title: Chronic light reduction reduces overall resilience to additional shading stress in the seagrass Halophila ovalis.
abstract: Seagrasses have substantial capacity to survive long periods of light reduction, but how acclimation to chronic low light environments may influence their ability to cope with additional stress is poorly understood. This study examines the effect of temporal light reduction by adding two levels of shading to Halophila ovalis plants in two meadows with different light histories, one characterized by a low light (turbid) environment and the other by a relatively high light (clear) environment. Additional shading resulted in complete mortality for both shading treatments at the turbid site while the clear site showed a pattern of decreased shoot density and increased photochemical efficiency (Fv/Fm) with increased shading. These contrasting results for the same species in two different locations indicate that acclimation to chronic low light regimes can affect seagrass resilience and highlights the importance of light history in determining the outcome of exposure to further (short-term) stress.
authors.affiliation: Experimental Marine Ecology Laboratory, Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Blk S2 #02-02, Singapore 117557, Singapore; Singapore-Delft Water Alliance, National University of Singapore, Blk E1 Engineering Drive 2, #08-25, Singapore 117567, Singapore.
authors.forename: Siti M
authors.initials: SM
authors.lastname: Yaakub
authors.affiliation: Experimental Marine Ecology Laboratory, Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Blk S2 #02-02, Singapore 117557, Singapore.
authors.forename: Eugene
authors.initials: E
authors.lastname: Chen
authors.affiliation: Singapore-Delft Water Alliance, National University of Singapore, Blk E1 Engineering Drive 2, #08-25, Singapore 117567, Singapore; Royal Netherlands Institute for Sea Research (NIOZ), Korringaweg 7, 4401 NT Yerseke, The Netherlands.
authors.forename: Tjeerd J
authors.initials: TJ
authors.lastname: Bouma
authors.affiliation: The UWA Oceans Institute, University of Western Australia, 35 Stirling Highway, 6009 Crawley, WA, Australia; Sinclair Knight Merz (SKM), P.O. Box H615, Perth, WA 6000, Australia.
authors.forename: Paul L A
authors.initials: PL
authors.lastname: Erftemeijer
authors.affiliation: Experimental Marine Ecology Laboratory, Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Blk S2 #02-02, Singapore 117557, Singapore; Singapore-Delft Water Alliance, National University of Singapore, Blk E1 Engineering Drive 2, #08-25, Singapore 117567, Singapore. Electronic address: dbspat@nus.edu.sg.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Todd
mesh_terms: D000064:Acclimatization; D004777:Environment; D031321:Hydrocharitaceae / Q000502:physiology* / Q000528:radiation effects; D008027:Light; D010788:Photosynthesis / Q000502:physiology
keywords: Acclimation; Light history; Sediment; Singapore; Turbidity