• Over a long period of time does the salinity of the ocean change from ~35ppt?
– No, even though salinity can build up from erosion, animals take up ions and convert them in to shells and other things which recycle the salts back in to the sediments.
– Salt spray along coastlines also removes salt. ~3.6 billion metric tons of salt removed annually
– Oceanic retreat from land leaves salt behind as well.
• Why is ocean water salty?
– Salts eroded from the crust of millions of years.
• How much salt is in the ocean?
– If dried and spread evenly, it would cover the world at a depth of 500ft.