The variability of biogenic sulfur flux from a temperate salt marsh on short time and space scales

Abstract

Three emission chambers were deployed simultaneously to measure rates of emission of dimethyl sulfide, methane thiol and carbonyl sulfide within or across vegetation zones in a New Hampshire salt marsh. Short term (a few hours) variation in fluxes of all S gases from replicate sites were small within a monospecific stand of either Spartina alterniflora or S. patens. The quantity of emergent biomass and the type of vegetation present were the primary factors regulating the rate of emission. Dimethyl sulfide fluxes from the S. alterniflora soils ranged from 800 to 18,000 nmol m −2 h −1 compared to emissions of 25–120 nmol m −2 h −1 from S. patens. This difference was probably due to the presence of the dimethyl-sulfide precursor dimethylsulfoniopropionate which is an osmoregulator in S. alterniflora but not in S. patens. Methane thiol emissions from S. alterniflora were 20–280 nmol m −2 h −1 and they displayed a similar diel trend as dimethyl sulfide, although at much lower rates, suggesting that methane thiol is produced primarily by leaves. Methane thiol emissions from S. patens were 20–70 nmol m −2 h −1. Net uptake of carbonyl sulfide of 25–40 nmol m −2 h −1 occurred in stands of S. alterniflora while net efflux of 10–36 nmol m −2 h −1 of carbonyl sulfide occurred in stands of S. patens. In general, ranges of emissions of sulfur gases were similar to most other published values.