Ocean-to-nearshore circulation patterns around Curaçao: a southern Caribbean reef island exposed to distinct flow regimes

Abstract

Shallow-water coral reef ecosystems are positioned at the critical interface between terrestrial and marine environments, where ocean circulation patterns control the delivery and distribution of nutrients and land-derived substances. This study examines three-dimensional circulation patterns around Curaçao, a southern Caribbean reef island, using Lagrangian particle tracking analysis with the SCARIBOS hydrodynamic model for the period 2020-2024. We analyze two distinct surface flow regimes previously identified around the island: NW-flow periods dominated by the northwestward Caribbean Surface Current, and EDDY-flow periods characterized by cyclonic eddies or low-energy conditions. These regimes create contrasting patterns in horizontal surface circulation and vertical exchange, with significant differences in surface flow direction and enhanced upwelling during EDDY-flow conditions. However, analysis of offshore-to-nearshore connectivity using conditional pathways reveals that these large-scale surface regimes have no apparent influence on the delivery of deeper waters to nearshore coral reef areas. Spatial analysis reveals that volumetric transport decreases from east to west along the southern coastline. The West Point segment exhibits the lowest horizontal transport but the highest vertical exchange, receiving 48% of its volume transport from subsurface layers, contrasting with other segments where surface volume transport dominates (75-87%). These findings demonstrate that three-dimensional circulation patterns create spatially variable conditions for water renewal, nutrient delivery, and thermal regulation, improving our understanding of coral reef ecosystem dynamics and supporting reef management strategies.