Exposure to high temperatures causes the production of heat shock proteins (HSPs) that enable cell survival (Ravaux et al., 2003). The HSPs repair and prevent the gathering of proteins that denature in extreme heat however, HSPs can be damaging if produced in normal temperature conditions (Ravaux et al., 2003). The temperature of the mixing zone can change rapidly, therefore the expression and inactivation of HSPs must also be rapid to avoid damaging proteins. The production of HSPs was recorded as low as 25oC in R. exoculata and so their optimal habitat would likely be below 25oC (Ravaux et al., 2003). These findings were consistent with more precise, recently recorded in situ temperatures that were between 3oC – 18oC and considering the optimal temperature for bacteria growth it can be inferred that optimality for both organisms is below 25oC (Ravaux et al., 2003; Schmidt et al., 2008; Jan et al., 2014).
Rimicaris exoculata must navigate itself to avoid areas of lethal temperatures (Ravaux et al., 2003). In an environment where thermal gradients range from extreme heat to extreme cold over several centimetres, this can be challenging. Behavioural escape responses to high heat have been observed in experiments but the question remains, how are R. exoculata able to detect the vents before they get too close (Ravaux et al., 2003)?
In an environment devoid of sunlight R. exoculata has evolved other methods of navigating its way around hydrothermal vents (Jannasch, 1985; Schmidt et al., 2008). Read the next section of this blog to find out how the shrimp move around without perishing in the superheated vent fluid.
Next up – Adaptations to heat avoidance