ANALYZING POSSIBLE INFLUENCES IN KARST REGIONS CONTRIBUTING TO HARMFUL ALGAL BLOOM OCCURENCES IN FRESHWATER LAKES

HABs, or harmful algal blooms, are occurring in lakes in central Kentucky. These HABs consist of blue-green algae (cyanobacteria), which can bloom in high enough densities to pose a threat to human health through the production of cyanotoxins. During the year of 2013, several Kentucky lakes and reservoirs were placed under water quality advisories by the United States Army Corps of Engineers (USACE) in regards to high cell count densities of cyanobacteria, per World Health Organization (WHO) guidelines. Both Nolin River Lake and Rough River Lake were placed under advisory. These lakes play important roles to the local communities as sources of water, recreation, income, and flood control as well as serving as the communities’ economic centers. The HABs pose a threat to these communities yet little has been done to study their formation or spatial distribution. Interestingly, these lakes have seen HABs forming in winter months, a rare occurrence. This winter bloom phenomenon has not yet been studied, though understanding why it occurs is important due to the health threats presented by these HABs. The geology in this region is karst in nature and little has been done in the way to study its influence on these HABs as well. The USACE monitored the cyanobacteria cell counts in the lakes for the last two years, but the lakes were sampled on different schedules and different selection criteria were used to select the sample sites. Currently, monitoring is being done on a bi-weekly basis for multiple parameters, which include pH, SpC, temperature, nutrients, and N isotopes. Together, these data will be used with the existing data in a GIS to spatially analyze the possible karst influences on HAB occurrences in the two lakes being studied. Spatial analysis of the historic sample sites and cell count data for 2013 were entered into a geodatabase and examined utilizing the inverse distance weighted average tool from Desktop or ArcGIS 10.2.2. Results indicate possible contributions from karst groundwater inputs may be contributing to the timing and occurrence of HABs in these karst influenced lakes.