title: Short-term arsenic exposure reduces diatom cell size in biofilm communities.
abstract: Arsenic (As) pollution in water has important impacts for human and ecosystem health. In freshwaters, arsenate (As(V)) can be taken up by microalgae due to its similarity with phosphate molecules, its toxicity being aggravated under phosphate depletion. An experiment combining ecological and ecotoxicological descriptors was conducted to investigate the effects of As(V) (130 μg L(-1) over 13 days) on the structure and function of fluvial biofilm under phosphate-limiting conditions. We further incorporated fish (Gambusia holbrooki) into our experimental system, expecting fish to provide more available phosphate for algae and, consequently, protecting algae against As toxicity. However, this protection role was not fully achieved. Arsenic inhibited algal growth and productivity but not bacteria. The diatom community was clearly affected showing a strong reduction in cell biovolume; selection for tolerant species, in particular Achnanthidium minutissimum; and a reduction in species richness. Our results have important implications for risk assessment, as the experimental As concentration used was lower than acute toxicity criteria established by the USEPA.
authors.affiliation: Institute of Aquatic Ecology, University of Girona, E-17071, Girona, Spain. laura.barral.fraga@gmail.com.
authors.forename: Laura
authors.initials: L
authors.lastname: Barral-Fraga
authors.affiliation: Irstea, UR EABX, Bordeaux, France.
authors.forename: Soizic
authors.initials: S
authors.lastname: Morin
authors.affiliation: Institute of Aquatic Ecology, University of Girona, E-17071, Girona, Spain.|Bio-Protection Research Centre, Lincoln University, PO Box 85084, Lincoln, New Zealand.
authors.forename: Marona D M
authors.initials: MD
authors.lastname: Rovira
authors.affiliation: Institute of Aquatic Ecology, University of Girona, E-17071, Girona, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Urrea
authors.affiliation: Institute of Aquatic Ecology, University of Girona, E-17071, Girona, Spain.
authors.forename: Kit
authors.initials: K
authors.lastname: Magellan
authors.affiliation: Institute of Aquatic Ecology, University of Girona, E-17071, Girona, Spain.
authors.forename: Helena
authors.initials: H
authors.lastname: Guasch
mesh_terms: D000818:Animals; D001149:Arsenates / Q000032:analysis / Q000633:toxicity*; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D003532:Cyprinodontiformes / Q000378:metabolism; D017377:Diatoms / Q000187:drug effects* / Q000254:growth & development; D017753:Ecosystem; D005618:Fresh Water / Q000737:chemistry; D006801:Humans; D010710:Phosphates / Q000494:pharmacology; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D001149:Arsenates; D010710:Phosphates; D014874:Water Pollutants, Chemical; C025657:arsenic acid
keywords: Arsenate; Ecotoxicology; Fish; Fluvial biofilm; Laboratory streams; Multi-trophic studies; Phosphate