Dissolved Oxygen Environment of the Fish Farm in Yashima Bay, Japan. I. Primary Productivity of Sea Water

Abstract

The Steele’s equation was applied for estimation of primary productivity of sea water from fish culture area in Yashima Bay and expressed in the term:

                   

where P=Production rate per unit surface (mgO₂ / m²hr), P_(a)max = maximum production rate based on chl-a (mgO₂/mg chl-a hr), chl-a = chlorophyll-a concentration (mg/m³) , Kd = extinction coefficient (m^-1), i₀ = incident light at the sea surface (klux), i_z = light quantum at depth z meter (klux), imax =maximum light intensity that gave maximum production rate (klux). The extinction coefficient was evaluated from the equation: 

                   K_d = 0.06 + 0.060(SS) + 0.015 (chl-a)+ 0.002(COD_d)

where SS=dry weight of suspended particulate matter (g/m³), COD_d = chemical oxygen demand of dissolved organic matter in sea water (g/m³). Day rate intergrals were calculated according to the equation based on the summation of rates of short intervals Thus, the primary productivity in Yashima Bay was 7.40 gO₂/m²d with the values of P_(a)max as 65.5 mgO₂/mg chl-a hr and i_max 50.5 klux.