Effects of Historic Tidal Restrictions on Salt Marsh Sediment Chemistry

The effects of tidal restrictions by diking on salt marsh biogeochemistry were interpreted by comparing the hydrology, porewater chemistry and solid phase composition of both seasonally flooded and drained diked marshes with adjacent natural salt marshes on Cape Cod, Massachusetts. Flooding periods were greatest in natural and least in drained marshes. Differences between the chemistry of the natural and diked marshes depended upon the depth of the water table and the supply of sulfate for anaerobic metabolism. Drained marsh sediments were highly acidic (pH