EFFECTS OF SULFIDE ON THE GROWTH OF THREE SALT MARSH HALOPHYTES OF THE SOUTHEASTERN UNITED STATES

A hydroponic culture experiment was performed to ascertain whether sediment soluble sulfide at in situ concentrations plays a role in the determination of height forms of Spartina alterniflora in salt marshes of the United States. Additional experiments were conducted for both Spartina cynosuroides and Borrichia frutescens to determine if sulfide also influences the overall distribution of these species in the marsh. In situ soluble sulfide concentrations ranged from 0.02 mm in creek bank sites up to 3.0 mm in the inner marsh. In culture treatments, both plant height and biomass production of S. alterniflora were inhibited at a sulfide concentration as low as 1.0 mm , strongly suggesting a role for sulfide in the determination of height forms in the marsh. Production of S. cynosuroides was inhibited at high sulfide concentrations. However, over a range of concentrations similar to in situ values, no significant reduction in growth was observed, indicating sulfide was not a primary determinant of growth in stands of S. cynosuroides on Sapelo Island, Georgia. A sulfide concentration of 0.5 mm inhibited production in B. frutescens. In situ sulfide concentrations as high as 0.5 mm were found only in mixed stands of Juncus roemerianus and B. frutescens.