Plateaus
An oceanic plateau is a raised area of seafloor, elevated above the adjacent abyssal plains and different from seamounts in that they are a very large, often relatively flat piece of seafloor. South Africa has only one plateau in its ocean territory, the Agulhas Plateau, a feature that formed more than 90 million years ago and a key remnant of the break up of the supercontinent Gondwana. The Agulhas Plateau formed as the moving plates passed over a hotspot, similar to how the Hawaiian Island chain has formed. The Agulhas Plateau formed near what is known as the “Triple junction” where Gondwanaland broke up into Africa, Antarctica and South America. It rises 2 500 m above the surrounding seafloor and covers an area of about 300 000 km2.
The Agulhas Plateau is bounded by a very deep abyssal channel known as the Agulhas Passage to the north; by the abyssal Agulhas Basin to the west; and by the Transkei Basin to the north-east. Nobody has ever seen the ecosystems of the Agulhas plateau but these will be protected within the proposed Agulhas Front MPA. Elsewhere in the world, plateau ecosystems are known to host distinctive biodiversity. Key pressures in these ecosystems include seabed mining and risks associated with drilling for petroleum in deep water.
The proposed Agulhas Front MPA will protect a small proportion of the Agulhas Plateau in an area most frequently visited by our Critically Endangered Leatherback Turtles.
