FIG. 2.

Aerobic incubation of thawed ice samples in the dark. Samples collected in 1997 were supplemented with 98,000 dpm of sodium [2-¹⁴C]acetate and incubated at 8°C for 270 days with gyratory shaking at 200 rpm (■, basal ice plus dilute R2A medium; □, glacier ice plus dilute R2A medium; ◊, dilute R2A medium). Samples collected in 1998 were supplemented with 195,000 dpm of sodium [2-¹⁴C]acetate and incubated statically at 4°C for 157 days (●, basal ice without R2A medium; ○, glacier ice without R2A medium).