FIGURE 4.

Interface microbial metabolism: relative humidity and hygroscopic matrices – single microcosms. Carbon dioxide production at (A) bentonite-air interfaces and (B) PEG-air interfaces, measured in a closed-loop CEMS system. Samples were inoculated with microbial biomass (mixed community, Table 1) that had been pre-incubated under static conditions for 2 days on the respective substrate (bentonite and PEG), dried overnight, and incubated at low (30%) RH and high (75% RH) for 48 h before connecting to the CEMS system for measurement of CO₂ accumulation.