This is a sample of the information contained in the Estuarine Ecology Appendix of the Estuary-Net Project.

ESTUARINE HABITATS AND COMMUNITIES
 

THE MARSH

Salt marshes are a common type of wetland of extreme importance to the balance of certain estuarine ecosystems. Marshes are dominated by important  grasses that provide food and shelter to marine organisms that are permanent and  transient residents of the estuary. Marshes are divided into two basic zones:  high marsh and low marsh, which are defined by differences in flooding and soil salinity. Marshes usually have different bands of vegetation creating high and low zones within the marsh.
 

Despite its varied and lush vegetation, the marsh is home to  relatively few terrestrial animals. Deer, migratory birds, grasshoppers and other animals consume marsh grasses. Small animals, such as shrews and mice,  provide prey for larger mammals and birds of prey that also live in or around  the marsh.

Marsh grasses are thought to be low in nutritive value and to contain toxic compounds; so even with all of these consumers little of the vegetation is eaten. Rather, most of the plants die and are deposited on the ground to become peat. Some pieces of the plants are then washed into the water to become detritus, decaying particles coated with bacteria, which serve as a  nutrient base for the estuarine food web. Detritus is consumed by filter-feeders such as clams, detritivores such as mummichogs, and deposit feeders such as polychaete worms. In general, estuaries are known as hosts for abundant aquatic and avian, rather then terrestrial, animals.

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