Benthic metabolism and sulfate reduction in a Southeast Asian mangrove swamp

Abstract

At the Ao Nam Bor mangrove, Phuket, Thailand, sulfate reduction was highest at 6-10 cm depth at all stations (600-800 nmol S cm-3 d-1), indicating that significant activity may have occurred <10 cm. Vertical translocation of metabolizable organic substrates, either due to subsurface root growth or due to downward transport of newly deposited organic matter by bioturbation appeared responsible for the high subsurface activity. The estimated areal based rates of sulfate reduction (0 to 10 cm, 28 to 50 mmol m-2d-1) could support c100% (65-142%) of the measured CO2 flux across the sediment-water interface. This implies a deficient or non-steady state CO2 flux. -from Authors