Responses of a coral reef shark acutely exposed to ocean acidification conditions
- PDF / 456,132 Bytes
- 6 Pages / 595.276 x 790.866 pts Page_size
- 1 Downloads / 216 Views
NOTE
Responses of a coral reef shark acutely exposed to ocean acidification conditions Jodie L. Rummer1 Serge Planes2,3
•
Ian A. Bouyoucos1,2 • Johann Mourier2,3,4 • Nao Nakamura2,3
•
Received: 27 August 2019 / Accepted: 23 June 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Anthropogenic ocean acidification (OA) is a threat to coral reef fishes, but few studies have investigated responses of high-trophic-level predators, including sharks. We tested the effects of 72-hr exposure to OA-relevant elevated partial pressures of carbon dioxide (pCO2) on oxygen uptake rates, acid–base status, and haematology of newborn tropical blacktip reef sharks (Carcharhinus melanopterus). Acute exposure to end-of-century pCO2 levels resulted in elevated haematocrit (i.e. stress or compensation of oxygen uptake rates) and blood lactate concentrations (i.e. prolonged recovery) in the newborns. Conversely, whole blood and mean corpuscular haemoglobin concentrations, blood pH, estimates of standard and maximum metabolic rates, and aerobic scope remained unaffected. Taken together, newborn blacktip reef sharks appear physiologically robust to end-of-century pCO2 levels, but less so than other, previously investigated, tropical carpet sharks. Our results suggest peak fluctuating pCO2 levels in coral reef lagoons could still physiologically affect newborn reef sharks, but studies assessing the
Topic Editor Michael Lee Berumen & Jodie L. Rummer [email protected] 1
Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, Australia
2
PSL Research University, EPHE-UPVD-CNRS, USR 3278, Universite´ de Perpignan, Perpignan, France
3
Laboratoire d’Excellence ‘‘CORAIL’’, CRIOBE, Papetoai, Moorea, French Polynesia
4
UMR MARBEC (IRD, Ifremer, Univ. Montpellier, CNRS), Se`te, France
effects of long-term exposure and in combination with other anthropogenic stressors are needed. Keywords Acid–base Blacktip reef shark Haematology Climate change Oxygen uptake rates Physiology
Introduction The oceans are absorbing approximately 30% of atmospheric carbon dioxide (CO2)—a phenomenon referred to as ocean acidification (OA)—that is predicted to increase CO2 partial pressures (pCO2) from 400 latm to 1000 latm by the year 2100 if current rates of greenhouse gas emissions remain unabated (Meinshausen et al. 2011). There are many documented cases of deleterious physiological responses of marine ectotherms to elevated pCO2 (Heuer and Grosell 2014; Hannan and Rummer 2018). Coral reef fishes were thought to be resilient to OA because of exposure to much higher pCO2 during their evolutionary history; however, recent evidence suggests that these fishes remain vulnerable to current unprecedented rates of environmental change, including OA (Rummer and Munday 2017; Munday et al. 2019). To date, studies have focused on identifying behavioural (e.g. foraging, activity, cognitive ability) and physiological responses (e.g. metabolic rate, acid–base status, haemato
Data Loading...
