Natural Factors:

• Precipitation and River Runoff: Freshwater from rain and rivers are continually diluting the salinity, especially near river mouths and in areas with high rainfall.

• Sea Ice Formation and Melting: As sea ice forms, saltier water is left behind, increasing salinity. Conversely, melting ice is adding freshwater and lowering salinity. This is especially important in polar regions.

• Evaporation: Evaporation is concentrating salts in the remaining water, making salinity higher in areas with high evaporation rates.

• Wind: Wind is moving surface water around, influencing salinity distribution. Strong winds can also cause upwelling, bringing saltier deep ocean water to the surface.

• Ocean Currents: Global ocean circulation patterns are playing a major role in distributing salt throughout the oceans.

  
  

Anthropogenic Factors:

• Climate Change: Rising global temperatures can increase evaporation rates in some areas, concentrating salts. Additionally, melting glaciers and ice sheets are adding freshwater, potentially affecting salinity in certain regions.

• Dam Construction and Water Diversion: Dams on rivers can reduce the amount of freshwater reaching the ocean, impacting salinity levels near river mouths. Water diversion for irrigation can also be contributing to this effect.

• Pollution: While not a direct impact, some pollutants can be altering ocean chemistry and indirectly affecting salinity.