The primary source of DIC in the ocean is atmospheric CO₂, which dissolves into seawater and forms carbonic acid (H₂CO₃).

Iron is not a major nutrient for phytoplankton growth in the ocean, although it is required in small amounts.

Photosynthesis is the process by which phytoplankton convert carbon dioxide into organic matter using sunlight as an energy source.

Export production is the term for the sinking of organic matter from the surface ocean to the deep ocean.

Calcium carbonate (CaCO₃) is not a major component of the marine carbon cycle, although it is a significant component of the marine carbonate system.

Remineralization is the process by which bacteria convert organic matter into inorganic nutrients.

Sunlight is not a major factor influencing the distribution of marine organisms, although it is important for photosynthesis.

Respiration is the process by which marine organisms take up and release carbon dioxide.

Deep-sea hydrothermal vents are not a major type of marine ecosystem, although they are a unique and important habitat for specialized organisms.

Nitrogen fixation is the process by which nitrogen gas is converted into a form that can be used by plants.

Cyanobacteria are not a major type of marine phytoplankton, although they are important in some freshwater and terrestrial ecosystems.

Respiration is the process by which marine organisms take up and release oxygen.

Jellyfish are not a major type of marine zooplankton, although they are common and important predators in the marine ecosystem.

Respiration is the process by which marine organisms convert organic matter into energy.

Jellyfish are not a major type of marine fish, although they are common and important predators in the marine ecosystem.