The (K)helpful forests of South Africa

by CapeNature

By Nicole Horn, Biodiversity Capabilities

South Africa has one of the biggest forests on the planet. It is just somewhat less noticeable due to it being hidden under the ocean surface. Craig Foster, author of the book Sea Change refers to it as a three-dimensional liquid forest or ‘golden forest’ where one can float amongst the high canopy, jump off the top and fly down to the forest floor.

Kelp Forest, Copyright Steve Benjamin

Unlike many other kelp forests in the world currently, South African kelp forests are doing extremely well due to the south-easterly winds we experience on the west coast which cause an upwelling of cool nutrient-rich waters that kelp forests thrive off. Our kelp forests dominate the west coast of South Africa forming large beds in the southern portion of the Benguela region. They are as productive per unit area as a tropical rainforest. In South African kelp forests, the main algal species are Ecklonia maxima and Laminaria pallida. Ecklonia algae reaches up to 17m in length and has extended its distribution further east reaching the De Hoop Marine Protected Area.

Kelp Surface, copyright Steve Benjamin

Kelp forests are a unique habitat that provide food for marine life and shelter through some of the roughest storms. They play an important role in preserving the health of the oceans through photosynthesis, and purify surrounding water by removing waste produced by its inhabitants. Kelp forests are important as they help reduce the effects of global warming due to their incredibly fast growth rate and by exporting large portions of biomass via gas-filled bladders out into the deep sea where carbon is then sequestered.

Kelp Starfish, copyright Steve Benjamin

South Africa’s swaying underwater forest extends for about 1 000km more or less parallel to the shoreline from the west coast to the southern coast where it reaches De Hoop Nature Reserve.  It extends about 100m offshore and is extremely rich in marine life and biodiversity, containing about 14 000 different species. The variety of species found amongst these long brown seaweeds includes cuttlefish, octopuses, starfish as well as rock lobsters that feed off of grazers like spiny sea urchins and juvenile abalone that hide between the urchin spines. Kelp forests also play host to many fish species endemic to South Africa including seven-gill cow sharks, broad-nose seven-gill cow sharks, pyjama catsharks and puffadder shysharks. These sharks lay their eggs on algae in these kelp forests by weaving the tendrils of the egg casing around the algae until it is suspended and the egg sinks to the bottom of the case to continue its development process.

Kelp Seal, Copyright Steve Benjamin

 

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