Kelp forests collapse reduces understorey seaweed β-diversity.

Background And Aims: Kelps are the primary foundation species in temperate subtidal rocky shores worldwide. However, global change is causing their decline with consequences for the organisms that rely on them. An accurate assessment of these consequences may depend on which attributes of the associated community are considered.

Physiological response to warming in intertidal macroalgae with different thermal affinity.

Changes in the abundance and distribution of seaweeds have been reported worldwide. In Northwest Iberia, cold and warm affinity seaweeds have respectively decreased and increased their abundance. To improve our understanding of their vulnerability to future warming scenarios, the effects of warming on the photosynthetic and respiratory performance of seaweeds with cold-water (Fucus serratus and Vertebrata lanosa) and warm-water (Padina pavonica and Gigartina pistillata) affinities were compared in a highly resolved temperature gradient (7-31 °C) under controlled laboratory conditions.