The Ocean and Life in the Ocean Shape the Features of Earth
A. Many earth materials and biogeochemical cycles originate
in the ocean. Many of the sedimentary rocks now exposed
on land were formed in the ocean. Ocean life laid down
the vast volume of siliceous and carbonate rocks.
B. Sea level changes over time have expanded and
contracted continental shelves, created and destroyed
inland seas, and shaped the surface of land.
C. Erosion—the wearing away of rock, soil and other biotic
and abiotic earth materials—occurs in coastal areas as
wind, waves, and currents in rivers and the ocean, and
the processes associated with plate tectonics move
sediments. Most beach sand (tiny bits of animals, plants,
rocks, and minerals) is eroded from land sources and
carried to the coast by rivers; sand is also eroded from
coastal sources by surf. Sand is redistributed seasonally
by waves and coastal currents.
D. The ocean is the largest reservoir of rapidly cycling carbon
on Earth. Many organisms use carbon dissolved in the
ocean to form shells, other skeletal parts, and coral reefs.
E. Tectonic activity, sea level changes, and the force of
waves influence the physical structure and landforms
of the coast.