title: Will jumping snails prevail? Influence of near-future CO₂, temperature and hypoxia on respiratory performance in the tropical conch Gibberulus gibberulus gibbosus.
abstract: Tropical coral reef organisms are predicted to be especially sensitive to ocean warming because many already live close to their upper thermal limit, and the expected rise in ocean CO2 is proposed to further reduce thermal tolerance. Little, however, is known about the thermal sensitivity of a diverse and abundant group of reef animals, the gastropods. The humpbacked conch (Gibberulus gibberulus gibbosus), inhabiting subtidal zones of the Great Barrier Reef, was chosen as a model because vigorous jumping, causing increased oxygen uptake (ṀO2 ), can be induced by exposure to odour from a predatory cone snail (Conus marmoreus). We investigated the effect of present-day ambient (417-454 µatm) and projected-future (955-987 µatm) PCO2 on resting (ṀO2 , rest) and maximum (ṀO2 , max) ṀO2 , as well as ṀO2 during hypoxia and critical oxygen tension (PO2 , crit), in snails kept at present-day ambient (28°C) or projected-future temperature (33°C). ṀO2 , rest and ṀO2 , max were measured both at the acclimation temperature and during an acute 5°C increase. Jumping caused a 4- to 6-fold increase in ṀO2 , and ṀO2 , max increased with temperature so that absolute aerobic scope was maintained even at 38°C, although factorial scope was reduced. The humpbacked conch has a high hypoxia tolerance with a PO2 , crit of 2.5 kPa at 28°C and 3.5 kPa at 33°C. There was no effect of elevated CO2 on respiratory performance at any temperature. Long-term temperature records and our field measurements suggest that habitat temperature rarely exceeds 32.6°C during the summer, indicating that these snails have aerobic capacity in excess of current and future needs.
authors.affiliation: Section for Physiology and Cell Biology, Department of Biosciences, University of Oslo, Oslo NO-0316, Norway sjannie.lefevre@imbv.uio.no.
authors.forename: Sjannie
authors.initials: S
authors.lastname: Lefevre
authors.affiliation: ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.
authors.forename: Sue-Ann
authors.initials: SA
authors.lastname: Watson
authors.affiliation: ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia.
authors.forename: Philip L
authors.initials: PL
authors.lastname: Munday
authors.affiliation: Section for Physiology and Cell Biology, Department of Biosciences, University of Oslo, Oslo NO-0316, Norway.
authors.forename: Göran E
authors.initials: GE
authors.lastname: Nilsson
mesh_terms: D000064:Acclimatization / Q000502:physiology; D000818:Animals; D002245:Carbon Dioxide / Q000737:chemistry*; D057231:Climate Change; D049851:Gastropoda / Q000502:physiology*; D008124:Locomotion / Q000502:physiology; D010100:Oxygen / Q000378:metabolism*; D012623:Seawater / Q000737:chemistry*; D013696:Temperature
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen
keywords: Aerobic scope; Climate change; Gastropod; Global warming; Mollusc; Ocean acidification