The thermal window for aerobic scope in shallow water marine invertebrates.
The energy metabolism supports the processes that animals need in order to function. It can be determined by measurement of respiration rate (i.e., oxygen used per time unit). The standard metabolic rate (SMR) is defined as the minimal rate of energy expenditure per unit time (i.e., resting and no active digestion). The SMR in Poikilothermic animals, such as marine invertebrates, are affected by the temperature of the surrounding water. The effect of temperature follows a power function (Q10) and normally the SMR doubles - triples when temperature is increased with 10 °C (i.e., Q10 = 2 - 3). The maximum metabolic rate (MMR) is defined as the energy expenditure per unit time that an animal can achieve at a given temperature under any ecologically relevant circumstance. The effect of temperature on MMR follows a parabolic function. At any given temperature subtracting the MMR from the SMR gives the metabolic rate an animal has available for other functions than the SMR. This is called the aerobic scope (AS). At the temperatures were the SMR and the MMR are equal the aerobic scope is zero and the temperatures at which this occur is called the critical temperature (Tcrit). The temperature at which the aerobic scope is largest is termed the optimal temperature (Topt). Finally, the thermal window is defined as the temperature range between the two critical temperatures. Outside this window animals will have no available energy for anything else than SMR and they will die if kept outside the window for a prolonged period of time.
|Anvendte metoder:||Computer controlled intermittent respirometry.|
|Keywords:||Marine bivalves and or crustaceans, physiology, respirometry, global warming.|