title: Dissolved organic carbon reduces the toxicity of copper to germlings of the macroalgae, Fucus vesiculosus.
abstract: This study investigates the effects of waterborne copper exposure on germling growth in chemically defined seawater. Germlings of the macroalgae, Fucus vesiculosus were exposed to a range of copper and dissolved organic carbon (DOC as humic acid) concentrations over 14 days. Germling growth was found to be a sensitive indicator of copper exposure with total copper (TCu) and labile copper (LCu) EC(50) values of approximately 40 and 20 microg/L, respectively, in the absence of added DOC. The addition of DOC into the exposure media provided germlings with protection against copper toxicity, with an increased TCu EC(50) value of 117.3 microg/L at a corrected DOC (cDOC from humic acid only) concentration of 2.03 mg/L. The LCu EC(50) was not affected by a cDOC concentration of 1.65 mg/L or less, suggesting that the LCu concentration not the TCu concentration was responsible for inhibiting germling growth. However, at a cDOC concentration of approximately 2mg/L an increase in the LCu EC(50) suggests that the LCu concentration may play a role in the overall toxicity to the germlings. This is contrary to current understanding of aquatic copper toxicity and possible explanations for this are discussed.
authors.affiliation: Centre for Environment Fisheries and Aquaculture Science, Burnham Laboratory, Remembrance Avenue, Burnham-on-Crouch, Essex CM0 8HA, UK. steven.brooks@cefas.co.uk
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Brooks
authors.forename: Thi
authors.initials: T
authors.lastname: Bolam
authors.forename: Laura
authors.initials: L
authors.lastname: Tolhurst
authors.forename: Janice
authors.initials: J
authors.lastname: Bassett
authors.forename: Jay
authors.initials: J
authors.lastname: La Roche
authors.forename: Mike
authors.initials: M
authors.lastname: Waldock
authors.forename: Jon
authors.initials: J
authors.lastname: Barry
authors.forename: Kevin V
authors.initials: KV
authors.lastname: Thomas
mesh_terms: D002244:Carbon / Q000494:pharmacology*; D003300:Copper / Q000633:toxicity*; D044645:Fucus / Q000187:drug effects* / Q000254:growth & development; D006812:Humic Substances; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D006812:Humic Substances; D014874:Water Pollutants, Chemical; D002244:Carbon; D003300:Copper