Reef Monitoring Network flags stress markers in Caribbean waters

The Costa Mar Reef Monitoring Network reported elevated phosphate and nitrogen levels at its main Caribbean station on Thursday, the first sustained reading above seasonal norms since the autumn of 2024. Water temperature at the same site has climbed to 29.4 degrees Celsius, approximately 1.2 degrees above the five-year June average. The readings, taken at 14:00 local time over three consecutive days, suggest either upstream agricultural runoff or a thermal anomaly tied to shifting ocean currents.

Marina Castellanos, the Network's lead analyst, said the data pattern resembles conditions that preceded a partial bleaching event in 2023, though she cautioned against premature conclusions. The surge in nutrient concentration coincides with the tail end of Costa Mar's dry season, when reduced river flow typically dilutes coastal waters. The current readings instead suggest concentrated sources—either a single large discharge or cumulative seepage from multiple farms in the interior valleys.

The discovery has already prompted the dive cooperatives to discuss voluntary reduction in weekly site visits to three of the reef's most popular shallow sections. Tourism operators fear that any federal conservation order would arrive mid-season, when occupancy rates depend on reef-based activities. The Marine Ministry in Puerto Azul has scheduled a briefing for Friday morning.