title: Effects of high salinity from desalination brine on growth, photosynthesis, water relations and osmolyte concentrations of seagrass Posidonia australis.
abstract: Highly saline brines from desalination plants expose seagrass communities to salt stress. We examined effects of raised salinity (46 and 54psu) compared with seawater controls (37psu) over 6weeks on the seagrass, Posidonia australis, growing in tanks with the aim of separating effects of salinity from other potentially deleterious components of brine and determining appropriate bioindicators. Plants survived exposures of 2-4weeks at 54psu, the maximum salinity of brine released from a nearby desalination plant. Salinity significantly reduced maximum quantum yield of PSII (chlorophyll a fluorescence emissions). Leaf water potential (Ψw) and osmotic potential (Ψπ) were more negative at increased salinity, while turgor pressure (Ψp) was unaffected. Leaf concentrations of K+and Ca2+decreased, whereas concentrations of sugars (mainly sucrose) and amino acids increased. We recommend leaf osmolarity, ion, sugar and amino acid concentrations as bioindicators for salinity effects, associated with brine released in desalination plant outfalls.
authors.affiliation: UWA Oceans Institute and School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia. Electronic address: marion.cambridge@uwa.edu.au.
authors.forename: M L
authors.initials: ML
authors.lastname: Cambridge
authors.affiliation: UWA Oceans Institute and School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Zavala-Perez
authors.affiliation: School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia.
authors.forename: G R
authors.initials: GR
authors.lastname: Cawthray
authors.affiliation: School of Life and Environmental Science, Deakin University, PO Box 423, Warrnambool, Victoria 3280, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Mondon
authors.affiliation: UWA Oceans Institute and School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia.
authors.forename: G A
authors.initials: GA
authors.lastname: Kendrick
mesh_terms: D035961:Alismatales / Q000502:physiology*; D010788:Photosynthesis; D054712:Salinity; D012965:Sodium Chloride; D014867:Water
chemical_list: D014867:Water; D012965:Sodium Chloride
keywords: Amino acids; Bioindicators; Brine; Ions; Sugars