Chloride is the most abundant ion in seawater, accounting for approximately 55% of the total dissolved solids.

Sodium is the second most abundant ion in seawater, accounting for approximately 31% of the total dissolved solids.

Magnesium is the third most abundant ion in seawater, accounting for approximately 13% of the total dissolved solids.

Calcium is the fourth most abundant ion in seawater, accounting for approximately 4% of the total dissolved solids.

Potassium is the fifth most abundant ion in seawater, accounting for approximately 2% of the total dissolved solids.

Nitrogen is the most abundant gas in seawater, accounting for approximately 65% of the total dissolved gases.

Oxygen is the second most abundant gas in seawater, accounting for approximately 35% of the total dissolved gases.

Carbon Dioxide is the third most abundant gas in seawater, accounting for approximately 1% of the total dissolved gases.

Argon is the fourth most abundant gas in seawater, accounting for approximately 0.5% of the total dissolved gases.

Helium is the fifth most abundant gas in seawater, accounting for approximately 0.005% of the total dissolved gases.

The average salinity of seawater is approximately 35 parts per thousand, meaning that there are 35 grams of dissolved solids in every kilogram of seawater.

The pH of seawater is typically around 8.1, indicating that it is slightly alkaline.

Dissolved solids in seawater come from a variety of sources, including weathering of rocks, volcanic eruptions, and hydrothermal vents.

The chemical composition of seawater remains relatively constant with depth, except for minor variations in certain regions.

The chemical composition of seawater can vary with latitude, depending on factors such as temperature, precipitation, and ocean currents.