How do rivers, wind-blown particles, and hydrothermal vents add chemicals to seawater?

The chemical composition of seawater is shaped by various transport mechanisms that introduce dissolved and particulate materials into the ocean. These inputs include:1

• Rivers: These act as a primary source, transporting dissolved and particulate chemicals from land to oceanic margins. While river water has a much lower salinity than seawater, it contributes significant amounts of elements like carbon, calcium, and silicon.12
• Wind-blown particles: Wind-borne particulates are transported from continental source areas to mid-ocean regions, sometimes traveling thousands of kilometers before settling into the water.1
• Hydrothermal vents: These features occur when cold seawater percolates into the hot oceanic crust, where it is heated and chemically altered. As this solution returns to the seafloor, it discharges both dissolved and particulate materials—such as iron, copper, and zinc—into the deep ocean.341

These regional inputs, combined with biological processes and physical mixing, create the complex chemical distribution observed in the world's oceans.1