Figure 1
From: Novel microbial assemblages inhabiting crustal fluids within mid-ocean ridge flank subsurface basalt
Pristine deep subseafloor basement fluids are readily distinguishable from seawater and mixed samples based on geochemistry. Principal components analysis biplot of (a) all samples and (b) borehole U1301A, U1362A, and U1362B high-quality deep subsurface fluid samples based on eigenvalues derived from their corresponding chemical data. Dashed arrows indicate the direction of increase for measured chemical parameters while arrow length indicates the degree of correlation with the ordination axis. Only the first two principal component axes are shown. Details of individual samples are described in Supplementary Tables S1 and S2. Alk, alkalinity; DOC, dissolved organic carbon; TOC, total organic carbon; TDN, total dissolved nitrogen; TN, total nitrogen; dFe, dissolved iron.
