Methodology:

Three species of Antarctic marine invertebrate: Nacella concinna (limpet), Paraceradocus miersi (crustacean) and Sterechinus neumayeri (urchin) were collected at 8-15m depth from South Cove near Rothera Research Station, Adelaide Island, Antarctic Peninsula (67° 4' 07" S, 68° 07' 30" W). Size metrics were taken for all animals in this study (length, height and width of shell for Nacella concinna, wet weight for Paraceradocus miersi and test diameter for Sterechinus neumayeri).

In the acclimation experiment animals were transferred to aquaria at either control temperature or to aquaria with heaters in to raise the temperature to +2°C. Tank temperatures were recorded daily. The Upper Thermal Limits (UTLs) of a set of control animals at time point 0 were evaluated. This was performed by transferring the animals to a 60 L jacketed tank with aerated sea water at the same temperature as the ambient sea water (0°C) and connected to a thermocirculator (Grant Instruments Ltd, Cambridge, UK). The temperature was raised at 1°C per hour with the temperature limit of each animal noted when they no longer responded to tactile stimuli. This UTL test was repeated at the end of the 2 month period, using the same methodology described above with animals which had been kept at 0°C (control) temperatures for 2 months and also animals which had been kept at 2°C. In the case of the latter, the UTL start temperature was 2°C.

In the thermal ramping experiments animals were transferred to a 60 L jacketed tank with aerated sea water at the same temperature as the ambient sea water (0°C) and connected to a thermocirculator (Grant Instruments Ltd, Cambridge, UK). The temperature was raised at either 1°C per hour, 1°C per day or 1°C per 3 days and the animals sampled at a temperature 10% lower than their previously evaluated UTLs at that particular rate of change. For the longer term experiments (1°C per day or 1°C per 3 days), control animals were sampled at time point 0 and at the end of the experiment. For the 1°C per hour, only one set of controls was needed.