The Simulated in situ Measurements of Oceanic Primary Production

Abstract

Simultaneous measurements with two types of incubators were made on replicate samples both in the incubators and in situ in the ocean. Both incubators used sunlight and blue glass filters to simulate light conditions at depths in the ocean. The first gave measurements of column production 1.58 times those in situ. This was due to the fact that at depths greater than 20 m the incubator gave much higher results with no significant relation to those measured in situ. In the second incubator the accuracy of reproduction of oceanic light conditions was improved by reducing reflected light and using a balance-by-depth twin photometer system for determining the depths of sampling. The measurements of column production in the second incubator were 1.03 times the in situ values.