Cyanobacteria and nitrates in karstic systems of Yucatan (Mexico) and Texas (USA)

Groundwater underlying karstic formations, which flows through associated surface lentic and lotic systems, is at increased risk from anthropogenic activities due to the high permeability of these features. In the work presented here, we investigated cyanobacteria abundance, cyanotoxin presence, and nitrate concentrations in lentic karst systems, called cenotes, throughout Yucatan, Mexico and lotic karst systems, spring fed creeks, throughout central Texas, USA. The findings presented highlight the presence of cyanotoxin producing species at study sites in both regions and the unknown potential for high toxin producing conditions in the future. The potential for health risks arising due to the use of these sites for recreation (Texas and Mexico) and drinking water (Mexico) is of concern and merits continued observation of cyanobacteria and their toxins in karstic systems. Further, in the Mexico sites, the health risk is exacerbated by high nitrates.