title: Response of intertidal benthic microalgal biofilms to a coupled light-temperature stress: evidence for latitudinal adaptation along the Atlantic coast of Southern Europe.
abstract: Although estuarine microphytobenthos (MPB) is frequently exposed to excessive light and temperature conditions, little is known on their interactive effects on MPB primary productivity. Laboratory and in situ experiments were combined to investigate the short-term joint effects of high light (HL) and high temperature (37 °C versus 27 °C) on the operating efficiency of photoprotective processes [vertical migration versus non-photochemical quenching (NPQ)] exhibited by natural benthic diatom communities from two intertidal flats in France (FR) and Portugal (PT). A clear latitudinal pattern was observed, with PT biofilms being more resistant to HL stress, regardless the effect of temperature, and displaying a lower relative contribution of vertical migration to photoprotection and a stronger NPQ in situ. However, higher temperature leads to comparable effects, with photoinhibition increasing to about three times (i.e. from 3% to 10% and from 8% to 22% in PT and FR sites respectively). By using a number of methodological novelties in MPB research (lipid peroxidation quantification, Lhcx proteins immunodetection), this study brings a physiological basis to the previously reported depression of MPB photosynthetic productivity in summer. They emphasize the joint role of temperature and light in limiting, at least transiently (i.e. during emersion), MPB photosynthetic activity in situ.
authors.affiliation: Departamento de Biologia and CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Aveiro, Portugal.
authors.forename: Martin
authors.identifier: http://orcid.org/0000-0002-9719-7158
authors.initials: M
authors.lastname: Laviale
authors.affiliation: UMRi7266 LIENSs 'Littoral, Environnement et Sociétés', CNRS/Université de La Rochelle, Institut du Littoral et de l'Environnement, La Rochelle, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Barnett
authors.affiliation: Departamento de Biologia and CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Aveiro, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Ezequiel
authors.affiliation: UMRi7266 LIENSs 'Littoral, Environnement et Sociétés', CNRS/Université de La Rochelle, Institut du Littoral et de l'Environnement, La Rochelle, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Lepetit
authors.affiliation: Departamento de Biologia and CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Aveiro, Portugal.
authors.forename: Silja
authors.initials: S
authors.lastname: Frankenbach
authors.affiliation: LUNAM Université, Université de Nantes, EA 21 60 MMS 'Mer, Molécules, Santé', Nantes, France.
authors.forename: Vona
authors.initials: V
authors.lastname: Méléder
authors.affiliation: Departamento de Biologia and CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Aveiro, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Serôdio
authors.affiliation: UMRi7266 LIENSs 'Littoral, Environnement et Sociétés', CNRS/Université de La Rochelle, Institut du Littoral et de l'Environnement, La Rochelle, France.
authors.forename: Johann
authors.initials: J
authors.lastname: Lavaud
mesh_terms: D000064:Acclimatization; D001267:Atlantic Ocean; D018441:Biofilms / Q000254:growth & development*; D017377:Diatoms / Q000378:metabolism*; D004777:Environment; D063366:Estuaries; D005602:France; D019015:Geologic Sediments / Q000737:chemistry; D008027:Light; D058086:Microalgae / Q000378:metabolism* / Q000502:physiology; D010788:Photosynthesis / Q000502:physiology*; D011174:Portugal; D012621:Seasons; D013312:Stress, Physiological / Q000502:physiology*; D013696:Temperature