Resilience of the temperate coral Oculina arbuscula to ocean acidification extends to the physiological level
- PDF / 1,129,279 Bytes
- 14 Pages / 595.276 x 790.866 pts Page_size
- 2 Downloads / 184 Views
REPORT
Resilience of the temperate coral Oculina arbuscula to ocean acidification extends to the physiological level Cydney Wang1 • Erin M. Arneson2 • Daniel F. Gleason2 • Brian M. Hopkinson1
Received: 30 June 2020 / Accepted: 6 November 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Both juvenile and adult life stages of the temperate scleractinian coral Oculina arbuscula are resilient to the effects of moderate ocean acidification (OA) in contrast to many tropical corals in which growth and calcification rates are suppressed. Here, potential mechanisms of resilience to OA related to photosynthetic physiology and inorganic carbon processing were studied in adult O. arbuscula colonies. After exposing colonies to ambient and elevated carbon dioxide (CO2) treatments for 7 weeks, photosynthetic performance was characterized using photosynthesis versus irradiance experiments, chlorophyll fluorescence kinetics, and algal pigment content. Inorganic carbon-processing capabilities were assessed by measurement of internal and external carbonic anhydrase activity of the coral host, internal carbonic anhydrase activity of symbiotic algae, and the reliance of photosynthesis on external carbonic anhydrase. Photosynthetic physiology was unaffected by OA ruling out the possibility that resilience was mediated by increased photosynthetic energy supply. Carbonic anhydrase activities were maintained at elevated CO2 suggesting no major rearrangements of the inorganic carbon-processing machinery, but this could be a Topic Editor Anastazia Teresa Banaszak
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00338-020-02029-y) contains supplementary material, which is available to authorized users. & Brian M. Hopkinson [email protected] 1
Department of Marine Sciences, University of Georgia, Athens, GA 30602, USA
2
James H. Oliver, Jr., Institute for Coastal Plain Science, Georgia Southern University, Statesboro, GA 30460-8042, USA
sign of resilience since tropical corals often down-regulate carbonic anhydrases at high CO2. The general lack of effect of ocean acidification on these physiological traits suggests other characteristics, such as maintenance of calcifying fluid pH and ability to acquire energy from heterotrophy, may be more important for the resilience of O. arbuscula to OA. Keywords Ocean acidification Coral Resilience Physiology Oculina
Introduction The oceans absorb approximately 30% of the carbon dioxide (CO2) released by anthropogenic activities such as fossil fuel burning and land use change (Gruber et al. 2019). Absorption of CO2 creates carbonic acid (H2CO3) causing a decrease in the pH of seawater and numerous associated chemical changes collectively referred to as ocean acidification (OA) (Doney et al. 2009). Most notable among these changes are decreased carbonate ion (CO23) concentrations and increased bicarbonate (HCO3-) concentrations, which are consequences of re-equilibration of the carbonate buffer system after CO2 absorpti
Data Loading...
