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Title: Apparent temperature sensitivity of soil respiration can result from temperature driven changes in microbial biomass

Abstract

The ongoing increase of atmospheric temperatures is expected to induce the loss of soil organic carbon (CS) and ultimately exacerbate the greenhouse effect. There is a great effort to understand and mathematically describe the functional relationship between temperature and the heterotrophic soil respiration rate (RSOIL) since it has significant implications for understanding current carbon cycle dynamics as well as the future evolution of the Earth system. Respiration is a biological process and thus, it depends on the size of respiring microbial biomass (CMB). When RSOIL is measured without concurrent measurement of CMB, temperature sensitivity of RSOIL could be misinterpreted since CMB can change with temperature within days or weeks of the warming experiment. Here we use a meta-analysis of 27 laboratory and field experiments conducted at different temporal scales (1 – 730 days) and under a wide range of temperatures (2 – 50 °C) and soil conditions, to examine how CMB affects the apparent temperature sensitivity of RSOIL. Across all studies, the apparent temperature sensitivity of RSOIL decreases when CMB decreases and vice versa. Observed steep decrease of CMB above optimal temperature (25.2 ± 2.4 °C) attenuates the apparent temperature sensitivity of RSOIL, an aspect which was previously explained bymore » the existence of reaction rate temperature optima. The temperature response of microbial biomass specific respiration rate is, however, highly non-linear and soil specific. CMB explains a significant amount of variability in RSOIL across all studies, but decreases the capability of simple exponential function to fit the temperature trends of RSOIL within individual studies. Including CMB in soil biogeochemical models requires careful consideration of the variability of temperature-associated physiological changes of soil microorganisms, especially the microbial death rate. Without it, microbially explicit biogeochemical models cannot predict temperature induced loss of CS better than older, empirical models based on first order reaction kinetic.« less

Authors:
 [1];  [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. BATTELLE (PACIFIC NW LAB)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1571501
Report Number(s):
PNNL-SA-140117
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Soil Biology and Biochemistry
Additional Journal Information:
Journal Volume: 135
Country of Publication:
United States
Language:
English
Subject:
Soil, respiration rate, temperature sensitivity, meta-analysis, microbial biomass, stress metabolism, death rate

Citation Formats

Capek, Petr, Starke, Robert F., Hofmockel, Kirsten S., Bond-Lamberty, Benjamin, and Hess, Nancy J. Apparent temperature sensitivity of soil respiration can result from temperature driven changes in microbial biomass. United States: N. p., 2019. Web. doi:10.1016/J.SOILBIO.2019.05.016.
Capek, Petr, Starke, Robert F., Hofmockel, Kirsten S., Bond-Lamberty, Benjamin, & Hess, Nancy J. Apparent temperature sensitivity of soil respiration can result from temperature driven changes in microbial biomass. United States. doi:10.1016/J.SOILBIO.2019.05.016.
Capek, Petr, Starke, Robert F., Hofmockel, Kirsten S., Bond-Lamberty, Benjamin, and Hess, Nancy J. Thu . "Apparent temperature sensitivity of soil respiration can result from temperature driven changes in microbial biomass". United States. doi:10.1016/J.SOILBIO.2019.05.016.
@article{osti_1571501,
title = {Apparent temperature sensitivity of soil respiration can result from temperature driven changes in microbial biomass},
author = {Capek, Petr and Starke, Robert F. and Hofmockel, Kirsten S. and Bond-Lamberty, Benjamin and Hess, Nancy J.},
abstractNote = {The ongoing increase of atmospheric temperatures is expected to induce the loss of soil organic carbon (CS) and ultimately exacerbate the greenhouse effect. There is a great effort to understand and mathematically describe the functional relationship between temperature and the heterotrophic soil respiration rate (RSOIL) since it has significant implications for understanding current carbon cycle dynamics as well as the future evolution of the Earth system. Respiration is a biological process and thus, it depends on the size of respiring microbial biomass (CMB). When RSOIL is measured without concurrent measurement of CMB, temperature sensitivity of RSOIL could be misinterpreted since CMB can change with temperature within days or weeks of the warming experiment. Here we use a meta-analysis of 27 laboratory and field experiments conducted at different temporal scales (1 – 730 days) and under a wide range of temperatures (2 – 50 °C) and soil conditions, to examine how CMB affects the apparent temperature sensitivity of RSOIL. Across all studies, the apparent temperature sensitivity of RSOIL decreases when CMB decreases and vice versa. Observed steep decrease of CMB above optimal temperature (25.2 ± 2.4 °C) attenuates the apparent temperature sensitivity of RSOIL, an aspect which was previously explained by the existence of reaction rate temperature optima. The temperature response of microbial biomass specific respiration rate is, however, highly non-linear and soil specific. CMB explains a significant amount of variability in RSOIL across all studies, but decreases the capability of simple exponential function to fit the temperature trends of RSOIL within individual studies. Including CMB in soil biogeochemical models requires careful consideration of the variability of temperature-associated physiological changes of soil microorganisms, especially the microbial death rate. Without it, microbially explicit biogeochemical models cannot predict temperature induced loss of CS better than older, empirical models based on first order reaction kinetic.},
doi = {10.1016/J.SOILBIO.2019.05.016},
journal = {Soil Biology and Biochemistry},
number = ,
volume = 135,
place = {United States},
year = {2019},
month = {8}
}