Figure 1.

Environmental drivers of soil metagenomes. (a) The impact of environmental factors. HA: humic acid; FA: fulvic acid; Ald: dithionite extractable Al; MAT: mean annual temperature; Fed: dithionite extractable Fe; Feo: amorphous sesquioxide Fe; MAP: mean annual precipitation; TOC: total organic carbon; DOC: dissolved organic carbon; AK: available K; TDN: total dissolved N; Alo: amorphous sesquioxide Al. (b) Distance-decay of Bray-Curtis similarity of metagenomes. (c) Structure equation models (SEM) between soil metagenomes (MG) and major environmental/soil drivers, including LAT, MAT, HA, soil pH, Ald, and Fed. (d) Spearman's correlation between biomarker genes of biogeochemical process and environmental/soil factors. (e) Correlation of H′ diversity and richness of functional genes in forest soil metagenomes. (f) Principal coordinate analysis (PCoA) of functional genes in forest soil metagenomes; point color represents latitude of sampling sites.