Carbon flow in a small turbid man-made impoundment

Intensive studies were carried out for some years on a shallow turbid impounding reservoir in South Africa, which had a large littoral macrophyte community and which received large amounts of sediment, which reduced the volume of the reservoir by more than 30 per cent over the period 1961-79. The carbon flux for the reservoir was investigated and used to develop a matrix flow model which identified three dominant components in the system, namely dissolved inorganic carbon, particulate organic carbon, and fish. Phytoplankton and organic detritus from macrophytes were the most important components of particulate organic carbon, and variations in these affected the whole system. The carbon cycle in the reservoir is illustrated diagrammatically.