The climate on and near the ocean is different in many ways than on land.  The constant wind on the ocean causes most waves.  The currents mix the water with nutrients making the sea richer in food.  Tides are made by the gravitational forces from the moon and sun.  The moon causes high and low tides.  When the sun and moon are one in front of the other "spring tides" occur,  which are the highest tides.  Lowest tides occur when the sun and moon are at a right angle.
There is cycle which is a battle between the land and sea.  The sea constantly wares away the rock and sweeps the sand.  The sand in the water is thrown on land creating new beaches.  Occasionally strong storms, high tides and storm surges can erode and have damaging effects to a beach area.