Water quality of inlets' water bodies in a growing touristic barrier reef Island “Isla Holbox” at the Yucatan Peninsula

Holbox Island faces issues related to the availability of freshwater and living space given the increasing coastal migration and tourism development in the region. We report the water quality of 12 tidal inlets (which are geomorphological features of barrier islands), which neighbor hotels. Because no previous studies of tidal inlets exist on Holbox, we used reference published values of water quality and unpublished water values collected at 43 sampling sites throughout the Yalahau Lagoon. Analyses of water quality variables and the trophic index (TRIX) were measured. Inlets sites salinity values ranged from 11 to 36 psu. Average values for nitrates (0.83 μmol l−1), and nitrites (0.14 μmol l−1), at inlets, had lower values in the fronts season. Soluble reactive phosphate (48.8μmol l−1), and silicate (78.6 μmol l−1) were higher at inlets during rains and chlorophyll-α (29.7 mg/m3) was more top at inlets during fronts. TRIX values for inlets ranged between 2 and 6, indicating low water quality in most inlets associated with hotel sites. Seasonal changes in soluble reactive phosphate and chlorophyll-α at inlets suggests these could be receiving sewage water discharges from human activities. Besides inlet's higher water residence time and slower water interchange rate can favor the accumulation of pollutants. Results demonstrate that water quality issues exist on Holbox and need management actions to prevent the decay of coastal ecosystem services. These are necessary for positive feedback between local communities' wellbeing and successful tourism development in the region.