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Vertical cell movement is a primary response of intertidal benthic biofilms to increasing light dose

2010; Inter-Research; Volume: 416; Linguagem: Inglês

10.3354/meps08787

1616-1599

RG Perkins, Johann Lavaud, João Serôdio, Jean‐Luc Mouget, Paulo Cartaxana, Priscila Vieira Rosa, Laurent Barillé, Vanda Brotas, Bruno Jesus,

Marine and coastal plant biology

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 416:93-103 (2010) - DOI: https://doi.org/10.3354/meps08787 Vertical cell movement is a primary response of intertidal benthic biofilms to increasing light dose R. G. Perkins1,*, J. Lavaud2, J. Serôdio3, J. L. Mouget4, P. Cartaxana5, P. Rosa6, L. Barille6, V. Brotas5, B. M. Jesus5,7 1School of Earth, Ocean and Planetary Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3YE, UK 2UMR CNRS 6250 ‘LIENSs’, Institute for Coastal and Environmental Research (ILE), University of La Rochelle, 2 rue Olympe de Gouges, 17042 La Rochelle Cedex, France 3Departamento de Biologia, Universidade de Aveiro, Aveiro 3810-193, Portugal 4Laboratoire de Physiologie et Biochimie Végétales, Faculté des Sciences et Techniques, Université du Maine, EA2663, Av. O. Messiaen, 72085 Le Mans Cedex 9, France 5Centro de Oceanografia, Faculdade de Ciências da Universidade de Lisboa, Lisboa 1749-016, Portugal 6EA 2160 ‘Mer, Molécules, Santé’, Faculté des Sciences et Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, 44322 Nantes cedex 3, France 7Centro de Biodiversidade, Genómica Integrativa e Funcional (BioFIG), Faculdade de Ciências, Universidade de Lisboa, Lisboa 1749-016, Portugal *Email: perkinsr@cf.ac.uk ABSTRACT: Intertidal soft sediment microphytobenthic biofilms are often dominated by diatoms, which are able to regulate their photosynthesis by physiological processes (e.g. down-regulation through the xanthophyll cycle, referred to as non-photochemical quenching, NPQ) and behavioural processes (e.g. vertical cell movement in the sediment–biofilm matrix). This study investigated these 2 processes over a 6 h emersion period using chemical inhibitors under 2 light treatments (ambient and constant light at 300 µmol m–2 s–1). Latrunculin A (Lat A) was used to inhibit cell movement and dithiothreitol (DTT) to inhibit NPQ. HPLC analysis for chlorophyll a and spectral analysis (Normalised Difference Vegetation Index) indicated that Lat A significantly inhibited cell movement. Photosynthetic activity was measured using variable chlorophyll fluorescence and radiolabelled carbon uptake and showed that the non-migratory, Lat A-treated biofilms were severely inhibited as a result of the high accumulated light dose (significantly reduced maximum relative electron transport rate, rETRmax, and light utilisation coefficient, α, compared to the migratory DTT and control-treated biofilms). No significant patterns were observed for 14C data, although a decrease in uptake rate was observed over the measurement period. NPQ was investigated using HPLC analysis of xanthophyll pigments (diatoxanthin and the percentage de-epoxidation of diadinoxanthin), chlorophyll fluorescence (change in maximum fluorescence yield) and the 2nd order spectral derivative index (diatoxanthin index). Patterns between methods varied, but overall data indicated greater NPQ induction in the non-migratory Lat A treatment and little or no NPQ induction in the DTT and control treatments. Overall, the data resulted in 2 main conclusions: (1) the primary response to accumulated light dose was vertical movement, which when inhibited resulted in severe down-regulation/photoinhibition; (2) diatoms down-regulated their photosynthetic activity in response to accumulated light dose (e.g. over an emersion period) using a combination of vertical migration and physiological mechanisms that may contribute to diel and/or tidal patterns in productivity. KEY WORDS: Benthic · Diatom · Down-regulation · Migration · Photophysiology · Productivity Full text in pdf format PreviousNextCite this article as: Perkins RG, Lavaud J, Serôdio J, Mouget JL and others (2010) Vertical cell movement is a primary response of intertidal benthic biofilms to increasing light dose. Mar Ecol Prog Ser 416:93-103. https://doi.org/10.3354/meps08787 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 416. Online publication date: October 14, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.