Linking microbial community composition to C loss rates during wood decomposition

Abstract

Although decaying wood plays an important role in global carbon (C) cycling, how changes in microbial community are related to wood C quality and then affect wood organic C loss during wood decomposition remains unclear. In this study, a chronosequence method was used to examine the relationships between wood C loss rates and microbial community compositions during Chinese fir (Cunninghamia lanceolata) stump decomposition. Our results showed that microbial community shifted from fungi-dominated at early stages (0-15 years) to relatively more bacteria-dominated at later stages (15-35 years) of wood decomposition. Fungal phospholipid fatty acid (PLFA) content primarily explained wood C loss rates at early stages of wood decomposition. Fungal biomass was positively correlated with proportions of relatively high-quality C (e.g., O-alkyl C), but bacterial biomass was positively correlated with low-quality C. In addition, fungi appeared to be the dominated community under low wood moisture (< 20%) at early stages, but fungal biomass tended to decrease and bacterial biomass increased with increasing wood moisture at later stages. Our findings suggest that the fungal community is the dominant decomposer of wood at early stages and may be positively influenced by relatively high-quality wood C and low wood moisture. Bacterial community may benefited from lowquality wood C and high wood moisture at later stages. Enhanced understanding of microbial responses to wood quality and environment is important to improve predictions in wood decomposition models.

Bacteria inhabiting deadwood of 13 tree species are heterogeneously distributed between sapwood and heartwood

“…and Betula sp., where they make up, respectively, 12%, 20% and 32% of all sequences. As bacteria seem to benefit from high wood moisture (Hu et al, 2017), it can be anticipated that they will make a contribution to decomposition under the conditions of this experiment.…”

Traits drive global wood decomposition rates more than climate

“…Wood traits involved in C quality and nutrient availability strongly influence microbial community on decomposition processes (Manning, Rosemond, Gulis, Benstead, & Kominoski, 2018;van der Wal et al, 2007). These traits also influence how microbial community composition might respond to changes in the environment (e.g., warming and drought; Lavorel & Garnier, 2002;Matulich & Martiny, 2015), whereas microbial taxa determine microbial decay capacity and decomposition rates (Hu et al, 2017). Therefore, wood traits may play a dominant role in determining the microbial taxa for wood decomposition across global climate gradients.…”

Effects of long-term mowing on the fractions and chemical composition of soil organic matter in a semiarid grassland

“…The elemental analysis suggested that long-term mowing practice had major impacts on the elemental composition of SOM. The lower H / C ratio indicated more aromatic compounds or higher aromaticity and saturability, and the higher O / C ratio indicated more carboxyl groups, phenol or carbohydrates with oxygen (Ma et al, 2001;Steelink, 1985;Kim et al, 1991). 13 C NMR apparently differentiated the lignin C (including alkyl, N-alkyl and aryl C) and carbohydrate C (including O-alkyl, di-Oalkyl, carbonyl and carboxyl C) (Hu et al, 2017).…”