Figure 3
(a) Ratio of organic carbon-to-organic nitrogen (OC/ON) in organic layers (Oe, Oa, OA horizons) underneath aboveground litter, light fraction (LF) material of mineral topsoils as well as heavy fraction (HF) material of topsoils and subsoils along the Franz Josef chronosequence where aboveground litter quality decreases with site age. The blue and orange shaded areas indicate 95% confidence intervals of regressions of site age versus the OC/ON ratios of organic layers and HFs of topsoils. (b) Carbon and nitrogen isotopic composition of replicated aboveground litter (Oi horizons) and organic layers (Oe, Oa, OA horizons) as well as HF samples along the soil chronosequence. Individual data points denote replicated soil horizons. Linear regressions lines were included to depict major trends.
