Variations des teneurs en chlorophylle <a> et en sels nutritifs dans la lagune de l'Ichkeul

Abstract

The chlorophyll and nutritive salt follow up in Ichkeul lagoon in 1993 allows us to better understand the functioning of this original and complex ecosystem. The chlorophyll and nutritive salt yearly cycles show important weekly fluctuations. A high phytoplankton biomass was observed during winter with an outflow in oued Tinja, whereas significant concentrations of dissolved reactive phosphorus occured only in inflows through oued Tinja. Nitrate and nitrite were more irregular with no marked seasonality. The concentrations which have been measured during 1993 did not differ from those of the previous years.