Oxygen utilization rate in sea water during decomposition of pellet fish food

Abstract

       Vessels with 20 litters nonfiltered sea water and pellet concentrations of 10, 20, 40, 80, 160 mg dm^-3 were incubated in the dark at 17°C with strong aeration during 26 days. Every two days sam­ples of the water were taken in the WINKLER’s bottles. Oxygen concentrations were measured by WINKLER method two days after incubation.

       Initial velocity of oxygen consumption at decomposition of pellet fish food in the sea water increases with increasing pellet concentration. It can be mathematically described by equation of rectangular hyperbola (v_o (mgO₂dm^-3 day^-1) = 4.2C_F/(31.2+C_F), C_F in mg dm^-3). Apparent MICHAELIS-MENTEN constant indicates that initial rate of oxygen consumption changes a little with increasing pellet concentration above 60 mg dm^-3. At low pellet concentration initial rate of oxygen consumption could be probably expressed simpler with kinetic reaction of first order.