Validity of net primary productivity estimation by light and dark bottle oxygen technique in tropical inshore waters, with a note on primary productivity of the surf zone at Cochin

Abstract

Light and dark bottle oxygen technique is widely used to estimate the rate of gross and net photosynthetic production (G.P.P. and N.P.P.) in the marine environment, of which N.P.P. determines the fertility of the sea and is also used for the assessment of potential fishery resources. But in the shallow coastal waters of tropical seas, where organic load is considerably high, bacterial oxidation and reduction processes involving utilisation and release of oxygen tend to interfere significantly in the L-I values often leading to unreliable and unrealistic values of net photosynthetic production.