Analysis of Limnological Variables Associated to Water Quality in Lakes of Northwestern Hillsborough County, Florida

A Pearson correlation analysis was conducted on a database containing eight limnological variables of 34 lakes located in northwestern Hillsborough County. Lake water concentrations of total phosphorus (TP), total nitrogen (TN), and chlorophyll-a; submerged aquatic vegetation (SAV) as measured by percentage of area covered with vegetation (PAC) and percentage of volume infested with vegetation (PVI); and mean depth, lake surface area, and lake volume were examined. The purpose of this study was to examine the theory by Bachmann and co-workers (2002) that SAV may reduce nutrients in the water column. The stronger statistically significant inverse correlations were found between chlorophyll-a and SAV as represented by PVI and PAC (r 5 20.45 and 20.41, respectively), and between lake water TP and PAC and PVI (r 5 20.49 and 20.35, respectively). Weaker but also significant were the inverse correlations found between TP and mean depth (r 5 20.33) as well as that between TN and PAC (r 5 20.31). Statistically significant direct correlations were found between chlorophyll-a and TN and TP (r 5 0.38 and 0.32, respectively), and weaker but still significant, between mean depth and PVI and PAC (r 5 0.31 and 0.30, respectively). In conclusion the examined theory is supported.