Sponge bioerosion on reef-building corals: Dependent on the environment or on skeletal density?

Abstract

X-radiographic techniques were used to measure the skeletal density and percentage of bioerosion in Montastraea annularis and Porites astreoides growing in reefs subjected to suboptimal (Veracruz Reef System, VRS) and optimal (Mahahual, MH) environmental conditions for coral reef development. Skeletal density was higher in P. astreoides than in M. annularis and was higher in corals from MH than from the VRS. The percentage of the skeleton excavated by boring sponges was significantly correlated with skeletal density. These results are the first contribution that seeks to understand the interactions of the environment and coral skeletal density on sponge bioerosion and suggest that bioerosion is linked to coral skeletal density rather than to environmental conditions. Finally, based on the differences in growth strategies between the two species, the effects of climate change on sponge bioerosion rates could have repercussions on coral reef biodiversity and community structure.