Non-growing-season soil respiration is controlled by freezing and thawing processes in the summer monsoon-dominated Tibetan alpine grassland

The Tibetan alpine grasslands, sharing many features with arctic tundra ecosystems, have a unique non-growing-season climate that is usually dry and without persistent snow cover. Pronounced winter warming recently observed in this ecosystem may significantly alter the non-growing-season carbon cycl...

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Bibliographic Details
Published in:Global Biogeochemical Cycles
Main Authors: Wang, Yonghui, Liu, Huiying, Chung, Haegeun, Yu, Lingfei, Mi, Zhaorong, Geng, Yan, Jing, Xin, Wang, Shiping, Zeng, Hui, Cao, Guangmin, Zhao, Xinquan, He, Jin-Sheng
Other Authors: He, JS (reprint author), Peking Univ, Dept Ecol, Coll Urban & Environm Sci, Beijing 100871, Peoples R China., Peking Univ, Dept Ecol, Coll Urban & Environm Sci, Beijing 100871, Peoples R China., Peking Univ, Key Lab Earth Surface Proc, Minist Educ, Beijing 100871, Peoples R China., Konkuk Univ, Dept Environm Engn, Seoul, South Korea., Chinese Acad Sci, State Key Lab Vegetat & Environm Change, Inst Bot, Beijing, Peoples R China., Chinese Acad Sci, Key Lab Adaptat & Evolut Plateau Biota, Northwest Inst Plateau Biol, Xining, Peoples R China., Chinese Acad Sci, Key Lab Tibetan Environm Changes & Land Surface P, Inst Tibetan Plateau Res, Beijing, Peoples R China., Peking Univ, Key Lab Urban Habitat Environm Sci & Technol, Shenzhen Grad Sch, Shenzhen, Peoples R China.
Format: Journal/Newspaper
Language:English
Published: global biogeochemical cycles 2014
Subjects:
winter soil respiration
carbon cycling
alpine ecosystem
soil freezing
Tibetan Plateau
INCREASED SNOW DEPTH
CO2 EFFLUX
TEMPERATURE SENSITIVITY
CLIMATE-CHANGE
ARCTIC TUNDRA
MICROBIAL RESPIRATION
ECOSYSTEM RESPIRATION
SOLAR-RADIATION
VEGETATION TYPE
NORTH-AMERICA
Arctic
Climate change
Tundra
Online Access:https://hdl.handle.net/20.500.11897/160875
https://doi.org/10.1002/2013GB004760
Description
Summary:The Tibetan alpine grasslands, sharing many features with arctic tundra ecosystems, have a unique non-growing-season climate that is usually dry and without persistent snow cover. Pronounced winter warming recently observed in this ecosystem may significantly alter the non-growing-season carbon cycle processes such as soil respiration (R-s), but detailed measurements to assess the patterns, drivers of, and potential feedbacks on R-s have not been made yet. We conducted a 4 year study on R-s using a unique R-s measuring system, composed of an automated soil CO2 flux sampling system and a custom-made container, to facilitate measurements in this extreme environment. We found that in the nongrowing season, (1) cumulative R-s was 82-89g C m(-2), accounting for 11.8-13.2% of the annual total R-s; (2) surface soil freezing controlled the diurnal pattern of R-s and bulk soil freezing induced lower reference respiration rate (R-0) and temperature sensitivity (Q(10)) than those in the growing season (0.40-0.53 versus 0.84-1.32 mu mol CO2 m(-2)s(-1) for R-0 and 2.5-2.9 versus 2.9-5.6 for Q(10)); and (3) the intraannual variation in cumulative R-s was controlled by accumulated surface soil temperature. We found that in the summer monsoon-dominated Tibetan alpine grassland, surface soil freezing, bulk soil freezing, and accumulated surface soil temperature are the day-, season-, and year-scale drivers of the non-growing-season R-s, respectively. Our results suggest that warmer winters can trigger carbon loss from this ecosystem because of higher Q(10) of thawed than frozen soils. http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000344797500005&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 Environmental Sciences Geosciences, Multidisciplinary Meteorology & Atmospheric Sciences SCI(E) 6 ARTICLE jshe@pku.edu.cn 10 1081-1095 28

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