![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Summary
The bottom substrates of the freshwater Lake Sibayi are mainly fine sands. Silt substrates occur mainly in the valleys leading from the western and northern arms of the lake underwater in the main basin of the lake.
The fauna included an estuarine crustacean component and a polychaete. The freshwater component consisted principally of chironomid larvae, oligochaetes and molluscs.
Differences in density of animals were shown for three species in depths up to 20 metres and depths below 20 metres. Other animals are more evenly distributed with regard to depth.
The infauna of the bottom sediments is mainly confined to sandy substrates. The epifauna is more generally distributed. The fauna of weed beds far from the shore of the lake in 5 metres of water is like that of the marginal vegetation.
Some of the fauna showed seasonal changes in density.
The value of different methods that were used in the survey are discussed.