![]() ![]() In the latter case, there was even a synergistic effect of CO2, increasing PO2,crit further at elevated temperature. Fry, 1947 Fry and Hart, 1948), as shown for some coral reef fish (Nilsson et al., 2010) and cuttlefish (Rosa et al., 2013). Additionally, elevated temperature may reduce not only aerobic scope but also hypoxia tolerance (measured as the critical oxygen tension, PO2,crit) (e.g. Portner et al., 2005 Rosa and Seibel, 2008 Portner and Farrell, 2008 Dissanayake and Ishimatsu, 2011). Hypoxia, high CO2, and thereby low pH, may act to narrow the temperature range where aerobic scope is maintained (e.g. (Mo2,max) and minimum (MO2,min) (AAS=MO2,max- M/c^min), or asįactorial aerobic scope (FAS), which is the proportional difference (FAS=MO2jmax/MO2jmin) (e.g. ![]() It can be expressed either as absolute aerobic scope (AAS), which is the difference in oxygen uptake (MO2) between the maximum ![]() The aerobic scope indicates how much oxygen is available for processes beyond basic maintenance. Temperature (Fry, 1947 Fry and Hart, 1948), below and above which the capacity for activity, growth and reproduction will be reduced (Wang and Overgaard, 2007). *Author for correspondence Received 6 February 2015 Accepted 21 July 2015 3College of Marine and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia. 2ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia. Rising ocean temperatures have been predicted to negatively influence fitness of aquatic ectotherms because the scope for aerobic metabolism is hypothesized to have an optimalġSection for Physiology and Cell Biology, Department of Biosciences, University of Oslo, Oslo NO-0316, Norway. A huge research effort is currently devoted to studying the effects of these changes on aquatic life, with the main focus on organisms that may be at particular risk, such as calcifying marine invertebrates and coral reef fish (Hoegh-Guldberg et al., 2007 Munday et al., 2012 Portner etal., 2014). Ocean temperature and carbon dioxide (CO2) levels are rising and this is projected to continue throughout this century (IPCC, 2013). KEY WORDS: Aerobic scope, Global warming, Climate change, Ocean acidification, Gastropod, Mollusc Long-term temperature records and our field measurements suggest that habitat temperature rarely exceeds 32.6☌ during the summer, indicating that these snails have aerobic capacity in excess of current and future needs. There was no effect of elevated CO2 on respiratory performance at any temperature. The humpbacked conch has a high hypoxia tolerance with a PO2,crit of 2.5 kPa at 28☌ and 3.5 kPa at 33☌. Jumping caused a 4- to 6-fold increase in MO2, and MO2,max increased with temperature so that absolute aerobic scope was maintained even at 38☌, although factorial scope was reduced. MO2rest and MO2,Īt the acclimation temperature and during an acute 5☌ increase. We investigated the effect of present-day ambient (417-454 ^atm) and projected-future (955-987 ^atm) PCO2 on resting (MO2,rest) and maximum (MO2,max) MO2, as well as MO2 during hypoxia and critical oxygen tension (PO2,crit), in snails kept at present-day ambient (28☌) or projected-įuture temperature (33☌). 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 (MO2), can be induced by exposure to odour from a predatory cone snail (Conus marmoreus). Little, however, is known about the thermal sensitivity of a diverse and abundant group of reef animals, the gastropods. 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. Sjannie Lefevre1*, Sue-Ann Watson2, Philip L. Will jumping snails prevail? Influence of near-future CO2, temperature and hypoxia on respiratory performance in the tropical conch Gibberulus gibberulus gibbosus ![]()
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