The Great African Seaforest is a unique large-scale marine ecosystem that covers about 1000 kilometres of the South African coast line.Credit: Jannes Landschoff

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Marine researchers at Stellenbosch University (SU) and the not-for-profit Sea Change Project are teaming up to study the world’s only giant bamboo kelp forest, stretching 1,000 kilometres from Cape Town in South Africa, into Namibia.

Jannes Landschoff, a marine biologist at Sea Change, leads the 1001 Seaforest Species project studying the biodiversity of the Great African Seaforest and its distinctive species. The scientists have identified 500 different species so far.

Ecklonia maxima, the scientific name of the giant bamboo kelp, is limited to the southern Atlantic. The team is conducting a taxonomic investigation of the biodiversity present in kelp holdfasts — the root-like structures that anchor the kelp to rocks, helping them to weather turbulent conditions. They are investigating the large-scale patterns of kelp-associated biodiversity using DNA-based molecular tools.

"Even though we expected large numbers of species from the start, two years later, each holdfast sample still leaves us astounded at the new and wonderful things we find,,” says Nasreen Peer, a marine biologist at the SU’s Department of botany and Zoology.

Picture 2 Holdfasts of the Bamboo kelp Ecklonia maxima provide a habitat for diverse and understudied invertebrate communities.Credit: Jannes Landschoff

Landschoff says that in just 10 holdfasts they “found about 100 species of crustaceans alone, most of them amphipods, which are small, shrimp-like creatures. They are the cleaning forces of the ocean, and many species like eating them. Their diversity keeps these ecosystems healthy. ”

They focused mostly on the crustaceans, but they find a large number of juvenile urchins, crabs, [and] sea stars. “This makes sense because the interstitial spaces are not large enough for anything much bigger than juveniles. Also, the holdfast microhabitat is much more biodiverse than other parts of the kelp structure,” explains Peer.

Kelp is not a critical component of the associated ecosystems, but also has many other uses for humans. Laura Blamey, a marine ecologist at CSIRO, in Australia, who published a paper in the Journal of Marine Systems on South African kelps says they are important for the ecosystem and various industries. “Kelp forests are home to a diverse array of marine species, including the economically important species such as fish, lobster and abalone. When intact, they provide a unique 3-D habitat with different components of the forest supporting different groups of species. But even when broken off and washed ashore, they support other marine life communities on sandy beaches when they wash up,” says Blamey, who was not involved in the Great African Seaforest project.

Blamey adds that they provide critical nurseries for juveniles to find protection and protect coastlines by attenuating waves before they break onshore. With the cold-water reefs and its species attracting recreational divers, kelps also support tourism as well as aquaculture farms as they are harvested for feeding. “The algin, a bonding agent that is extracted from kelp, is used in many products such as toothpaste, shampoo and pharmaceuticals,” adds Blamey.

She says South African kelp forests around Cape Town were one of the most researched kelp forests in the late 1970s and 1980s.

“However, we know relatively little about kelp forests further north along the west coast [which the Great Sea Project looks into] or further east past Hermanus,” she says. This is largely because these areas are more isolated from diving facilities and so research underwater becomes more difficult and costly,” explains Blamey. In the last 15 years, the interest in kelp research has increased elsewhere in the world, especially under climate change and as habitats become more vulnerable to warming waters.