Ocean water is primarily composed of water, but it also contains dissolved substances, most notably salts.
The Composition of Ocean Water
The two most common elements in seawater, after oxygen and hydrogen, are sodium and chloride. These two elements combine to form the compound we know as table salt, or sodium chloride (NaCl).
Salinity
- Seawater's salinity, or saltiness, is expressed as a ratio of salt in grams to liters of water and is measured in parts per thousand (ppt).
- This means that, on average, for every liter of seawater, there are approximately 35 grams of salt.
Key Components
- Sodium (Na+) : A metallic element that's a key part of salt.
- Chloride (Cl-): An element that combines with sodium to form salt.
- Other Elements: While sodium and chloride are the most abundant, seawater contains many other elements and compounds.
Understanding Salinity
The salt content, or salinity, of ocean water can vary. It is affected by:
- Evaporation: High evaporation rates in warmer regions lead to higher salt concentrations.
- Precipitation: Rainfall and river runoff dilute the salt content, decreasing salinity.
- Freezing: When seawater freezes, it leaves behind the salt, increasing salinity in the remaining water.
In Summary
Ocean water primarily contains:
- Water
- Sodium and chloride, which together form table salt (NaCl)
- Numerous other dissolved minerals and compounds.
The concentration of salt in seawater is referred to as salinity, measured in parts per thousand (ppt). The salinity is most influenced by evaporation, precipitation, and freezing.
