For carbon dioxide, the ocean is a huge reservoir. A quarter of the carbon dioxide produced by human activities is stored in the ocean, and 40% of it is absorbed into the ocean by the Southern Ocean. Compared with other oceans, the Southern Ocean is more like a powerful carbon dioxide absorber.
So why can the Southern Ocean absorb so much carbon dioxide? How did so much carbon dioxide enter the Southern Ocean? It turns out that this is due to the westerly wind that prevails all year round on the surface of the Southern Ocean. In the Southern Ocean, the westerly winds are very strong, gradually forming the famous "Roaring Westerly Belt." Wind-driven waves stir the surface of the Southern Ocean, continuously dissolving carbon dioxide gas in the atmosphere into the surface water of the Southern Ocean. However, although strong winds and waves brought 40% of the total carbon dioxide absorbed by the ocean into the Southern Ocean, only 9% of the total remained in the Southern Ocean's own waters. Where did the remaining carbon dioxide go? How do they migrate through the ocean?
It turns out that carbon dioxide dissolved in the surface water of the Southern Ocean will be transported from the Southern Ocean to the subtropical sea area under the joint action of the Southern Ocean currents and eddies. In other words, most of the carbon dioxide absorbed by the Southern Ocean is transported north.
Observations found that near 55° south latitude, Antarctic surface water sinks here, bringing a large amount of carbon dioxide dissolved in the surface water to a depth of 1000 meters. The carbon dioxide then travels north with ocean currents and reaches near the equator, which takes about 1000 years.
In addition to the sinking of seawater due to convergence of seawater, a counterclockwise vortex with an average diameter of about 100 kilometers also plays an important role in the sinking of carbon dioxide. It is like a huge funnel that sucks carbon dioxide from the ocean surface into the ocean interior.