Ocean fertilizationOcean fertilization or ocean nourishment is a type of technology for carbon dioxide removal from the ocean based on the purposeful introduction of plant nutrients to the upper ocean to increase marine food production and to remove carbon dioxide from the atmosphere. Ocean nutrient fertilization, for example iron fertilization, could stimulate photosynthesis in phytoplankton. The phytoplankton would convert the ocean's dissolved carbon dioxide into carbohydrate, some of which would sink into the deeper ocean before oxidizing.
Direct air captureDirect air capture (DAC) is the use of chemical or physical processes to extract carbon dioxide directly from the ambient air. If the extracted is then sequestered in safe long-term storage (called direct air carbon capture and sequestration (DACCS)), the overall process will achieve carbon dioxide removal and be a "negative emissions technology" (NET). As of 2022, DAC has yet to become profitable because the cost of using DAC to sequester carbon dioxide is several times the carbon price.
Carbonate compensation depthThe carbonate compensation depth (CCD) is the depth, in the oceans, at which the rate of supply of calcium carbonates matches the rate of solvation. That is, solvation 'compensates' supply. Below the CCD solvation is faster, so that carbonate particles dissolve and the carbonate shells (tests) of animals are not preserved. Carbonate particles cannot accumulate in the sediments where the sea floor is below this depth. Calcite is the least soluble of these carbonates, so the CCD is normally the compensation depth for calcite.
Marine larval ecologyMarine larval ecology is the study of the factors influencing dispersing larvae, which many marine invertebrates and fishes have. Marine animals with a larva typically release many larvae into the water column, where the larvae develop before metamorphosing into adults. Marine larvae can disperse over long distances, although determining the actual distance is challenging, because of their size and the lack of a good tracking method. Knowing dispersal distances is important for managing fisheries, effectively designing marine reserves, and controlling invasive species.
