1. Weathering and Erosion of Rocks: This is the primary source of dissolved salts in the ocean. As rivers flow over land, they pick up minerals and salts from rocks through weathering and erosion. These dissolved substances are then carried to the ocean. The continuous process of weathering and erosion over millions of years has led to the high salinity we observe in the ocean today.

2. Hydrothermal Vents: These are openings on the seafloor where hot, mineral-rich water is released from the Earth's interior. These vents often release dissolved substances like sulfur, iron, manganese, and other minerals that contribute to the overall composition of the ocean.

Let me know if you would like to know about other sources of dissolved substances in the ocean!