THE ECOLOGY OF SOUTH AFRICAN ESTUARIES

Abstract

Section A describes the topography and physico-chemical characteristics of the Milnerton river system. Slightly brackish water from the Diep River flows into the shallow basin of Riet Vlei and from there escapes through Milnerton Lagoon into the sea. The estuary is open to the sea during winter and spring and is closed by a sand-bar in summer. In late summer Diep River and Riet Vlei dry up, the Lagoon becomes hypersaline and a reversed salinity gradient is established. The interaction of the various physical factors is discussed. The biotic divisions of the system are discussed in Section B, and the fauna and flora of each part are described. Seasonal changes are discussed in relation to the changing environment. The fauna of the Milnerton river system is compared with that of other South African estuaries. An annotated faunistic list is appended.