title: Ocean acidification increases copper toxicity differentially in two key marine invertebrates with distinct acid-base responses.
abstract: Ocean acidification (OA) is expected to indirectly impact biota living in contaminated coastal environments by altering the bioavailability and potentially toxicity of many pH-sensitive metals. Here, we show that OA (pH 7.71; pCO2 1480 μatm) significantly increases the toxicity responses to a global coastal contaminant (copper ~0.1 μM) in two keystone benthic species; mussels (Mytilus edulis) and purple sea urchins (Paracentrotus lividus). Mussels showed an extracellular acidosis in response to OA and copper individually which was enhanced during combined exposure. In contrast, urchins maintained extracellular fluid pH under OA by accumulating bicarbonate but exhibited a slight alkalosis in response to copper either alone or with OA. Importantly, copper-induced damage to DNA and lipids was significantly greater under OA compared to control conditions (pH 8.14; pCO2 470 μatm) for both species. However, this increase in DNA-damage was four times lower in urchins than mussels, suggesting that internal acid-base regulation in urchins may substantially moderate the magnitude of this OA-induced copper toxicity effect. Thus, changes in metal toxicity under OA may not purely be driven by metal speciation in seawater and may be far more diverse than either single-stressor or single-species studies indicate. This has important implications for future environmental management strategies.
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
authors.forename: Ceri
authors.initials: C
authors.lastname: Lewis
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Ellis
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
authors.forename: Emily
authors.initials: E
authors.lastname: Vernon
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
authors.forename: Katie
authors.initials: K
authors.lastname: Elliot
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
authors.forename: Sam
authors.initials: S
authors.lastname: Newbatt
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
authors.forename: Rod W
authors.initials: RW
authors.lastname: Wilson
mesh_terms: D000143:Acids / Q000378:metabolism*; D000818:Animals; D059001:Aquatic Organisms / Q000187:drug effects* / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism / Q000633:toxicity*; D057231:Climate Change; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D049880:Mytilus edulis / Q000187:drug effects / Q000378:metabolism; D009792:Oceans and Seas; D012623:Seawater / Q000737:chemistry; D047270:Strongylocentrotus purpuratus / Q000187:drug effects / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity
chemical_list: D000143:Acids; D014874:Water Pollutants, Chemical; D002245:Carbon Dioxide; D003300:Copper