Student: Dr N Griffin
Supervisor: Dr WJ Muller
Degree: Postdoctorate

Diatoms have wide acceptance as indicators of water quality in a number of largely temperate countries worldwide. They are commonly used together with macroinvertebrates in water quality monitoring programmes, as the two groups have differing and complementary sensitivities to various water quality parameters. In particular, shifts in diatom species complement reflect changes in dissolved salts and nutrients.

The Orange River Development Project was an ambitious project formally proposed in a White Paper in 1962. Among its many objectives, it aimed to transfer water from the Gariep Dam (then the HF Verwoerd Dam) on the Orange River to the Sundays and Fish River catchments with the primary objectives of increasing agricultural production and providing water for municipal use. Orange River water first reached the Sundays River valley in 1976.

Large changes to the macroinvertebrate fauna of the Fish River were detected after the Interbasin transfer was initiated, and it seems likely that impacts are not restricted to the macroinvertebrates. Over the period 1967-1970, before water transfer began, REM Archibald sampled diatoms along the lengths of the Fish and Sundays Rivers. His dataset provides a unique opportunity to compare diatom distributions prior to initiation of the Interbasin transfer scheme with post-transfer community structure.

Last Modified: Fri, 14 Aug 2015 11:35:10 SAST