Oxygen consumption and energy budget of the barnacle Balanus amphitrite amphitrite (Darwin, 1854) in an estuarine ecosystem, Basrah-Iraq

Abstract

The annual O₂ consumption, annual energy budget and the ecological efficiencies of a population of the barnacle Balanus amphitrite amphitrite were estimated in Garmat-Ali river, in the period October 1994-September 1995. The annual O₂ consumption was 2156 kJ/ m²/yr, the rate of O₂ consumption increased with increasing temperature and body weight, the barnacle consumes oxygen at a rate of 0.622 µlO₂/mg/h at 15°C, 0.84 µlO₂/mg/h at 23°C and 0.954 µlO₂/mg/h at 30°C. The Q₁₀ values increased with increasing size of barnacle. The food items provided were the alga, Chlorella sp. with a calorific contents of 3.2 kcal/g DW, and a flesh of the clam C. fluminea with 5.4 kcal/g DW. The barnacle assimilates the flesh of the clam about 7 times more than assimilating the Chlorella. The barnacle allocates 45-55% of the assimilated energy for net growth and 27-37% for metabolic energy expenditure, whereas 18% is channeled for faeces production. The respiratory coefficient (R/P) of this barnacle was 0.6. The assimilation efficiency for the plant and animal food were 88-91%. The annual energy budget equation for a population of barnacle at Garmat-Ali river is: C_p 16271.14 = P_p 11639.55 + R_p 2156 + F_p 2475.60.