title: Acclimation and adaptation to common marine pollutants in the copepod Tigriopus californicus.
abstract: Establishing water quality criteria using bioassays is complicated by variation in chemical tolerance between populations. Two major contributors to this variation are acclimation and adaptation, which are both linked to exposure history, but differ in how long their effects are maintained. Our study examines how tolerance changes over multiple generations of exposure to two common marine pollutants, copper (Cu) and tributyltin oxide (TBTO), in a sexually reproducing marine copepod, Tigriopus californicus. Lines of T. californicus were chronically exposed to sub-lethal levels of Cu and TBTO for 12 generations followed by a recovery period of 3 generations in seawater control conditions. At each generation, the average number of offspring produced and survived to 28 d was determined and used as the metric of tolerance. Lines exposed to Cu and TBTO showed an overall increase in tolerance over time. Increased Cu tolerance arose by generation 3 in the chronically exposed lines and was lost after 3 generations in seawater control conditions. Increased TBTO tolerance was detected at generation 7 and was maintained even after 3 generations in seawater control conditions. It was concluded from this study that tolerance to Cu is consistent with acclimation, a quick gain and loss of tolerance. In contrast, TBTO tolerance is consistent with adaptation, in which onset of tolerance was delayed relative to an acclimation response and maintained in the absence of exposure. These findings illustrate that consideration of exposure history is necessary when using bioassays to measure chemical tolerance.
authors.affiliation: Department of Biological Science and Wrigley Institute for Environmental Studies, University of Southern California, Los Angeles, CA, United States. Electronic address: patricys@usc.edu.
authors.forename: Patrick Y
authors.initials: PY
authors.lastname: Sun
authors.affiliation: Department of Biological Science and Wrigley Institute for Environmental Studies, University of Southern California, Los Angeles, CA, United States.
authors.forename: Helen B
authors.initials: HB
authors.lastname: Foley
authors.affiliation: Department of Biological Science and Wrigley Institute for Environmental Studies, University of Southern California, Los Angeles, CA, United States.
authors.forename: Lisa
authors.initials: L
authors.lastname: Handschumacher
authors.affiliation: Department of Biological Science and Wrigley Institute for Environmental Studies, University of Southern California, Los Angeles, CA, United States.
authors.forename: Amanda
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of Biological Science and Wrigley Institute for Environmental Studies, University of Southern California, Los Angeles, CA, United States.
authors.forename: Tigran
authors.initials: T
authors.lastname: Karamanukyan
authors.affiliation: Department of Biological Science and Wrigley Institute for Environmental Studies, University of Southern California, Los Angeles, CA, United States.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Edmands
mesh_terms: D000064:Acclimatization / Q000187:drug effects*; D000818:Animals; D001681:Biological Assay; D033342:Copepoda / Q000187:drug effects* / Q000502:physiology*; D003300:Copper / Q000633:toxicity*; D003627:Data Interpretation, Statistical; D012623:Seawater / Q000737:chemistry*; D013997:Time Factors; D014220:Trialkyltin Compounds / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D060753:Water Quality
chemical_list: D014220:Trialkyltin Compounds; D014874:Water Pollutants, Chemical; C005961:bis(tri-n-butyltin)oxide; D003300:Copper
keywords: Bioassay; Copper; Multigeneration exposure; Sub-lethal; Tolerance; Tributyltin