Salt Marshes


Salt marshes are an important life source for Barnstable Harbor.  These coastal wetlands that are flooded and drained by salt water brought in by the tides. They are marshy because the soil may be composed of deep mud and peat. Peat is made of decomposing plant matter that is often several feet thick. Peat is waterlogged, root-filled, and very spongy.

Barnstable Harbor is surrounded by hundreds of acres of salt marsh

Salt marshes are frequently submerged by the tides and contain a lot of decomposing plant material.  Low oxygen levels in the peat—a condition called hypoxia is caused by the growth of bacteria which produce the sulfurous rotten-egg smell that is often associated with marshes and mud flats.

These intertidal habitats are essential for healthy fisheries as they provide essential food, refuge, or nursery habitat for many fisheries species, including shrimp, blue crab, and many finfish.

Salt marshes also protect shorelines from erosion by buffering wave action and trapping sediments. They reduce flooding by slowing and absorbing rainwater and protect water quality by filtering runoff, and by metabolizing excess nutrients.  They are integral to long term coastal resilience as they grow and migrate inland.  Coastal land acquisition is an important element in allowing this growth in the face of rising sea levels.

Here is a PDF linking to the Redfield Marsh Study conducted in Barnstable Harbor in 1972: