kazakhstan
Article first published online: 4 DEC 2013
© 2013 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Ecology and Evolution
Volume 4, Issue 1, pages 14–26, January 2014
How to Cite
Ecology and Evolution 2014; 4(1):14–26.
- Issue published online: 3 JAN 2014
- Article first published online: 4 DEC 2013
- Manuscript Accepted: 7 NOV 2013
- Manuscript Revised: 28 OCT 2013
- Manuscript Received: 10 AUG 2013
- National Basic Research Program of China. Grant Number: 2009CB825105
- “Hundred Talent” Project of Chinese Academy of Sciences. Grant Number: Y174051001
- National Natural Science Foundation of China. Grant Number: 41171094
- alkaline soil;
- carbon sequestration;
- CO2 absorption;
- desert ecosystem.
Central Asia is covered by vast desert ecosystems, and the majority of these ecosystems have alkaline soils. Their contribution to global net ecosystem CO2 exchange (NEE) is of significance simply because of their immense spatial extent. Some of the latest research reported considerable abiotic CO2 absorption by alkaline soil, but the rate of CO2 absorption has been questioned by peer communities. To investigate the issue of carbon cycle in Central Asian desert ecosystems with alkaline soils, we have measured the NEE using eddy covariance (EC) method at two alkaline sites during growing season in Kazakhstan. The diurnal course of mean monthly NEE followed a clear sinusoidal pattern during growing season at both sites. Both sites showed significant net carbon uptake during daytime on sunny days with high photosynthetically active radiation (PAR) but net carbon loss at nighttime and on cloudy and rainy days. NEE has strong dependency on PAR and the response of NEE to precipitation resulted in an initial and significant carbon release to the atmosphere, similar to other ecosystems. These findings indicate that biotic processes dominated the carbon processes, and the contribution of abiotic carbon process to net ecosystem CO2 exchange may be trivial in alkaline soil desert ecosystems over Central Asia.