Interaction of mangrove surface coverage and groundwater inputs on the temperature and water level near Tulum, Quintana Roo, Mexico: Observations and modelling

We report on a series of high resolution sensor measurements from within the Yax Chen cave system near the city of Tulum, Quintana Roo, Mexico and a box model of mangrove-groundwater interactions. The sensors were positioned in the cave following a transect moving inland. Conductivity, water pressure and temperature data were collected at 30 min intervals for a span of two years. Temperature, water level, and conductivity records showed a response to large rainfall events (Hurricane Nate in October 2017 and Topical Storm Philippe in November 2017) which coincided with differences in surficial vegetation. Groundwater with areas of mangrove coverage showed an input of warm mangrove water as the water level receded to pre-rainfall levels and, the temperature effect was not observed in areas dominated by an upland forested terrain. A model of the groundwater-mangrove interaction was developed with an on-off switch for the flow of mangrove water into the groundwater system when the rainfall is sufficiently large. The model reproduces the observed timing difference in the temperature and conductivity response, and matches the field data during rainfall events. This model shows the effectiveness of simple box models in understanding a complicated geophysical processes and provides quantitative support to this previously hypothesized groundwater interaction.