Chemical oceanography is considered a niche area within the broader field of oceanography. Along with biological, physical, and geographical oceanography, it is one of the four main oceanographic areas. It is said that chemical oceanographers work at the “boundaries between chemistry and biology, geology and physics” and “apply their efforts to a broad spectrum of interdisciplinary challenges.” That is because the chemistry of the ocean is closely tied to ocean circulation and climate (physical oceanography), the plants and animals that live in the ocean (biological oceanography), and the exchange of material with the atmosphere, cryosphere, continents, and mantle (geological oceanography). Chemical oceanographers are essentially oceanographers, but rather than studying the physics, biology, or geology of the oceans as a broad subject; they examine the chemical composition of this particular environment.
Chemical oceanography is an excellent career choice for anyone interested in working on the front lines in the battle against the twin evils of ocean acidification and climate change. The interdisciplinary nature of chemical oceanography will also allow you to satisfy your other ocean science-related interests.