The ocean is an important carbon sink, taking up CO₂ that is released into the atmosphere by anthropogenic activities, such as fossil fuel burning and lang use changes. It is estimated that the ocean takes up about 37% of fossil fuel CO₂ emissions.

Marine primary production is the foundation of the marine food chain and ocean ecosystems. It primarily occurs via photosynthesis by phytoplankton, which use inorganic carbon and nutrients to produce organic matter.