title: Variation in thermal stress response in two populations of the brown seaweed, Fucus distichus, from the Arctic and subarctic intertidal.
abstract: 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.
authors.affiliation: Faculty of Biosciences and Aquaculture , University of Nordland , Bodø 8049, Norway.
authors.forename: Irina
authors.initials: I
authors.lastname: Smolina
authors.affiliation: Faculty of Biosciences and Aquaculture , University of Nordland , Bodø 8049, Norway.
authors.forename: Spyros
authors.initials: S
authors.lastname: Kollias
authors.affiliation: Faculty of Biosciences and Aquaculture , University of Nordland , Bodø 8049, Norway.
authors.forename: Alexander
authors.initials: A
authors.lastname: Jueterbock
authors.affiliation: Shoals Marine Laboratory , Cornell University , 400 Little Harbor Road, Portsmouth, NH 03801, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Coyer
authors.affiliation: Faculty of Biosciences and Aquaculture , University of Nordland , Bodø 8049, Norway.
authors.forename: Galice
authors.initials: G
authors.lastname: Hoarau
keywords: brown algae; heat shock protein genes; local adaptation; photosynthetic performance; thermal stress response