2.7.1. Nitrate and Nitrite uptake
Nitrate (NO3−) uptake in untreated and
treated cyanobacterial cells was estimated spectrophotometrically at 210
nm by measuring the depletion of NO3−from the external medium following the method of Cawse (1967).
Nitrite (NO2−) uptake in each sample
was estimated spectrophotometrically at 540 nm by measuring the
depletion of NO2− from the external
medium following the method of Snell and Snell (1949).