Surely it is Hydrogen, as the water molecule is made up of two atoms of Hydrogen to one atom of Oxygen: H2O. Any other element is simply dissolved in the water, but cannot be more abundant than the elements that make up water itself. Elementary, dear Watson. Angela. read more
The most abundant elements in ocean water are hydrogen and oxygen, the two elements that constitute the water molecule. Excluding the water molecule, the most abundant elements in ocean water are sodium and chlorine. read more
The ocean being made of water, hydrogen and oxygen are the most common elements in the ocean. Also, the ocean is made up of salt water, so, sodium, chlorine, magnesium, sulfur, calcium, and potassium are abundant in the ocean. read more