Fig. 2. Microcosm setup: (a) darkened 19-cm high, 15-cm-diameter plastic vessel; (b) redox electrode; (c) pH electrode; (d) porous cup; (e) tube and tap, connected to syringe; (f) CO₂ effluent tube; (g) electrical-resistance adaptors, connected to a data logger; (h) data logger; (i) sealing cover.