What special function does the spleen of the seal do

The spleen of the Arctic Weddell seal contains so much extra oxygenated blood that it often is referred to as a SCUBA tank; in fact, the release of red blood cells into the circulation is so tightly regulated that arterial oxygen content doesn't decrease for the first 15–18 min underwater.

Iwolud you, but i dont know what you are asking.

It would be the equator.