Given what you know at this point about marine iguanas and the abiotic effects of enso, develop two possible directions of research that liz should pursue to understand exactly why the iguanas suffered such a high mortality. keep in mind that you need to consider indirect effects. while environmental temperature does change metabolic rates of ectotherms, the iguanas are exposed to a wide range of temperatures as they feed and bask on the lava. direct mortality in response to a temperature change of a couple of degrees is unlikely.