How Salty is Seawater?
Seawater's saltiness, or salinity, is approximately 3.5%, meaning about 35 parts per thousand (ppt). This translates to roughly 35 grams of dissolved salts in every liter of seawater.
The salinity of seawater isn't uniform across the globe. While the average is around 35 ppt, it can fluctuate between 33 ppt and 38 ppt depending on location and factors like evaporation, precipitation, and freshwater inflow from rivers. For example:
- Open ocean: Typically around 35 ppt.
- Coastal areas: Salinity can be lower due to river runoff.
- Enclosed seas: Salinity can be higher due to increased evaporation.
A cubic mile of seawater contains an astonishing 120 million tons of salt, primarily sodium chloride. This massive amount of dissolved salt contributes significantly to the density and other properties of seawater.
The various sources cited confirm the average salinity of seawater to be around 35 parts per thousand, or 3.5% by weight. This means that for every 100 grams of seawater, approximately 3.5 grams are dissolved salts. This is a crucial factor in marine ecosystems and influences various oceanographic processes.
The USGS (https://www.usgs.gov/faqs/why-ocean-salty) and NOAA (https://oceanservice.noaa.gov/facts/whysalty.html) both provide reliable information supporting the 35 ppt average salinity figure. Other sources corroborate this finding, highlighting the consistency of this measurement across different studies.
