Dynamics of above- and belowground organic matter in a high latitude macrotidal saltmarsh

Seasonal variations in above- and belowground biomass were examined over th e 1994 growing season (May to October) in the 3 major plant zones of a salt marsh located on the Bay of Fundy. Standing crop of aboveground biomass was measured over the growing season. Belowground samples were processed at de pth intervals of 2 cm, providing high-resolution vertical profiles to a dep th of 40 cm. Spartina alterniflora showed evidence of the translocation of belowground biomass to aboveground tissue in the early part of the growing season, when the rate of aboveground growth is at a maximum. Shifts in S. a lterniflora organic matter storage were most dynamic in the surface 16 cm. Biomass translocation generally was not significant in the S. patens stands , where the rate of aboveground growth was consistent throughout the growin g season. All seasonal changes associated with Plantago maritima biomass se em to occur before July, since no changes in above- and belowground biomass were observed between July and October. P. maritima contributes the least to marsh soil organic matter.