PS 15-209 - The relationship between heat tolerance and lifespan in different populations of an intertidal copepod species Tigriopus californicus

Abstract: Much interest of fitness in relation to climate change have focused on survivorship of maximal temperature exposures. However, populations will also experience higher frequency of sublethal heat stress that may also impact fitness through decreased lifespan and fecundity. This study uses an environmentally relevant temperature as a chronic heat stressor at varying frequencies on two populations of the intertidal copepod Tigriopus californicus with different heat tolerances. Results illustrate that chronic exposure to these current day temperatures do decrease lifespan in temperature sensitive populations, in part due the inactivity of the master antioxidant regulating gene, Nrf2. The heat tolerant population had an extended lifespan with an active Nrf2 expression pattern whereas the heat sensitive population had a decreased lifespan with a depressed Nrf2 expression. Examining the link between the molecular mechanisms of heat tolerance and aging may provide more predictive power in determining which populations are at greatest risk to climate change stressors.