Water Biomes Marshland is covered with grasses, reeds, sedges, and cattails. These plants all have their roots in soil covered or saturated with water and its leaves held above water.Marshes may be freshwater or salt. Freshwater marshes develop along the shallow edges of lakes and slow-moving rivers, forming when ponds and lakes become filled with sediment. Salt marshes occur on coastal tidal flats. Inland salt marshes occupy the edges of lakes. They affect the …showed first 75 words of 770 total…

…showed last 75 words of 770 total…the lugworm, which burrows through the sand and feeds on organic matter; and the coquina clam Donax, which advances up the beach and retreats with the tides. Among the sand grains live small copepods and worms that feed on microscopic algae, bacteria, and organic matter.         On the lower beach, which remains uncovered for only a short period of time, live clams, crabs, starfish, and sand dollars, whose calcareous skeletons lie partially buried in the sand.