Currents, waves, and wind normally transport sediment throughout the littoral system. Armoring of the coast can interfere with littoral transport, which in a natural state may reach a dynamic equilibrium.

Layers of sediment lay at the bottom of the riverbed.

Agriculture, forestry and urbanization are increasing the amount of sediment, chemicals and plastics flowing into the oceans, and contaminating the coastline.

Stromatolites are the limestone structures formed by photosynthesizing bacteria called cyanobacteria. They created layers of alternating slimy bacteria and sediment in very shallow water, dominating shallow seas until predators, such as trilobites, came into the picture.

Sediment cores from the bottom of Yellowstone’s lakes contain fossils of pollen deposited during the Late Pleistocene. These pollen records show which plants were present at that time and allow researchers to infer climate conditions.

Sandstone is a kind of sedimentary rock.

Wetlands also absorb excess nutrients, sediments, and other pollutants before they reach rivers, lakes, and other waterbodies.

Shale rock is a sedimentary rock made up of clay, compacted together by pressure.

Sedimentary rock contains fossils because it was built up layer upon layer, often trapping and preserving animals, plants, footprints, and more within the layers of sediment.

If all the conditions are right, fossils are formed as the layers of sediment turn into rock.