Ocean Water & Ocean Life
Unit 5 Chapter 15
Chapter 15.1 The Composition of Seawater
Seawater is approximately 96.5% water and 3.5% dissolved substances.
Salinity: total amount of solid material dissolved in water.
Expressed in parts per thousand (ppt)
Seawater is on average 35ppt
Where does the salt come from?
● Chemical weathering of rocks washed out to the ocean
● Material from volcanoes-sulfur dioxide and chlorine
● Precipitation
● Icebergs and sea ice melting
● Evaporation
Decreases of salinity:
Increases of salinity:
● runoff from land