Thermal acclimation capacity for four Arctic marine benthic species

There are areas on Earth where it is pressing that we obtain an understanding of the thermal limits and acclimationcapacities of the species living there. These are the zones where environmental temperatures are currently changing more rapidly and are predicted to continue to do so in the future. The foremost amongst these is possibly the Arctic, where in some areas air temperatures have risen on average by over 1.7 °C in the last 30 years, and sea ice cover has markedly decreased in recent decades. Here we present data on responses of 4Arcticmarinebenthicspecies to elevated temperature. There is very strong evidence that the urchin Strongylocentrotus droebachiensis and the gastropod Margarites helicinus can acclimate to 10.3 °C, and some evidence that some individuals of the bivalve Serripes groenlandicus and the amphipod Onisimus sp. can also acclimate to this temperature. This is more than 3 °C higher than experienced maximum summer temperatures. Acclimation to 7.1 °C produced reductions in acute upper temperature limits (CTmax) in all species, whereas acclimation to 10.3 °C produced increases. Although data are still limited, a capacity to acclimate to temperatures 3–5 °C above those experienced in the summer is similar to capacities of cold temperate species and higher than reported values for tropical or Antarctic marine invertebrates