Fig. 2.

Metabolic activity of Campylobacteria cells from Crab Spa fluids after short-term incubations at in situ pressure as quantified by HISH-SIMS. Rows represent different experimental treatments as follows: (A–C) control treatment (10% H¹³CO₃⁻) and (D–I) oxygen amendments (110 μM O₂ + 10% H¹³CO₃⁻). Cells were hybridized with general Campylobacteria probe (A–F) and with a specific Nautiliales probe (G–I), using Fluorine-containing tyramides. Columns display parallel secondary ion images of ¹²C¹⁴N as total biomass indicator (A, D, and G), ¹⁹F as a marker for cell identity (B, E, and H) and the ¹³C enrichment inferred from secondary ions (¹³C−, ¹²C−) given as atomic percentage [100 × ¹³C/(¹²C + ¹³C; at %)], as indicator of cell activity. [Scale bar, 2 μm (A–F) and 3 μm (G–I).]