Which element would be surprisingly considered a trace element in the ocean despite its abundance in the atmosphere?

Question

Quizplus · Accepted Answer

Nitrogen is a trace element in the ocean despite its abundance in the atmosphere. Any element that is less than 1 part per million is considered a trace element. Although trace elements are such small quantities, they are often crucial to life processes. Information can be found in the section Seawater Consists of Water and Dissolved Solids.

Which Element Would Be Surprisingly Considered a Trace Element in the Ocean