Figure 6 : Regressions over depth of polyp fecundity, polyp-spacing, Orbicella spp. coral cover, and the resulting product which estimates the number of ova produced over a 1 km2 unit reef over depth.

From: Fertile fathoms: Deep reproductive refugia for threatened shallow corals

Figure 6

(a) A significant positive linear relationship was found between per polyp ova production and depth (p = 0.001, R2 = 0.18). (b) Mid-depth and mesophotic corals were found to have similar polyp-spacing, whereas shallow corals had significantly higher polyp densities (one-way ANOVA, p = 0.012, N = 15). A significant negative linear relationship was found after log transformation (p = 0.014, R2 = 0.381). (c) Third degree polynomial model of Orbicella spp. coral cover versus depth (p < 0.0001, R2 = 0.51). Orbicella spp. cover is used as a proxy for O. faveolata cover. (d) Expected Orbicella spp. reproductive output from hypothetical 1 km2 USVI reefs over depth. (I) Assumes equal polyp fecundity over depth27 (96 eggs per polyp32); (II) assumes empirically estimated depth-specific fecundity.