Near-future pH conditions severely impact calcification, metabolism and the nervous system in the pteropod Heliconoides inflatus.
Shelled pteropods play key roles in the global carbon cycle and food webs of various ecosystems. Their thin external shell is sensitive to small changes in pH, and shell dissolution has already been observed in areas where aragonite saturation state is ~1. A decline in pteropod abundance has the potential to disrupt trophic networks and directly impact commercial fisheries. Therefore, it is crucial to understand how pteropods will be affected by global environmental change, particularly ocean acidification. In this study, physiological and molecular approaches were used to investigate the response of the Mediterranean pteropod, Heliconoides inflatus, to pH values projected for 2100 under a moderate emissions trajectory (RCP6.0). Pteropods were subjected to pHT7.9 for 3 days, and gene expression levels, calcification and respiration rates were measured relative to pHT8.1 controls. Gross calcification decreased markedly under low pH conditions, while genes potentially involved in calcification were up-regulated, reflecting the inability of pteropods to maintain calcification rates. Gene expression data imply that under low pH conditions, both metabolic processes and protein synthesis may be compromised, while genes involved in acid-base regulation were up-regulated. A large number of genes related to nervous system structure and function were also up-regulated in the low pH treatment, including a GABAAreceptor subunit. This observation is particularly interesting because GABAAreceptor disturbances, leading to altered behavior, have been documented in several other marine animals after exposure to elevated CO2. The up-regulation of many genes involved in nervous system function suggests that exposure to low pH could have major effects on pteropod behavior. This study illustrates the power of combining physiological and molecular approaches. It also reveals the importance of behavioral analyses in studies aimed at understanding the impacts of low pH on marine animals.
ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Qld, 4811, Australia.|UPMC Univ Paris 06, CNRS-INSU, Laboratoire d'Océanographie de Villefranche, Sorbonne Universités, 181 chemin du Lazaret, Villefranche-sur-mer, F-06230, France.
Aurelie
A
Moya
UPMC Univ Paris 06, CNRS-INSU, Laboratoire d'Océanographie de Villefranche, Sorbonne Universités, 181 chemin du Lazaret, Villefranche-sur-mer, F-06230, France.|Marine Biogeosciences, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung, Am Handelshafen 12, Bremerhaven, D-27570, Germany.
Ella L
EL
Howes
Littoral, Environnement et Sociétés (LIENSs), UMR 7266, CNRS-Université de La Rochelle, 2 rue Olympe de Gouges, La Rochelle Cedex, 17000, France.|Marine Environmental Laboratories, International Atomic Energy Agency, 4 quai Antoine 1er, Monaco, 98000, Principality of Monaco.
Thomas
T
Lacoue-Labarthe
Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia.
Sylvain
S
Forêt
Department of Biology, Penn State University, University Park, PA, 16802, USA.
Bishoy
B
Hanna
Department of Biology, Penn State University, University Park, PA, 16802, USA.
Mónica
M
Medina
ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Qld, 4811, Australia.
Philip L
PL
Munday
Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia.
Jue-Sheng
JS
Ong
Marine Environmental Laboratories, International Atomic Energy Agency, 4 quai Antoine 1er, Monaco, 98000, Principality of Monaco.
Jean-Louis
JL
Teyssié
ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Qld, 4811, Australia.|Australian Institute of Marine Science, PMB 3, Townsville, Qld, 4810, Australia.
Gergely
G
Torda
ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Qld, 4811, Australia.
Sue-Ann
SA
Watson
ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Qld, 4811, Australia.|Comparative Genomics Centre and Department of Molecular and Cell Biology, James Cook University, Townsville, Qld, 4811, Australia.
David J
DJ
Miller
Marine Biogeosciences, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung, Am Handelshafen 12, Bremerhaven, D-27570, Germany.
Jelle
J
Bijma
UPMC Univ Paris 06, CNRS-INSU, Laboratoire d'Océanographie de Villefranche, Sorbonne Universités, 181 chemin du Lazaret, Villefranche-sur-mer, F-06230, France.|Sciences Po, Institute for Sustainable Development and International Relations, 27 rue Saint Guillaume, Paris, F-75007, France.
Jean-Pierre
JP
Gattuso
D060105:Animal Shells; D000818:Animals; D002113:Calcification, Physiologic; D057486:Carbon Cycle; D017753:Ecosystem; D020387:Food Chain; D049851:Gastropoda / Q000378:metabolism / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D009420:Nervous System / Q000378:metabolism*
GABAA receptor; RNA sequencing; calcification; gene expression; global change biology; nervous system; ocean acidification; pteropods; respiration