Fig. 2: Relationship between mercury (Hg) concentration and latitude, precipitation, and altitude.
From: Root uptake dominates mercury accumulation in permafrost plants of Qinghai-Tibet Plateau

a Correlations for Hg concentration versus latitude, b Δ199Hg in soils versus latitude, c precipitation versus Hg concentration in soils, d precipitation versus pool size in soils, e Δ199Hg in vegetation versus altitude, f Δ199Hg in surface soils versus altitude. The shading of a−f represents the 95% confidence interval for regression and error bars stand for 1σ.