tidal litter

An accumulation of dead plant remains and other material either on the surface or buried by wave action in the top layers of sand and silt.

In saltmarshes, organic litter mostly consists of small pieces of plant litter although occasional wood and other flotsam are included.  Beach litter can consist of beds of decaying seaweed as well as larger debris, such wood, man-made rubbish and rocks. These often form bands of material along the high tide mark.