La production algale dans les rizières de Camargue pendant la période de submersion

Click to increase image sizeClick to decrease image size

Summary

The seasonal fluctuation of the biomass and production of planktonic and benthic algae has been investigated in a ricefield of the Camargue. Phytoplankton reached its maximum values of biomass (250 mg · m⁻³, chlorophyll) and production (1.5 g C · m² · d¹) in May and June, whereas the maximum values of biomass and production of Charophyta (respectively 65 g dry weight · m⁻² and 1 g C · m⁻² · d⁻¹) have been measured in July and August. Benthic algae were always present and its production largely exceeded that of the phytoplankton (3 to 7 times) in summer. Total production of algae (68 g C · m⁻²) was divided in nearly equal parts by phytoplankton (38 %), benthic algae (25%) and Charophyta (37%). The most important habitat factor which affects the primary production of algae is light in relation with growth of rice vegetation.