Decomposition ofSpartina alterniflora in different seasons and habitats of a Northern Massachusetts salt marsh,and a comparison with other Atlantic regions

Packets of freshly harvested liveSpartina alterniflora were placed on the marsh surface, in a tidal ditch, in a pool contacting sides and bottom, and in the center-bottom of the same pool in September 1972. Rates of loss were the same for all four sites through day 242. After that packets on the marsh surface decomposed slower. A second experiment was begun in July only at the marsh surface and pool side sites. These lost dry weight much more rapidly than packets started in September. Populations of bacteria, fungi, diatoms, flagellates, ciliates and nematodes within the packets peaked within 60 days then decreased proportionately with the loss of dry weight in packets through day 242. After this, bacterial numbers decreased more rapidly presumably in response to a qualitative change in the packet material. Populations of flagellates and ciliates also declined rapidly after day 300. This decline occurred in new packets at around this date as well. In a limited set of samples 12 taxa were analyzed for date or detritus-age dependent occurrence. Of these, eight were data dependent, two were dependent on packet age, and two could not be determined from the data.