The relationships between chemical measures and potential predictors of the eutrophication status of inlets

Measurements of nutrients, dissolved oxygen and trace metals in bottom wate rs, taken just before the fall turnover, have been evaluated as indicators of eutrophication in inlets. Samples for these analyses were collected ill 34 inlets in eastern Canada. The dominant factor (31% of the variance of th e dataset) from a principal component analysis of the resulting data was cl early related to eutrophication, This factor included phosphate, ammonia, s ilicate, dissolved oxygen, iron and manganese, but not cadmium and zinc. It was used to rank inlets according to eutrophication, Comparisons of these rankings with measures of inlet shape revealed that several measures of the significance of sills were good predictors of the eutrophication status. T idal prism flushing times, and other geometric measures, were poor predicto rs of eutrophication, Measures of anthropogenic inputs to the inlets were a lso poor predictors of the eutrophication status: apparently natural proces ses dominate anthropogenic inputs in these inlets. (C) 1999 Elsevier Scienc e Ltd. All rights reserved.