Chlorophyll a determination of periphyton on sediments: identification of problems and recommendation of method

Abstract

SUMMARY. 1. The aim of this study was to evaluate the impact of different amounts of water and organic material on the extraction of periphytic algal chlorophyll from lake sediments. 2. Methanol extracted less chlorophyll than acetone from fresh sediment samples. The ratio between the amount of chlorophyll extracted with methanol and acetone increased with decreasing water content of the sample. 3. When sediments were freeze‐dried prior to extraction of chlorophyll, the extraction efficiency increased between 3.4 and 10.0 times compared with fresh samples. It is suggested that the higher extraction efficiency for freeze‐dried samples is due to reduction in water content and pulverization of the sediment, allowing improved exposure to the solvent. 4. As a result of these studies freeze‐drying, prior to extraction in acetone (90%) or ethanol (96%), is recommended as the best available method for quantification of chlorophyll a in sediments.