The primitive ocean was composed of dissolved iron. This could have given it a reddish colour. The iron existed from volcanic activity. After the evolution of photosynthesis, the iron precipitated out and oxygen has composed the qualities it has today.
Regarding the composition of ocean water, I would describe it as a homogeneous mixture, or solution.
Yes.
from minerals in rivers and lakes running into the ocean
I think it is the pacific
It is a branch of chemistry which studying chemical processes and chemical composition of ocean waters.
Ocean topography has been determined through sonar detection.
The Pacific Ocean
Most rocks with a basaltic composition are typically found in oceanic crust, such as the ocean floors and mid-ocean ridges. Basaltic rocks are also common in volcanic regions like Hawaii and Iceland.
Helium contributed least to the early composition of the atmosphere, as it is relatively rare and not produced in significant quantities by natural processes on Earth.
Hydrogen is the most common element in the Earth's ocean, making up about 11% of the ocean's composition.
Indian ocean
Indian ocean