Marine biodiversity of South Africa

The continental shelf of southern Africa varies considerably in width along the coast, and the shelf edge also varies in depth. To the north-east the shelf is narrow to very narrow, with a relatively shallow break, but it is much wider over the Agulhas Bank off the southern tip of the continent. This gradual increase in width affects the path of the powerful Agulhas Current, pushing it further offshore towards the Southern Ocean.

Eddies of the Agulhas Current meanders past the Agulhas Bank leaking warm and salty water into the South Atlantic before retroflecting back into the Indian Ocean

Mean chlorophyl-a concentration map of the oceans surrounding Southern Africa for 2009. Note the high productivity water in the Agulhas Retroflection and the very high concentrations along the west coast, due to the upwelling of mineral rich water from the cold depths the South Atlantic Ocean, forming the Benguela Current.

Benguela Current in the South Atlantic Gyre

The Agulhas Current is the western boundary current of the southwest Indan Ocean. It flows south along the African east coast and along the south-eastern edge of the bank. It then retroflects back into the Indian Ocean south-west of the bank. This retroflection results in intense eddy activities such as meanders, eddies, and filaments.[2] In upper layer water, the Agulhas rings and eddies move warm and salty water into the large South Atlantic gyre, which exports it to the tropics. In the lower ocean layers water is transported in the opposite direction.[3]

The Agulhas acts as an oceanic convergence zone. Due to mass continuity this drives surface waters down, resulting in the upwelling of cold, nutrient rich water south of the current. Additionally, the convergence tends to increase the concentration of plankton in and around the Agulhas. Both of these factors result in the area being one of enhanced primary productivity as compared to the surrounding waters. This is especially notable in the Agulhas Retroflection waters, where chlorophyll-a concentrations tend to be significantly higher than the surrounding South Indian Ocean and South Atlantic Ocean waters.[4] Warm core rings are known to have lower primary productivity than surrounding cold waters. Agulhas Rings have been observed to carry waters with low chlorophyll-a concentration water into the South Atlantic. The size of phytoplankton in Agulhas Rings tends to be smaller than in the surrounding water (around 20 µm in diameter).[4] Agulhas Rings have also been observed as removing larval and juvenile fish from the continental shelf.

The Benguela Current is the broad, northward flowing ocean current that forms the eastern portion of the South Atlantic Ocean gyre. The current extends from roughly Cape Point in the south, to the position of the Angola-Benguela front in the north, at around 16°S. The current is driven by the prevailing south easterly trade winds. Inshore of the Benguela Current proper, the south easterly winds drive coastal upwelling, forming the Benguela Upwelling System. The cold, nutrient rich waters that upwell from around 200–300 m depth in turn fuel high rates of phytoplankton growth, and sustain the productive Benguela ecosystem.

If the wind blows parallel to the coast with sea to the left in the southern hemisphere (such as along the west coast of South Africa), then Ekman transport can produce a net offshore movement of surface water. This may result in coastal upwelling.

Upwelling is an oceanographic phenomenon that involves wind-driven motion of surface water away from the coast, which is replaced by a flow of deeper dense, cooler, and usually nutrient-rich water towards the ocean surface, The nutrient-rich upwelled water stimulates the growth and reproduction of primary producers such as phytoplankton. Due to the biomass of phytoplankton and presence of cool water in these regions, upwelling zones can be identified by cool sea surface temperatures (SST) and high concentrations of chlorophyll-a.[5][6] The increased availability of nutrients in upwelling regions results in high levels of primary production. Upwellings that are driven by coastal currents or diverging open ocean have the greatest impact on nutrient-enriched waters and global fishery yields.[7][4]

Marine animals

• List of comb jellies of South Africa
• List of echinoderms of South Africa
• List of marine and coastal birds of South Africa
• List of marine arthropods of South Africa
  • List of marine crustaceans of South Africa
  • List of sea spiders of South Africa
• List of marine bristleworms of South Africa
• List of marine bryozoans of South Africa
• List of marine cnidarians of South Africa
• List of marine fishes of South Africa
  • List of marine bony fishes of South Africa
    • List of marine spiny-finned fishes of South Africa
      • List of marine Perciform fishes of South Africa
        • List of marine fishes of the suborder Percoidei of South Africa
• List of marine flatworms of South Africa
• List of marine mammals of South Africa
• List of marine molluscs of South Africa
  • List of marine gastropods of South Africa
    • List of marine heterobranch gastropods of South Africa
• List of marine reptiles of South Africa
• List of sponges of South Africa

Seaweeds

• List of seaweeds of South Africa
  • List of red seaweeds of South Africa

Prokaryotes

• List of marine animals of the Cape Peninsula and False Bay
• List of seaweeds of the Cape Peninsula and False Bay

Field guides:

