Primary productivity studies in the shelf waters off Alleppey, south-west India, during the post-monsoon, 1967

TLDR: Primary productivity was measured by the radio-carbon method, its relation to the distribution of inorganic phosphate and dissolved oxygen off the south-west coast of India is discussed and dark bottle correction at lower levels of the euphotic zone in coastal waters is discussed.

Abstract: Primary productivity was measured by the radio-carbon method, its relation to the distribution of inorganic phosphate and dissolved oxygen off the south-west coast of India is discussed. The study was conducted during the post-monsson season which is associated with coastal upwelling. Productivity rates were generally high (807 mgC/m2/day), and so was the nutrient level in the euphotic zone. Inorganic phosphate was measured and taken as representative index of nutrients in general. Carbon assimilation rates were correlated with chlorophyll a, as well as with chlorophylls a, b plus c. Plant carotenoids were also measured but their role is not clear. Standing crop estimations failed to show any good agreement with carbon assimilation. Dark bottle correction at lower levels of the euphotic zone in coastal waters is discussed. The various results are interpreted from the point of view of light ecology. Fluctuations in productivity are mainly due to variations in incident solar radiation.