For this experiment, the urchins were placed into a testing tank.  The temperature of these testing tanks was changed, in order to test the urchins thermal tolerance, by removing a small amount of the existing tank water and adding in some heated water.  This added water was then mixed into the tank, so that the heat was displaced to the whole tank.  The temperature of the tank was collected constantly so that the temperature of the water could be maintained.
In order to calculate the thermal tolerance, the urchins were placed upside-down (they were inverted).  The time it took them to right themselves was then calculated.  Elizabeth Sherman considered the thermal tolerance of the urchin to be the temperature at which the urchin was no longer able to right itself. 
Statistic tests were than conducted to figure out whether there was a significant difference between the different sea urchins thermal tolerance.  A two- way ANOVA test was used (species and collection temperature=fixed factors, righting time=dependant variable).  Regression tests were also done in order to see if there was any significant differences to be found. 

 

Information Credit: Sherman E.  2015.  Can sea urchins beat the heat? Sea urchins, thermal tolerance, and climate change.  [Cited November 16, 2015].  PeerJ 3:e1006  Available from: http://dx.doi.org/10.7717/peerj.1006

Photo Credit: Sherman E. 2015.  Can sea urchins beat the heat? Sea urchins, thermal tolerance and climate change.  [Cited November 14, 2015].  PeerJ 3:e1006 Available from: http://dx.doi.org/10.7717/peerj.1006