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 NO3from 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).