Are the oceans getting saltier with time?

That’s a great question! After all, since rivers and volcanic vents are continually adding more salt to the oceans, you might think that the oceans would be gradually getting saltier with time. However, while there can be variations in the salinity of the ocean water with time, overall the oceans seem to be in balance, keeping the same average salinity. The reason is that while salt is continually being added to the oceans, it is also continually dropping out as sediment on the ocean floor. Measurements suggest that the total amount of salt being deposited on the ocean floor as sediment each year is approximately equal to the amount being added by rivers and volcanic vents, thereby keeping the ocean salinity stays fairly constant.