Evaluation of Surface Sampling for Estimates of Chlorophyll, Total Phosphorus, and Total Nitrogen Concentrations in Shallow Florida Lakes

Abstract

ABSTRACT A study of 11 north-central Florida lakes was conducted to determine if surface sampling (0.5 m) provided the same estimates of chlorophyll, total phosphorus, and total nitrogen concentrations as samples collected with a Kemmerer bottle at 1 m and 2 m, and a 2-m pvc tube sampler (integrated column). The absolute values of differences between surface estimates of chlorophyll, total phosphorus, and total nitrogen concentrations and estimates obtained by use of other sampling methods were small and from a practical standpoint would not preclude the use of the surface estimates. Only a few statistically significant differences were detected for some individual lakes. For this group of Florida lakes, the greatest amount of variability in estimates was attributed to differences among lakes (≥95%). Surface estimates were also highly correlated (r ranged from 0.95 to 0.98) to estimates obtained by other methods. Because surface sampling is simple, cost-effective, and provides comparable estimates of chlorophyll, total phosphorus, and total nitrogen concentrations, surface water sampling is recommended if a large number of Florida lakes are to be sampled.