title: Ocean Acidification Has Multiple Modes of Action on Bivalve Larvae.
abstract: Ocean acidification (OA) is altering the chemistry of the world's oceans at rates unparalleled in the past roughly 1 million years. Understanding the impacts of this rapid change in baseline carbonate chemistry on marine organisms needs a precise, mechanistic understanding of physiological responses to carbonate chemistry. Recent experimental work has shown shell development and growth in some bivalve larvae, have direct sensitivities to calcium carbonate saturation state that is not modulated through organismal acid-base chemistry. To understand different modes of action of OA on bivalve larvae, we experimentally tested how pH, PCO2, and saturation state independently affect shell growth and development, respiration rate, and initiation of feeding in Mytilus californianus embryos and larvae. We found, as documented in other bivalve larvae, that shell development and growth were affected by aragonite saturation state, and not by pH or PCO2. Respiration rate was elevated under very low pH (~7.4) with no change between pH of ~ 8.3 to ~7.8. Initiation of feeding appeared to be most sensitive to PCO2, and possibly minor response to pH under elevated PCO2. Although different components of physiology responded to different carbonate system variables, the inability to normally develop a shell due to lower saturation state precludes pH or PCO2 effects later in the life history. However, saturation state effects during early shell development will carry-over to later stages, where pH or PCO2 effects can compound OA effects on bivalve larvae. Our findings suggest OA may be a multi-stressor unto itself. Shell development and growth of the native mussel, M. californianus, was indistinguishable from the Mediterranean mussel, Mytilus galloprovincialis, collected from the southern U.S. Pacific coast, an area not subjected to seasonal upwelling. The concordance in responses suggests a fundamental OA bottleneck during development of the first shell material affected only by saturation state.
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States of America.
authors.forename: George G
authors.initials: GG
authors.lastname: Waldbusser
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States of America.
authors.forename: Burke
authors.initials: B
authors.lastname: Hales
authors.affiliation: Coastal Oregon Marine Experimental Station and Department of Fisheries and Wildlife, Hatfield Marine Science Center, Oregon State University, Newport OR, United States of America.
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Langdon
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States of America.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Haley
authors.affiliation: Coastal Oregon Marine Experimental Station and Department of Fisheries and Wildlife, Hatfield Marine Science Center, Oregon State University, Newport OR, United States of America.
authors.forename: Paul
authors.initials: P
authors.lastname: Schrader
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States of America.
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Brunner
authors.affiliation: Coastal Oregon Marine Experimental Station and Department of Fisheries and Wildlife, Hatfield Marine Science Center, Oregon State University, Newport OR, United States of America.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Gray
authors.affiliation: Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Oregon State University, Corvallis, OR, United States of America.
authors.forename: Cale A
authors.initials: CA
authors.lastname: Miller
authors.affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States of America.
authors.forename: Iria
authors.initials: I
authors.lastname: Gimenez
authors.affiliation: Coastal Oregon Marine Experimental Station and Department of Fisheries and Wildlife, Hatfield Marine Science Center, Oregon State University, Newport OR, United States of America.
authors.forename: Greg
authors.initials: G
authors.lastname: Hutchinson
mesh_terms: D060105:Animal Shells / Q000737:chemistry*; D000818:Animals; D049872:Bivalvia / Q000254:growth & development / Q000502:physiology*; D002119:Calcium Carbonate / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007814:Larva / Q000254:growth & development; D008018:Life Cycle Stages; D049878:Mytilus; D009792:Oceans and Seas; D056152:Respiratory Rate; D012623:Seawater / Q000032:analysis / Q000737:chemistry*
chemical_list: D002119:Calcium Carbonate