Creatures of the Marsh
By Frances Boyd
W
hile gazing out onto the Kiawah River and its surrounding marshes and hammock
islands, one rarely thinks about what goes on below the surface. The salt marsh is a
complex ecosystem and home to a wide array of life forms that vary depending on the
time of year, the salinity of the water and the marsh zone. The low marsh, filled with
spartina (in this area a variety called Spartina alterniflora), is flooded twice daily. The high marsh floods
twice a month due to the moon cycle and during storms and typically consists of both spartina and black
needlerush before transitioning to maritime shrubs.
The marsh’s tiniest creatures are benthic meiofauna. These microscopic organisms provide food for
invertebrates, the animal group that includes grass shrimp, fiddler crabs, oysters, mud snails, and mussels.
Grasshoppers, spiders, dragonflies, and xanthid crabs are also important consumers of the meiofauna.
Not only do invertebrates provide a vital role in the food web, but they also keep the marsh sediment
stirred up to promote continuous growth. The larvae of many insects reside in the spartina, as do adult
gnats and flies. Mosquitoes live in the high marsh.
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Photo by Ken Ball