Development of Predictive Equations for Chlorophyll Concentration
and Secchi Depth for Nova Scotia Lakes
SUMMARY
In an attempt to improve the usefulness of a recently developed model to predict the phosphorus concentration in Nova Scotia lakes based on lake morphometric and drainage basin characteristics, existing data on Nova Scotia lakes was used to develop predictive regression equations for chlorophyll concentration and Secchi depth. The regressions developed appear to be significantly different when compared to other published regressions developed for lakes in other regions of the world, and suggest that Nova Scotia lakes produce less chlorophyll per unit of total phosphorus. In addition, regressions for both chlorophyll and Secchi depth explained less variability than most published regressions. This may be due, in part, to the limited range in chlorophyll values within the Nova Scotia lake database, which in most cases is limited to two orders of magnitude in contrast to the three orders of magnitude typically available for similar studies in other regions of the world.
Development of a predictive regression equation for Secchi depth indicated that, based on the Nova Scotia lake database, Secchi depth is more strongly influenced by water color than by chlorophyll concentration. This makes Secchi depth unlikely to be a useful indicator of a lake’s trophic state for Nova Scotia lakes.