title: Salinity-dependent nickel accumulation and effects on respiration, ion regulation and oxidative stress in the galaxiid fish, Galaxias maculatus.
abstract: Inanga (Galaxias maculatus) are a euryhaline and amphidromous Southern hemisphere fish species inhabiting waters highly contaminated in trace elements such as nickel (Ni). Ni is known to exert its toxic effects on aquatic biota via three key mechanisms: inhibition of respiration, impaired ion regulation, and stimulation of oxidative stress. Inanga acclimated to freshwater (FW), 50% seawater (SW) or 100% SW were exposed to 0, 150 or 2000 μg Ni L(-1), and tissue Ni accumulation, metabolic rate, ion regulation (tissue ions, calcium (Ca) ion influx), and oxidative stress (catalase activity, protein carbonylation) were measured after 96 h. Ni accumulation increased with Ni exposure concentration in gill, gut and remaining body, but not in liver. Only in the gill was Ni accumulation affected by exposure salinity, with lower branchial Ni burdens in 100% and 50% SW inanga, relative to FW fish. There were no Ni-dependent effects on respiration, or Ca influx, and the only Ni-dependent effect on tissue ion content was on gill potassium. Catalase activity and protein carbonylation were affected by Ni, primarily in FW, but only at 150 μg Ni L(-1). Salinity therefore offsets the effects of Ni, despite minimal changes in Ni bioavailability. These data suggest only minor effects of Ni in inanga, even at highly elevated environmental Ni concentrations.
authors.affiliation: Department of Biology, McMaster University, Ontario, Canada; Department of Biological Sciences, University of Alberta, Canada. Electronic address: t.blewett@alberta.ca.
authors.forename: Tamzin A
authors.initials: TA
authors.lastname: Blewett
authors.affiliation: Department of Biology, McMaster University, Ontario, Canada; Department of Zoology, University of British Columbia, Canada.
authors.forename: Chris M
authors.initials: CM
authors.lastname: Wood
authors.affiliation: School of Biological Sciences, University of Canterbury, New Zealand; Faculty of Science and Technology, Athabasca University, Alberta, Canada.
authors.forename: Chris N
authors.initials: CN
authors.lastname: Glover
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects*; D005618:Fresh Water / Q000737:chemistry; D005880:Gills / Q000378:metabolism; D007477:Ions / Q000378:metabolism; D009532:Nickel / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity; D036441:Osmeriformes / Q000502:physiology*; D018384:Oxidative Stress / Q000187:drug effects*; D050050:Protein Carbonylation / Q000187:drug effects*; D054712:Salinity; D012623:Seawater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D007477:Ions; D014874:Water Pollutants, Chemical; D009532:Nickel; D002374:Catalase
keywords: Acid-mine drainage; Biotic ligand model; Estuaries; Galaxiid fish; Nickel; Salinity