Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: patterns and causes

CORC > 地理科学与资源研究所 > 中国科学院地理科学与资源研究所 > 生态系统研究网络观测与模拟重点实验室 > 生态网络实验室

	Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: patterns and causes
	Song, B; Sun, J; Zhou, QP; Zong, N; Li, LH; Niu, SL
刊名	BIOGEOSCIENCES
	2017
卷号	14 期号:17 页码:3947-3956
ISSN号	1726-4170
英文摘要	Increases in nitrogen (N) deposition can greatly stimulate ecosystem net carbon (C) sequestration through positive N-induced effects on plant productivity. However, how net ecosystem CO2 exchange (NEE) and its components respond to different N addition rates remains unclear. Using an N addition gradient experiment (six levels: 0, 2, 4, 8, 16, 32 gNm 2 yr(-1) in an alpine meadow on the Qinghai-Tibetan Plateau, we explored the responses of different ecosystem C fluxes to an N addition gradient and revealed mechanisms underlying the dynamic responses. Results showed that NEE, ecosystem respiration (ER), and gross ecosystem production (GEP) all increased linearly with N addition rates in the first year of treatment but shifted to N saturation responses in the second year with the highest NEE (7.77 +/- 0.48 mu molm(-2) s(-1) occurring under an N addition rate of 8 gNm(-2) yr(-1). The saturation responses of NEE and GEP were caused by N-induced accumulation of standing litter, which limited light availability for plant growth under high N addition. The saturation response of ER was mainly due to an N-induced saturation response of aboveground plant respiration and decreasing soil microbial respiration along the N addition gradient, while decreases in soil microbial respiration under high N addition were caused by N-induced reductions in soil pH. We also found that various components of ER, including aboveground plant respiration, soil respiration, root respiration, and microbial respiration, responded differentially to the N addition gradient. These results reveal temporal dynamics of N impacts and the rapid
学科主题	Environmental Sciences & Ecology ; Geology
语种	英语
出版者	COPERNICUS GESELLSCHAFT MBH
WOS记录号	WOS:000410559400001
内容类型	期刊论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/44004]
专题	生态系统网络观测与模拟院重点实验室_生态网络实验室
推荐引用方式 GB/T 7714	Song, B,Sun, J,Zhou, QP,et al. Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: patterns and causes[J]. BIOGEOSCIENCES,2017,14(17):3947-3956.
APA	Song, B,Sun, J,Zhou, QP,Zong, N,Li, LH,&Niu, SL.(2017).Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: patterns and causes.BIOGEOSCIENCES,14(17),3947-3956.
MLA	Song, B,et al."Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: patterns and causes".BIOGEOSCIENCES 14.17(2017):3947-3956.