Unique Ecosystem Discovered in the Distinctive Kelp Beds of iSimangaliso Marine Protected Area

Johannesburg – The iSimangaliso Wetland Park, renowned for its extraordinary biodiversity and eco-tourism potential, has recently amazed the scientific community with a stunning kelp discovery, showcasing South Africa’s hidden marine treasures.

During an exploratory mission aboard the WILDTRUST research vessel, the Angra Pequena, researchers revealed South Africa’s concealed underwater forests, vital for the ecosystem, located within the Park’s mesophotic zone; an area where sunlight barely penetrates.

In the recent research expedition aimed at examining the kelp forest characteristics, a team identified extensive fields of rhodoliths – free-living, calcareous red algae that appear as pink-colored nodules scattered across the seafloor.

These seemingly unremarkable formations play a crucial role in marine ecosystems. Rhodolith beds are recognized worldwide as biodiversity hotspots, similar to coral reefs and seagrass meadows.

They provide shelter and nursery habitats for a variety of marine species, from invertebrates to juvenile fish.

Their complex, three-dimensional structures stabilize sediments, enhance habitat diversity, and serve as essential substrates for kelp and other macroalgae.

Although rhodoliths were suspected to exist in the broader iSimangaliso region, their extent and intricate connection with the kelp bed represent a groundbreaking finding.

The research initiative was led by Dr. Welly Qwabe and Professor Lucy Woodall from Ezemvelo KZN Wildlife and the University of Exeter (UK), alongside Dr. Vivienne Coetzee, a postdoctoral fellow at the University of Cape Town, who is working under the WILDOCEANS program.

This remarkable discovery was made possible through support and funding from the National Research Foundation (NRF), Blue Action Fund, the National Department of Forestry, Fisheries and the Environment, Nekton, the South African Environmental Observation Network (SAEON), and Oceans 5, along with several local and international partners and collaborators.

A Rare Ecological Gem

This marks only the second rhodolith bed ever documented in South African waters, with the first discovered off the Kei River in the Eastern Cape.

This finding represents an unprecedented ecological milestone for KwaZulu-Natal, especially for the extraordinary iSimangaliso Wetland Park, a World Heritage Site.

The rhodolith beds were found alongside a dense forest of Ecklonia radiata (golden kelp), sprawling 35 kilometers along the seafloor.

“Together, these ecosystems form a complex partnership,” noted Coetzee, a postdoc who will further investigate these newly discovered extensive rhodolith areas.

“Rhodoliths provide hard surfaces essential for kelp attachment, while kelp forests create canopy habitats that influence light, nutrient levels, and water movement.

“Their interconnected roles aid carbon sequestration and provide crucial nursery grounds for commercially important fish species, vital for biodiversity conservation and sustainable fisheries.”

A Call for Conservation

“Rhodolith beds are fragile and slow-growing, often requiring centuries to recover from disturbances. Threats like bottom trawling, pollution, and ocean acidification endanger these critical habitats,” stated Woodall.

“The discovery within iSimangaliso Wetland Park highlights the urgent need to protect not only the visible ecosystems but also the hidden seascapes beneath the ocean’s surface.”

Dr. Jean Harris, WILDTRUST Strategic Ocean Lead and Captain of the Angra Pequena, remarked: “This discovery is a reminder of how much still awaits to be uncovered beneath the waves.

“South Africa’s mesophotic habitats are essential biodiversity reservoirs, playing a pivotal role in climate resilience and future blue economy prospects.”

Riaan Cedras, Ecologist at iSimangaliso Wetland Park Authority, commented: “iSimangaliso MPA encompasses unique and diverse marine ecosystems typical of the East Coast of South Africa.

“The findings of this study are progressively illuminating the mysteries of the deep.

“Coral reefs. Kelp beds. The plankton and fish that sustain us.

“Research on species and ecosystems by partners in this World Heritage Site underscores the necessity for continued research in this area.”

As WILDTRUST and research partners strive to uncover and map these twilight treasures, the demand for enhanced marine protections grows stronger.

Safeguarding these ecosystems will ensure they continue to deliver invaluable services for generations to come.