Effects of stream ecosystem metabolisms on CO2 ( )emissions in two headwater catchments, Southeastern China

doi:10.1016/j.ecolind.2021.108136

	Effects of stream ecosystem metabolisms on CO2 ( )emissions in two headwater catchments, Southeastern China
	Gong, Chen 1,2; Yan, Weijin 1; Zhang, Peipei 1; Yu, Qibiao 1; Li, Yanqian 1; Li, Xinyan 3; Wang, Dongsheng 4,5; Jiao, Ruyuan 4,5
刊名	ECOLOGICAL INDICATORS
	2021-11-01
卷号	130 页码:14
关键词	CO2 Ecosystem respiration Gross primary production Headwater streams In-stream DOC removal efficiency Uptake velocity
ISSN号	1470-160X
DOI	10.1016/j.ecolind.2021.108136
通讯作者	Yan, Weijin(yanwj@igsnrr.ac.cn) ; Jiao, Ruyuan(ryjiao@rcees.ac.cn)
英文摘要	Headwater streams, as critical zones due to their proximity to terrestrial sources, emit large quantities of CO2 owing to their higher drainage density of catchments, substantial total areas, and stream lengths. Stream ecosystem metabolism (EM, i.e. photosynthesis and respiration) can significantly affect the in-stream carbon cycle. However, how stream CO2 emissions respond to ecosystem respiration (ER) is still not well known. Here we report in-situ daily observations of headwater stream gross primary production (GPP), ecosystem respiration (ER), isotopic composition of dissolved inorganic carbon (delta C-13(DIC)) and CO2 emissions conducted in five streams in two headwater catchments of the Changjiang River in Southeastern China. The results show that delta C-13(DIC), pCO(2), and CO2 emission rates have significant diel variations. Both the day and night delta C-13(DIC) values were more depleted than the theoretical values in the two catchments, but the nocturnal depletion was greater. The headwater streams have high EM, with an average ER of -1.99 +/- 0.82 g C m(-2) d(-1) and GPP of 1.52 +/- 0.84 g C m(-)(2 )d(-1) in the two catchments. ER increases with DOC concentration but decreases with water discharge. The nocturnal pCO(2) (3885 +/- 2959 mu atm) was significantly higher than in daytime (2525 +/- 2221 mu atm). The higher nocturnal CO2 emission rate (225 +/- 165 mg C m(-2 )h(-1)) was about 42 % higher than in daytime. DOC uptake velocity (V-f) was 0.46 +/- 0.14 m d(-1), and increased with lower water discharge and lower catchment-scale DOC yield. DOC loss rate (0 was 0.96 +/- 1.25 d(-1) and declined exponentially with higher water discharge and catchment-scale DOC yield. Moreover, the removal fraction of DOC via ER was about 0.32 +/- 0.14, contributing to 31 +/- 16 % of the CO2 flux in streams. The re-estimated annual CO2 flux was about 14.62 +/- 4.99 Tg C yr(-1 )from the Changjiang headwater streams network. This study emphasizes the necessity of incorporating the effects of EM into the river network's CO2 emissions and the importance of the headwater streams to river carbon cycling.
资助项目	National Key Research and Development Program of China[2016YFA0601004] ; National Natural Science Foundation of China[42077304] ; National Natural Science Foundation of China[41877483] ; National Natural Science Foundation of China[41371454] ; National Natural Science Foundation of China[41671479]
WOS关键词	DISSOLVED ORGANIC-CARBON ; INORGANIC CARBON ; DIOXIDE SUPERSATURATION ; PARTIAL-PRESSURE ; GAS-EXCHANGE ; RIVER ; MATTER ; DYNAMICS ; EMISSIONS ; REMOVAL
WOS研究方向	Biodiversity & Conservation ; Environmental Sciences & Ecology
语种	英语
出版者	ELSEVIER
WOS记录号	WOS:000693363200004
资助机构	National Key Research and Development Program of China ; National Natural Science Foundation of China
内容类型	期刊论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/165383]
专题	中国科学院地理科学与资源研究所
通讯作者	Yan, Weijin; Jiao, Ruyuan
作者单位	1.Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, Beijing 100101, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Chinese Acad Sci, Nanjing Inst Geog & Limnol, Nanjing 210008, Peoples R China 4.Chinese Acad Sci, Res Ctr Ecoenvironm Sci, State Key Lab Environm Aquat Chem, Beijing 100085, Peoples R China 5.Chinese Acad Sci, Res Ctr Ecoenvironm Sci, Yangtze River Delta Branch, Yiwu City 322000, Zhejiang, Peoples R China
推荐引用方式 GB/T 7714	Gong, Chen,Yan, Weijin,Zhang, Peipei,et al. Effects of stream ecosystem metabolisms on CO2 ( )emissions in two headwater catchments, Southeastern China[J]. ECOLOGICAL INDICATORS,2021,130:14.
APA	Gong, Chen.,Yan, Weijin.,Zhang, Peipei.,Yu, Qibiao.,Li, Yanqian.,...&Jiao, Ruyuan.(2021).Effects of stream ecosystem metabolisms on CO2 ( )emissions in two headwater catchments, Southeastern China.ECOLOGICAL INDICATORS,130,14.
MLA	Gong, Chen,et al."Effects of stream ecosystem metabolisms on CO2 ( )emissions in two headwater catchments, Southeastern China".ECOLOGICAL INDICATORS 130(2021):14.