Rosado-Torres, A.A.; Mariño-Tapia, I., and Acevedo-Ramírez, C., 2019. Decreased roughness and macroalgae dominance in a coral reef environment with strong influence of submarine groundwater discharges. In: Silva, R.; Martínez, M.L.; Chávez, V., and Lithgow, D. (eds.), Integrating Biophysical Components in Coastal Engineering Practices. Journal of Coastal Research, Special Issue No. 92, pp. 13–21. Coconut Creek (Florida), ISSN 0749-0208.

The coral reefs of the Caribbean are heavily deteriorated, being found in low abundance and diversity. Their mortality is associated with the loss of architectural complexity and the flattening of the reef. Under this scenario, an ecological imbalance that commonly occurs is the reduction of coral cover and the dominance of macroalgae which is a clear indication of a phase shift. In the present study the links between reef roughness, benthic cover and groundwater influence are investigated with the aid of in situ oceanographic instrumentation. High resolution bathymetric profiles are used to assess roughness, video transects to characterise morphofunctional groups (stony corals, macroalgae, gorgonians, sponges, seagrasses and substratum), salinity and water quality measurements to establish continental water influence. The methodology allows to make the studies at the scale of the whole reef lagoon (several kilometres) and not only for small reef parcels. Results show clear links between low roughness, high macroalgae cover and groundwater influence in terms of diluted sea water and high nutrients.