title: Physiological response of fucoid algae to environmental stress: comparing range centre and southern populations.
abstract: Climate change has led to alterations in assemblage composition. Species of temperate macroalgae at their southern limits in the Iberian Peninsula have shown shifts in geographical range and a decline in abundance ultimately related to climate, but with the proximate factors largely unknown. We performed manipulative experiments to compare physiological responses of Fucus vesiculosus and Fucus spiralis from Portugal and Wales (UK), representing, respectively, southern and central areas of their distribution, to different intensities of solar radiation and different air temperatures. Following exposure to stressful emerged conditions, Portuguese and Welsh individuals of both fucoid species showed increased frond temperature, high desiccation levels and reduced photophysiological performance that was evident even after a 16 h recovery period, with light and temperature acting in an additive, not an interactive, manner. The level of physiological decline was influenced by geographical origin of populations and species identity, with algae from the south and those living higher on the shore coping better with stressful conditions. The negative effect of summer conditions on photophysiology may contribute to changes in fucoid abundance and distribution in southern Europe. Our results emphasise how physiological performance of geographically distinct populations can differ, which is particularly relevant when predicting responses to climate change.
authors.affiliation: School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB, UK.
authors.forename: João G
authors.initials: JG
authors.lastname: Ferreira
authors.affiliation: Laboratory of Coastal Biodiversity, Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Rua dos Bragas 289, 4050-123, Porto, Portugal.
authors.forename: Francisco
authors.initials: F
authors.lastname: Arenas
authors.affiliation: Área de Biodiversidad y Conservación, Rey Juan Carlos University, 28933, Móstoles, Madrid, Spain.
authors.forename: Brezo
authors.initials: B
authors.lastname: Martínez
authors.affiliation: School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB, UK.|Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, European Way, Southampton, SO14 3ZH, UK.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Hawkins
authors.affiliation: School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB, UK.
authors.forename: Stuart R
authors.initials: SR
authors.lastname: Jenkins
mesh_terms: D000064:Acclimatization; D057231:Climate Change; D004777:Environment; D005060:Europe; D044645:Fucus / Q000502:physiology* / Q000528:radiation effects; D005843:Geography; D015233:Models, Statistical; D010788:Photosynthesis; D012621:Seasons; D013045:Species Specificity; D013312:Stress, Physiological; D013472:Sunlight; D013696:Temperature
keywords: Fucus spiralis; Fucus vesiculosus; abiotic; air temperature; photosynthesis; physiological limit; range edge; solar radiation