An estimation method of uplift forces exerted underneath a horizontal deck of platform has been proposed in the present report on the basis of experimental results. The uplift pressure is expressed as the sum of shock pressure component and static pressure component. The non-dimensional function k(x,t) is the most important function which characterizes the shack pressures and Dunaliella tertiolecta, is chosen as the test specie. After some basic cultivation tests, an assay procedure, which has good sensitivity and reproducibility to nutrient status, is proposed.
　This procedure is applied to obtain the spatial and seasonal distribution of A.G.P. in the Bay of Osaka, which is known to be very eutrophic. It is confirmed that nutrients are loaded into the Bay mainly through rivers and anaerobic sediment in summer, and that vertical mixing is developed in winter.
　By this A.G.P. test, organic productivity of seawater is estimated comprehensively and rationally.