Acclimation potential and biochemical response of four temperate macroalgae to light and future seasonal temperature scenarios

Abstract

Resilience and biochemical response to predicted future North Atlantic Ocean temperature conditions (+2 °C of current seasonal observations) and different light conditions were investigated in four commercially valuable macroalgae that naturally inhabit different shore levels (Ascophyllum nodosum, Fucus serratus, Laminaria digitata and Palmaria palmata). Increased irradiances had a positive effect on growth rates of the intertidal species (Ascophyllum. nodosum and Fucus serratus). Growth and chlorophyll contents of Laminaria digitata were most strongly impacted by temperature, but its fatty acid contents and composition were more strongly controlled by light. Neither changes in light nor temperature affected growth of Palmaria palmata although biochemical composition was highly sensitive to temperature. Pigments and polyunsaturated fatty acids exhibited a correlated response in the brown canopy-forming macroalgae, with decreasing concentrations with increasing light conditions. By integrating growth and changes in biochemical composition, new production of essential and commercially relevant biomolecules was evaluated, Effects of individual and combined environmental factors on growth and key biochemical composition were linked to the specific acclimation potential of macroalgae from different habitats. Results demonstrate that future global change will not only impact on coastal food webs but also has likely impacts on sustainable production of algal biomass and high-value compounds due to changes in productivity and biochemical composition under anticipated future environmental regimes.