No temperature acclimation of soil extracellular enzymes to experimental warming in an alpine grassland ecosystem on the Tibetan Plateau

• Published in: Biogeochemistry
• Main Authors: Jing, Xin, Wang, Yonghui, Chung, Haegeun, Mi, Zhaorong, Wang, Shiping, Zeng, Hui, He, Jin-Sheng
• Other Authors: He, JS (reprint author), Chinese Acad Sci, Northwest Inst Plateau Biol, Key Lab Adaptat & Evolut Plateau Biota, 23 Xinning Rd, Xining 810008, Peoples R China., Peking Univ, Coll Urban & Environm Sci, Dept Ecol, Beijing 100871, Peoples R China., Peking Univ, Minist Educ, Key Lab Earth Surface Proc, Beijing 100871, Peoples R China., Konkuk Univ, Dept Environm Engn, Seoul 143701, South Korea., Chinese Acad Sci, Northwest Inst Plateau Biol, Key Lab Adaptat & Evolut Plateau Biota, Xining 810008, Peoples R China., Chinese Acad Sci, Inst Tibetan Plateau Res, Lab Alpine Ecol & Biodivers, Beijing 100085, Peoples R China., Peking Univ, Shenzhen Grad Sch, Key Lab Urban Habitat Environm Sci & Technol, Shenzhen 518055, Peoples R China., Chinese Acad Sci, Northwest Inst Plateau Biol, Key Lab Adaptat & Evolut Plateau Biota, 23 Xinning Rd, Xining 810008, Peoples R China.
• Format: Journal/Newspaper
• Language: English
• Published: biogeochemistry 2014
• Subjects: Global warming; Temperature acclimation; Soil extracellular enzyme activity; Q(10); Alpine grassland; Tibetan plateau; CARBON-CYCLE FEEDBACKS; MICROBIAL COMMUNITY STRUCTURE; ARCTIC TUNDRA SOILS; BOREAL FOREST SOILS; CLIMATE-CHANGE; ORGANIC-CARBON; THERMODYNAMIC PARAMETERS; ELEVATED-TEMPERATURE; NITROGEN DEPOSITION; THERMAL ADAPTATION; Arctic; Climate change; Tundra
• Online Access: https://hdl.handle.net/20.500.11897/160951; https://doi.org/10.1007/s10533-013-9844-2

Alpine grassland soils store large amounts of soil organic carbon (SOC) and are susceptible to rising air temperature. Soil extracellular enzymes catalyze the rate-limiting step in SOC decomposition and their catalysis, production and degradation rates are regulated by temperature. Therefore, the responses of these enzymes to warming could have a profound impact on carbon cycling in the alpine grassland ecosystems. This study was conducted to measure the responses of soil extracellular enzyme activity and temperature sensitivity (Q(10)) to experimental warming in samples from an alpine grassland ecosystem on the Tibetan Plateau. A free air-temperature enhancement system was set up in May 2006. We measured soil microbial biomass, nutrient availability and the activity of five extracellular enzymes in 2009 and 2010. The Q(10) of each enzyme was calculated using a simple first-order exponential equation. We found that warming had no significant effects on soil microbial biomass C, the labile C or N content, or nutrient availability. Significant differences in the activity of most extracellular enzymes among sampling dates were found, with typically higher enzyme activity during the warm period of the year. The effects of warming on the activity of the five extracellular enzymes at 20 A degrees C were not significant. Enzyme activity in vitro strongly increased with temperature up to 27 A degrees C or over 30 A degrees C (optimum temperature; T-opt). Seasonal variations in the Q(10) were found, but the effects of warming on Q(10) were not significant. We conclude that soil extracellular enzymes adapted to seasonal temperature variations, but did not acclimate to the field experimental warming. Environmental Sciences Geosciences, Multidisciplinary SCI(E) 5 ARTICLE [e-mail] 1 39-54 117