Organic content of some saline lake sediments in western Victoria

Abstract

The organic content (in joules) of surface sediment in two saline lakes was measured using a wet oxidation technique; Kjeldahl nitrogen and percentage organic matter (by ignition) were also determined. The mean organic content of samples taken monthly in Pink Lake for 6 months was 883.2 J g^-1 dry weight of washed sediment and the organic nitrogen concentration was 1.8 mg g^-1; two samples from Lake Cundare had an organic content of 300.2 J g^-1. Percentage organic content indicated higher values than these; loss of water of hydration during ignition is a possible explanation. The completeness of protein oxidation was also discussed. Measurements of organic content were taken as part of a study on the rates of sediment ingestion by Parartemia zietziana, an anostracan crustacean which dominates the fauna of both lakes. It produces faeces with an organic content of 1198.7 J g^-1.