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. 2015 Sep 8;112(38):E5253–E5260. doi: 10.1073/pnas.1508945112

Table S1.

Chemical transformations of litter over 6 y of decomposition

13C-NMR
FTIR‡ relative absorbance, % LDPI§, relative intensity, % Aromatic Sacch Aliphatics
Sample Year C/N*, ratio Mntotal*, mg⋅g−1 Mnpyro*, % Mnred*, % Mn+x† Amide Aromatic Sacch ∑ar− ∑ar+ Car-O Car-R C-OH CHx
Fresh needles# 2012 48 ± 2 0.9 ± 0.1 55 ± 1 45 ± 9 2.07 13 0.7 47 n.a. n.a. n.a. n.a. n.a. n.a.
Litter layer 1 2011–10 47 ± 2 1.2 ± 0.0 66 ± 3 34 ± 3 2.15 15 0.9 46 5 1.5 6.5 10.6 39 20
Litter layer 2 2010–09 39 ± 3 1.5 ± 0.1 74 ± 4 26 ± 2 2.22 17 1.1 44 4 2.3 7.0 10.7 37 22
Litter layer 3 2009–08 35 ± 1 1.8 ± 0.1 85 ± 4 15 ± 1 2.31 20 1.1 44 3 1.4 8.0 11.1 35 22
Litter layer 4 2008–07 37 ± 2 2.1 ± 0.1 87 ± 6 14 ± 1 2.49 22 1.3 42 3 2.3 8.2 11.7 32 23
Litter layer 5 2007–06 36 ± 1 2.5 ± 0.1 83 ± 4 17 ± 2 2.59 21 1.2 44 2 2.4 8.7 12.5 32 22
Litter layer 6 2006–05 38 ± 1 2.5 ± 0.1 74 ± 3 26 ± 2 2.74 21 1.4 41 2 2.5 8.7 13.1 29 25
O horizon (needle litter) <2005 45 ± 2 1.4 ± 0.2 72 ± 2 28 ± 6 2.83 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.
A horizon (2–20 cm) n.a. 24 ± 1 1.0 ± 0.1 26 ± 2 74 ± 11 3.14 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.
A/B horizon (20–37 cm) n.a. 23 ± 2 0.9 ± 0.0 5 ± 0 95 ± 4 3.03 n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.

Sacch, saccharides; n.a., not available.

*

Values given as mean ± SE. SEs are based on three analytical replicates.

†

x, average oxidation state of Mn as determined by linear combination fitting of Mn XANES spectra.

‡

Peak deconvolution results for absorbance bands at 1,640–1,700 and 1,580–1,530 (amide I and II), 1,510 (lignin), and 1,180–950 (saccharides) cm−1.

§

∑ar− and ∑ar+ denote the sums of peak intensities of masses identified in LDPI spectra shown in Fig. 2C. ∑ar+ is the sum of normalized intensities of peaks that increase with litter age (m/z = 340–370) whereas ∑ar− represents the sum of normalized intensities of peaks decreasing over time (m/z = 396–414).

Peak integration results using chemical shift regions of 0–47 (aliphatic), 92–58 (saccharides), and 140–112/160–140 ppm (Car-R/Car-O aromatic).

#

Reported values are for mature needles on the tree (6 y and older). Young needles (younger than 1 y) showed significantly lower Mn contents (0.2 mg⋅g−1).