title: Microelectrode characterization of coral daytime interior pH and carbonate chemistry.
abstract: Reliably predicting how coral calcification may respond to ocean acidification and warming depends on our understanding of coral calcification mechanisms. However, the concentration and speciation of dissolved inorganic carbon (DIC) inside corals remain unclear, as only pH has been measured while a necessary second parameter to constrain carbonate chemistry has been missing. Here we report the first carbonate ion concentration ([CO3(2-)]) measurements together with pH inside corals during the light period. We observe sharp increases in [CO3(2-)] and pH from the gastric cavity to the calcifying fluid, confirming the existence of a proton (H(+)) pumping mechanism. We also show that corals can achieve a high aragonite saturation state (Ωarag) in the calcifying fluid by elevating pH while at the same time keeping [DIC] low. Such a mechanism may require less H(+)-pumping and energy for upregulating pH compared with the high [DIC] scenario and thus may allow corals to be more resistant to climate change related stressors.
authors.affiliation: School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, USA.|Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Wei-Jun
authors.initials: WJ
authors.lastname: Cai
authors.affiliation: School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, USA.|Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Yuening
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Hopkinson
authors.affiliation: School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Andréa G
authors.initials: AG
authors.lastname: Grottoli
authors.affiliation: School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, USA.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Warner
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA.|Ocean College, Zhejiang University, Hangzhou 310058, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Ding
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA.|Department of Physical and Environmental Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA.
authors.forename: Xinping
authors.initials: X
authors.lastname: Hu
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA.|Key Laboratory of Marine Bio-resources Sustainable Utilization, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
authors.forename: Xiangchen
authors.initials: X
authors.lastname: Yuan
authors.affiliation: School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA.|ARC Centre of Excellence for Coral Reef Studies, School of Earth and Environment and UWA Oceans Institute, University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Verena
authors.initials: V
authors.lastname: Schoepf
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA.|Ocean College, Zhejiang University, Hangzhou 310058, China.|School of Mechanical Engineering and Automation, Zhejiang Sci-Tech University, Hangzhou 310023, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA.|Ocean College, Zhejiang University, Hangzhou 310058, China.|Key Laboratory of Marine Ecosystem and Environment, State Oceanic Administration (SOA) Second Institute of Oceanography, Hangzhou 310012, China.
authors.forename: Chenhua
authors.initials: C
authors.lastname: Han
authors.affiliation: Reef Systems Coral Farm, New Albany, Ohio 43054, USA.
authors.forename: Todd F
authors.initials: TF
authors.lastname: Melman
authors.affiliation: School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, USA.
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Hoadley
authors.affiliation: School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, USA.
authors.forename: D Tye
authors.initials: DT
authors.lastname: Pettay
authors.affiliation: School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Yohei
authors.identifier: http://orcid.org/0000-0001-7690-0222
authors.initials: Y
authors.lastname: Matsui
authors.affiliation: School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Justin H
authors.initials: JH
authors.lastname: Baumann
authors.affiliation: School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Levas
authors.affiliation: Ocean College, Zhejiang University, Hangzhou 310058, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Ying
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Yongchen
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000737:chemistry*; D002254:Carbonates / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D008839:Microelectrodes
chemical_list: D002254:Carbonates