Data from: Variation in thermal stress response in two populations of the brown seaweed, Fucus distichus, from the Arctic and subarctic intertidal

It is unclear whether intertidal organisms are ‘preadapted’ to cope with
the increase of temperature and temperature variability or if they are
currently at their thermal tolerance limits. To address the dichotomy, we
focused on an important ecosystem engineer of the Arctic intertidal rocky
shores, the seaweed Fucus distichus and investigated thermal stress
responses of two populations from different temperature regimes (Svalbard
and Kirkenes, Norway). Thermal stress responses at 20°C, 24°C and 28°C
were assessed by measuring photosynthetic performance and expression of
heat shock protein (HSP) genes (shsp, hsp90 and hsp70). We detected
population-specific responses between the two populations of F. distichus,
as the Svalbard population revealed a smaller decrease in photosynthesis
performance but a greater activation of molecular defence mechanisms
(indicated by a wider repertoire of HSP genes and their stronger
upregulation) compared with the Kirkenes population. Although the
temperatures used in our study exceed temperatures encountered by F.
distichus at the study sites, we believe response to these temperatures
may serve as a proxy for the species’ potential to respond to
climate-related stresses.