Soil microbial responses to warming and increased precipitation and their implications for ecosystem C cycling

• Published in: Oecologia
• Main Authors: Zhang, Naili, Liu, Weixing, Yang, Haijun, Yu, Xingjun, Gutknecht, Jessica L. M., Zhang, Zhe, Wan, Shiqiang, Ma, Keping
• Format: Article in Journal/Newspaper
• Language: English
• Published: SPRINGER 2013
• Subjects: Carbon utilization; Microbial biomass; Microbial community composition; Respiratory loss of soil carbon; Semi-arid grassland; Ecology; FATTY-ACID PROFILES; CLIMATE-CHANGE; THERMAL ADAPTATION; ORGANIC-MATTER; FUNCTIONAL DIVERSITY; UTILIZATION PATTERNS; COMMUNITY STRUCTURE; NITROGEN ADDITION; PLANT DIVERSITY; ARCTIC SOIL; Science Citation Index Expanded (SCI-EXPANDED); Arctic; Climate change
• Online Access: http://ir.ibcas.ac.cn/handle/2S10CLM1/28177; https://doi.org/10.1007/s00442-013-2685-9

A better understanding of soil microbial ecology is critical to gaining an understanding of terrestrial carbon (C) cycle-climate change feedbacks. However, current knowledge limits our ability to predict microbial community dynamics in the face of multiple global change drivers and their implications for respiratory loss of soil carbon. Whether microorganisms will acclimate to climate warming and ameliorate predicted respiratory C losses is still debated. It also remains unclear how precipitation, another important climate change driver, will interact with warming to affect microorganisms and their regulation of respiratory C loss. We explore the dynamics of microorganisms and their contributions to respiratory C loss using a 4-year (2006-2009) field experiment in a semi-arid grassland with increased temperature and precipitation in a full factorial design. We found no response of mass-specific (per unit microbial biomass C) heterotrophic respiration to warming, suggesting that respiratory C loss is directly from microbial growth rather than total physiological respiratory responses to warming. Increased precipitation did stimulate both microbial biomass and mass-specific respiration, both of which make large contributions to respiratory loss of soil carbon. Taken together, these results suggest that, in semi-arid grasslands, soil moisture and related substrate availability may inhibit physiological respiratory responses to warming (where soil moisture was significantly lower), while they are not inhibited under elevated precipitation. Although we found no total physiological response to warming, warming increased bacterial C utilization (measured by BIOLOG EcoPlates) and increased bacterial oxidation of carbohydrates and phenols. Non-metric multidimensional scaling analysis as well as ANOVA testing showed that warming or increased precipitation did not change microbial community structure, which could suggest that microbial communities in semi-arid grasslands are already adapted to fluctuating climatic ...