Fact of the Day: What is the Antarctic convergence?

What is the Antarctic convergence?

The Antarctic Convergence, also known as the Antarctic Polar Front marks the true outer edge of Antarctica. It is a circumpolar strip of sea around the southern most reaches of the Atlantic, Indian and Pacific oceans varying between about 45° and 60° South. It’s exact position is somewhat variable, but it is a very real and permanent feature. The surface temperature changes by 2-3°C from one side of the convergence (polar front) to the other.

There is sufficient difference across the convergence that the seas around Antarctica are known as a distinct “Southern” or “Antarctic” ocean, rather than simply being the most southerly parts of the Atlantic, Indian and Pacific oceans.

The  Antarctic Convergence zone also forms a significant biological boundary. Within this zone, the cold, dense surface waters of the circumpolar ocean sink and flow northward, thus creating a major meridional circulation system.  There are many species of plants, birds, fish and other animals that are typical of Antarctic water and rare on the other side of the convergence.