01818nas a2200229   4500008004100000245010800041210006900149300001300218490000700231520103400238653001901272653002301291653001901314653001701333653002301350653002501373100001601398700001601414700001801430700001701448856012301465       1999                        eng d00aVariations in microbial activity due to fluctuations in soil water content at the water table interface0 aVariations in microbial activity due to fluctuations in soil wat  a479 -5050 v343 aA soil column experiment was designed to investigate the response of an indigenous microbial population to a vertically fluctuating water table. A subsurface environment with a transitional zone was simulated. The water table in the soil columns was raised and lowered, and compared to columns under static conditions. Carbon dioxide and oxygen concentrations were measured. Peaks of CO2 occurred in the fluctuating columns immediately following a rise in the water table. Dissolved O2 in the fluctuating columns was consistently lower throughout the experiment, but these lower concentrations were exaggerated immediately following a rise in the water table. Values for total organic carbon in the pore water were slightly lower in the fluctuating columns. The results of this soil column study indicate that vertical fluctuation of the water table can enhance microbial activity of indigenous soil microbial populations. This increase in microbial activity suggests an increased rate of available carbon under these conditions.10abioremediation10amicrobial activity10asoil interface10asoil texture10aSoil water content10asubsurface sediments1 aBanks, M.K.1 aClennan, C.1 aDodds, W., K.1 aRice, C., W.  uhttp://knz.lternet.edu/content/variations-microbial-activity-due-fluctuations-soil-water-content-water-table-interface