The Drake Passage is well known for its violent seas, with waves that can top 12 meters and powerful converging currents, some flowing as fast as 150 million cubic meters per second. Cold water from the Southern Ocean and warmer water from the north collide here, producing powerful and energetic eddies.
New research shows how the Drake Passage and a few other specific areas of the Southern Ocean play an outsize role in how the oceans lock up carbon from the atmosphere. This is crucial for our understanding of the climate.
The global ocean is a massive reservoir of carbon, holding more than 50 times as much carbon as the atmosphere. However, it is only when water carrying carbon sinks to the deep ocean that carbon can be stored for long periods-up to centuries or millennia.
The ocean is composed of layers. With constant surface waves and winds the upper layer is constantly stirring around, mixing waters. This stirring mixes in solar heat and gases, including carbon taken up from the atmosphere.
In general, water density increases as the waters get deeper and saltier and colder. That forms density layers that are basically flat. Since water prefers to keep its density constant, it mostly moves horizontally and does not easily move between the surface and deep ocean.
Despite this physical barrier, carbon dioxide produced by human activities is reaching the deep ocean. One pathway is through chemistry: Carbon dioxide dissolves in water, creating carbonic acid.
The main flow of the Drake Passage is created by the strong westerly winds across the Southern Ocean. Scientists have discovered that the westerly winds create a slope in the water density. Also, the flow of the Southern Ocean interacts with an underwater mountain in the Drake Passage which mixes the ocean.