Premières observations sur les valeurs de poids sec chez quelques copépodes de méditerranée

Works on plankton carried out to this day in the Mediterranean Sea only very rarely measure dry weight of the different organisms (Vucetic, 1957; Deveze, 1959). However, many northern European, Soviet and American researchers frequently use quantities of dry planktonic matter to express their results. Trégouboff (1961) in re-examining the data of Bogorov (1957) underlines the importance of this procedure in quantitative studies. We will first address this aspect of the issue.We always use dry weight and not wet weight. The wet weight of an organism depends mainly on, as we will see later, the percentage of water that composes it and this percentage is very variable. Dry weight (organic substances and ashes) is less subject to variation.