Carbon(C)and nitrogen(N)coupling processes in terrestrial ecosystems have the potential to modify the sensitivity of the global C cycle to climate change.But the degree to which C–N interactions contribute to the seq...Carbon(C)and nitrogen(N)coupling processes in terrestrial ecosystems have the potential to modify the sensitivity of the global C cycle to climate change.But the degree to which C–N interactions contribute to the sequestration of terrestrial ecosystem C(C_(seq)),both now and in the future,remains uncertain.In this study,we used a meta-analysis to quantitatively synthesize C and N responses from feld experiments on grasslands subjected to simulated warming and assessed the relative importance of three properties(changes in ecosystem N amount,redistribution of N among soil,litter and vegetation,and modifcations in the C:N ratio)associated with grassland C_(seq) in response to warming.Warming increased soil,litter and vegetation C:N ratios and approximately 2%of N shifted from the soil to vegetation and litter.Warming-induced grassland C_(seq) was the result of the net balance between increases in vegetation and litter C(111.2 g·m^(−2))and decreases in soil C(30.0 g·m^(−2)).Warming-induced accumulation of C stocks in grassland ecosystems indicated that the three processes examined were the main contributors to C_(seq),with the changes in C:N ratios in soil,litter and vegetation as the major contributors,followed by N redistribution,whilst a decrease in total N had a negative effect on C_(seq).These results indicate that elevated temperatures have a signifcant infuence on grassland C and N stocks and their coupling processes,suggesting that ecological models need to include C–N interactions for more accurate predictions of future terrestrial C storage.展开更多
基金supported by the Excellent Youth Scholars Program and the Special Project on Hi-Tech Innovation Capacity(KJCX20210416)from Beijing Academy of Agriculture and Forestry Sciences(BAAFS)the National Key Research and Development Program of China(2017YFA0604604).
文摘Carbon(C)and nitrogen(N)coupling processes in terrestrial ecosystems have the potential to modify the sensitivity of the global C cycle to climate change.But the degree to which C–N interactions contribute to the sequestration of terrestrial ecosystem C(C_(seq)),both now and in the future,remains uncertain.In this study,we used a meta-analysis to quantitatively synthesize C and N responses from feld experiments on grasslands subjected to simulated warming and assessed the relative importance of three properties(changes in ecosystem N amount,redistribution of N among soil,litter and vegetation,and modifcations in the C:N ratio)associated with grassland C_(seq) in response to warming.Warming increased soil,litter and vegetation C:N ratios and approximately 2%of N shifted from the soil to vegetation and litter.Warming-induced grassland C_(seq) was the result of the net balance between increases in vegetation and litter C(111.2 g·m^(−2))and decreases in soil C(30.0 g·m^(−2)).Warming-induced accumulation of C stocks in grassland ecosystems indicated that the three processes examined were the main contributors to C_(seq),with the changes in C:N ratios in soil,litter and vegetation as the major contributors,followed by N redistribution,whilst a decrease in total N had a negative effect on C_(seq).These results indicate that elevated temperatures have a signifcant infuence on grassland C and N stocks and their coupling processes,suggesting that ecological models need to include C–N interactions for more accurate predictions of future terrestrial C storage.
