Investigating the Relationship Between Nutrient Levels and Sargassum Biomass on Antigua’s Beaches

Sargassum has become an increasing problem in the Caribbean, especially in Antigua, where it frequently washes up on beaches. While sargassum can support marine life offshore, large quantities onshore cause serious problems for the environment, tourism, and local communities. This study examined water temperature and phosphate concentration in relation to sargassum biomass on Antigua’s beaches. Water samples were collected and analyzed for phosphate concentration at six beaches in Antigua, including three sites known to be affected by sargassum and three unaffected sites. Water temperature and pH were also recorded at each site. Sargassum biomass was collected using a standardized method, dried to constant weight, and weighed to determine dry biomass. Biomass was observed at each of the affected areas, yet there was no significant difference across sites. Phosphate concentrations were significantly higher at the affected sites compared to the unaffected sites. Temperature and pH were similar across sites. These results suggest that nutrient levels, especially phosphate, play a significant role in sargassum buildup on beaches, which aligns with other studies indicating high nutrient concentrations influence sargassum growth. Managing local runoff and monitoring water quality could help reduce problems related to sargassum blooms in the future.