Somewhere at the tip of Africa, there is a delightful place, a place where two oceans meet. Where the warm, powerful waters of the east coast meets the cold, nutrient-rich waters of the west. A place where the mixing of waters creates a magical, melting pot of oceanic conditions and marine life to behold.
Where exactly is this place, you may ask? Well, the exact location appears to be controversial and perhaps ever-shifting between Cape Point, along the Cape Peninsula in Cape Town, and Cape Agulhas — known as the Southernmost tip of Africa.
If we look at the marine life, both plants and animals, we see a unique and diverse community along the Cape Peninsula that encompasses parts of both the east (or rather south) and west coasts. Therefore, although many sources indicate that the two oceans meet at Cape Agulhas, when we look at the patterns in animal and plant life, we really see a difference at the tip of the Cape Peninsula.
What happens at the meeting of the oceans?
Along the west coast of South Africa, there are cold, nutrient-rich waters due to a phenomenon known as upwelling. Deep, cold waters are brought up by the Benguela current in the Atlantic Ocean, heading northwards and delivering rich nutrients to the coastline. This influx of nutrients provides food for plants at the surface and with increased plant life, there is abundant food for animals. This is one of the reasons why fish stocks are more abundant on the west coast compared to the east coast. But while the west coast is known to be a highly productive coastline, we tend to find fewer species there.
Contrastingly, the east coast is more diverse. There are many species but not much productivity compared to the west coast.
Along the east coast, there is a powerful current known as the Agulhas current, in the Indian Ocean, that delivers warm, tropical waters in a southerly direction along the coast. While the water is mostly warm, there are some areas of upwelling along the east coast where cells of colder, nutrient-filled waters occur. Due to the tropical nature of the east coast, there are many colourful species that are vastly different to those found along the west coast, such as corals and tropical fish.
How the meeting of the oceans impacts marine life
So as you can imagine, where the waters of these two currents meet, we have a remarkable mixture of oceanic conditions and therefore, life. Together, the two currents form unique conditions where we find many range-restricted species along the rocky shores and even within the coastal waters, partly due to the living conditions found there.
Further, the region between Cape Point and Cape Agulhas is an important breeding ground for several fish, shark and whale species. This mixed oceanic region therefore offers an important nursery area for some animals, and at certain times of the year species such as the Southern Right whale migrate to this region to give birth to their young.
Although we cannot see where the oceans meet with the naked eye, we can look towards the patterns we see in the life that occurs there, as well as the physical oceanic conditions and how this influences what is able to live there. When we do this, we find the most interesting patterns, continuously revealing the extraordinary qualities of the ocean.
Image by Callum Evans
About the author:
Koebraa is a marine biologist who grew up on the Cape Flats. Her love for the ocean was instilled by her dad, through frequent visits to the beach, exploring the rocky and sandy shores.
Today she gets to live her dream by working in and for the ocean. She also gets to teach others about the sea in her role as a Marine Science Lecturer at the Cape Peninsula University of Technology and works on marine bioinvasions as part of her research.
Want to know more about Cape Town’s oceans?
Our unique marine biosphere is one of the focuses of the local knowledge project, so watch this space! In the meantime, you can read: