Fig. 5

Comparisons of plant and surface peat chemistry across the latitudinal transect. Each plot shows estimated a carbohydrate or b aromatic contents in dominant plant types at each site category (green), peat from ≤50 cm at each site category (brown), and the difference (peat – plants) (yellow). For peat samples, Boreal Bogs includes MN Bogs and Mer Bleue, and Boreal Fens includes MN Fens. Error bars represent standard deviations (1 SD) of the measured samples (shown individually as points), and do not account for uncertainty in species composition of peat-forming plants. Significance of differences between plants and peat (unpaired t test) are indicated with asterisks: *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001; ****p ≤ 0.0001; NS = not significant; N/A = significance could not be determined due to n = 1. Numbers of plant samples (Supplementary Table 3): Stordalen, n = 13; Boreal Bogs, n = 3; Boreal Fens, n = 8; NC Pocosin, n = 6; Loxahatchee, n = 1; and Mendaram, n = 8. Numbers of peat samples (Supplementary Table 2): Stordalen, n = 5; Boreal Bogs, n = 35; Boreal Fens, n = 7; NC Pocosin, n = 12; Loxahatchee, n = 22; and Mendaram, n = 6