title: Arsenic uptake and depuration kinetics in Microcystis aeruginosa under different phosphate regimes.
abstract: Strategies used by Microcystis aeruginosa, bloom-forming cyanobacteria, for potential inorganic arsenic (arsenate and arsenite) uptake, and depuration kinetics under phosphate-enriched (+P) and depleted (-P) treatments were examined via short- and long-term experiments. Phosphate depletion improved arsenate or arsenite uptake rate constants. M. aeruginosa arsenite influx occurred considerably faster than arsenate influx under +P or -P treatments. Different phosphate regimes yielded significant impacts on long-term but not on short-term arsenic (As) uptake. In addition, considerable differences were observed in short-term As efflux between live and dead cells after arsenate or arsenite pre-exposure. Arsenic depuration rates in live M. aeruginosa cells were affected not only by accumulation rates of different As inorganic species but also by phosphate concentrations in tested media, which was inferred from estimated kinetic parameters. Specifically, +P was clearly found to inhibit As efflux after live M. aeruginosa cells were pre-exposed to As(V). Efflux was higher for dead cells no matter the inorganic As species involved. Owing to higher As uptake and depuration rates under -P treatments, P deficiency will considerably accelerate As uptake and efflux processes in aquatic environments.
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000, China.
authors.forename: Zhenhong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
authors.forename: Zhuanxi
authors.initials: Z
authors.lastname: Luo
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China. Electronic address: czyan@iue.ac.cn.
authors.forename: Changzhou
authors.initials: C
authors.lastname: Yan
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Che
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
authors.forename: Yameng
authors.initials: Y
authors.lastname: Yan
mesh_terms: D001151:Arsenic / Q000493:pharmacokinetics*; D007700:Kinetics; D046931:Microcystis / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*
chemical_list: D010710:Phosphates; D001151:Arsenic
keywords: Algae; Depuration; Inorganic arsenic; Phosphate; Uptake kinetics