Water sampling: carbonate chemistry parameters (Total alkalinity and Dissolved Inorganic Carbon), nutrients and salinity were measured from seasonal water samples collected in three locations along the Pacific coast of Costa Rica. Sampling was carried out during rainy (July-August 2013) and dry (January-February 2014) season, for eight consecutive days in each location, during high and low tide. When possible, samples were collected at two different depths, 0.5 m below the surface and directly over the reef, the latter depth differed between sites (3-10 m). The number of sampling sites in each location was determined by the presence of coral reefs. Seawater temperature was measured in situ using HOBO®Pendant Temperature data loggers (Bajo Rojo, Matapalito, Matapalo, Bajo Mauren) and a WTW probe (Cond3310) (Matapalito, Pochote, Tómbolo, Tres Hermanas). Reef surveys: benthic community composition was quantified at three reefs in Santa Elena (Bajo Rojo, Matapalito, Cabros), one in Matapalo (Matapalo) and one in Marino Ballena (Bajo Mauren). Due to fieldwork logistics, reef surveys were conducted in different temporal resolution at each location (monthly at Santa Elena and Matapalo, yearly at Marino Ballena) and averaged over all available data points. Benthic surveys were conducted following the chain method (Rogers et al., 1994), with 10 m transects and five replicates per transect.