• Atkinson, LJ; Sink, KJ, eds. (2018). Field Guide to the Offshore Marine Invertebrates of South Africa (PDF). Pretoria: Malachite Marketing and Media. doi:10.15493/SAEON.PUB.10000001.
• Branch, G.M.; Branch, M.L. (1985). The Living Shores of Southern Africa (3rd impression ed.). Cape Town: C. Struik. ISBN 0 86977 115 9.
• Branch, G.M.; Branch, M.L.; Griffiths, C.L.; Beckley, L.E. (2010). Two Oceans: a guide to the marine life of southern Africa (2nd ed.). Cape Town: Struik Nature. ISBN 978 1 77007 772 0.
• Day, J.H. (1969). A guide to marine life on South African shores. Cape Town: Balkema.
• De Clerck, O.; Bolton, J.J.; Anderson, R. J.; Coppejans, E. (2005). Guide to the Seaweeds of KwazZulu-Natal. Scripta Botanica Belgica Volume 33. Joint publication of: National Botanical gardens of Belgium, VLIZ Flanders Marine Institute and Flemish Community. ISBN 90-72619-64-1.
• Gosliner, T.M. (1987). Nudibranchs of Southern Africa. ISBN 0-930118-13-8.
• Jones, Georgina (2008). A field guide to the marine animals of the Cape Peninsula. Cape Town: SURG. ISBN 978-0-620-41639-9.
• Heemstra, Phil; Heemstra, Elaine (2004). Coastal Fishes of Southern Africa. NISC/SAIAB. ISBN 1920033017.
• Kilburn, R.; Rippey, E. (1982). Sea Shells of Southern Africa. Macmillan. ISBN 0-86954-094-7.
• King, Dennis (1996). Reef fishes and corals: East coast of southern Africa. Cape Town: Struik. ISBN 1 86825 981 1.
• King, D.; Fraser, V. (2001). More Reef Fishes and Nudibranchs. Cape Town: Struik. ISBN 1-86872-686-X.
• King, Dennis; Fraser, Valda (2014). The Reef Guide: East and South Coasts of Southern Africa. Cape Town: Struik Nature. ISBN 9781775840183.
• Liltved, William Rune (2000). Cowries and their relatives of southern Africa: A study of the southern African Cypraeacean and Velutinacean gatropod fauna (2nd ed.). Gordon Verhoef, Seacomber Publications. ISBN 0908 42089 7.
• Smith, Margaret M; Heemstra, P., eds. (2003). Smith's sea fishes. Cape Town: Struik. ISBN 1 86872 890 0.
• Smith, J.L.B.; Smith, Margaret M. (1966). Fishes of the Tsitsikamma Coastal National Park. Johannesburg: Swan Press.
• Stegenga, H.; Bolton, J.J.; Anderson, R.J. (1997). Seaweeds of the South African West Coast. Contributions from the Bolus Herbarium, University of Cape Town. ISBN 0-7992-1793-X.
• Steyn, D.G.; Lussi, M. (2005). Offshore Shells of Southern Africa. ISBN 0-620-33607-2.
• Zsilavecz, Guido (2005). Coastal fishes of the Cape Peninsula and False Bay: A divers' identification guide. Cape Town: SURG. ISBN 0-620-34230-7.
• Zsilavecz, G. (2007). Nudibranchs of the Cape Peninsula and False Bay. Cape Town: SURG. ISBN 0-620-38054-3.

• Annals of the South African Museum

• South African National Spatial Biodiversity Assessment 2004
  • Summary Report
    • Driver, A., Maze, K., Lombard, A.T., Nel, J., Rouget, M., Turpie, J.K., Cowling, R.M., Desmet, P., Goodman, P., Harris, J., Jonas, Z., Reyers, B., Sink, K. & Strauss, T. 2004. South African National Spatial Biodiversity Assessment 2004: Summary Report. Pretoria: South African National Biodiversity Institute.
  • Technical Reports
    • Volume 3: Estuary Component
      • Turpie, J.K. 2004. South African National Spatial Biodiversity Assessment 2004: Technical Report. Volume 3: Estuary Component. Pretoria: South African National Biodiversity Institute.
    • Volume 4: Marine Component
      • Lombard, A.T.; Strauss, T.; Harris, J.; Sink, K.; Attwood, C.; Hutchings, L. (2004). South African National Spatial Biodiversity Assessment 2004: Technical Report (PDF) (Report). Volume 4: Marine Component. Pretoria: South African National Biodiversity Institute.
• National Biodiversity Assessment 2011
  • Sink, K; Holness, S; Harris, L; Majiedt, P; Atkinson, L; Robinson, T; Kirkman, S; Hutchings, L; Leslie, R; Lamberth, S; Kerwath, S; von der Heyden, S; Lombard, A; Attwood, C; Branch, G; Fairweather, T.; Taljaard, S.; Weerts, S.; Cowley, P.; Awad, A.; Halpern, B.; Grantham, H; Wolf, T. (2012). National Biodiversity Assessment 2011: Technical Report (PDF) (Report). Volume 4: Marine and Coastal Component. Pretoria: South African National Biodiversity Institute.

National Biodiversity Assessment for 2018 (NBA2018)