RAINWATER ISOTOPIC MONITORING NETWORK IN THE YUCATAN PENÍNSULA, MEXICO, INVOLVING STUDENTS AT SELECTED SECONDARY AND HIGH SCHOOLS

The scientific goal of this project is to implement an isotopic monitoring network to establish the local oxygen-hydrogen isotopic precipitation line for the northern Yucatan Peninsula and to map the isotopic signature of precipitation and groundwater throughout the region. This background information is essential to our ultimate objective of using the distinctive isotopic signature of extraordinary meteorologic events (severe tropical storms) as a geochemical tool for evaluation of hydrogeologic parameters of the regional aquifer system and for developing proxies, such as speleothem analysis, for the study of climate change.

A parallel objective is to enlist the help of middle school-to-college level students in the Mexican states of the Peninsula (Campeche, Yucatan, and Quintana Roo) to assist in the collection of samples and to participate in the evaluation of data. The scientific benefit is that the network established with the help of students will allow coverage of the area at a significantly more detailed level than would otherwise be possible with available resources. Benefits to students will be significant. Many attend schools with limited resources for hands-on scientific training and exploration. Participating in this project will hone their abilities in acquisition and evaluation of quantitative data and expose them to locally important aspects of hydrogeology and meteorology. Moreover, this is an innovative strategy for the Mexican Educational System that will enhance interaction between scientists and educators.

Hurricanes and major tropical storms pass frequently over the Yucatan Península, and storm precipitation has a distinctive isotopic signature, as noted by Lawrence (1998). The average value for d18O in Yucatan rain is -4‰ and -22‰ for dD, whereas tropical storms passing over the Peninsula have been measured to have an isotopic signature of approximately -9‰ for d18O and -60‰ for dD. Because of this large difference, the isotopic composition of recharge from hurricanes can be used as a groundwater tracer to better understand the hydrodynamics of the peninsular aquifer.

The first students to participate in this project are part of a pilot project undertaken at a middle school in Cancun, Quintana Roo. The water samples they obtain will be analyzed at NIU, and the results of this student-scientist interaction will be presented.