Just Blue, the site for Ascidian info
Just Blue, the site for Ascidian info

The Southern African coast is a diverse region including a number of different habitats each with a wide variety of fauna and flora and it is estimated that there is over 10 000 species of marine organisms (Branch et al 1994). A number of books, although small is relationship to those published on the better know terrestrial fauna and flora of this biologically rich and diverse tip of Africa, are available on the marine habitats and the organisms found within this unique area (see under more literature material section for a list).

The diversity of fauna en flora present along the southern African coast is a reflection of the different water masses that influence the climate, sea temperature and other factors associated with the different geographical (Branch et al 1994). The narrow continental shelf on the East Coast North of East London bathes the coastal area in warm water brought down by the Agulhas current from the subtropics. As the continental self widens to the south the near shore temperature becomes cooler and more temperate. The west coast is however chilled by northward drifting cold water from the Benguela current. This and the added occurrence of up-welling where cold nutrient rich water from the deep replaces surface water blown off shore set the scene for an coastal region with a higher productivity but lower diversity that the eastern coast (Branch et al 1994).

The Southern African coast can thus be divided into three zones. The highly productive but cold west coast, north of Cape point. The diverse temperate south coast, between Cape point and just north of East London and the more tropical coastal area to the north of East London. The area north of Durban is characterized by coral reefs otherwise not found along the southern African coast.

Algoa Bay

The southern Cape coast from Cape St. Francis Bay to Woody Cape is a number of half-heart bays with rocky headlands protruding into the sea. The sand accumulates along the northern and eastern regions of the bays. In Algoa Bay the deposition of sea-born sand on its northern shores has formed the largest dune field on the eastern coast of southern Africa, the Alexandra dune field (Lubke et al. 1988). The climate in the area is very variable. The area fall between the countries winter and summer rainfall areas and rain can be expected any time of the year. The area is also considered as one of the windiest part (predominately westerly) of southern Africa (although not strictly true). The maximum tidal range on the eastern Cape coast is only 2m and in Algoa Bay spring low tide falls around 10h00 and 22h00.

Further reading or related literature

Day, J. H. 1974. Guide to Marine Life of South African Shores. A. A, Balkema, Cape Town, 272 pp.
Branch, G. and Branch, M, 1981. The Living shores of Southern Africa. C. Struik, Cape Town, 272 pp.
Griffiths, C., Griffiths, R. and Thorpe, D. 1988. Seashore Life. Struik Guide Series, Struik Publ., Cape Town, 64pp.
Lubke, R.A., Gess, F.W. and Bruton, M.N. 1988 A field Guide to the Eastern Cape Coast. Wildlife Society of Southern Africa, Grahamstown, 520 pp.
Payne, A.I.L., Crawford, R.J.M. and van Dalsen, A. 1989 Oceans of Life off Southern Africa. Vlaeberg Publ. Cape Town, 380pp.
The Reader's Digest Association South Africa 1984. Atlas of Southern Africa. Produced in conjunction with the Directorate of Surveys and Mapping, Department, which prepared the maps for " Our land in close up'. pp 256.
Branch, G.M., Griffiths, C.L., Branch, M.L. and Beckley, L.E. 1994 Two Oceans. A Guide to the Marine Life of Southern Africa. David Philip Publ (Pty)Ltd. 360 pp