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The responses of soil and rhizosphere respiration to simulated climatic changes vary by season
Author(s) -
Suseela Vidya,
Dukes Jeffrey S.
Publication year - 2013
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/12-0150.1
Subject(s) - environmental science , q10 , soil respiration , precipitation , ecosystem , growing season , rhizosphere , respiration , global warming , water content , climate change , ecosystem respiration , soil water , soil carbon , moisture , agronomy , ecology , primary production , biology , chemistry , soil science , botany , bacteria , engineering , genetics , geotechnical engineering , organic chemistry , meteorology , physics
Responses of soil respiration ( R s ) to anthropogenic climate change will affect terrestrial carbon storage and, thus, feed back to warming. To provide insight into how warming and changes in precipitation regimes affect the rate and temperature sensitivity of R s and rhizosphere respiration ( R r ) across the year, we subjected a New England old‐field ecosystem to four levels of warming and three levels of precipitation (ambient, drought, and wet treatments). We measured R s and heterotrophic respiration ( R h ) monthly (in areas of the plots with and without plants, respectively) and estimated R r by calculating the difference in respiration between R s and R h . Even in this mesic ecosystem, R s and R r responded strongly to the precipitation treatments. Drought reduced R s and R r , both annually and during the growing season. Annual cumulative R s responded nonlinearly to precipitation treatments; both drought and supplemental precipitation suppressed R s compared to the ambient treatment. Warming increased R s and R r in spring and winter when soil moisture was optimal but decreased these rates in summer when moisture was limiting. Cumulative winter R r increased by about 200% in the high warming (∼3.5°C) treatment. The effect of climate treatments on the temperature sensitivity of R s depended on the season. In the fall, the drought treatment decreased apparent Q 10 relative to the other precipitation treatments. The responses of R s to warming and altered precipitation were largely driven by changes in R r . We emphasize the importance of incorporating realistic soil moisture responses into simulations of soil carbon fluxes; the long‐term effects of warming on carbon–climate feedback will depend on future precipitation regimes. Our results highlight the nonlinear responses of soil respiration to soil moisture and, to our knowledge, quantify for the first time the loss of carbon through winter rhizosphere respiration due to warming. While this additional loss is small relative to the cumulative annual flux in this system, such increases in rhizosphere respiration during the non‐growing season could have greater consequences in ecosystems where they offset or reduce subsequent warming‐induced gains in plant growth.