Fig. 5
Lucky B plume sample characteristics plotted against water depth. Anomalies in ORP (a) correlate with high H2 and CH4 concentrations (b), with δ3He excursions (c), and with enrichments in dMn (d). Gray backgrounds mark depth intervals in which our sensors detected hydrothermal anomalies in the shallow and deep plumes (Figs. 2 and 3, Supplementary Figs. S2–S4). Note considerable δ3He anomalies and slightly elevated CH4 concentrations (~ 4–10 nM) at >3,000 m depth (see also insets in Fig. 7a, b). Refer to Fig. 3 for sampling locations.
