FIG. 5.

Plots of quantities of model compounds in slurry experiments with Wadi Gaza microbial mats versus time. (a) Twelve hours of light and 12 h of darkness; (b) 24 h of darkness; (c) control with autoclaved biomass, 12 h of light and 12 h of darkness; (d) control without biomass, 24 h of darkness. The data are expressed as percentages relative to the amounts of the compounds initially introduced into the system (i.e., 3.33 mg of each model compound adsorbed on 100 mg of organo-clay complex particles). Solid bars, pristane; bars with diamonds, dibenzothiophene; open bars, phenanthrene; cross-hatched bars, n-octadecane.