The adenylate energy charge in marine phytoplantkon: The effect of temperature on the physiological state of Skeletonema costatum (Grev.) Cleve

The adenylate energy charge $\text{(ATP] +}\text{1}\text{2}\text{ADP])}\text{0ATP+ADP+AMP]}$ was measured in axenic batch cultures of Skeletonema costatum (Grev.) Cleve at 2°, 10°, 15°, 20°, 24° and 30°C. The results suggest that this eurythermal diatom is physiologically capable of adapting to the 28 °C range of temperature with little apparent difference in the potential energy available to the cell. In N-limited continuous cultures at 15 °C, the energy charge values were lower than those observed in batch culture by 0.2, implying nutrient stress may result in decreased intracellular chemical energy. The utilization of the adenylate energy charge as an indicator of physiological state is suggested.