Lagoon

 A body of shallow salt or blackish water. Usually formed by a build-up of sandbanks or reefs along shallow waters.

sediment- Sand, rocks, salt marshes , mud

Tidal Flats

Sand or mud areas that typically don’t have that much plant life.

sediments-Sand, salt marshes, mud

Reefs

A rock or sandbar under the surface of water.

sediments-Sand, rocks

Continental Shelf

An extension of a continent under the sea. A continental shelf can stretch for many miles out to sea.

sediments- Icebergs, boulders, sand, silt

Continental Slope&Rise

The continental shelf breaks and under the break is the continental slope. And below the slope is the continental rise.

sediments-Sand, silt, clay

Abyssal Plain

Sloping areas of the deep ocean basin floor. These are flat sediment covered areas.

sediments-Sand, shells, rocks