Respiration of aquatic organisms using a respirometer
Energy is obtained from food, a proportion of this energy is required for basic survival, called maintenance. The energy obtained from food drives cellular processes such as active transport and protein synthesis.
Importantly, the conversion efficiency cannot exceed the remainder of the energy once maintenance and movement have been subtracted.
ATP is generated from ADP using the energy obtained from the food and this process consumes oxygen and generates carbon dioxide.
This can be measured using a respirometer, which in the case of aquatic organisms is a closed tank with a probe which measures the gas concentrations of one or more of the aforementioned gasses.
To measure the rate of oxygen consumption (VO2) we can use the equation:
S equals the solubility of oxygen in water (ml O2/L*kPa)
V equals the volume of water in the respirometer (L)
and
Once the organism is used to the new surroundings the gasses can be measured for a period of time.
To calculate the rate of oxygen consumption (VO2) we need to retain the drop in partial pressure of
To calculate the oxygen consumption we simply multiply the number of Joules required per ml of oxygen; say it cost 10
To combine multiple energy sources, we need to know the percentage burned of each type of energy, for example: an organism gets 40% of its energy from oxidizing carbohydrates (20.8 J/ml O2) and 60% of its energy from lipids (19.4 J/ml O2), and it is using 50ml