Supplementary materials

Secondary successional forests undergo tightly-coupled changes in soil microbial

community structure and soil organic matter

Pengshuai Shaoa,b, Chao Lianga*, Kennedy Rubert-Nasonc, Xiangzhen Lid, Hongtu

Xiea, Xuelian Baoa

a Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese

Academy of Sciences, Shenyang 110016, China

b University of Chinese Academy of Sciences, Beijing 100049, China

c Department of Entomology, University of Wisconsin-Madison, Madison, WI 53706, U.S.A.

d Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology,

Chinese Academy of Sciences, Sichuan 610041, China

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Fig. S1. Average mid-infrared spectra of topsoil and subsoil from all stages of forest

succession. The specific peaks marked by dotted lines represent different functional

groups (Calderón et al., 2011; Calderón et al., 2013; Demyan et al. 2012; Giacometti

et al. 2013; Grube et al., 2006): stretching O–H and stretching N–H (3400 cm-1),

aliphatic C group (2930 cm-1 and 2850 cm-1), aromatic C and NH (amide II) groups

(1620 cm-1), lignin-like structures (1545 cm-1 and 1515 cm-1), bending (CH2) in

polysaccharides and proteins (1450 cm-1), mineral material (1370 cm-1),

polysaccharides or carbohydrates (1034 cm-1).

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Figure S2. Linear regression analyses among dominant prokaryotic phyla, and SOC

concentration and the relative abundance (%) of C functional groups across secondary

forest successional stages in topsoil (black circle) and subsoil (grey circle). Solid lines

depict significant linear relationships (P < 0.05), while plots without regression lines

are not linearly related (P > 0.05).

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Fig. S3. The relationship between Candidatus Nitrososphaera (a dominant genus of

Crenarchaeota) and nitrate in topsoil and subsoil across the successional forest stages.

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Table S1. Latitude, longitude and altitude of sites corresponding to five forest

successional stages in Changbai Mountain.

Stage of succession a

(years) Latitude (N) Longitude (E) Elevation (m)

20 42º20´19´´ 127º54´43´´ 922

80 42º21´26´´ 127º58´59´´ 869

120 42º21´09´´ 127º56´54´´ 887

200 42º21´13´´ 128º05´41´´ 784

300 42º21´04´´ 127º59´16´´ 801

a Five stages of secondary forest succession: 20, 80, 120, 200 and ≥ 300 years

(hereinafter replaced with “300 years”).

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Table S2. Relationships between soil parameters and, prokaryotic community

richness and α-diversity.

　 　 Topsoil 　 Subsoil

Variables Chao1 richness

Shannon's diversity

Faith's Phylogenetic diversity 　 Chao1

richness Shannon's diversity

Faith's Phylogenetic diversity

pH n.s. n.s. n.s. 　 n.s. n.s. n.s.

SOC (g kg-1) n.s. n.s. n.s. 　 n.s. n.s. n.s.

SOC: TN n.s. n.s. n.s. 　 n.s. n.s. n.s.

Nitrate (mg kg-1) n.s. n.s. n.s. -0.42* -0.51** -0.39*

Aliphatic (%) n.s. n.s. n.s. 　 n.s. n.s. n.s.

Aromatic (%) n.s. n.s. n.s. 　 -0.45* -0.48** n.s.

Polysaccharides (%) n.s. n.s. n.s. 　 0.43* 0.46* n.s.

Significance levels: not significant (n.s.); *P < 0.05; **P < 0.01. Abbreviations: soil

organic carbon (SOC), SOC to total nitrogen ratio (SOC: TN).

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References

Calderón, F.J., Reeves, J.B., Collins, H.P., Paul, E.A., 2011. Chemical differences in

soil organic matter fractions determined by diffuse-reflectance mid-infrared

spectroscopy. Soil Science Society of America Journal 75, 568-579.

Calderón, F., Haddix, M., Conant, R., Magrini-Bair, K., Paul, E., 2013. Diffuse-

reflectance Fourier-transform mid-infrared spectroscopy as a method of

characterizing changes in soil organic matter. Soil Science Society of America

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Demyan, M., Rasche, F., Schulz, E., Breulmann, M., Müller, T., Cadisch, G., 2012.

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infrared spectroscopy to study the composition of organic matter in a Haplic

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Giacometti, C., Demyan, M.S., Cavani, L., Marzadori, C., Ciavatta, C., Kandeler, E.,

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differentiate fertilization regimes in temperate agroecosystems. Applied Soil

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Grube, M., Lin, J., Lee, P., Kokorevicha, S., 2006. Evaluation of sewage sludge-based

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