Experimental comparison of skeletal growth rates in the cold-water coral Madrepora oculata Linnaeus, 1758 and three tropical scleractinian corals

Abstract

The skeletal growth rate of the cold-water coral (CWC) Madrepora oculata Linnaeus, 1758 was measured during 3 months under controlled conditions (at 12 °C in the dark, fed five times a week), using the buoyant weight technique. In order to interpret CWC growth in a wider context, we also measured the skeletal growth rates of three tropical scleractinian species: Stylophora pistillata (Esper, 1797), Turbinaria reniformis (Bernard, 1896) and Galaxea fascicularis (Linnaeus, 1767), likewise maintained under controlled conditions (at 25 °C, 250 μmol photons m− 2 s− 1, either fed five times a week or unfed). The skeletal growth rate of M. oculata was equal to 0.20 ± 0.09% d− 1 (mean ± SD), similar to the growth of unfed and fed nubbins of G. fascicularis (0.14 ± 0.01% d− 1 and 0.36 ± 0.11% d− 1 respectively) despite the large differences in seawater temperatures. Skeletal growth rates of S. pistillata (1.20 ± 0.49% d− 1 to 2.68 ± 0.65% d− 1 unfed/fed) and T. reniformis (0.78 ± 0.34% d− 1 to 0.94 ± 0.14% d− 1 unfed/fed) were significantly higher. These results confirm that the CWC M. oculata can grow at rates that are comparable to those of some tropical corals, despite the lack of autotrophy (lacking zooxanthellae) and the low temperatures of its environment