Fig. 5. Soil layer comparison of (a) bulk soil carbon content, (b) dissolved organic carbon (DOC) of the soil extractions, (c) specific ultraviolet light absorption (SUVA) of the extracted DOC, (d) available carbon content (measured as CO2 produced in 40 d) of bulk soils, (e) total trihalomethane formation potential (TTHMFP), and (f) specific trihalomethane formation potential (STHMFP) of the extracted DOC at Twitchell Island, California. PL, plow layer; BPL, below-plow layer.