Microbial community structure mediates response of soil C
decomposition to litter addition and warming

Creamer, CA; De Menezes, AB; Krull, E; Sanderman, J; Newton-Walters, R; Farrell, M

Abstract

Microbial activity has been highlighted as one of the main unknowns controlling the fate and turnover of
soil organic matter (SOM) in response to climate change. How microbial community structure and
function may (or may not) interact with increasing temperature to impact the fate and turnover of SOM,
in particular when combined with changes in litter chemistry, is not well understood. The primary aim of
this study was to determine if litter chemistry impacted the decomposition of soil and litter-derived
carbon (C), and its interaction with temperature, and whether this response was controlled by microbial
community structure and function. Fresh or pre-incubated eucalyptus leaf litter (13C enriched) was
added to a woodland soil and incubated at 12, 22, or 32 �C. We tracked the movement of litter and soilderived
C into CO2, water-extractable organic carbon (WEOC), and microbial phospholipids (PLFA). The
litter additions produced significant changes in every parameter measured, while temperature, interacting
with litter chemistry, predominately affected soil C respiration (priming and temperature sensitivity),
microbial community structure, and the metabolic quotient (a proxy for microbial carbon use
efficiency [CUE]). The direction of priming varied with the litter additions (negative with fresh litter,
positive with pre-incubated litter) and was related to differences in the composition of microbial communities
degrading soil-C, particularly gram-positive and gram-negative bacteria, resulting from litter
addition. Soil-C decomposition in both litter treatments was more temperature sensitive (higher Q10)
than in the soil-only control, and soil-C priming became increasingly positive with temperature. However,
microbes utilizing soil-C in the litter treatments had higher CUE, suggesting the longer-term stability
of soil-C may be increased at higher temperature with litter addition. Our results show that in the
same soil, the growth of distinct microbial communities can alter the turnover and fate of SOM and, in
the context of global change, its response to temperature.

Citation

decomposition to litter addition and warming. Soil Biology and Biochemistry, 80, 175-188. https://doi.org/10.1016/j.soilbio.2014.10.008

• Journal Article Type: Article
• Acceptance Date: Oct 4, 2014
• Online Publication Date: Oct 18, 2014
• Publication Date: Jan 1, 2015
• Deposit Date: Dec 9, 2015
• Journal: Soil Biology and Biochemistry
• Print ISSN: 0038-0717
• Publisher: Elsevier
• Volume: 80
• Pages: 175-188
• DOI: https://doi.org/10.1016/j.soilbio.2014.10.008
• Publisher URL: https://doi.org/10.1016/j.soilbio.2014.10.008
• Related Public URLs: http://www.elsevier.com/wps/product/cws_home/332/description
• Additional Information: Funders : CSIRO Office of the Chief Executive (OCE)