BICARBONATE STIMULATION OF CALCIFICATION AND PHOTOSYNTHESIS IN TWO HERMATYPIC CORALS1 |
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| Authors: | Lydie Herfort Brenda Thake Isabelle Taubner |
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| Institution: | 1. School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK;2. Present address: Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Science University, 20000 NW Walker Rd., Beaverton, OR 97006, USA. E‐mail: .;3. Author for correspondence: e‐mail . |
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| Abstract: | A wide range of bicarbonate concentrations was used to monitor the kinetics of bicarbonate (HCO3?) use in both photosynthesis and calcification in two reef‐building corals, Porites porites and Acropora sp. Experiments carried out close to the P. porites collection site in Barbados showed that additions of NaHCO3 to synthetic seawater proportionally increased the calcification rate of this coral until the concentration exceeded three times that of seawater (6 mM). Photosynthetic rates were also stimulated by HCO3? addition, but these became saturated at a lower concentration (4 mM). Similar experiments on aquarium‐acclimated colonies of Indo‐Pacific Acropora sp. showed that calcification and photosynthesis in this coral were enhanced to an even greater extent than P. porites, with calcification continuing to increase above 8 mM HCO3?, and photosynthesis saturating at 6 mM. Calcification rates of Acropora sp. were also monitored in the dark, and, although these were lower than in the light for a given HCO3? concentration, they still increased dramatically with HCO3? addition, showing that calcification in this coral is light stimulated but not light dependent. |
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| Keywords: | calcification corals dissolved inorganic carbon photosynthesis |
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