TABLE 1

Comparison of variables measured in sediment cores at an initial time (“baseline”), after incubation in the dark (control), and in a 12:12-h light/dark cycle that stimulated the growth of a photosynthetic biofilm (treatment)

TreatmentAvg ± SDa
Sulfide depth (mm)pH minimumOPD (mm)DOU (mmol m−2 h−1)Current density (mA m−2)
Baseline7.7 ± 0.66.66 ± 0.041.12 ± 0.080.78 ± 0.0544.5 ± 6.0
Dark (control)9.6 ± 0.9*6.46 ± 0.00*1.08 ± 0.110.87 ± 0.06*27.2 ± 0.0
Light/dark cycle (treatment)14.6 ± 2.0*6.36 ± 0.01*0.78 ± 0.111.26 ± 0.11*52.3 ± 28.8
  • a OPD, oxygen penetration depth; DOU, diffusive oxygen uptake. Differences were statistically tested between treatment and control cores with a two-tailed Student t test, and significance at α = 0.05 is indicated with an asterisk (*). Data represent averages of results from two replicate cores for treatments and controls and from three replicate cores for baseline measurements.