A system for investigation of the temperature responses of emergent aquatic plants

We describe a system designed to experimentally elevate or depress water temperature in outdoor aquatic plant culture tanks while maintaining diurnal temperature fluctuations and other annual changes experienced by plants under field conditions. This system was developed to investigate the responses of potentially invasive aquatic plants to modified climatic conditions without the risk of experimental release.Water temperature is controlled by means of submerged electrical heating elements for warmed tanks, and by submerged refrigeration coils for cooled tanks. Vertical temperature gradients were removed by drawing water over the elements with a small pump and recirculating it to the top of the tank.Temperature records show that the system is capable of maintaining the set temperature differentials while replicating diurnal and seasonal temperature fluctuations.