Author's personal copy Growth and luminescence characteristics in skeletons of massive Porites from a depth gradient in the central Great Barrier Reef Juan P. Carricart-Ganivet a, ⁎ , Janice M. Lough b , David J. Barnes b a El Colegio de la Frontera Sur, Unidad Chetumal, Apdo. Postal 424, Chetumal Q. Roo, 77000, México b Australian Institute of Marine Science, PMB 3, Townsville MC, Queensland 4810, Australia Received 16 January 2007; received in revised form 16 May 2007; accepted 20 May 2007 Abstract Growth characteristics (tissue thickness, extension rate, density, and calcification rate), luminescence and luminescent lines were analyzed in skeletal slices cut from similar sized and shaped colonies of massive Porites collected from Rib Reef, central Great Barrier Reef (GBR). Colonies were collected at four depths; 0–5, 5–10, 10–15 and 15–20 m. Relationships amongst the annual growth characteristics were similar to those reported for massive Porites growing at shallow depths (0–5 m) in other localities. Growth characteristics, luminescence and luminescent lines did not change significantly with increasing depth to a depth of 20 m. © 2007 Elsevier B.V. All rights reserved. Keywords: Calcification rate; Coral skeleton; Density; Extension rate; Luminescence; Proxy environmental records 1. Introduction Growth in massive corals is achieved by deposition of calcium carbonate by the narrow layer of living tissue at the outer surface of the colony (Barnes and Lough, 1993). The discovery of annual density banding in massive coral skeletons (Knuston et al., 1972) made it possible to map and date skeletal growth. Such banding has provided invaluable information about coral skeletal growth, growth rates and the environmental conditions under which growth took place (e.g., Dodge and Vaisnys, 1975; Flor and Moore, 1977; Barnes and Lough, 1996, 1999; Carricart-Ganivet and Merino, 2001). Annual calcification rate is the product of annual extension rate and the density of skeleton deposited during that year (g cm - 2 y - 1 = cm y - 1 × g cm - 3 ; Dodge and Brass, 1984). Tissue thickness is the depth to which skeleton is occupied by tissue (Barnes and Lough, 1992). Variations in coral growth characteristics reflect environmental conditions that force changes in these growth variables (Barnes et al., 1995). The responses of different coral species under similar environments are not, however, clear at this moment. In massive Caribbean corals, notably the Montas- traea annularis sibling species complex (see Knowlton et al., 1992), several authors have identified a decrease in extension rate and increase in skeletal density with increasing water depth (Baker and Weber, 1975; Graus and Macintyre, 1982; Huston 1985; Bosscher, 1993; Bosscher and Mesters, 1993). This is linked with a decrease in the amount of light available for photosyn- thesis with increasing water depth (Bosscher, 1993). The M. annularis species complex is the Caribbean Journal of Experimental Marine Biology and Ecology 351 (2007) 27 – 36 www.elsevier.com/locate/jembe ⁎ Corresponding author. E-mail address: carricart@ecosur.mx (J.P. Carricart-Ganivet). 0022-0981/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jembe.2007.05.038