title: Ocean acidification induces biochemical and morphological changes in the calcification process of large benthic foraminifera.
abstract: Large benthic foraminifera are significant contributors to sediment formation on coral reefs, yet they are vulnerable to ocean acidification. Here, we assessed the biochemical and morphological impacts of acidification on the calcification of Amphistegina lessonii and Marginopora vertebralis exposed to different pH conditions. We measured growth rates (surface area and buoyant weight) and Ca-ATPase and Mg-ATPase activities and calculated shell density using micro-computer tomography images. In A. lessonii, we detected a significant decrease in buoyant weight, a reduction in the density of inner skeletal chambers, and an increase of Ca-ATPase and Mg-ATPase activities at pH 7.6 when compared with ambient conditions of pH 8.1. By contrast, M. vertebralis showed an inhibition in Mg-ATPase activity under lowered pH, with growth rate and skeletal density remaining constant. While M. vertebralis is considered to be more sensitive than A. lessonii owing to its high-Mg-calcite skeleton, it appears to be less affected by changes in pH, based on the parameters assessed in this study. We suggest difference in biochemical pathways of calcification as the main factor influencing response to changes in pH levels, and that A. lessonii and M. vertebralis have the ability to regulate biochemical functions to cope with short-term increases in acidity.
authors.affiliation: Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies and School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia m.prazeres@uq.edu.au.
authors.forename: Martina
authors.initials: M
authors.lastname: Prazeres
authors.affiliation: Australian Institute of Marine Science, PMB No. 3, Townsville, Queensland 4810, Australia.
authors.forename: Sven
authors.initials: S
authors.lastname: Uthicke
authors.affiliation: Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies and School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: John M
authors.identifier: http://orcid.org/0000-0003-3047-6694
authors.initials: JM
authors.lastname: Pandolfi
mesh_terms: D060105:Animal Shells / Q000254:growth & development / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002113:Calcification, Physiologic; D002119:Calcium Carbonate / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D056908:Foraminifera / Q000254:growth & development / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D012623:Seawater
chemical_list: D002245:Carbon Dioxide; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002119:Calcium Carbonate
keywords: Ca-ATPase; calcification; large benthic foraminifera; ocean acidification